Fin-based lateral bipolar junction transistor with reduced base resistance and method

Abstract

A disclosed structure includes a fin-based bipolar junction transistor (BJT) with reduced base resistance. The BJT includes one or more semiconductor fins. Each semiconductor fin has opposing sidewalls, a first width, and a base recess, which extends across the first width through the opposing sidewalls. The BJT includes a base region positioned laterally between collector and emitter regions. The base region includes a base semiconductor layer (e.g., an intrinsic base layer), which fills the base recess and which has a second width greater than the first width such that the base semiconductor layer extends laterally beyond the opposing sidewalls. In a BJT with multiple semiconductor fins, the base recess on each semiconductor fin is filled with a discrete base semiconductor layer. The base region further includes an additional base semiconductor layer (e.g., an extrinsic base layer) covering the base semiconductor layer(s). Also disclosed is a method of forming the structure.