Modeling of 2DEG characteristics of InxAl1−xN/AlN/GaN-Based HEMT Considering Polarization and Quantum Mechanical Effect

Abstract

A comprehensive model for 2DEG characteristics of InxAl1−xN/AlN/GaN heterostructure has been presented, taking both polarization and bulk ionized charge into account. Investigations on the 2DEG density and electron distribution across the heterostructure have been carried out using solutions of coupled 1-D Schrödinger-Poisson equations solved by an improved iterative scheme. The proposed model extends a previous approach allowing for estimating the quantum mechanical effect for a generic InAlN/GaN-based HEMT within the range of the Hartree approximation. A critical AlN thickness (~2.28 nm) is predicted when considering the 2DEG density in dependence on a lattice matched In0.17Al0.83N thickness. The obtained results present in this work provide a guideline for the experimental observation of the subband structure of InAlN/GaN heterostructure and may be used as a design tool for the optimization of that epilayer structure.