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

Abstract

Rapid-thermal-chemical-vapor-deposition (RT-CVD) SiN_{<italic>x</italic>} 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_{<italic>x</italic>} 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_{<italic>x</italic>} interfacial layer exhibits low <inline-formula> <tex-math notation= LaTeX >${V}_{\\text {TH}}$ </tex-math></inline-formula>-hysteresis (0.1 V at <inline-formula> <tex-math notation= LaTeX >${V}_{\\text {GS}} = 1, 10$ </tex-math></inline-formula> 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.