US Patent 9368594 Method of forming a fin-like BJT

A bipolar junction transistor (BJT) formed using a fin field-effect transistor (FinFET) complimentary metal-oxide-semiconductor (CMOS) process flow is provided. The BJT includes an emitter fin, a base fin, and a collector fin formed on a substrate. The base fin encloses the emitter fin and collector fin encloses the emitter fin. In some embodiments, the emitter fin, base fin, and collector fin have a square shape when viewed from above and are concentric with each other.