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Archive for the 'Racism' Category
"Sinister slogan" says Jonathan Freedland.
A comrade at the Chartist AGM said, roughly, this:
"Labour looks like two groups of people who want to expel each other".
There are good reasons why people should be concerned with the way in which a fringe have broadcast anti-Semitic views.
As in this:
Labour anti-Semitism row: Scots activist who claims 'Holocaust was exaggerated' formed anti-Zionist group while suspended https://t.co/qINV5zHSwu
— Andrew Coates (@Pabloite) July 15, 2019
For the background to the man in the story, Pete Gregson, see: A Stir in the Suburbs.
..the question still remains – does anti-Zionist obsession turn people into loons, or are loons attracted to anti-Zionism?
If people still bury their heads in the sand one can suggest they follow Steve Cook's Twitter feed
3/ Charles Harding had after all accused me of being funded by Israel in the status update to which Janet Silver was replying. Did she really need any more clues? She wouldn't have had to look far afield to find them as his Facebook timeline is replete with full-on Jew-hatred. pic.twitter.com/JcuGv4L4vG
— Steve Cooke (@Steve_Cooke) July 9, 2019
Not to mention the Monster Raving Greenstein's responses:
Tony says "Hi". I'm not sure how comrade Greenstein infers that my calling out a Nazi such as Michael Morgan means I therefore support any particular statements of the @BoardofDeputies or actions of the Israeli government/military. #Antisemitism #Panorama #IsLabourAntisemitic pic.twitter.com/tpj23IN6kw
— Steve Cooke (@Steve_Cooke) July 10, 2019
This does not mean following everybody in the other camp, many of whom seem equally fixated on this issue.
Jonathan Freedland, in the Guardian has made one of many efforts to associate Labour with anti-Jewish hatred in recent days, claims that Corbyn's 'left-wing populism' leaves the way open for anti-Semitic messages.
The roots of Labour's antisemitism lie deep within the populist left.
Populism, is a "politics that pits the virtuous mass of ordinary people against a wicked, corrupt elite." Freeland continues, singling out populist figures such as Nigel Farage, Hungary's Orbán and Boris Johnson bending to the present national populist wind.
But Freedland's main target is the "huge chunks of the egregious anti-Jewish racism spewed out in left circles and on social media has nothing to do with Israel or Palestine: it's all bankers and Rothschilds, control of the media and Holocaust denial. Of course, sometimes "Zionism" is deployed as a handy codeword, but today's anti-Jewish racists have often left the Middle East behind. It's Jews they're obsessed with."
He then plunges further,
Matt Bolton and Frederick Harry Pitts argue that Corbynism's big move is away from seeing capitalism as a system with its own unalterable dynamics, compelling all within it to operate according to its own logic, to seeing its cruelties instead as the work of malign individuals. "From this perspective," they write, "capitalist crises, poverty and inequality are wholly avoidable phenomena. They are the result of an immoral minority wilfully using the power of money, financial trickery and ideology to undermine – or, indeed, 'rig' – a society based on 'real' production which would otherwise work to the benefit of all."
Such a view of capitalism – focusing on individuals, not structures – doesn't necessarily end in hatred of Jews: you might blame some other "immoral minority". But this is the problem with talking endlessly of the "many, not the few" (a sinister slogan which I loathed when Tony Blair was using it). Pretty soon, and especially after the 2008 crash, people will ask: who exactly are this few, working so hard to deny the rest of us our utopia? The antisemite has a ready answer…
Without bothering to discuss what the "populist left" is – examples, one might think spring to mind, would then go to the best known theorist of left-wing populism, Chantal Mouffe, or to explicitly populist left-wing parties, above all, La France insoumise (LFI) and Podemos. LFI is noted for its sovereigntism – the nationalist road against globalisation. It is Corbyn and his advisers' tendency to this socialism in one country, defying the globalised world which is the focus of Bolton and Pitts.
This is a different claim to Freedland's that the 'floating signifier' of immoral minorities washes up in anti-semitism.
No proof for this sweeping claim is offered.
A more common direction is for left-populists, the case for a handful of supporters of Jean-Luc Mélenchon is to take their national soveriegnty seriously and end up on the National Populist right.
If we look at Labour how many accept the "ready answer" of the anti-semite when Labour's policy is against anti-semitism?
Like Mouffe (not to mention Ernesto Laclau) at her most abstract Freedland seems to think it's enough for a 'discourse' to be articulated for it to find a ready audience.
Critics of left-wing populism, including this Blog (cited in Bolton and Pitt's book, Corbynism: A Critical Approach (2018), oppose the idea that one can pit a federated "people" against the "oligarchy" and the elite,. This is not just because of a belief in the structures of class, and the economics of capitalism, but because socialist and left-wing Enlightenment thinking mean thinking, not emotion, internationalist values, not populist nationalism, plebiscitary rule, in a left form.
Many would consider that Freedland relies on charged emotions, or as Frédéric Lordon would call them, "affects", to carry his argument through.
A similar attempt to associate left-wing populism (not a term barely used by Corbyn supporters, and not that common even in articles in small circulation left magazines), is made by David Hirsch.
Why antisemitism and populism go hand-in-hand
The populist demagogues construct communities of the good and they cast out those who do not fit. The Corbynites call the bad people, the 'one per cent', the Zionists, the bankers or the elites. The Brexiters call them betrayers of the will of the people or they denounce those who side with foreign nations and bureaucrats against 'us'. There is much contempt for the 'liberal elite', cosmopolitans, globalists and citizens of nowhere. Populism embraces nostalgic nationalism but it has one eye on a more radical project for the whole of humanity.
That an academic cites no sources to prove his case to associate Corbyn and the Labour Party in this string of assertions is hardly surprising.
Otherwise known as an "amalgam" (amalgame, "Mélange d'éléments hétérogènes) this is a polemical technique, not an argument.
Academics are adept at making floating signifiers float…
Or to put it another way Hirsch is a conspiracy theory about populism, "Each populism is at heart an irrational conspiracy fantasy" as conspiracy theories.
Labour and anti-Semitism.
Many people are irked by the charges of anti-semitism.
Lindsey German is – and we say this despite our deep differences – not wrong when she says this in her Weekly Briefing,
Antisemitism exists in the Labour Party and needs to be dealt with (ironically much of the slowness in all this predated the tenure of Jennie Formby). But it needs to be put in perspective and not to be blamed on Jeremy Corbyn who has a lifelong record of anti-racism, including opposing racism against Jews. However, since in particular the attack by Margaret Hodge on Corbyn last year, any such perspective has been abandoned.
Indeed. Labour is not a seed-bed of anti-semitism. Parts – on the evidence small parts – of the party have become the territory that forces hostile to our democratic principles. This should be "dealt with".
However, German's following call, from a member of the non-Labour Counterfire, which spent many years backing red-brown George Galloway, is not helpful.
The Labour left needs to start giving as good at it gets from its enemies or it will lose, argues Lindsey German
I have always been hesitant about the tactic of reselection of MPs, because it has often backfired in the past. But really I see no alternative to the members challenging MPs who constantly attack the leadership and refuse to listen or make any compromise.
Accommodating these people hasn't worked, so it's time to replace them with people who respect the leadership and the membership.
Another, much less serious, and much smaller, groupuscule, Labour Party Marxists, closely connected to Labour Against the Witch-hunt, whose Vice-Chair is the above Greenstein, yesterday endorsed the following approach:
Getting rid of some of the biggest saboteurs in the Parliamentary Labour Party is crucial in the fight to transform the party into a weapon of and for the working class.
So we have two prongs of an appeal, to rid the party of the "populist left", accused of encouraging anti-Semitism, and the groupuscules calling to expel the right.
Boris Johnson is going to be British PM.
This chap is going to be in a key position of influence.
Jacob Rees-Mogg ridiculed for linking England's Cricket World Cup triumph to Brexit https://t.co/LarczZKdO4
Most of us intend to spend most of our time fighting them and the hard-right Brexit project.
Just remember: this is the Vice Chair of Labour Against the Witch-hunt:
Posted in Anti-Fascism, Britain, Europe, European Elections, European Left, Fascism, French Left, Jews, Labour Movement, Labour Party, Marxism, Nationalism, Populism, Racism
Tagged with Anti-Semitism, Brexit, European Left, Labour Party, Left Populism, Populism
The Red-Brown front – Spiked – defends Boris Johnson.
Plebeian Cadres of the Red-Brown Front.
There is a new guru on the left.
Let's call him the Heg.
He has direct line of communication to the nether spheres where the red-brown front does its pondering.
Heg busy defending internationalist good sense in the Western borderlands, has many a string to his bow.
In a prescient post Heg, predicted that Brendan O'Neill would chew the carpet and start spitting nails against the female Greenpeace activist assaulted by Mark Field.
In last night's scuffle between Conservative MP Mark Field and a Greenpeace protester, which of them was really behaving in an entitled manner?
We can guess the answer:
it wasn't Field who displayed colossal levels of entitlement last night — it was the protesters. It was these increasingly smug and disruptive climate activists who behaved in a morally arrogant fashion.
The moral arrogance of the Mansion House climate protestors
Today, well, let's say this from Brendan O'Neill today was amply predicted by the Man they call Mystic Heg.
The hacking of Boris Johnson's home
The Guardian's invasion of Boris's privacy is a new low for broadsheet journalism.
Brendan O'Neill, ex-Revolutionary Communist Party.
The chattering classes are lapping it up. These are the kind of people who look down their noses at tabloid-reading plebs who like to hear about the private lives of celebs. Yet now they priggishly pore over the hacked conversation of a politician and his girlfriend and hold it up as proof of what foul or tragic people they are. The worst aspect is the naked sexism they're displaying towards Ms Symonds. They decree, in their infinite wisdom, that she is a victim and should get the hell out.
The great man concludes, with this,
I hope they will agree that if the liberal broadsheets develop a habit of listening through the walls of private citizens' homes, then both the right to a private life and the standards of journalism in this country will suffer badly.
On the background of this national populist current see:
Some background on Brendan O'Neill, #SpikedOnline and their views on Irish politics, the #GoodFridayAgreement and #Brexit.https://t.co/O87JFbLQMK
— John Rogan (@JRogan3000) December 18, 2018
Posted in Britain, Conservative Party, European Elections, European Left, Fascism, Free Speech, Left, Nationalism, Populism, Racism
Tagged with boris johnson, Brendan O'Neill, Fascism, Red-Brown Front, Spiked
Boris Johnson, the "Trumpification of British Politics" and the Left.
Our Ruling Class.
Talleyrand – Charles-Maurice de Talleyrand-Périgord (1754 – 1838) – was the most famous European statesman of his day.
His house. the Hôtel de Talleyrand, was celebrated,
Into this palace, as a spider into its web, he enticed and captured, one by one, heroes, thinkers, conquerors, princes, emperors, Bonaparte, Sieyès, Mme de Stael, Chateaubriand, Benjamin Constant, Alexandre de Russie, Guillaume de Prusse, François d'Autriche, Louis XVIII, Louis Philippe, and all the gilded glittering flies which buzz through the history of these past forty years. All this glittering swarm, fascinated by the penetrating eye of this man, passed in turn under this gloomy entrance bearing on it the inscription: Hôtel Talleyrand.
In the collection of writings from which this comes Victor Hugo described the death of the man who became a by-word by cynical diplomacy.
In Choses Vues the author of Les Misérables describes his embalming, in the ancient Egyptian style.
The corpse lay in an empty chamber when a valet walked in.
He found that they had left the brain on the side-table.
The servant picked it up, and finding no other way of disposing of it, threw it into the outside sewer.
It is said that people have been looking for someone with Tallyrand's cerebrum ever since.
Many would say that dealing Boris Johnson would be hard even for the most experienced politician.
El Pais says that "La única persona capaz de derrotar a Boris Johnson —y ya hay precedentes— sería el propio Boris Johnson." ("the only person capable of defeating Boris Johnson – and there are precedents – is Boris Johnson himself")
The European Press is full of such scorn for the man Le Monde calls a "buffoon" (while politely asking him to stop being one):
Le Monde, in an excoriating editorial, said Johnson had shown himself to be "a stranger to logic and convictions" in a career rich in "deceits, blunders and failures". In the run-up to the 2016 referendum he "told lies on the side of a bus, promised the UK could have its cake and eat it, and compared the EU to the Third Reich," it said.
As foreign secretary he "made his country an object of ridicule around the world with his amateurism, flippancy and ignorance", France's newspaper of record continued. Rivalling Nigel Farage for populism, Johnson's "jingoistic rhetoric" promised Britons an unrealistic "glorious global future".
His threat to withhold the €39bn Brexit divorce settlement would have "incalculable consequences", damaging the international credibility of a country priding itself on being a champion of the rule of law, Le Monde said. And for the EU a Johnson premiership would mean "a mini-Trump across the Channel, dedicated to its sabotage". Britain would become "a hostile principality, built on social, fiscal and environmental deregulation."
'Mini-Trump across the Channel': EU media on Boris Johnson as British PM https://t.co/AuInySKLqZ
— Andrew Coates (@Pabloite) June 14, 2019
Boris Johnson à la tête du Royaume-Uni ? Non merci ! https://t.co/bF2Cfyl72N via @lemondefr
Amongst the articles cited by the Guardian this stands out (Corriere della Sera)
Lord Chris Pattern says that Johnson is part of the " una "trumpificazione" della nostra politica., the Trumpification of our politics.
He is equally,
Trump's poodle: a liar who does not pay attention to the detail of reality, tells people what they want to hear and relies on their ignorance".
Patten said Johnson exemplified the "collapse of rationality, of the relationship between the facts and what we believe" in present-day politics. "What he is offering is impossible.
All this looks as if it implies some serious thinking about changing Labour's strategy.
A bounder in his own bailiwick is going to be hard to dislodge.
The Trumpification of British politics has begun; it does not look if a hasty declaration of an "insurgency" against Johnson is going to thwart it.
To begin with there is the impact of start-up political business, The Brexit Party. Helped by the 'red-brown' front, not to mention the support of former leftists, it has become a political player, and how to fight it. The Brexit Party is part of a broader trend towards national populism, which has helped dislodge the left from its historic bases of support in Italy and France. Left-wing populisms – in France and Spain – have been unable to counter the nationalist call to fight 'oligarchies' and 'elites' on behalf of the Nation.
The Brexit Party is not about to vanish:
Latest Westminster voting intention (9-10 June)
Brexit Party – 26%
Lib Dem – 22%
Lab – 19%
Con – 17%
Green – 8%
Other – 9%https://t.co/iTBwIJMHmg pic.twitter.com/YgiuxSv5Z7
— YouGov (@YouGov) June 14, 2019
Is an appeal to our own 'identity politics' of the people, the left-behind, the self-identifying native working class better than trying to build alliances on universal, internationalist, fights for rights and interests?
Then there Johnson's strategy: will Farage assist the disintegration of the Tory party, or will the Brexit Party pave the way for his victory as part of a new "great moving right show" that can resonate deeply into the country's electorate and culture ? Johnson hopes to rebuild the electoral support that got May- just – elected and to extent it. How can an alternative be created from shards from the same ideology, which, the experience of European left populism indicates, is a sure way to strengthen the carnival of reaction, not to challenge it?
All these issues boil down to one: the Brexit project. Will Labour let Johnson pursue the goal – however much he twists and turns over the details – of a Hard Right Brexit, the only actually existing Brexit.
Apparently the Lexit left has the answer: it needs to back their version of Brexit.
The Morning Star editorialises.
..the trade union movement and the left has to make a decisions it to remain stuck in an increasingly sterile and immobilising debate for and against the EU? Or is it to shift the ground to the kind of withdrawal from the EU that must be secured to protect working people and to advance a progressive agenda that can beat the Tories?
Only class politics can defeat Johnson in Labour's working-class heartlands. The dangers of not preparing are too serious to be contemplated.
The beginnings of a different approach are there, and have strong support on the left.
This is an excellent reply to such views:
Let's show Brexit for what it always has been: a hard-right Tory project – via @LabourList https://t.co/JRgerG0gIg
— Mike Hirst (@Hirst6Mike) June 14, 2019
Urte Macikene, an activist in Labour for a Socialist Europe says,
Labour must re-energise the Corbyn project by opposing Brexit
witnessing the party's continued ambiguity and evasion, many of the members who resolutely defended Corbyn as leader in the face of an establishment onslaught are asking themselves whether the values of straight-talking honest politics only apply if you agree with the leader. Going into a general election with the current policy on Brexit would be disastrous. By bringing its policy back into line with the democratic will of its members, and anchoring its support for Remain in a programme of cross-border resistance, Labour can clearly differentiate itself from the pro-business globalism of the Lib Dems and the utopian optimism of the Greens to win back disillusioned supporters.
With a vision aimed at defending the interests of all workers, British or not, Labour can win here and lead a Europe-wide offensive against capitalist exploitation. Co-ordinating this cross-border coalition will require conferences and organising events attracting activists with shared goals from across Europe. Labour can be the force to convene such events on a mass scale, to begin the fight for a democratic, socialist Europe.
Posted in Anti-Fascism, Britain, British Govern, Capitalism, Conservative Party, European Elections, European Left, Fascism, French Left, Italy, Labour Movement, Labour Party, Nationalism, Populism, Racism
Tagged with boris johnson, Brexit, Europe, European Left, National Populism, Populism, Trump
After Backing anti-Gay Protests is Roger Godsiff Labour MP for the Chop?
Bigots still Demonstrating last week against Equality Teaching.
Labour MP Roger Godsiff to Anderton Park School protesters on their homophobic protest.
"I will continue to fight your corner, because you're right, nothing more, nothing less, you're right on this one."
h/t @CamBeavanKing @andy4wm @jessphillips @wesstreeting pic.twitter.com/qEW8DevbkK
— Corbyn in The Times (@TimesCorbyn) June 8, 2019
Roger Godsiff is on the side of the protesters who have been harassing Anderton Park School for months, spreading homophobic & transphobic materials, encouraging lies and misinformation to the parents and public, targeting teachers for their sexuality and religion.. #GodsiffOut
— Support 'No Outsiders' (@NoOutsidersUK) June 8, 2019
The row over gender equality teaching continues to grow.
The campaign is supported by Islamists, some parents, and the far-right StopRSE campaign against 'sexual liberation' and "cultural Marxism".
This is the mixture of extreme right wing and Islamists latest statement (June the 7th).
Muslims against LGBT which we all know it isn't ….
As Muslims or people of faith we do not need to justify that we are not homophobic – because we are not – in the same way that as Muslims we do not have to apologise for terror attacks – because we are not terrorists…. don't fall into this trap of apologising for something you haven't done as it deflects the conversation away from what needs to be discussed …
We are against RSE because it is a clear erosion of parental rights and a state take over of the parenting role which is one of the first steps of a totalitarian regime
We are against RSE because it is open to abuse by nefarious Lobby groups who will use it to push their own sexual ideologies into the classroom
Schools should be about education and that's all …. ideology must not be allowed through the school gate
The sexual ideologues however are using RSE as a back door in to schools
Do not be fooled by the terms 'inclusion, diversity, tolerance, equality etc – they have very specific definitions to those who use them than to the way in which the rest of us interpret them …
People are thankfully starting to wake up to the political machinations being played but we have to stay awake and not be lulled back into the warm water 🐸
StopRSE
The protests are continuing now with the backing of right-wing Labour MP Roger Godsiff.
Updates from Anderton School LGBT protest, outside exclusion zone https://t.co/YkyUVmvdVh
— Andrew Coates (@Pabloite) June 9, 2019
Labour MP criticised for siding with Birmingham school protesters
Roger Godsiff reported to chief whip for telling campaigners protesting against LGBT lessons 'you're right'
A Labour MP has been reported to the chief whip for telling campaigners protesting against LGBT teaching at a Birmingham primary school "you're right".
Roger Godsiff, the MP for the city's Hall Green constituency, which includes Anderton Park Primary school, also told protesters they had a "just cause" and criticised the headteacher.
The shadow education secretary, Angela Rayner, said she had reported the "discriminatory and irresponsible" comments to the chief whip, Nick Brown.
Parents have staged weeks of protests outside the school against the teaching of LGBT rights, claiming the lessons were "overemphasising a gay ethos" and contradicting Islam.
The demonstrations, which were described last week as "homophobic" by the West Midlands mayor, Andy Street, led the council to apply for a high court interim injunction, which banned rallies outside the gates from Friday.
Godsiff, who has previously said the equality lessons were not "age appropriate", was seen telling the protesters they were "right" in a video that emerged this weekend.
The veteran MP, who is seen with Shakeel Afsar, the lead organiser of the protests, said: "I think you have a just cause and I regret the fact that it hasn't been reciprocated by the headteacher."
He asked demonstrators to consider calling off the protest as he said they had made their point, but added it would be their choice to do so. He then said: "I will continue to try and fight your corner because you're right. Nothing more, nothing less. You're right."
Wes Streeting, the Labour MP for Ilford North, said he would be tabling a formal complaint to the party about Godsiff. He said: "This made me feel sick to my stomach. One of my own Labour colleagues stood with people who have peddled hatred and bigotry on school gates, intimidating pupils, teachers and parents."
The Labour LGBT group also called for the whip to be removed and condemned Godsiff's remarks "unreservedly and unequivocally".
Birmingham LGBT row: MP reported after backing school protest
BBC.
The MP for a primary school facing protests over LGBT teaching has been reported to the chief whip after telling campaigners "you're right".
In a video circulated on social media, Birmingham Hall Green MP Roger Godsiff told the Anderton Park Primary School protesters they had a "just cause".
Shadow education secretary Angela Rayner said she had reported the comments to the chief whip.
Mr Godsiff previously said the equality lessons were not "age appropriate".
A High Court injunction is in place banning protests, which have been going on for months, outside the school.
Parents started to gather at the gates over concerns children were "too young" to learn about LGBT relationships. They also said the lessons contradicted Islam.
In the video, Mr Godsiff, who is seen with Shakeel Afsar, the lead organiser of the protests, said: "If I had the opportunity of rolling the clock back I would do exactly the same thing again.
"Because I think you have a just cause and I regret the fact that it hasn't been reciprocated by the head teacher."
In the 2016 United Kingdom European Union membership referendum Godsiff supported the Leave campaign,[8] although his constituency voted by 66.4% to remain in the European Union.[1] Unusually for a Brexit-supporting MP, he abstained from the vote to invoke Article 50, to commence the UK's process of withdrawal from the EU, on the grounds that he was respecting his constituents' pro-Remain vote.
In 2011, The Guardian declared that based on his participation in votes, Godsiff was "Britain's laziest MP", being absent from 88% of votes at the start of that year. He has attended less than 50% of parliamentary debates during his whole time in office and refuses to take any part in hustings meetings.[14] He responded to the Birmingham Mail about his participation, saying "when you are in opposition and the government has a substantial majority, you know perfectly well that you aren't going to be able to have an effect on every vote".[15]
Godsiff opposed marriage equality in 2013, saying that he did not want to "[redefine] the current definition of marriage."
Petition calls on Labour Party to drop @RogerGodsiff over support for school protestshttps://t.co/9jatAKV0rR
— Birmingham Live (@birmingham_live) June 8, 2019
Posted in Anti-Fascism, Conspiracies, Culture, European Left, Islamism, Multi-Culturalism, Racism
Tagged with Anderton Park Primary school, Birmingham, Fascism, Islamism, LGBT rights
Far Right to Get Involved with Islamists in Birmingham School Protests against LGBT Equality?
Brag or True?
Farrow is involved with CitizensGo,
CitizenGO is an advocacy group founded in Madrid, Spain, in 2013 by HazteOir.
The foundation promotes petitions in 50 countries, including petitions defending Christian and Catholic causes, and those opposing same-sex marriage, abortion,and euthanasia.
There is a precedent for a link between far-right anti-gender equality ideology and the protests in Birmingham.
There have been alliances of Traditionalist (far-right) Catholics and Conservative (far-Right) Muslims in France on the issue of Gender Equality teaching.
La "théorie du genre" à l'école: vers un front uni entre musulmans conservateurs et extrême droite?
In 2014 France saw a wave of pupils being withdrawn from school where a new programme of gender equality was taught.
One of the linchpins of the movement was Farida Belghoul, close to the essayist Alain Soral (a convicted Holocaust denier) and his organisation Equality and Reconciliation. This brought into clear view an alliance, which was known for some time ago, between a part of the extreme right in the broad sense, Catholic fundamentalist or not, and some very conservative Muslims, generally on the periphery of the Muslim Brotherhood.
These are the kind of rumours propagated (and still are).
dispensé dans le premier degré, cet enseignement favoriserait la légalisation de la pédophilie, impliquerait l'apprentissage de la masturbation et de 'l'amour anal' dès l'école maternelle.
how to sex education from the first years at primary school, this teaching that would promote the legalisation of paedophilia, imply learning how to masturbate and 'anal love' from kindergarten.
Looking at the campaigning site Stop RSE, (Stop RSE was set up in 2018 as a resource for parents and carers in the UK to inform and support families concerned about the mandatory introduction of Relationship Education and Relationship & Sex Education into all schools across England from September 2020) we find this, articles based on long-standing alt-right/conservative conspiracy theories about the "sexual revolution" 'cultural Marxism' and 'feminism'
History of the Sexual Revolution
"If you want to destroy any nation without war, make adultery or nudity common in the young generation."
Salahuddin Ayyubi (12th Century )
Quotes from articles in this section:
"The philosophy behind this new compulsory sex education agenda can be traced back to the sexual revolution, which had its heyday in the 1960s, and is influenced by various social and political movements. Ideologies from Marxism, radical feminism and gender theory have all contributed to this new sexual ideology. They have intertwined with the thought of various protagonists, the most notable being Alfred Kinsey, who is seen as the master architect of sexuality education as it is now being taught."
"The Frankfurt School combined Marxist thought with psychoanalytical theory as believed people were socially and economically as well as sexually repressed. Religion, the family, marriage, heterosexuality and gender hierarchies, were all viewed as part of the problem. Key members include Max Horkheimer, Theodor, Adorno, Erich Froerber. "
Marcuse was a German-American philosopher, sociologist and political theorist. He was a key member of the Frankfurt School and had the most direct influence on the sexual revolution. He was nicknamed the "Father of the New Left." And for many young radicals of the time, Marcuse's 'Eros and Civilisation,' published in 1955, formed the cornerstone of the sexual revolution.
He wrote excessively on sexual liberation and based his ideas on Freud's theory of 'polymorphous perversity', which asserted that children were sexual from birth and receive sexual pleasure from all parts of their body until society represses them. However, whilst Freud believed sexual urges needed to be suppressed for the function of society, Marcuse thought that due to the level of affluence and civilization that society had reached, it could withstand the release of sexual passion. He espoused a sexual utopia based on sexual freedom and promoted individuals to fulfil their perverse sexual fantasies on the basis that such fantasies were grounded in childlike innocence."
Two of the books on the curriculum at Anderton Park are "My Princess Boy" which has been reviewed as "addressing the needs of transgender children."
Another is "The Prince & the Frog", reviewed below by Peter Tatchell. pic.twitter.com/aBfLDhPSXk
— Caroline Farrow (@CF_Farrow) June 3, 2019
Birmingham LGBT row parents vow to continue school protests
Protesters against LGBT teaching at a Birmingham primary school have vowed to continue their opposition despite being banned from gathering outside the gates.
Birmingham City Council pursued the legal action after months of demonstrations outside Anderton Park Primary School.
The school shut early before half-term due to escalating action.
The council said it sought the urgent injunction after the risk to children became "too serious to tolerate".
It said the behaviour of demonstrators was "increasingly unacceptable".
On Monday, parent Rosie Afsar, speaking on behalf of the protesters, said: "We will challenge the injunction in court. We will not be silenced."
Posted in Anti-Fascism, Britain, Conspiracies, Europe, Fascism, Feminism, Human Rights, Islamism, Left, New Left, Racism, Religion
Tagged with Birmingham, Equality, Feminism, Islamism, Religion
Brexit and Trump are "two sides of the same coin" which no protest can ignore.
Protest Against Trump's Vision of a Brexit Britain.
Trump waded into the U.K.'s fraught politics on the first day of a state visit, urging his hosts to proceed with Brexit and dangling the promise of a U.S. trade deal he said would swiftly follow. https://t.co/s8VwKrcZtv via @bpolitics
Viewers of Channel Four last night know that apart from the free entry of US business chancers into the NHS Trump is also demanding that this should be in the supermarkets.
US wants NHS and chlorinated chicken included in UK trade deal https://t.co/sV09PSw790 via @vsmacdonald
The Truth About Chlorinated Chicken review – an instant appetite-ruiner
Just in time for Trump's UK visit, Channel 4's Dispatches looked at the food standard implications of a post-Brexit trade deal with the US. It wasn't a pretty sight
Chlorine washing may prevent the detection of contaminants through ordinary testing, because it partially masks the problem. Quilton had no trouble finding a Texas restaurant owner who will swear there is nothing wrong with American chicken – "Not a thing. Superior quality and flavour". But the numbers speak for themselves: US rates of campylobacter infection are 10 times higher than in the UK. The US records hundreds of salmonella deaths a year; the UK has in recent years recorded none.
Central to the programme was footage shot inside a giant processing plant by an undercover employee. Looking at it, a former EU meat inspector was able to identify several flagrant violations of good hygiene practice and even the plant's own policies, but there was more sickening stuff on display: a supervisor is overheard talking about "a trend of adulterated product", by which she means glass in the chicken, and also making reference to a recent "amputation". To me, the word amputation brings to mind an operation performed by a professional for the good of a patient, and not, as in this instance, some poultry worker losing three fingers in a machine.
One study found 95 such "amputations" over a single year in American poultry processing, making it one of the most dangerous occupations in the US. Debbie Berkowitz, a former chief of staff at the Occupational Safety and Health Administration (OSHA), who now campaigns for employment rights, maintains that the industry is also exploitative: employees, her office found, were routinely denied basic rights, including toilet breaks. "Workers did not want to have to soil themselves," she said. "So they wore diapers (nappies) on the line.
Who we are: Stop Trump Coalition.
We will make it clear to the British government that it's not OK to normalise Trump's agenda and the hate and fear it has sparked.
Trumpism directly threatens steps towards tackling:
Fighting discrimination, particularly against already marginalised groups like migrants and Muslims
And – this is not mentioned – Brexit!
It was not mentioned, at least I did not hear it, in the interviews with the Stop Trump demo on the telly this morning.
Yet this is the core of Trump's agenda, as his support for Farage and Boris Johnson and present touting of "trade deals" makes clear.
One can only imagine the squirming that's going on amongst the Brexit left who cannot bring themselves to admit that there is a link, a tight bond, between the carnival of reaction that is the Brexit Party and the Tory No Deal Right and Trump's agenda.
Will they see that the demand for a Sovereign nation battling it out with Trade Deals with Trump, and – who knows since he's iffy about it, the WTO, would be a burden for a left government.
Will they continue to indulge that section of the left, as yet only a section, that by its talk of the "real" people who back Brexit, and loathing of "rootless cosmopolitans" has become the the fellow travellers of National Populism?
Like this chap, who's something of hero o the red-brown front?
Another Europe certainly does not think so.
Brexit and Trump are two sides of the same coin – the same brand of toxic right wing nationalism. We need to stop both.
Help us take this message to tomorrow's protests: sign up to volunteer! There will be plenty to do and we need every pair of hands. 👇https://t.co/SlgCLtEyku
— Another Europe (@Another_Europe) June 3, 2019
Listening to Trump, we can see what Britain's post-Brexit future would look like.
Forget taking back control, forget sovereignty and definitely forget £350 million a week for the NHS.
Resist. Resist. Resist. #StopTrumpism #StopBrexit @zoesqwilliamshttps://t.co/xBj6ppEm21
Even the Liberals are getting in on the act.
Visit of #Trump becoming nightmare for UK. He is no friend of Britain and enemy of our values and interests. #ClimateEmergency destroying #WTO trade system and warmongering with China and Iran End of #SpecialRelationship.
— Vince Cable (@vincecable) June 2, 2019
Trump's response so far.
….Fake News will be working hard to find them. Great love all around. Also, big Trade Deal is possible once U.K. gets rid of the shackles. Already starting to talk!
— Donald J. Trump (@realDonaldTrump) June 3, 2019
Hey @realDonaldTrump, we read the story about the sailors on a US warship being ordered to hide from you because you're triggered by the name on their hats. So we turned Madame Tussaud's into a giant USS John McCain baseball cap. Welcome to London! pic.twitter.com/KuynOwupFm
— Led By Donkeys (@ByDonkeys) June 3, 2019
Posted in Anti-Fascism, British Govern, Capitalism, Conservatives, Europe, European Elections, European Left, Fascism, Human Rights, Imperialism, Labour Party, Left, Populism, Racism
Tagged with Brexit, Donald Trump, Fascism, National Populism, NIgel Farage, Populism
Galloway Sacked from Talk Radio for "blatent Anti-Semitism" as Red-Brown Front Cracks.
George Galloway 'sacked' from TalkRadio over Champion's League comments
Evening Standard.
George Galloway has revealed he has been sacked from Talk Radio following a huge backlash to comments he made about Liverpool's Champions League win over Tottenham Hotspur.
The former Labour party member, who has hosted a TalkRadio show since 2016, faced criticism and was condemned by Spurs after he was accused of "blatant anti-Semitism" by the club.
In congratulating the Merseyside club, Mr Galloway tweeted: "Congratulations to the great people of Liverpool to the memory of socialist miner Bill Shankley, to the fallen #96, to those who fought for justice for them and to the Liverpool dockers.
"No Israel flags on the cup".
On Monday morning, Mr Galloway said he had been given a "red card" from TalkRadio, and said: "I've just been sacked by TalkRadio. See you in court guys. #Palestine #Moats Long live Palestine".
talkRADIO has terminated George Galloway's weekly show with immediate effect.
As a fair and balanced news provider, talkRADIO does not tolerate anti-semitic views. pic.twitter.com/upDUaNPoi0
— talkRADIO (@talkRADIO) June 3, 2019
George Galloway sacked from TalkRadio over 'anti-Semetic' tweet https://t.co/hKJIINzaDP
I've just been sacked by @talkRADIO See you in Court guys. #Palestine #Moats Long live Palestine.
— George Galloway (@georgegalloway) June 3, 2019
Note that Galloway always spells Israel with a tréma as in above, 'Israël.
The reason is bleeding obvious, "Israël" is the French spelling. It's not an umlaut but a tréma as in Noël, maïs, ambiguë. Galloway can thus make Israel sound 'foreign' in the language of a secular state he hates almost as much as Israel.
In the meantime another Brexit Party supporter, Ann Widdecombe finds herself in a spot of bother.
BBC News – MEP Ann Widdecombe sparks fury with gay science comments https://t.co/CJwc5cd4RM
Posted in Conspiracies, Fascism, Israel, Jews, Left, Nationalism, Populism, Racism
Tagged with Anti-Semitism, Brexit, George Galloway, Israel, Red-Brown Front


text:
Justia Patents Diamond Or Silicon CarbideUS Patent Application for SIC EPITAXIAL WAFER AND METHOD FOR MANUFACTURING SAME Patent Application (Application #20140175461)
SIC EPITAXIAL WAFER AND METHOD FOR MANUFACTURING SAME
Sep 4, 2012 - SHOWA DENKO K.K.
Provided are a SiC epitaxial wafer in which the surface density of stacking faults is reduced, and a manufacturing method thereof. The method for manufacturing such a SiC epitaxial wafer comprises a step of determining a ratio of basal plane dislocations (BPD), which causes stacking faults in a SiC epitaxial film of a prescribed thickness which is formed on a SiC single crystal substrate having an off angle, to basal plane dislocations which are present on a growth surface of the SiC single crystal substrate, a step of determining an upper limit of surface density of basal plane dislocations on the growth surface of a SiC single crystal substrate used based on the above ratio, and a step of preparing a SiC single crystal substrate which has surface density equal to or less than the above upper limit, and forming a SiC epitaxial film on the SiC single crystal substrate under the same conditions as the growth conditions of the epitaxial film used in the step of determining the ratio.
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The present invention relates to a SiC epitaxial wafer and a manufacturing method thereof.
The present application claims priority on the basis of Japanese Patent Application No. 2011-197626, filed in Japan on Sep. 9, 2011, the contents of which are incorporated herein by reference.
Silicon carbide (SiC) has the superior properties of having insulation breakdown voltage roughly ten times stronger and bandgap roughly three times larger than silicon (Si), and is expected to be used in applications such as power devices, high-temperature operation devices.
These SiC devices are normally fabricated using SiC epitaxial wafers obtained by growing a SiC epitaxial film serving as the active region of the device by a method such as chemical vapor deposition (CVD) on a SiC single crystal substrate obtained by processing SiC bulk single crystals grown by a method such as sublimation recrystallization.
SiC single crystal substrates contain numerous crystal defects, and these crystal defects are known to propagate to the epitaxial film. Consequently, technologies have been developed for improving the quality of epitaxial films in consideration of this propagation.
Known examples of methods used to non-destructively detect crystal defects such as dislocations or stacking faults contained in SiC single crystal substrates and SiC epitaxial wafers, where an epitaxial film is formed on the substrate, include X-ray topography (Non-Patent Documents 1 and 2) and photoluminescence (Patent Document 1).
Three types of dislocations (consisting of threading screw dislocations (TSD), threading edge dislocations (TED) and basal plane dislocations (BPD)) are known to be present as linear crystal defects in SiC single crystals. TSD are dislocations in which the Burgers vector that propagates in the direction of the c-axis is <0001> or double thereof. TED are dislocations in which the Burgers vector that propagates in the direction of the c-axis is ⅓<11-20>. BPD are Dislocations in which the Burgers vector present on the c-plane is ⅓<11-20>.
SiC epitaxial films are typically formed by using a surface in which step density has been intentionally increased by inclining a SiC single crystal substrate from the (0001) plane (c-plane) in the direction of <11-20> at an off angle of within 10° as a growth surface, and growing crystals in the horizontal direction of the step (step flow growth).
Since a surface having an off angle with respect to the c-plane is used for the growth surface in this manner, basal plane dislocations (BPD) present on the c-plane are exposed on the growth surface. In addition, threading screw dislocations (TSD) and threading edge dislocations (TED) extending in the direction of the c-axis are also exposed on the growth surface.
Basal plane dislocations (BPD) that have propagated to an epitaxial film are not stable in the epitaxial film and easily degrade to two energetically advantageous Shockley partial dislocations, resulting in the formation of stacking faults between these two Shockley partial dislocations. Since stacking faults act as carrier lifetime killers, current ends up concentrating in those regions where stacking faults are not present, and as a result of a decrease in the surface area where current flows, on-resistance ends up increasing. Moreover, in bipolar devices such as pn diodes, one of the aforementioned two partial dislocations has Si as the core thereof while the other has C as the core thereof. Therefore, only the partial dislocation having a Si core migrates due to recombination energy of electrons and holes, and the area of the stacking fault ends up increasing (Non-Patent Document 3).
In addition, carrot defects present in epitaxial films are known to be formed by interaction between basal plane dislocations (BPD) and threading screw dislocations (TSD) of SiC single crystal substrates.
BACKGROUND ART DOCUMENTS Patent Documents
Patent Document 1: Japanese Unexamined Patent Application, First Publication No. 2004-289023
Non-Patent Documents
Non-Patent Document 1: J. Crystal Growth, 271 (2004) 1
Non-Patent Document 2: Mat. Sci. Forum, 527-529 (2006) 23
Non-Patent Document 3: H. Jacobson, et al., J. Appl. Phys. 95 (2004) 1485
DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
As has been previously described, a portion of the basal plane dislocation (BPD) present on the growth surface of SiC single crystal substrates are known to become stacking faults in SiC epitaxial films. In addition, carrot defects are known to be formed by interaction between basal plane dislocations (BPD) and threading screw dislocations (TSD) of SiC single crystal substrates.
A persons with ordinary skill in the art recognized that the ratio of basal plane dislocations present on the growth surface of SiC single crystal substrates that become stacking faults in a SiC epitaxial film formed on SiC single crystal substrates is dependent on various factors, the identity of those factors as well as which of those factors. However, functions as the primary factor are not fully understood even by such a person. Consequently, a person with ordinary skill in the art would not be able to predict to what degree a given amount of the surface density of basal plane dislocation (BPD) of a SiC single crystal substrate would effect a given amount of surface density of stacking faults of a SiC epitaxial film, where the stacking faults originate from the basal plane dislocations (BPD). This applies similarly to carrot defects as well.
The inventors of the present invention found that, in the case of forming a SiC epitaxial film of a prescribed thickness on the surface of a SiC single crystal substrate having a prescribed off angle under prescribed epitaxial film growth conditions, the surface density of stacking faults, which are caused by basal plane dislocations (BPD) of a substrate and are formed in the SiC epitaxial film, has regularity in that the surface density is nearly proportional to the surface density of the basal plane dislocations (BPD) in the SiC single crystal substrate. As a result, in the case of forming a SiC epitaxial film of a prescribed thickness using a SiC single crystal substrate having a prescribed off angle under prescribed epitaxial film growth conditions, the surface density of stacking faults which are caused by basal plane dislocations (BPD) and formed in the SiC epitaxial film formed can be predicted if the surface density of basal plane dislocations (BPD) on the growth surface of the SiC single crystal substrate is known, thereby leading to completion of the present invention.
In addition, with respect to carrot defects, it was found that, in the case densities of basal plane dislocations (BPD) and threading screw dislocations (TSD) are high, the surface density of carrot defects in a SiC epitaxial film correlates with the surface density of basal plane dislocations (BPD) in a SiC single crystal substrate. As a result, in the case of forming a SiC epitaxial film of a prescribed thickness using a SiC single crystal substrate having a prescribed off angle under prescribed epitaxial film growth conditions, the surface density of carrot defects in the SiC epitaxial film formed can be predicted if the surface densities of basal plane dislocations (BPD) and threading screw dislocations (TSD) on the growth surface of the SiC single crystal substrate are known, thereby also leading to completion of the present invention.
An object of the present invention is to provide a SiC epitaxial wafer, in which the surface density of stacking faults present in a SiC epitaxial film attributable to basal plane dislocations on the growth surface of a SiC single crystal substrate is reduced, and a manufacturing method thereof.
In addition, an object of the present invention is to provide a SiC epitaxial wafer, in which the surface density of carrot defects present in a SiC epitaxial film are reduced, and a manufacturing method thereof.
Means for Solving the Problems
The present invention employs the following configurations to achieve the aforementioned objectives.
(1) A method of manufacturing a SiC epitaxial wafer in which a SiC epitaxial layer is provided on a SiC single crystal substrate having an off angle, comprising:
a step of determining a ratio of basal plane dislocations (BPD), which causes stacking faults in a SiC epitaxial film of a prescribed thickness which is formed on a SiC single crystal substrate having an off angle, to basal plane dislocations which are present on a growth surface of the SiC single crystal substrate,
a step of determining an upper limit of surface density of basal plane dislocations on the growth surface of a SiC single crystal substrate used based on the above ratio, and
a step of preparing a SiC single crystal substrate which has surface density equal to or less than the above upper limit, and forming a SiC epitaxial film on the SiC single crystal substrate under the same conditions as the growth conditions of the epitaxial film used in the step of determining the ratio.
(2) The method of manufacturing a SiC epitaxial wafer according to claim 1, in which, when determining the ratio, the surface density of BPD on the growth surface and a surface density of stacking faults in the SiC epitaxial film caused by the BPD on the growth surface are measured by X-ray topography or photoluminescence.
(3) The method of manufacturing a SiC epitaxial wafer according to claim 1 or claim 2, in which the upper limit is 1.0×103 BPD/cm2 or less.
(4) A method of manufacturing a SiC epitaxial wafer provided with a SiC epitaxial layer on a SiC single crystal substrate having an off angle, comprising:
a step of determining a ratio of basal plane dislocations (BPD), which cause carrot defects in a SiC epitaxial film of a prescribed thickness which is formed on a SiC single crystal substrate having an off angle, to all basal plane dislocations which are present on a growth surface of the SiC single crystal substrate,
a step of determining an upper limit of surface density of BPD and TSD on the growth surface of a SiC single crystal substrate used based on the above ratio, and
(5) A SiC epitaxial wafer provided with a SiC epitaxial layer on a SiC single crystal substrate having an off angle, in which the surface density of stacking faults caused by BPD of the SiC single crystal substrate is 0.1 stacking faults/cm2 or less in the SiC epitaxial film.
Effects of the Invention
According to the aforementioned configurations, a SiC epitaxial wafer can be provided in which the surface density of stacking faults is reduced. In addition, a SiC epitaxial wafer can be provided in which the surface density of carrot defects is reduced.
FIG. 1 are topographs of SiC single crystal substrates, with (a) indicating that having a basal plane dislocation (BPD) density of 6.5×104 BPD/cm2, and (b) indicating that having a basal plane dislocation (BPD) density of 5.5×103 BPD/cm2.
FIG. 2 are PL images of SiC epitaxial wafers using the SiC single crystal substrates shown in FIG. 1, with (a) indicating that having a stacking fault (SF) density of 2.5×102 SF/cm2, and (b) indicating that having a stacking fault (SF) density of 9.2 SF/cm2.
FIG. 3 is a graph indicating the correlation between basal plane dislocation (BPD) density of a SiC single crystal substrate and stacking fault (SF) density in an epitaxial film based on the data shown in Table 1.
FIG. 4 are topographs of SiC single crystal substrates, with (a) indicating that having a basal plane dislocation (BPD) density of 5.0×104 BPD/cm2 and a threading screw dislocation (TSD) density of 2.8×104 TSD/cm2, and (b) indicating that having a basal plane dislocation (BPD) density of 2.0×104 BPD/cm2 and a threading screw dislocation (TSD) density of 5.4×103 TDS/cm2.
FIG. 5 are Candela images of SiC epitaxial wafers using the SiC single crystal substrates shown in FIG. 4, with (a) indicating that using the SiC single crystal substrate shown in FIG. 4(a), and (b) indicating that using the SiC single crystal substrate used in FIG. 4(b).
FIG. 6 are images of measuring the Si surface of a SiC epitaxial wafer having an off angle of 4° with an optical surface inspection apparatus using laser light, with (a) indicating an image of the SiC epitaxial wafer of the present invention, and (b) indicating an image of a conventional SiC epitaxial wafer.
BEST MODE FOR CARRYING OUT THE INVENTION
The following provides a detailed explanation of a SiC epitaxial wafer and manufacturing method thereof to which the present invention is applied with reference to the drawings.
[SiC Epitaxial Wafer]
FIGS. 1(a) and 1(b) depict topographs of SiC single crystal substrates obtained by X-ray topography. FIGS. 1(a) and 1(b) indicate that having a basal plane dislocation (BPD) density of 6.5×104 BPD/cm2 and 5.5×103 BPD/cm2, respectively.
The arrows in the topographs indicate a portion of the basal plane dislocations (BPD).
<X-Ray Topography Measurement>
In the present invention, crystal defects in the wafer surface can be detected by measuring diffracted X-rays from single crystal wafers of silicon carbide using reflection X-ray topography. The use of reflection X-ray topography offers the advantage of being able to detect the locations of crystal defects non-destructively without using etching or other destructive techniques.
Synchrotron radiation was used for the X-ray source used in the present invention, and it enables independent detection of basal plane dislocations, threading edge dislocations and threading screw dislocations present in crystals. The data indicated in the present description was obtained at the Spring-8 synchrotron radiation.
Reflection X-ray topography measurements were carried out using X-rays having a wavelength of 1.54 Å as determined using a monochromator for the incident light. Although there are no particular limitations on the diffraction vector (g-vector) used during X-ray diffraction provided it allows the object of the present invention to be achieved, a g-vector of 11-28 or 1-108 is ordinarily used for 4H—SiC crystals. Topography images indicated in the present description were obtained using a g-vector of 11-28.
Topographic images can be obtained by irradiating a sample with X-rays and detecting the diffracted light reflected from the sample. A recording medium such as a high-resolution X-ray film or nuclear plate is used to acquire these topographic images in order to obtain adequate resolution for determining the type of defect. A nuclear plate was used in the case described below. The numbers of basal plane dislocations, threading edge dislocations and threading screw dislocations are then counted from these images.
FIGS. 2(a) and 2(b) are PL images obtained by photoluminescence (PL) imaging of SiC epitaxial wafers provided with a SiC epitaxial film having a thickness of 10 μm formed on the SiC single crystal substrates shown in FIGS. 1(a) and 1(b). Furthermore, the SiC epitaxial wafers shown in FIGS. 2(a) and 2(b) were simultaneously formed using the same production lot.
In FIGS. 2(a) and 2(b), a stacking fault (SF) surface density in an epitaxial film thereof is 2.5×102 SF/cm2 and 9.2 SF/cm2, respectively.
The arrows in the images indicate a portion of the basal plane dislocations (BPD) or stacking faults (SF).
Table 1 indicates the four surface densities of basal plane dislocations (BPD) of SiC single crystal substrates, and surface densities of stacking faults in epitaxial films of SiC epitaxial wafers provided with SiC epitaxial films having a thickness of 10 μm formed on the SiC single crystal substrates having those BPD surface densities. The four surface densities of the basal plane dislocations (BPD) consist of the surface densities of the samples of SiC single crystal substrates shown in FIG. 1 as well as the surface densities of BPD densities of 3.2×104 BPD/cm2 and 3.0×102 BPD/cm2.
TABLE 1 Basal plane dislocation Stacking fault density (BPD/cm2) density (SF/cm2)
6.5 × 104 2.5 × 102 3.2 × 104 8.0 × 10 5.5 × 103 9.2 6.5 × 102 0.13
FIG. 3 depicts a graph in which the surface densities of basal plane dislocations (BPD) of SiC single crystal substrates are plotted on the horizontal axis and the surface densities of stacking faults (SF) in an epitaxial film are plotted on the vertical axis based on the data shown in Table 1.
BPD surface density and SF surface density can be understood to have a nearly proportional relationship. As a result of having this relationship, it is possible to determine the upper limit of BPD surface density of a SiC single crystal substrate required to fabricate a SiC epitaxial wafer having a desired SF surface density.
FIGS. 4 (a) and 4(b) depict topographic images of SiC single crystal substrates obtained by radiation topography.
FIGS. 4(a) and 4(b) respectively indicate SiC single crystal substrates having a basal plane dislocation (BPD) surface density of 5.0×104 BPD/cm2 and threading screw dislocation (TSD) surface density of 2.8×104 TSD/cm2, and a basal plane dislocation (BPD) surface density of 2.0×104 BPD/cm2 and threading screw dislocation (TSD) surface density of 5.4×103 TDS/cm2, respectively.
A typical basal plane dislocation (BPD) and threading screw dislocation (TSD) are shown in the image depicted in FIG. 4(a).
FIGS. 5(a) and 5(b) depict Candela images of SiC epitaxial wafers provided with a SiC epitaxial film having a thickness of 10 μm formed on the SiC single crystal substrates shown in FIGS. 4(a) and 4(b), and the images are obtained with an optical surface inspection apparatus (Candela). Furthermore, the SiC epitaxial wafers shown in FIGS. 5(a) and 5(b) were simultaneously formed using the same production lot.
In each of FIGS. 5(a) and 5(b), the image on the left indicates a defect map, while the image on the right is a Candela image indicated with the arrow of the defect map on the left.
In FIGS. 5(a) and 5(b), carrot defect densities in an epitaxial film are 20.2 defects/cm2 and 0.2 defects/cm2, respectively.
[Method for Manufacturing SiC Epitaxial Wafer]
The following provides a detailed explanation of embodiments of the present invention in the form of methods for manufacturing a SiC epitaxial wafer.
First Embodiment
A first embodiment of the present invention is a method of manufacturing a SiC epitaxial wafer, and is characterized as a method of manufacturing a SiC epitaxial wafer in which a SiC epitaxial layer is provided on a SiC single crystal substrate having an off angle. The method comprises: a step of determining a ratio of basal plane dislocations (BPD), which causes stacking faults in a SiC epitaxial film of a prescribed thickness which is formed on a SiC single crystal substrate having an off angle, to all basal plane dislocations which are present on a growth surface of the SiC single crystal substrate, a step of determining an upper limit of surface density of basal plane dislocations on the growth surface of a SiC single crystal substrate used based on the above ratio, and
a step of preparing a SiC single crystal substrate which has surface density equal to or less than the above upper limit, and forming a SiC epitaxial film on the SiC single crystal substrate under the same conditions as the growth conditions of the epitaxial film used in the step for determining the ratio.
<SiC Single Crystal Substrate>
Any type of polytype SiC single crystal substrate can be used for the SiC single crystal substrate, and a 4H—SiC single crystal substrate, which is mainly used to fabricate practical SiC devices, can be used. A SiC single crystal substrate processed from a bulk crystal fabricated by a method such as sublimation can be used for the substrate of the SiC device, and a SiC epitaxial film serving as the active region of the SiC device is normally formed thereon by chemical vapor deposition (CVD).
In addition, the off angle of the SiC single crystal substrate may be any arbitrary off angle, and although there are no limitations thereon, a SiC single crystal substrate having a small off angle of, for example, 0.4° to 5° is preferable from the viewpoint of reducing costs. An off angle of 0.4° C. can be said to be the lower limit for use as an off angle enabling step-flow growth.
In the case of a SiC single crystal substrate having a size up to about 2 inches, an off angle of 8° is mainly used for the off angle of the SiC single crystal substrate. This off angle results in a small terrace width of the wafer surface and allows step-flow growth to be easily obtained. However, since the number of wafers able to be obtained from a SiC ingot decreases as the off angle becomes larger, an off angle of about 4° is mainly used in the case of SiC substrates having a size of 3 inches or larger.
The terrace width of the surface of the SiC single crystal substrate increases as the off angle becomes smaller. Accordingly, in such a case, there is increased susceptibility to variation in the rate at which migrating atoms are incorporated into the step edges, or in other words, the growth rate of the step edges. As a result, steps having a faster growth rate end up catching up to steps having a slower growth rate, causing them to bunch together and resulting in increased susceptibility to the occurrence of step bunching. In the case of a substrate having an off angle of 0.4°, for example, terrace width is 10 times greater than a substrate having an off angle of 4°, and since the length over which step-flow growth occurs becomes longer by a factor of 10, it is necessary to note that the conditions for step-flow growth that have been used for a substrate having an off angle of 4° must be adjusted when using for a substrate having an off angle of 0.4°.
As a SiC single crystal substrate, a SiC single crystal substrate in which the growth surface of the SiC epitaxial layer convexly formed can be used.
When manufacturing a SiC epitaxial wafer (that is, when forming (growing) a SiC epitaxial layer), although the back surface of the SiC single crystal substrate is heated directly by a heated susceptor, the top surface (surface on which the SiC epitaxial layer is formed) is exposed to a vacuum space and is not heated directly. Moreover, since a carrier gas in the form of hydrogen flows over the top surface, heat ends up being carried away. On the basis of these circumstances, the top surface is at a lower temperature than the back surface during epitaxial growth. Due to this temperature difference, the magnitude of thermal expansion is smaller on the top surface than on the back surface, and the top surface of the SiC single crystal substrate ends up being deformed into a concave shape during epitaxial growth. Therefore, by using a SiC single crystal substrate in which the growth surface of the SiC epitaxial layer is convexly formed, epitaxial growth can be carried out while canceling out concave deformation (warping) of the SiC single crystal substrate during epitaxial growth.
Although there are no particular limitations on the thickness of the SiC epitaxial layer, it is, for example, 10 μm when carrying out deposition for 2.5 hours at a typical growth rate of 4 μm/h.
<Polishing Step>
Polishing is first carried out on the SiC single crystal substrate prior to forming a SiC epitaxial layer on the SiC single crystal substrate.
In this polishing step, polishing is carried out to a degree such that a lattice disorder layer of the surface thereof as described in Japanese Unexamined Patent Application, First Publication No. 2011-49496 is about 3 nm or less.
The "lattice disorder layer" refers to a layer in which a banded structure or a portion of the bands thereof corresponding to an atomic layer (lattice) of Si single crystal is not well-defined in a TEM lattice image (image enabling confirmation of the lattice) as shown in FIGS. 7 and 8 of Japanese Unexamined Patent Application, First Publication No. 2011-49496.
Here, the surface density of basal plane dislocations (BPD) present on the growth surface of a SiC single crystal substrate is primarily determined by the degree of finish of this polishing step.
In order to obtain a SiC epitaxial wafer having a desired stacking fault (SF) surface density, polishing is carried out using the polishing method described below until the surface density of basal plane dislocations (BPD) present on the growth surface of the SiC single crystal substrate becomes equal to or less than an upper limit of surface density as determined in the aforementioned upper limit determination step.
For example, the degree of finish of the polishing step required to manufacture a SiC epitaxial wafer having a stacking fault surface density of 0.1 stacking faults/cm2 or less is equivalent to the degree at which the aforementioned lattice disorder layer is 3 nm or less.
The following provides an explanation of an embodiment of this step.
The polishing step includes a plurality of polishing steps such as a rough polishing step normally referred to as wrapping, precision polishing step referred to as polishing, and ultra-precision polishing step in the form of chemical mechanical polishing (CMP). The polishing steps are frequently carried out using a wet method, and a common element to these polishing steps is that a polishing head having a silicon carbide substrate adhered thereto is pressed against a rotating surface plate affixed with an abrasive cloth while supplying polishing slurry. Although the polishing slurry used in the present invention is basically used in these forms, there are no particular limitations on the form used in so far as wet polishing using polishing slurry is used.
The particles used as abrasive grains are particles that disperse without dissolving in this pH range. In the present invention, the pH of the polishing liquid is preferably lower than 2, and in this case, examples of abrasive grains that can be used include diamond, silicon carbide, aluminum oxide, titanium oxide and silicon oxide. In the present invention, the abrasive grains used have a mean diameter of 1 nm to 400 nm, preferably 10 nm to 200 nm and even more preferably 10 nm to 150 nm. In order to obtain a favorable final finish surface, silica is preferable from the viewpoint of silica having a small particle diameter being available commercially and inexpensive. Colloidal silica is more preferable. The particle diameter of the colloidal silica or other abrasive can be suitably selected according to processing characteristics such as processing speed or surface roughness. In the case of requiring a higher polishing speed, an abrasive having a larger particle diameter can be used. When requiring low surface roughness, or in other words, when requiring a highly smooth surface, an abrasive having a small particle diameter can be used. Abrasives having a mean particle diameter in excess of 400 nm do not yield high polishing speed relative to their high cost, thereby making them uneconomical. The use of an abrasive having an extremely small particle diameter of less than 1 nm results in a considerable decrease in polishing speed.
The amount of abrasive grains added is 1% by mass to 30% by mass and preferably 1.5% by mass to 15% by mass. If the amount added exceeds 30% by mass, the drying speed of the abrasive grains becomes excessively fast, resulting in increasing risk of causing scratches as well as being uneconomical. In addition, if the amount of abrasive grains added is less than 1% by mass, processing speed becomes excessively slow, thereby making this undesirable.
The polishing slurry used in the present invention is aqueous polishing slurry that has a pH at 20° C. of lower than 2.0, preferably lower than 1.5 and more preferably lower than 1.2. Adequate polishing speed cannot be obtained at a pH of 2.0 or higher. On the other hand, lowering the pH of the slurry to lower than 2 remarkably increases the chemical reactivity to silicon carbide even in ordinary room environments, resulting in the potential for ultra-precision polishing. Rather than silicon carbide being removed directly by the mechanical action of oxide particles present in the polishing slurry, the mechanism is thought to involve the polishing liquid chemically altering the surface of the silicon carbide single crystal to silicon oxide, and that silicon oxide is then removed by the mechanical action of the abrasive grains. Thus, employing the polishing liquid composition in the form of a liquid that facilitates reaction of silicon carbide, namely lowering the pH to less than 2, and selecting oxide particles having a suitable hardness for use as abrasive grains are extremely important for obtaining a smooth surface that is free of scratches and processing-damaged layers.
The polishing slurry is prepared so that the pH is lower than 2 by using at least one type, and preferably two or more types, of acids such as hydrochloric acid, nitric acid, phosphoric acid or sulfuric acid. Although the reason why the use of a plurality of acids is effective is unknown, it has been confirmed experimentally, and there is the possibility that multiple acids ends up interacting thereby enhancing effectiveness. The amount of acid added is within the range of, for example, 0.5% by mass to 5% by mass in the case of sulfuric acid, 0.5% by mass to 5% by mass in the case of phosphoric acid, 0.5% by mass to 5% by mass in the case of nitric acid or 0.5% by mass to 5% by mass in the case of hydrochloric acid, and the type and amount thereof are suitably selected so that the pH is lower than 2.
The reason why inorganic acids are effective is that they are stronger acids than organic acids and are extremely favorable for preparing a prescribed strongly acidic polishing liquid. The use of organic acid makes it difficult to prepare a strongly acidic polishing liquid.
Polishing of silicon carbide is carried out by removing an oxide layer with oxide particles due to the reactivity of the strongly acidic polishing liquid to the oxide film formed on the surface of silicon carbide, and the addition of an oxidizing agent to the polishing slurry has been recognized to be even more effective for accelerating surface oxidation. Examples of oxidizing agents include hydrogen peroxide, perchloric acid, potassium dichromate and ammonium persulfate. Although the polishing speed is improved by, for example, adding 0.5% by mass to 5% by mass, and preferably 1.5% by mass to 4% by mass, of hydrogen peroxide, the oxidizing agent is not limited to hydrogen peroxide.
An antigelling agent can be added to the polishing slurry to inhibit gelling of the abrasive. Examples of antigelling agents that are used preferably include phosphoric acid ester-based chelating agents such as 1-hydroxyethylidene-1,1-disphosphonic acid or aminotriethylene phosphonic acid. The antigelling agent is added within the range of 0.01% by mass to 6% by mass and preferably within the range of 0.05% by mass to 2% by mass.
In order to make the lattice disorder layer of the surface to be 3 nm or less in the polishing step of the present invention, following conditions are preferable. The size of damaged layers is preferably held to 50 nm by making the processing pressure during mechanical polishing prior to CMP to be 350 g/cm2 or less and using abrasive grains having a diameter of 5 μm. During CMP, the polishing slurry preferably contains abrasive grains having a mean particle diameter of 10 nm to 150 nm and inorganic acid, and the pH at 20° C. is preferably lower than 2. It is more preferable that the abrasive grains are silica particles contained at 1% by mass to 30% by mass. It is more preferable that the inorganic acid is at least one selected from hydrochloric acid, nitric acid, phosphoric acid and sulfuric acid.
FIG. 6(a) depicts PL images obtained by photoluminescence (PL) imaging of a SiC epitaxial wafer. The wafer is obtained by forming a SiC epitaxial film having a thickness of 10 nm on a SiC single crystal substrate that underwent polishing to a finish such that the lattice disorder layer remained at about 10 nm or more. In the PL image shown at the top of the figure, the detection wavelength was infrared wavelength of 750 nm or longer, and in the image, those portions that appear darker than the surrounding area indicate stacking faults that become carrier traps (and the arrows indicate a portion thereof). In addition, in the PL image shown at the bottom of the figure, the detection wavelength, which was measured by a band-pass filter, was 450±10 nm, and those portions that appear lighter than the surrounding area indicate stacking faults having an 8H structure (and the arrows indicate a portion thereof).
FIG. 6(b) depicts PL images obtained from a SiC epitaxial wafer obtained by similarly forming a SiC epitaxial film having a thickness of 10 nm on a SiC single crystal substrate in which the sample shown in FIG. 6(a) was re-polished until the lattice disorder layer was 3 nm or less.
In the PL images shown in FIG. 6(b), there were hardly any stacking faults observed, and basal plane dislocations (BPD) that are converted to stacking faults were determined to be able to be reduced by polishing. In particular, basal plane dislocations (BPD) were determined to be able to be effectively reduced by polishing until the lattice disorder layer was 3 nm or less.
<Basal Plane Dislocation Density Measurement Step>
The density of basal plane dislocations on the growth surface of a SiC single crystal substrate after polishing is measured using reflection X-ray topography.
<Cleaning (Gas Etching) Step>
In the cleaning step, the surface of the substrate is cleaned (gas-etched) at a temperature of 1400° C. to 1800° C. after the aforementioned polishing (polishing and convexity processing in the case forming convexity) in a hydrogen atmosphere.
Gas etching is carried out for 5 minutes to 30 minutes at a hydrogen gas flow rate of 40 slm to 120 slm and pressure of 100 mbar to 250 mbar while holding the SiC single crystal substrate at 1400° C. to 1800° C.
After cleaning the SiC single crystal substrate after polishing, the substrate is placed in an epitaxial growth device such as a mass production type multi-wafer planetary CVD reactor. After introducing hydrogen gas into the device, the pressure is adjusted to 100 mbar to 250 mbar. Subsequently, the temperature of the device is raised so that the substrate temperature reaches 1400° C. to 1600° C. and preferably 1480° C. or higher, and gas etching is carried out on the substrate surface with hydrogen gas for 1 minute to 30 minutes. In the case of having carried out gas etching with hydrogen gas under these conditions, the etching amount is about 0.05 μm to 0.4 μm.
The substrate surface is subjected to damage by the polishing step, and in addition to damage that can be detected in the form of a "lattice disorder layer" by TEM, lattice strain and the like that is unable to be detected by TEM is also thought to be present at even greater depths. Although the purpose of gas etching is to remove a layer subjected to such damage (to be referred to as "damaged layers"), if damaged layer remain as a result of inadequate gas etching, heterogeneous polytypes, dislocations, stacking faults and the like end up being introduced into the epitaxial growth layer, while if etching is carried out excessively, the substrate surface undergoes surface reconstruction, and step bunching ends up occurring prior to the start of epitaxial growth. Accordingly, it is important to optimize the damaged layer and the gas etching amount. As a result conducting extensive research, the inventors of the present invention found that the combination of damaged layer resulting from reducing the thickness of the lattice disorder layer to 3 nm or less and the aforementioned gas etching conditions is an important condition for manufacturing SiC epitaxial wafers free of step bunching.
With respect to the surface of the substrate following cleaning (gas etching), the root mean square surface roughness Rq of the outermost surface of an epitaxial layer, which is obtained by analyzing a region covering 35% or more of the entire wafer using an optical surface inspection apparatus, can be confirmed to be 1.3 nm or less. In addition, in the case of measuring using an atomic force microscope, Rq is 1.0 nm or less for a square area measuring 10 μm on a side, 1.0 nm or less for a square area measuring 200 μm on a side, and the maximum height difference Ry during step bunching over a length of 100 μm to 500 μm observed in a square area measuring 200 μm on a side (short step bunching) can be confirmed to be 3.0 nm or less. In addition, the linear density of this step can be confirmed to be 5 mm−1 or less.
It is important to maintain this degree of flatness of the substrate surface in the subsequent deposition step and temperature lowering step.
SiH4 gas and/or C3H8 gas can also be added to the hydrogen gas. There are cases in which short step bunching may occur incidental to shallow pits attributable to screw dislocations. However, when gas etching is carried out by adding SiH4 gas to the hydrogen gas at a concentration of less than 0.009 mol % to make the environment in the reactor rich in Si, it is possible to reduce the depth of the shallow pits and inhibit the occurrence of short step bunching occurring incidental to the shallow pits.
In the case of adding SiH4 gas and/or C3H8 gas, the atmosphere inside the reactor is preferably returned to a hydrogen gas atmosphere by once evacuating the atmosphere inside the reactor prior to deposition (epitaxial growth) step.
<Deposition (Epitaxial Growth) Step>
In the deposition (epitaxial growth) step, the silicon carbide is made to undergo epitaxial growth by simultaneously supplying SiH4 gas and C3H8 gas at a concentration ratio C/Si of 0.7 to 1.2 in an amount required for epitaxial growth of silicon carbide to the surface of the substrate following the aforementioned cleaning. When the growth temperature of the epitaxial film is higher than the cleaning (gas-etching) temperature, the temperature is increased before epitaxial growth starts.
In addition, "simultaneously supplying" means that supply-time difference of the gases is within several seconds, and is not used in the sense of requiring the gases to be supplied at precisely the same time. In the case of using the Hot Wall SiC CVD (VP2400HW) manufactured by Aixtron indicated in Examples to be subsequently described, SiC epitaxial wafers free of step bunching can be manufactured provided the time difference between the supply of SiH4 gas and C3H8 gas is within 5 seconds.
The respective flow rate of the SiH4 gas and C3H8 gas, pressure of the SiH4 gas and C3H8 gas, substrate temperature and growth temperature are 15 sccm to 150 sccm, 3.5 sccm to 60 sccm, 80 mbar to 250 mbar, and higher than 1600° C. and 1800° C. or less, respectively, and are determined while controlling off angle, film thickness, carrier concentration uniformity and growth rate within a growth rate range of 1 μm to 20 μm per hour. Carrier concentration in the epitaxial layer can be controlled by introducing a doping gas in the form of nitrogen gas simultaneous to the start of deposition. Lowering the concentration ratio C/Si of the raw material gas supplied in order to increase the migration of Si atoms on the growth surface is known as a method of inhibiting step bunching during growth. In the present invention, the concentration ratio C/Si is 0.7 to 1.2. In addition, the film thickness of the epitaxial layer grown is normally about 5 μm to 20 μm, and the carrier concentration is about 2×1015 cm−3 to 15×1015 cm−3.
Deposition is carried out such that growth temperature and growth rate are determined as indicated below corresponding to the off angle of the SiC single crystal substrate, namely:
(1) in the case of using a 4H—SiC single crystal substrate having an off angle of 0.4° to 2°, deposition is carried out at a growth rate of 1 μm/h to 3 μm/h when the growth temperature at which the silicon carbide film is made to undergo epitaxial growth is 1600° C. to 1640° C., at a growth rate of 3 μm/h to 4 μm/h when the growth temperature is 1640° C. to 1700° C., and at a growth rate of 4 μm/h to 10 μm/h when the growth temperature is 1700° C. to 1800° C., and
(2) in the case of using a 4H—SiC single crystal substrate having an off angle of 2° to 5°, deposition is carried out at a growth rate of 2 μm/h to 4 μm/h when the growth temperature at which the silicon carbide film is made to undergo epitaxial growth is 1600° C. to 1640° C., at a growth rate of 4 μm/h to 10 μm/h when the growth temperature is 1640° C. to 1700° C., and at a growth rate of 10 μm/h to 20 μm/h when the growth temperature is 1700° C. to 1800° C.
<Temperature Lowering Step>
In the temperature lowering step, it is preferable that the temperature is lowered after simultaneously discontinuing the supply of SiH4 gas and C3H8 gas and maintaining the substrate temperature until the SiH4 gas and C3H8 gas are evacuated.
Following deposition, although the temperature is lowered after discontinuing the supply of SiH4 gas and C3H8 gas and discontinuing the introduction of nitrogen gas used as a doping gas, at this time as well, the morphology of the surface can be exacerbated due to the occurrence of gas etching on the surface of the SiC epitaxial film. In order to inhibit this exacerbation of surface morphology, the timing at which the supply of SiH4 gas and C3H8 gas is discontinued and the timing at which the temperature is lowered are important. It was determined that exacerbation of morphology is inhibited by maintaining the growth temperature until the supplied SiH4 gas and C3H8 gas are no longer present on the substrate surface after having simultaneously discontinued the supply of these gases, and subsequently lowering the temperature to room temperature at a rate of about 50° C. per minute.
<Conversion Ratio Determination Step>
In this step, a ratio of basal plane dislocations (BPD), which causes stacking faults in a SiC epitaxial film of a prescribed thickness which is formed on a SiC single crystal substrate, to all basal plane dislocations which are present on a growth surface of the SiC single crystal substrate is determined.
First, using photoluminescence (PL) imaging method, the surface density of stacking faults (SF) in a SiC epitaxial film is measured with respect to a SiC epitaxial wafer fabricated according to the aforementioned steps.
Next, a ratio of basal plane dislocations (BPD), which causes stacking faults in a SiC epitaxial film of a prescribed thickness which is formed on a SiC single crystal substrate, to all basal plane dislocations which are present on a growth surface of the SiC single crystal substrate is determined from the preliminarily measured surface density of basal plane dislocations (BPD) present on the growth surface of the SiC single crystal substrate and the surface density of stacking faults (SF) obtained.
More specifically, this ratio can be determined from the graph shown in FIG. 3.
Samples used for determining conversion ratio are preferably deposited simultaneously. This is because variations easily occur in growth conditions if samples of different production lots are used.
<BPD Surface Density Upper Limit Determination Step>
In this step, the upper limit of surface density of BPD on the growth surface of the SiC single crystal substrate used is determined based on the determined ratio.
Namely, the upper limit of surface density of BPD on the growth surface of the SiC single crystal substrate able to be used to obtain a SiC epitaxial wafer having a stacking fault surface density equal to or less than a desired surface density is determined from the determined ratio.
<SiC Epitaxial Film Formation Step>
In this step, a SiC epitaxial film is formed on the SiC single crystal substrate using a SiC single crystal substrate having a BPD surface density equal to or less than the determined upper limit under the same conditions as the epitaxial film growth conditions used in the step for determining the ratio.
Second Embodiment
The method of manufacturing a SiC epitaxial wafer of a second embodiment of the present invention is characterized as a method of manufacturing a SiC epitaxial wafer provided with a SiC epitaxial layer on a SiC single crystal substrate having an off angle. The method comprises: a step of determining a ratio of basal plane dislocations (BPD) and threading screw dislocations (TSD), which cause carrot defects in a SiC epitaxial film of a prescribed thickness which is formed on a SiC single crystal substrate having an off angle, to all basal plane dislocations and all threading screw dislocations which are present on a growth surface of the SiC single crystal substrate, a step of determining an upper limit of surface density of basal plane dislocations of the growth surface of a used SiC single crystal substrate based on the above ratio, and a step of preparing a SiC single crystal substrate which has surface density equal to or less than the above upper limit, and forming a SiC epitaxial film on the SiC single crystal substrate under the same conditions as the growth conditions of the epitaxial film used in the step of determining the ratio.
The following provides an explanation of the points of the method of manufacturing a SiC epitaxial wafer of the present embodiment that differ from those of the first embodiment.
<Basal Plane Dislocation Density and Threading Screw Dislocation Density Measurement Step>
The densities of basal plane dislocations and threading screw dislocations on the growth surface of a SiC single crystal substrate after polishing are measured using reflection X-ray topography.
In this step, a ratio of basal plane dislocations (BPD) and threading screw dislocations (TSD), which cause carrot defects in a SiC epitaxial film of a prescribed thickness which is formed on a SiC single crystal substrate having an off angle, to all basal plane dislocations and all threading screw dislocations which are present on a growth surface of the SiC single crystal substrate is determined.
Since carrot defects are formed as a result of interaction between basal plane dislocations (BPD) and threading screw dislocations (TSD), the conversion ratio to carrot defects dependent on the two variables (two types of dislocation densities). Namely, for example, even if the surface density of basal plane dislocations is the same, in the case that the surface densities of threading screw dislocations differ, the conversion ratios of carrot defects also differ.
However, in the case that the surface density of threading screw dislocations is adequately high (such as in the case the surface density of threading screw dislocations is 103 TSD/cm2 or more relative to the surface density of basal plane dislocations being 104 BPD/cm2 or more), the carrot defect conversion ratio is roughly 1/10,000 to 1/100,000 of the surface density of the basal plane dislocations.
Thus, in the case that the surface density of threading screw dislocations is adequately high in the relationship with the surface density of basal plane dislocations, the carrot defect conversion ratio with respect to the surface density of the basal plane dislocations can be used as the aforementioned ratio.
First, with respect to a fabricated SiC epitaxial wafer, the surface density of carrot defects in a SiC epitaxial film thereof is measured using photoluminescence (PL) imaging method.
Next, a ratio of basal plane dislocations (BPD), which causes carrot defects in a SiC epitaxial film of a prescribed thickness which is formed on a SiC single crystal substrate, to all basal plane dislocations which are present on a growth surface of the SiC single crystal substrate is determined from the preliminarily measured surface densities of basal plane dislocations (BPD) and threading screw dislocations (TSD) present on the growth surface of the SiC single crystal substrate and the surface density of carrot defects obtained above.
<BPD and TSD Surface Density Upper Limit Determination Step>
In this step, the upper limit of surface density of BPD and TSD on the growth surface of the SiC single crystal substrate used is determined based on the determined ratio.
Namely, the upper limit of surface density of BPD and TSD on the growth surface of the SiC single crystal substrate able to be used to obtain a SiC epitaxial wafer having a stacking fault surface density equal to or less than a desired surface density is determined from the determined ratio.
In this step, a SiC epitaxial film is formed on a SiC single crystal substrate using a SiC single crystal substrate having a BPD and TSD surface density equal to or less than the determined upper limit under the same conditions as the epitaxial film growth conditions used in the step for determining the ratio.
Although the following provides a more detailed explanation of the present invention through examples thereof, the present invention is not limited to these examples.
In the present examples, SiH4 was used as a silicon-containing gas, C3H8 gas was used as a carbon-containing gas, N2 gas was used as a doping gas, H2 gas was used as a carrier gas and etching gas, and SiC epitaxial film was grown on a Si surface or C surface slightly inclined in the direction of the <11-20> axis with respect to the (0001) plane of 4H—SiC single crystal by using the Hot Wall SiC CVD (VP2400HW) manufactured by Aixtron which is amass production type multi-wafer planetary (rotary and revolutionary) CVD reactor.
SiC epitaxial wafers were manufactured in which a SiC epitaxial layer was formed on the Si surface of a 4H—SiC single crystal substrate inclined at an off angle of 4°.
In the present example, the 4H—SiC single crystal substrate was not subjected to convexity processing.
First, in order to determine the ratio of conversion to stacking faults (SF), four SiC single crystal substrates were polished under four types of polishing conditions. The four surface densities of the basal plane dislocations (BPD) shown in Table 1 are equivalent to the surface densities of basal plane dislocations (BPD) of SiC single crystal substrates polished under those polishing conditions.
The SiC single crystal substrate having the lowest BPD density was polished under the polishing conditions indicated below. Namely, mechanical polishing prior to CMP was carried out at a processing pressure of 350 g/cm2 using abrasive grains having a diameter of 5 μm or less. CMP was carried out for 30 minutes using polishing slurry containing sulfuric acid as inorganic acid and having a pH at 20° C. of 1.9 and silica particles having a mean particle diameter of 10 nm to 150 nm as the abrasive grains. As a result, the lattice disorder layer of the surface was 3 nm or less.
After subjecting the polished substrate to RCA cleaning, the substrate was loaded into a growth device. RCA cleaning refers to a wet cleaning method commonly used to clean Si wafers, and enables the removal of organic matter, heavy metals and particles on the substrate surface using a solution comprising a mixture of sulfuric acid, ammonia, hydrochloric acid and hydrogen peroxide water and a hydrofluoric acid solution.
In the cleaning (gas etching) step, gas etching was carried out for 20 minutes at a hydrogen gas flow rate of 100 slm, reactor internal pressure of 200 mbar and substrate temperature of 1500° C.
In the SiC epitaxial growth step, epitaxial growth was carried out by setting the substrate temperature to 1650° C., and simultaneously initiating supply of C3H8 gas at 24 scorn and SiH4 gas at 8 sccm so that both gases were simultaneously supplied to the main surface of the substrate. A value of 1.0 was selected for the C/Si ratio. The growth step was carried out for 2 hours by setting the reactor internal pressure to 200 mbar and the growth rate to 5 μm/h to deposit a SiC epitaxial layer having a thickness of 10 μm.
Next, the surface density of stacking faults (SF) in the SiC epitaxial film was measured for the obtained SiC epitaxial wafers using photoluminescence (PL) imaging method. The four values of stacking fault (SF) surface density shown in Table 1 were obtained.
Next, based on the graph shown in FIG. 3, a value of 1.0×103 BPD/cm2 was determined as the upper limit of BPD surface density of the growth surface of a SiC single crystal substrate used in order to obtain SiC epitaxial wafers having a stacking fault surface density of 0.1 SF/cm2 or less.
In order to obtain a SiC single crystal substrate having BPD surface density equal to or less than this upper limit, polishing conditions were adjusted so that the lattice disorder layer was 2.5 nm or less.
Basal plane dislocation density on the growth surface of the SiC single crystal substrate after polishing was measured by using reflection X-ray topography and said density was 0.9×103 BSD/cm2.
SiC epitaxial wafers were then manufactured using this SiC single crystal substrate by treating the substrate and forming a SiC epitaxial layer under the same conditions as the aforementioned conditions.
Stacking fault surface density of the resulting the SiC epitaxial wafer was measured by photoluminescence (PL) imaging method and said density was 0.09 SF/cm2.
The present invention can be applied to a SiC epitaxial wafer and a manufacturing method thereof.
1. A method of manufacturing a SiC epitaxial wafer wherein a SiC epitaxial layer is provided on a SiC single crystal substrate having an off angle, comprising:
2. The method of manufacturing a SiC epitaxial wafer according to claim 1, wherein, when determining the ratio, the surface density of BPD on the growth surface and a surface density of stacking faults in the SiC epitaxial film caused by the BPD on the growth surface are measured by X-ray topography or photoluminescence.
3. The method of manufacturing a SiC epitaxial wafer according to claim 1, wherein the upper limit is 1.0×103 BPD/cm2 or less.
4. A method of manufacturing a SiC epitaxial wafer provided with a SiC epitaxial layer on a SiC single crystal substrate having an off angle, comprising:
a step of determining a ratio of basal plane dislocations (BPD) and threading screw dislocations (TSD), which cause carrot defects in a SiC epitaxial film of a prescribed thickness which is formed on a SiC single crystal substrate having an off angle, to all basal plane dislocations and all threading screw dislocations which are present on a growth surface of the SiC single crystal substrate,
5. A SiC epitaxial wafer provided with a SiC epitaxial layer on a SiC single crystal substrate having an off angle, wherein the surface density of stacking faults caused by BPD of the SiC single crystal substrate is 0.1 stacking faults/cm2 or less in the SiC epitaxial film.
Filed: Sep 4, 2012
Publication Date: Jun 26, 2014
Applicant: SHOWA DENKO K.K. (Minato-ku, Tokyo)
Inventors: Kenji Momose (Chichibu-shi), Michiya Odawara (Chichibu-shi), Daisuke Muto (Chichibu-shi), Yoshiaki Kageshima (Chichibu-shi)
Current U.S. Class: Diamond Or Silicon Carbide (257/77); With A Step Of Measuring, Testing, Or Sensing (117/85)
International Classification: H01L 21/02 (20060101); H01L 29/16 (20060101);

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