for trenches in the first and second surfaces may be variable for the purposes of this disclosure the term u201c p type u201d refers to any degree of p doping which include the range from p to p u2212 doping concentrations the same applies to the term u201c n type u201d however the range will include concentrations from n u2212 to n it is noted that embodiments of the present invention may have one or more trenches 18 a 18 b on the first or second surfaces 14 16 in embodiments where there are more than one trench on either surface 14 16 the trenches are electrically connected through an at least partially electrically conductive material which in the case of p type trenches may be p type and in the case of n type trenches may be n type other at least partially electrically conductive materials may also be used a junction is formed by the first doped region 22 and second doped region 24 as can be seen in fig1 these regions may be separated by a central portion 20 of the substrate 12 the central portion 20 may be intrinsic or may be doped p u2212 or n u2212 the first and second doped regions 22 24 can be fabricated using a variety of doping methods in cases where the trenches are particularly narrow and deep conventional doping techniques may not penetrate into the trenches in this case doping can be carried out as follows for.