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

摘要

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 metaloxidesemiconductor high-electron-mobility transistors (MOSHEMTs). High-density sputtered-SiO _2 is utilized to reduce the gate leakage current and enhance the breakdown voltage while low-density PECVD-SiO _2 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 4.21×10 ~(-9)Amm ~(-1) and high breakdown voltage of 634V for a gatedrain distance of 6μm, demonstrating the promise of bimodal-SiO _2 deposition scheme for the development of GaN-based MOSHEMTs for high-power application.