| 摘要 |
PURPOSE:To prevent the element breakdown due to current concentration generating on a partial region of an anode base layer of the titled semiconductor device when a turn-ON position is given thereon by a method wherein, when an anode base layer is going to be provided, said anode base layer is formed in such a manner that the ON- voltage drop at a part of the region aligned on a signal application region is increased. CONSTITUTION:A thyristor has the first - fourth semiconductor layer 3-5 and 9 within its substrate. A main electrode 6 is provided on the main surface of the layer 3, a recessed part 3a is formed on the other surface of said layer 3 at the position aligned to a signal region, and a ringlike protruded part 3b is formed on the circumference of the recessed part 3a. Also, on one surface of a layer 4, a protruded part 4a is formed against the recessed part 3a, and a ringlike recessed part 4b is formed against the protruded part 3b. As a result, the values of ON voltage drop of the above two parts 4a and 4b when a turn-ON operation is performed or the main current is applied vary with each other are varied with each other. Accordingly, when a dv/dt turn-ON and the turn- ON by forward overvoltage are generated, a conductive condition is generated in ring shape along the B point as shown in the diagram, thereby enabling to eliminate the possibility of generation of the element breakdown due to current concentration. |
