Implementation of RTCVD-SiNₓ Gate Dielectric Into Enhancement-Mode GaN MIS-HEMTs Fabricated on Ultrathin-Barrier AlGaN/GaN-on-Si Platform

Rapid-thermal-chemical-vapor-deposition (RT-CVD) SiN
_x
gate dielectric was utilized for the fabrication of enhancement-mode GaN-based metal-insulator-semiconductor high electron mobility transistors (MIS-HEMTs) on ultrathin-barrier AlGaN/GaN heterostructure. A plasma-enhanced-atomic-layer-deposited (PEALD) SiN
_x
interfacial layer was adopted to mitigate the high-temperature RTCVD process-induced degradation of the dielectric/III-nitride interface. Based on the dc- and pulsed transfer measurement results, the device with the PEALD-SiN
_x
interfacial layer exhibits low V
_TH
-hysteresis (0.1 V at V
_GS
= 1, 10 V) and low interface trap density. Constant-capacitance deep-level transient spectroscopy and high-resolution transmission electron microscopy were also conducted to confirm the improvement of the interface quality.