Recent Progress in GaN-on-Si HEMT
With the benefits of low-loss conduction, high-frequency switching, and high-temperature operation, wide bandgap GaN heterojunction power devices are attractive candidates for next-generation energy-efficient and compact power conversion systems including household appliances, photovoltaic inverters, data centers, motor drives, and so on. From commercialization point of view, growing group III-nitride epitaxial structure on Si substrate is a compelling and cost-competitive choice to implement GaN-based lateral power devices. For high-voltage power electronics applications, normally-off or enhancement-mode (E-mode) power transistors with positive threshold voltage is highly desirable, because of their inherent fail-safe characteristic and simpler gate drive circuitry. Interface engineering techniques have been developed to improve the interface quality and reduce interface traps in insulated-gate GaN transistors, including plasma nitridation, thermal nitridation, plasma oxidation, and annealing. Even at higher junction temperature, wide bandgap GaN power devices are capable of delivering high conversion efficiency and high switching speed.