Interfacial charge effects on electron transport in III-Nitride metal insulator semiconductor transistors

Abstract

We report on the calculation of the two dimension electron gas (2DEG) mobility in scaled AlGaN/GaN metal-insulator-semiconductor high-electron-mobility-transistors. We investigate the effect of remote impurity and phonon scattering models on the 2DEG mobility of the dielectric/AlGaN/GaN structure and investigate its variation with dielectric/AlGaN interface charge density, 2DEG concentration, and AlGaN thickness. Remote impurity scattering was found to be the dominant mechanism when the 2DEG density is below 5 × 1012 cm−2 and dielectric/AlGaN interface charge density is above 5 × 1012 cm−2. The interfacial charge has significant effect on the mobility as the AlGaN cap layer thickness is scaled down below 5 nm.