Patent ID: 7776678

Claim:
A method for forming a bipolar junction transistor and a metal oxide semiconductor field effect transistor in a semiconductor layer, comprising: forming MOSFET structures in a MOSFET region of a semiconductor layer; forming bipolar junction transistor structures, including an emitter material layer, in a bipolar junction transistor region of the semiconductor layer; forming a first material layer over the emitter material layer; forming a hardmask material layer of silicon dioxide over the emitter material layer and the first material layer; patterning the hardmask material layer with a lithographic mask to form a patterned hardmask, comprising forming a photoresist layer over the hard mask layer, patterning the photoresist layer and patterning the hard mask layer according to a pattern in the photoresist layer; using the patterned hardmask to pattern the emitter material layer and the first material layer during an etch process to form an emitter electrode of a bipolar transistor, comprising: removing the photoresist layer; etching the first material layer according to a pattern in the hard mask layer; etching the emitter material layer according to the pattern in the hard mask layer; and removing the hard mask layer; and heating the semiconductor layer subsequent to forming the emitter electrode.