| 摘要 |
PROBLEM TO BE SOLVED: To modify the switching performance of a static induction thyristor. SOLUTION: P-type base layer 8 are respectively formed in the central parts of cathode slits 3 of a normally on type SITh to form partially SIThs, which are constituted in the slits 3, into normally off type SIThs. The reason for the slits 3 failure in a turn-off and thermal destruction is that concentration of a main current on the specified places occurs on the slits in the latter half of the turn-off period. In the slits 3, current concentration is generated in the central parts of the longitudinal directions of the slits 3. When the layers 8 are formed in the central parts of the slits 3, vicinities of these layers 8 are formed into normally off type SIThs. As a result, the turn-off time of the central parts of the slits 3 is shortened and the central parts are turned off earlier than those parts other than the central parts. Thereby, generation of current concentration is suppressed in the vicinities of the central parts of the slits 3 in the latter half of the turn-off time, current concentration is relaxed, and the maximum controllable current is improved.
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