| 摘要 |
PURPOSE: A method for fabricating a heterojunction bipolar transistor is provided to realize an improvement in electrical characteristics, simplified processes, and increased reliability. CONSTITUTION: After a semi-insulated InGaP buffer layer is grown on a semi-insulated GaAs substrate(1), an n+ GaAs sub-collector layer, an n- GaAs collector layer, a p+ GaAs base layer, an N InGaP emitter layer, and an n+ GaAs emitter cap layer are formed thereon in sequence. Then, by using an emitter metal deposited on the emitter cap layer as a mask, the emitter cap layer and the emitter layer are selectively etched. Thereafter, a base metal is formed by lift-off to be self-aligned with the emitter metal. While emitter/base regions are covered with a resist layer, the base layer and the collector layer are etched to expose the sub-collector layer. Next, a collector metal is formed by lift-off and covered with a resist layer, and then the sub-collector layer is etched to electrically isolate individual devices. A pad metal(12) is then deposited on the exposed buffer layer and connected to the device with an air-bridge metal. Thereafter, a via hole(14) is formed in the substrate(1), and a ground pad is formed.
|
