Patent ID: 8716096

Claim:
A method of fabricating a bipolar transistor, the method comprising: providing a substrate; providing a stack of films disposed above the substrate, the stack of films including an intrinsic base over the substrate, a first oxide layer over the intrinsic base, an extrinsic base over the first oxide layer, a second oxide layer over the extrinsic base, a nitride layer over the second oxide layer, and a third oxide layer over the nitride layer; forming a first opening in the third oxide layer, the nitride layer, and the second oxide layer, exposing a surface of the extrinsic base; forming a spacer on a sidewall of the first opening; forming a self-aligned oxide mask on the exposed surface of the extrinsic base; removing the spacer; using the self-aligned oxide mask, etching the exposed extrinsic base and the first oxide layer to expose the intrinsic base layer, forming a first slot and a second slot; and selectively growing a silicon layer stripe on at least one of the exposed intrinsic base layer and extrinsic base layer in each of the first slot and the second slot, wherein the silicon layer stripe in each of the first and second slots substantially fills the first and second slots.