Abstract: A semiconductor device having a semiconductor body including an anode layer, a first and second base layer, a cathode layer formed on the second base layer and an auxiliary region formed on the second base layer apart from the cathode layer. The semiconductor body has a peripheral zone, a gate peripheral zone, a corridor and an enlarged corridor, the corridor and the enlarged corridor being between a cathode electrode and an auxiliary electrode in contact with the auxiliary region. The width of the gate peripheral zone is larger than that of the peripheral zone and the width of the enlarged corridor is larger than that of the corridor.

Abstract: With a semiconductor device embodying this invention, a semiconductor element is clamped between a pair of electrodes in a housing. A hollow cylindrical explosion-proof member is so set in the housing as to enclose the semiconductor element. The hollow cylindrical explosion-proof element is prepared from soft elastic material capable of absorbing the force of the explosion of the semiconductor element.