Engineering PECVD SiN Passivation Layers to Enable AlGaN/GaN HEMTs with Low Leakage, Low Current Collapse and High Breakdown Voltage

摘要

The properties of composite plasma enhanced chemical vapor deposition (PECVD) SiN passivation layers, deposited on the surface of AlGaN/GaN high electron mobility transistors (HEMTs) are engineered to achieve low leakage current, low current collapse, and high breakdown voltage devices. High frequency (13.56 MHz) plasma, mixed frequency with alternating high and low frequency (100-360 kHz) plasma were varied to reduce off-state leakage current, improve dynamic on-resistance, and extend the breakdown voltage. Annealing high frequency SiN at 750°C for 30 minutes improves the breakdown voltage and reduces off-state leakage. This ex-situ deposited and annealed high frequency SiN can also serve as a gate insulator to reduce gate leakage current. Reducing the thickness of the annealed HF SiN degrades the dynamic response, but improves the off-state breakdown voltage.