Patent ID: 9728603
Date: 2017-08-08
CPC Classifications: H01L

Claim:
1. A method of fabricating a device structure for a bipolar junction transistor, the method comprising: forming a base layer comprised of a first semiconductor material; forming an emitter layer comprised of a second semiconductor material on the base layer; and patterning the emitter layer to form a first emitter finger located on the base layer, wherein the first emitter finger has a length, a first end surface, a second end surface spaced along the length from the first end surface, a first side surface that extends from the first end surface to the second end surface, a second side surface that extends from the first end surface to the second end surface, and a width between the first side surface and the second side surface, the width linearly decreases with increasing distance from the first end surface such that the first emitter finger tapers at a first angle along a first portion of the length of the first emitter finger, and the width linearly decreases with increasing distance from the second end surface such that the first emitter finger tapers at a second angle along a second portion of the length of the first emitter finger.