Design and fabrication of heterojunction bipolar transistors (HBT)

Abstract

This thesis presents the development of an AlGaAs/GaAs-based heterojunction bipolar transistor technology for microwave and power applications. The HBTs were fabricated on MOCVD grown epitaxial layers which consist of an InyGai.yAs emitter contact layer, a GaAs emitter cap layer, an aluminum composition graded AlGaAs emitter layer, a GaAs uniform base layer, a GaAs collector and a sub-collector layer. The base ohmic contact pattern is defined by both self-aligned and re-aligned approach for comparison purpose.