Comparative analysis of AlGaN/GaN high electron mobility transistor with sapphire and 4H-SiC substrate

Abstract

This paper aims to characterize two high electron mobility transistors analyzed with sapphire and 4H-SiC substrate. Comparison of the two structures are carried out in terms of threshold voltage (Vt), maximum drain current (ID), transconductance (gm), output conductance (gDS) and gate capacitances (CGS and CGD). Device with sapphire substrate is better in terms of threshold voltage, maximum drain current etc. whereas device with 4H-SiC exhibits better performance in terms of lower subthreshold slope, higher transconductance and lower gate capacitance. All the simulations are carried out using Silvaco ATLAS™. The proposed devices with sapphire and 4H-SiC substrate exhibit about 6.65 and 4.5 times higher drain current respectively as compared to the device reported in Wang et al. (Trans Electron Devices 61(2):498–504, 2014a). A significant decrease in subthreshold slope is achieved in the proposed devices as compared to the device reported in Wang et al. (Trans Electron Devices 61(2):498–504, 2014a). Device with sapphire achieves 1.2 times lower subthreshold slope as compared to the device in Wang et al. (Trans Electron Devices 61(2):498–504, 2014a), whereas device with 4H-SiC exhibits about 1.3 times lower subthreshold slope. About 12–13 times higher transconductance is obtained from the proposed devices as compared to the device in Wang et al. (Trans Electron Devices 61(2):498–504, 2014a).