SOI lateral bipolar junction transistor having a wide band gap emitter contact

A method of forming a semiconductor structure including a bipolar junction transistor (BJT), said method comprising:

• providing a substrate including a semiconductor portion comprising a first semiconductor material having a first band gap and having a doping of a first conductivity type;
• converting a region of said semiconductor portion into an emitter region by introducing dopants of a second conductivity type that is the opposite of said first conductivity type into said region of said semiconductor portion, wherein a remaining region of said semiconductor portion constitutes a base region that laterally contacts said emitter region;
• and
• depositing an emitter contact region comprising a portion of a second semiconductor material having a second band gap that is greater than said first band gap and having a doping of said second conductivity type directly on said emitter region, wherein said first semiconductor material is single crystalline germanium or a single crystalline silicon-germanium alloy, and said second semiconductor material is single crystalline silicon.

A method of forming a semiconductor structure including a bipolar junction transistor (BJT), said method comprising:

• providing a substrate including a semiconductor portion comprising a first semiconductor material having a first band gap and having a doping of a first conductivity type;
• converting a region of said semiconductor portion into an emitter region by introducing dopants of a second conductivity type that is the opposite of said first conductivity type into said region of said semiconductor portion, wherein a remaining region of said semiconductor portion constitutes a base region that laterally contacts said emitter region;
• depositing an emitter contact region comprising a portion of a second semiconductor material having a second band gap that is greater than said first band gap and having a doping of said second conductivity type directly on said emitter region;
• and
• forming an extrinsic base region on a portion of a top surface of said semiconductor portion by:
• depositing an extrinsic base layer comprising an extrinsic base semiconductor material having a doping of said first conductivity type on said semiconductor portion;
• and
• patterning said extrinsic base layer by an etch, wherein a remaining portion of said extrinsic base layer constitutes said extrinsic base region.