100 nm Gate-Length N-Polar GaN/AlGaN Metal-Oxide-Semiconductor High Electron Mobility Transistor on a Si Substrate via Thin-Layer Transfer Technique.

This work demonstrates a high-performance N-polar GaN/AlGaN metal-oxide-semiconductor high-electron-mobility transistor (MOSHEMT) fabricated via a thin-layer transfer technique. By transferring Ga-polar AlGaN/GaN epitaxial layers grown on a Si (111) substrate to a Si (100) substrate using surface activated bonding and Si substate removing techniques, high quality N-polar heterostructures on Si were achieved, which bypasses the direct N-polar epitaxial growth challenges. The fabricated N-polar MOSHEMT with 10 nm HfO₂ gate dielectric and a 100 nm gate length exhibits a maximum drain current (Idmax) of 1.1 A/mm, an on-resistance (Ron) of 3.8 Ω·mm, a peak transconductance (gmmax) of 125 mS/mm, and a cutoff frequency/maximum oscillation frequency (fT/fmax) of 29/40 GHz. This approach enables N-polar GaN integration with cost-effective Si platforms, offering a scalable pathway for high-speed, high-power mm-wave applications.