InP/InGaAs HBTs using crystallographically defined emitter contact technology

New self-alignment techniques employing crystallographically defined emitter contact (CDC) technologies have been developed to fabricate InP/InGaAs heterojunction bipolar transistors (HBTs). The CDC technologies utilize the anisotropic wet etching characteristics of the InP and InGaAs dummy emitter layers, grown on the typical HBT layer structure. The shape of the emitter contact is determined by the crystallographically etched profiles of the InP and InGaAs dummy emitter layers. The fabricated HBTs demonstrated excellent device performance characteristics, indicating the effectiveness of the new self-alignment technology.