A method of forming a semiconductor device is provided. The method includes forming a first fin above a substrate, forming a first emitter region in a first portion of the first fin, forming a first collector region in a second portion of the first fin, and forming a first base region in a third portion of the first fin. The third portion of the first fin is disposed underneath a first gate electrode. The method further includes forming a second fin adjacent to the first fin and above the substrate. The second fin is composed of a semiconductor material. The method also includes forming a first base contact over the second fin. The first base contact is coupled to the first base region through the second fin, the substrate, and the first fin.