| 摘要 |
PURPOSE:To make large the current capacity of a thyristor, and to improve gate reverse dielectric strength, by forming a buried region, which is of the same conduction type decreasing the horizontal resistance of a base layer and extremely high in impurity density, inside the base layer of the gate turn-off thyristor of four layers and three junctions according to a concentric pattern, etc. CONSTITUTION:On P type semiconductor substrate 1, N type layer 2 and P type layer 3 are formed and N type region 13 is also formed inside layer 3 to constitute the four layers and three junctions; and then, electrode 7 is fitted to the reverse surface of substrate 1, and electrode 15 to region 13, thereby obtaining the gate turn-off thyristor. In this constitution, low-resistance P<++> type region 11 is distributively formed in the middle part of P type layer 3 according to the fixed pattern, and gate electrode 12 is provided there. This region 11 is for the purpose of decreasing the horizontal resistance of base region, and its pattern is made into a concentrical shape, involute shape, lattice shape, radial shape, or parallel shape, thereby attaining uniform distribution. |
