High-Performance LPCVD-SiNx/InAlGaN/GaN MIS-HEMTs With 850-V 0.98- $\text{m}{\Omega} \cdot$ cm2 for Power Device Applications

We demonstrate the electrical performances of the quaternary InAlGaN/GaN MIS-HEMTs with high quality SiNx gate dielectric and surface passivation layer deposited by low pressure chemical vapor deposition (LPCVD) at 780 °C. Excellent LPCVD-SiNx/InAlGaN interface and SiNx film quality were obtained, resulting in very high output current density, a very small threshold voltage hysteresis and steep subthreshold slope. The LPCVD-SiNx/InAlGaN/GaN MIS-HEMT device exhibited high on/off current ratio, large gate voltage swing, high breakdown voltage, and very low dynamic on-resistance (RON) degradation, meaning effective current collapse suppression compared to the plasma enhanced chemical vapor deposition -SiNx/InAlGaN/GaN MIS-HEMTs. The corresponding specific on-resistance (RON,sp) for LPCVD-SiNx device was as low as 0.98 mΩ·cm², yielding a high figure of merit of 737 MW/cm². These results demonstrate a great potential of the LPCVD-SiNx/InAlGaN/GaN MIS-HEMTs for high-power switching applications.