Very High Output Power GaAs-Based HBTs with a Heterogeneously Integrated AlGaN Ultra-Wide Bandgap Collector
Frederick Anthony Kish
Project runs from 06/25/2021 to 12/24/2022
By integrating wide and ultra-wide bandgap collector regions with AlGaAs/GaAs HBTs, we intend to provide a 10x improvement in power density over current state-of-the-art power HBTs. AlGaAs/GaAs HBTs are well-established with proven high-gain performance throughout the mm-wave regime. This is in large part due to the high quality of the AlGaAs/GaAs emitter-base junction and well-controlled p-type doping in the GaAs base, which yield large emitter injection efficiency and low base resistance, respectively. The breakdown voltage, which determines the output power, is limited by the collector region’s critical electric field. We propose to replace the traditional (Al)GaAs collector with an ultra-wide bandgap Al(Ga)N collector in order to significantly boost the power handling of these devices. The proposed heterostructures will be realized via state-of-the-art direct wafer bonding, and will be thoroughly characterized to establish their promise for future high-power, high-frequency devices.