Bimodal gate-dielectric deposition for improved performance of AlGaN/GaN metal-oxide-semiconductor high-electron-mobility transistors

A bimodal deposition scheme combining radiofrequency magnetron sputtering and plasma enhanced chemical vapour deposition (PECVD) is proposed as a means for improving the performance of GaN-based metal-oxide-semiconductor high-electron-mobility transistors (MOSHEMTs). High-density sputtered-SiO2 is utilized to reduce the gate leakage current and enhance the breakdown voltage while low-density PECVD-SiO2 is employed to buffer the sputtering damage and further increase the drain current by engineering the stress-induced-polarization. Thus-fabricated MOSHEMT exhibited a low leakage current of 4.21 x 10(-9) A mm(-1) and high breakdown voltage of 634V for a gate-drain distance of 6 mu m, demonstrating the promise of bimodal-SiO2 deposition scheme for the development of GaN-based MOSHEMTs for high-power application.