Gallium nitride (GaN) high electron mobility transistors (HEMTs) are the core components for high-frequency, high-efficiency power conversion systems due to their high critical breakdown electric field,high-density two-dimensional electron gas (2DEG), and exceptional electron mobility. Current research on GaN power transistors is driven by the demands for higher breakdown voltages, improved reliability, minimized dynamic on-resistance (R_ON), and advanced integration.
This paper systematically reviews the challenges and recent progress of GaN power transistors across these domains. First, we introduce gate engineering, encompassing technologies for realizing normally-off operation and techniques for enhancing gate breakdown voltage. Next, we analyze technologies for improving breakdown voltage, discussing in detail field plates, trench terminations, fluorine ion implantation, lateral superjunctions, and polarization superjunctions. Furthermore, the degradation mechanisms of dynamic R_ON and their corresponding optimization strategies are discussed. Finally, we review the latest developmental trends in power integration technologies, covering bidirectional switches, half-bridge integration, monolithic drive-and-control integration, and GaN CMOS integration.
By tracing the trajectory of technological evolution, this review aims to elucidate the core structural, process, and integration challenges and research progress facing high-voltage, low-loss GaN power devices. Furthermore, it comparatively analyzes the advantages and limitations of different technical routes, elaborates on the trade-off relationships among various performance parameters in the design of GaN power devices, and ultimately provides perspectives on future development directions for realizing higher-voltage and higher-reliability GaN power transistors and their ICs: it is a road along the co-innovation of materials, devices, circuits, and systems.