48 GHz AlInAs/GaInAs heterojunction bipolar transistors

The authors report on the DC and RF performance of self-aligned Al/sub 0.48/In/sub 0.52/As-Ga/sub 0.47/In/sub 0.53/As heterojunction bipolar transistors (HBTs). The properties that make the AlInAs/GaInAs material system extremely attractive for HBTs are discussed The epitaxial layer structure was grown by molecular beam epitaxy on semi-insulating InP. The device structure is shown in cross section. A large variety of HBT devices with different emitter sizes and with different numbers of emitter fingers have been fabricated. The common emitter characteristics of a single 5- mu m*5 mu m emitter are reported.<>