E. Brusaterra, E. Bahat Treidel, P. Paul, I. Ostermay, F. Brunner, and O. Hilt

Published in:

International Conference on Compound Semiconductor Manufacturing Technology (CS ManTech 2025), New Orleans, USA, May 19-22, paper 2A.2 (2025).

Abstract:

In this study, vertical GaN trench MOSFETs were fabricated utilizing a novel gate dielectric composed of hafnium oxide (HfO₂) layered with aluminum oxide (Al₂O₃) to enhance device performance compared to those employing Al₂O₃ alone. The transistors incorporating the HfO₂ / Al₂O₃ layered gate dielectric exhibited up to three times increase in forward current, five times enhancement in gate breakdown voltage and significantly reduced threshold voltage shift induced by gate forward voltage stress, relative to devices with an Al₂O₃-only gate dielectric. Furthermore, the improved gate structure resulted in higher channel mobility (∼11.1 cm²/Vs) and a reduced ON-state resistance (3.1 ± 0.6 mΩ·cm²).

Keywords:

Gallium Nitride, GaN, Vertical, Trench MOSFET, Dielectric, HfO₂, Al₂O₃

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