Optimization of AlGaN/GaN HEMT SiN Passivation by Mixed Frequency PECVD

摘要

We demonstrate a high frequency (13.56 MHz)/low frequency (100-360 kHz) plasma enhanced CVD (PECVD) process, commonly employed for the passivation of AlGaN/GaN high electron mobility transistors (HEMTs), tuned to minimize surface degradation caused by low-frequency ion surface bombardment. Under optimized conditions, bilayer PECVD SiN maintained mobility, reduced on-resistance, improved drain-source current density, minimized dynamic on resistance degradation upon off-state drain voltage stress, and minimized additional tensile stress in the device.