Mesa bipolar transistor with sub base layer
AssigneeSony Corporation
InventorTakayuki Gomi
Life of this patent
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Abstract
A mesa bipolar transistor comprising a collector layer formed on a surface of a substrate, a base layer disposed on the substrate so as to be joined to the collector layer, an emitter layer disposed on the base layer is further provided with a sub base layer comprising at least one of a polysilicon layer containing impurities, a metallic silicide, and a diffused layer formed on the surface of the substrate and being disposed under or on the external base region which is a region of the base layer lateral to that under the emitter layer so that the thickness of the external base region is increased to provide high conductivity.
Claims10
A mesa bipolar transistor, comprising:
- a collector layer formed on a surface of a substrate;
- a base layer disposed on said substrate so as to be joined to said collector layer;
- an emitter layer disposed on said base layer;
- and
- a sub base layer comprising at least one of a polysilicon layer containing impurities, a metallic silicide, and a diffused layer formed on a surface layer of said substrate;
- said base layer having an external base region as a region lateral to that under said emitter layer, and said sub base layer being disposed under said external base region.
A mesa bipolar transistor, comprising:
- a collector layer formed on a surface of a substrate;
- a base layer formed on said substrate and being joined to said collector layer;
- an emitter layer disposed on said base layer;
- and
- a sub base layer disposed on said base layer, said sub base layer comprising a metallic silicide,
- said base layer having an external base region lateral to that under said emitter layer, and said sub base layer being disposed under said external base region and being insulated from said emitter layer.
Dependencies are inferred from the claim text.