초록 ▼

A self-aligned bipolar transistor which has a small base resistance and small emitter-base and collector-base capacitances and is operable at high speed is disclosed. This bipolar transistor is characterized in that a low concentration collector region made of single crystal Si--Ge is self-alignedly

A self-aligned bipolar transistor which has a small base resistance and small emitter-base and collector-base capacitances and is operable at high speed is disclosed. This bipolar transistor is characterized in that a low concentration collector region made of single crystal Si--Ge is self-alignedly formed between an intrinsic base of single crystal Si--Ge and an intrinsic base, and that an extrinsic base electrode and an intrinsic base are connected only through a doped external base. With this arrangement, an energy barrier is not established at the collector base interface owing to the formation of the low concentration region of single crystal Si--Ge, so that the transit time of the carriers charged from the emitter is shortened. The connection between the intrinsic base and the extrinsic base electrode via the doped external base results in the reduction of the base resistance. In addition, the self-aligned formation of the emitter-base-collector leads to the reduction in capacitance between the emitter and the base and also between the collector and the base. Accordingly, a high-speed bipolar transistor can be realized and thus, circuits using the transistor are operable at high speed.

대표청구항 ▼

[ What is claimed is:] [1.] A bipolar transistor comprising, at least:a multilayered film which includes a single crystal silicon layer of a first conductivity type, a first insulating layer formed on the surface of said single crystal silicon layer of the first conductivity type and having an openi

[ What is claimed is:] [1.] A bipolar transistor comprising, at least:a multilayered film which includes a single crystal silicon layer of a first conductivity type, a first insulating layer formed on the surface of said single crystal silicon layer of the first conductivity type and having an opening therein, a polycrystalline layer of a second conductivity type opposite to the first conductivity type, and a second insulating layer;a single crystal silicon germanium layer of the first conductivity type formed in the opening;a single crystal silicon germanium layer of the second conductivity type formed on said single crystal silicon germanium layer of the first conductivity type;a polysilicon germanium layer formed in contact with both said single crystal silicon germanium layer of the second conductivity type and said polycrystalline layer of the second conductivity type; anda second single crystal layer of the second conductivity type which is formed on said single crystal silicon germanium layer of the second conductivity type and is lower in impurity concentration than said single crystal silicon germanium layer of the second conductivity type.