Vertical gallium nitride MOSFETs: Advanced architectures, fabrication technologies, and performance breakthroughs for high-power applications

The rapid advancement of power electronics demands revolutionary semiconductor technologies that transcend the fundamental limitations of silicon-based devices. Vertical gallium nitride (GaN) metal-oxide-semiconductor field-effect transistors (MOSFETs) have emerged as transformative solutions, leveraging the exceptional material properties of GaN through innovative three-dimensional device architectures that enable unprecedented performance scaling. This comprehensive review examines the current state and future prospects of vertical GaN MOSFET technology, encompassing fundamental device physics, advanced architectural innovations, fabrication methodologies, and commercial implementation pathways. The unique advantages of vertical current conduction in GaN devices address critical limitations of conventional lateral architectures, including non-uniform electric field distributions, surface sensitivity, and voltage-current trade-off constraints. Recent technological breakthroughs have demonstrated remarkable achievements: breakdown voltages exceeding 1400 V, specific on-resistance values below 1.4 mΩ·cm², current densities surpassing 200 A/cm², and channel mobilities approaching 250 cm²/V·s. These performance metrics establish vertical GaN MOSFETs as competitive alternatives to silicon carbide devices while offering superior switching characteristics and system integration capabilities. This review systematically analyzes diverse device architectures, from conventional trench-gate structures to advanced three-dimensional concepts including FinFET-inspired designs, nanowire arrays, and dual-channel configurations. Manufacturing approaches spanning epitaxial regrowth techniques, all-ion implantation processes, and hybrid fabrication methodologies are evaluated for their impact on device performance and commercial viability. Critical challenges including substrate technology limitations, process integration complexity, reliability concerns, and cost optimization are comprehensively examined alongside emerging solutions and breakthrough innovations.