in an embodiment is shown the thin film transistor comprises a gate electrode 2 a gate dielectric layer 3 and a metal oxide semiconductor layer 4 the metal oxide semiconductor layer 4 is composed of a channel region 5 a source region 6 and a drain region 7 the gate electrode 2 is formed on a substrate 1 and the gate dielectric layer 3 is formed on the substrate 1 and gate electrode 2 and covers the gate electrode 2 the metal oxide semiconductor layer 4 is formed over the gate dielectric layer 3 the channel region 5 forms a central portion of the metal oxide semiconductor layer 4 and is arranged on the gate dielectric layer 3 covering the gate electrode 2 the source region 6 and drain region 7 form two end portions of the metal oxide semiconductor layer 4 the source region 6 and drain region 7 are arranged on the gate dielectric layer 3 and connected with the channel region 5 respectively in an example the gate electrode 2 may be formed from metal material such as chromium molybdenum titanium aluminium or the like and may be formed by for example magnetron sputtering or thermal evaporation in another example the gate electrode 2 may be formed into a transparent conductive film such as tin indium oxide ito or aluminum zinc oxide azo and may be formed by for example magnetron sputtering generally the gate electrode.