Semiconductor switching device.

摘要

A gate turn-off thyristor in which a cathode-emitter layer (2) is divided into a plurality of striplike regions which are radially arrayed on a major surface of a semiconductor substrate in a coaxial multi-ring pattern including a plurality of coaxially arrayed rings (R1, ..., Rs). The cathode-emitter strips (2) belonging to a given one of the rings have a same radial length. The cathode-emitter strips belonging to the inner ring of a coaxial multi-ring pattern have a smaller radial length than that of the cathode-emitter strips (2) constituting the outer ring. A cathode electrode (8) is contacted to the cathode-emitter strip (2) in low resistance ohmic contact. A gate electrode (9) is ohmic contacted with a low resistance to a cathode-base layer (3) located adjacent to the cathode-emitter strip (2) so as to enclose it. An anode electrode (7) is ohmic contacted with a low resistance to the anode-emitter layer (5). With the structure of GTO, turn-off operation of unit GTO's each including a cathode-emitter strip is equalized.