Certain aspects of the present disclosure generally relate to an integrated circuit (IC) having a heterojunction bipolar transistor (HBT) device. The HBT device generally includes an emitter region, a collector region, and a base region disposed between the emitter region and the collector region, the base region and the collector region comprising different semiconductor materials. The HBT device may also include an etch stop layer disposed between the collector region and the base region. The HBT device also includes an emitter contact, wherein the emitter region is between the emitter contact and the base region, and a collector contact, wherein the collector region is between the collector contact and the base region.