Emitter layer formation for bipolar junction transistor (bjt)

Abstract

The present disclosure generally relates to semiconductor processing for forming an emitter layer in a bipolar junction transistor (BJT). In an example, a BJT includes a collector, a base on the collector, and an emitter layer on the base. The emitter layer includes a first emitter sub-layer and a second emitter sub-layer over the first emitter sub-layer. The first emitter sub-layer includes boron and carbon. A concentration of carbon is uniform throughout the first emitter sub-layer. The second emitter sub-layer includes boron. A concentration of boron in the second emitter sub-layer is greater than a concentration of boron in the first emitter sub-layer.

Dependencies are inferred from the claim text.