Hitachi, Ltd.

Isamu Sanpei

Tsutomu Yatsuo

Yukimasa Satou

Takahiro Nagano

Susumu Murakami

Saburo Oikawa

Shuroku Sakurada

Hideo Honma

Kenji Yagishita

Masaru Nakagawa

In a turn off type semiconductor device, an n-type emitter layer is divided into a plurality of elements by trenches. A silicide layer of a high melting point metal is provided on a p-type layer adjacent to the individual elements of the n-type emitter layer on a bottom of each of the trenches. A gate electrode is provided on the associated silicide layer so as to surround the plurality of elements of the n-type emitter layer obtained by the division of the emitter layer. An insulator is filled in each of the trenches dividing the n-type emitter layer surrounded by the gate electrode. A cathode electrode is provided on both the insulators and the n-type emitter layer.

Turn off type semiconductor device, method of producing the same and the

The present invention relates to a buried gate type gate turn-off thyristor. A low-resistance layer which is buried in a cathode base layer has a multiplicity of small bores below a cathode emitter layer. The distance between each pair of adjacent small bores and the thickness of the low-resistance layer are each set so as to be smaller than the carrier diffusion length in an anode base layer. In an on-state, carries flow through the low-resistance layer, thereby allowing the low-resistance layer to become conductive, and thus lowering the on-state voltage. A reduction in the dimension of the small bores lowers the resistance of the low-resistance layer and hence lowers the gate drawing out resistance, so that the interrupting capacity is improved. When gate turn-off thyristor is arranged so as to have an amplifying gate structure, the distance between each pair of adjacent small bores in the amplifying auxiliary thyristor section is set so as to be greater than the carrier diffusion length in the anode base layer. In consequence, the on-state voltage in the auxiliary thyristor section is increased, so that the current selectively flows through the main thyristor section, and the auxiliary thyristor section automatically turns off. Accordingly, when the thyristor is to be turned off, it suffices to turn off the main thyristor section alone.

Gate turn-off thyristor

A gate turn-off thyristor of a short-circuited emitter configuration comprises a semiconductor substrate of a P.sub.E -N.sub.B -P.sub.B -N.sub.E four-layer structure, wherein a P.sub.E -layer is short-circuited through a N.sub.B -layer and an anode. The N.sub.B -layer includes heavily doped regions to which the anode is ohmic contacted with a low resistance. The P.sub.E -layer is provided at a location at least covered by a projection of the N.sub.E -layer. The thickness of the heavily doped regions is greater than that of the P.sub.E -layer. The improved structure assures satisfactory gate turn-off characteristics, although the semiconductor substrate is not doped with a life time killer impurity.

Gate turn-off thyristor with selective anode penetrating shorts

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Kitaibaraki, Japan

Isamu Sanpei