Indium phosphide-based heterojunction bipolar transistors for high-speed and RF power applications: Advanced emitter-base designs

The purpose of this research is to explore advanced Epitaxial layer and process designs for InP-based heterojunction bipolar transistors (HBTs), including lattice matched GaInAs/AlInAs, GaAsSb/AlInAs, and pseudomorphic GaInAs/Al_0.7In_0.3As material systems for high speed and RF wireless applications. In this research, the HBT material design, growth conditions, device fabrication, simulation, and measurement are carried out. Herein, we develop growth conditions for various InP-based HBTs, including heterojunction diodes, AlInAs/GaInAs single heterojunction bipolar transistors (SHBTs), and AlInAs/GaAsSb HBTs for high-frequency power applications. We use solid source molecular beam Epitaxy (SSMBE) to grow advanced structures as follows. In order to increase the valence band discontinuity at the GaInAs/AlInAs emitter-base junction, an investigation of lattice mismatched Al_xIn _1−xAs growth is performed to produce an Al-rich composite emitter. In order to characterize the pseudomorphic structure, several heterojunction p-n diodes are investigated with lattice mismatched Al_xIn _1−xAs. Then an investigation of the strained Al_xIn _1−xAs/GaInAs SHBT is performed. Finally, GaAsSb/GaInAs HBT research is addressed.