Abstract: A PNPN layer type gate turn-off thyristor including a first gate and a second gate comprises, in particular, a second P-type layer such that the impurity atom concentration at the auxiliary thyristor portion is lower than that at the main thyristor portion. Since the first gate disposed at the auxiliary thyristor portion is first fired and then the main thyristor portion is turned on, the above-mentioned impurity atom concentration profile is effective for reducing both the turn-on time and the turn-off time, that is, improving the di/dt capability of the thyristor.

Abstract: A gate controlled semiconductor device is provided having a main electrode member consisting of a cathode electrode assembly formed in one end layer of a wafer of semiconductive material and an anode electrode assembly formed in other end layer of said wafer, a main thyristor portion, an auxiliary thyristor portion and a bias controlling member. Said main thyristor portion is constructed by at least one control electrode assembly which is provided in the vicinity of the cathode electrode assembly of the main electrode member. Said auxiliary thyristor portion includes an additional layer which is provided on the one layer of the wafer and being adjacent to the cathode electrode assembly and the auxiliary thyristor portion is forcedly switched on and off by said bias controlling member.

Abstract: A gate controlled semiconductor device comprises two main electrode members provided on a wafer having at least one junction formed between two alternately different conductivity typed semiconductive layers and a control electrode member in which the same or a different conductivity typed surface is provided on one layer of the wafer. The control electrode member is provided on the wafer adjacent one of the main electrodes. The control electrode member includes a low resistance layer embedded in one surface of the wafer and consists of a wide bridging portion, a plurality of relatively wide main trunk portions projecting from the bridging portion and a plurality of narrow branch portions branching from the main trunk portions.

Abstract: The invention discloses a gate controlled semiconductor device in which a gate electrode is substantially divided into many pieces. And the semiconductor device comprises a semiconductive element having at least one P-N junction formed by at least a pair of P-type diffusion regions and N-type diffusion regions, a cathode assembly including a metallic layer deposited on a cathode-emitter layer formed on a surface of said semiconductive element, an anode electrode assembly and gate electrode assemblies which includes a plural separated metallic layers provided around the cathode electrode assemblies of the cathode-emitter layer.

Abstract: A gate controlled semiconductor device in which a gate electrode is substantially divided into many pieces. The semiconductor device comprises a semiconductive element having at least one P-N junction formed by at least a pair of P-type diffusion regions and N-type diffusion regions, a plurality of cathode assemblies including a metallic layer deposited on a cathode-emitter layer formed on a surface of said semiconductive element, an anode electrode assembly and gate electrode assemblies. The latter includes a plurality of separated metallic layers provided around the cathode electrode assemblies of the cathode-emitter layer. The cathode electrode assemblies are of a radial and spiral shape and the divided gate electrode assemblies have also a ring shape and/or circular shape.