Novel GaN-based double-channel p-heterostructure field-effect transistors with a p-GaN insertion layer

Abstract

GaN-based p-channel heterostructure field-effect transistors (p-HFETs) face significant constraints on the on-state currents compared to the n-channel high electron mobility transistors (n-HEMTs). In this work, we propose a novel double-heterostructure which introduces an additional p-GaN insertion layer into the traditional p-HFETs. The impact of the device structure on the hole densities and valence band energies of both the upper and lower channels is analyzed by using Silvaco TACD simulations, including the thickness of the upper AlGaN layer and the doping impurities and concentration in the GaN buffer layer, as well as the thickness and Mg doping concentration in the p-GaN insertion layer. With the help of the p-GaN insertion layer, the C-doping concentration in the GaN buffer layer can be reduced, while the density of two-dimensional hole gas (2DHG) in the lower channel is enhanced at the same time. This work suggests that the double heterostructure with a p-GaN insertion layer is a better approach to improve p-HFETs compared to those devices with C-doped buffer layer alone.