Comparison of conventional and thermally-stable cascode (TSC) AlGaAs/GaAs HBTs for microwave power applications

Conventional and thermally-stable cascode HBT (TSC-HBT) were fabricated using a self-aligned emitter-base process on MOCVD-grown wafers. The pronounced self-heating eAect of conventional AlGaAs/GaAs HBT was reduced dramatically by the cascode design approach. The DC, small and large-signal characteristics of conventional common‐emitter (CE) and TSC-HBTs were compared and a direct assessment of the new HBT design is provided. # 1999 Elsevier Science Ltd. All rights reserved.