Patent ID: 8710500

Claim:
A device structure for a bipolar junction transistor, the device structure comprising: an intrinsic base including a top surface; an extrinsic base on the top surface of the intrinsic base; a silicide layer on the extrinsic base; a plurality of first spacers having an outer surface, the first spacers oriented to project vertically relative to the top surface of the intrinsic base, the first spacers arranged to line an emitter window therebetween, and the emitter window extending through extrinsic base and the silicide layer to the top surface of the intrinsic base; and an emitter including a portion disposed in the emitter window and a head protruding out of the emitter window, the portion of the emitter in contact with the intrinsic base, and the portion of the emitter having a plurality of sidewalls that border the first spacers and that are separated from the extrinsic base and the silicide layer by the first spacers, wherein the silicide layer and the extrinsic base each terminate at the outer surface of the first spacers so that the silicide layer and the extrinsic base are aligned relative to each other and relative to the portion of the emitter by the first spacers.