High voltage low current collapse AlGaN/GaN MISHEMTs with in-situ SiN gate dielectric

This paper reports on high performance AlGaN/GaN MISHEMTs with an in-situ SiN gate dielectric. Resulting from the high-quality gate dielectric and dielectric/barrier interface, the MISHEMTs with a gate-drain distance of 15 µm exhibit a high maximum drain current density of 1050 mA/mm, a steep subthreshold slope of 72 mV/dec, and a low gate-drain leakage of 0.6 µA/mm at VGD of −900 V. The high breakdown voltage of 1200 V at ID of 10 µA/mm, and low specific DC on-resistance of 1.7 mΩ·cm², yield a high power figure of merit (FOM = VBR²/Ron,sp) of 847 MW/cm2 for the fabricated devices. Moreover, a small dynamic/DC on-resistance ratio of 1.03 is achieved in the MISHEMTs using the in-situ SiN/PECVD SiN bilayer passivation scheme.