Hitachi, Ltd.

Michihiro Misawa

Yoichi Nakashima

Katsumi Akabane

Sousi Suzuki

Yosikazu Takita

A semiconductor substrate comprises at the central portion a diode region which includes a P-type base layer, an N-type low impurity concentration layer and an N-type base layer and at the outer peripheral portion a thyristor region which includes an N-type emitter layer, a P-type base layer, an N-type low impurity concentration layer, an N-type base layer and a P-type emitter layer. The P-type base layer and the N-type emitter layer are in contact with a cathode electrode, the N-type base layer and the P-type emitter layer are in contact with an anode electrode, and the diode and thyristor regions are connected in anti-parallel. Contiguous to the outer periphery of the N-type base layer interposed between the N-type low impurity concentration layer and the P-type emitter layer is formed an N-type high impurity concentration region higher in impurity concentration than the N-type base layer. The N-type high impurity concentration region limits spreading of a depletion layer which is created when a forward voltage is applied to the thyristor region.

Growing community of inventors

Hitachi, Japan

Michihiro Misawa