High-Quality ICPCVD SiO₂ for Normally Off AlGaN/GaN-on-Si Recessed MOSHFETs

We have developed a high-qualitySiO₂deposition process using an inductively coupled plasma chemical vapor deposition system for use as a gate oxide of AlGaN/GaN-on-Si metal–oxide–semiconductor heterostructure field-effect transistor (MOSHFET) for power switching applications. A breakdown field of~12 MV/cm was achieved using the optimized deposition conditions that were successfully applied in fabrication of the normally off AlGaN/GaN-on-Si MOSHFETs. The fabricated device exhibited excellent characteristics: a maximum drain current density of 375 mA/mm, a threshold voltage of 3 V, and a breakdown voltage of 820 V.