From GaN-on-Si epitaxy to MHz-class power conversion: a unified advancement in GaN-based electronics

This work develops an integrated GaN power electronics platform that links advances in material growth, device engineering, and high-frequency power converter design. In the epitaxy stage, improved GaN-on-silicon structures with superlattice buffer layers and lattice-matched AlInGaN layers increase breakdown strength and improve thermal reliability. At the device level, optimizing p-GaN gate doping, adding an AlGaN cap layer, and using low-temperature annealing lead to more stable threshold voltage, lower gate leakage, and improved dynamic on-resistance. These device improvements enable compact, fast-switching MHz-class power converters with fully integrated all-GaN gate drivers using enhancement- and depletion-mode HEMTs. The converters demonstrate reduced gate ringing, clean switching behavior, and efficient circuit layouts. Experimental results show that resonant and buck converters achieve 96–97.1% peak efficiency and up to 1 kW output power. A 6.78-MHz wireless charging system for e-bikes further delivers 240 W output and 92.45% efficiency through optimized zero-voltage switching and magnetic design. Overall, this work demonstrates a vertically integrated GaN technology stack with strong potential for compact, reliable, and high-performance power systems in applications such as AI servers, electric vehicles, and wireless charging.