Monte Carlo simulation of hot-phonon and degeneracy effects in the AlGaN/GaN two-dimensional electron gas channel

Abstract

Ensemble Monte Carlo simulation of two-dimensional electron transport is carried out for an AlGaN/GaN heterostructure channel subjected to an electric field applied in the plane of electron confinement. The envelope wavefunctions for the confined electrons are calculated using a self-consistent Poisson-Schrödinger solver. The effects of electron-gas degeneracy and hot phonons on electron energy relaxation and drift velocity are investigated. The best fit between Monte Carlo simulation and experimental results is received with optical-phonon relaxation time τ ph = 1 ps. The results of simulation show that the degeneracy reduces the electron drift velocity while the hot phonons reduce the electron drift velocity and increase the electron energy relaxation time. Electron energy relaxation time approaches 0.3 ps at 10 kV cm −1 at room temperature.

Hot‐electron microwave noise and power dissipation in AlGaN/AlN/GaN channels for HEMTs

“…The extracted velocity value is lower than expected from either Monte Carlo simulation for AlGaN/GaN channels [8] or experiments on GaN p-i-n diodes [9]. Channel self-heating [10], hot-electron penetration into AlGaN layer [11], and accumulation of nonequilibrium (hot) phonons [12][13][14][15], are known to reduce the drift velocity in AlGaN/GaN channels. Hot-electron penetration is avoided in AlGaN/AlN/GaN when a thin AlN layer is inserted between AlGaN and GaN [16].…”

A deterministic study of hot phonon effects in a 2D electron gas channel formed at an AlGaN/GaN heterointerface

“…Following [12], in our numerical calculations we assume the polarization charge to be smeared out in a 1 nm symmetric region around the heterointerface. The 3D charge density of the confined electrons is evaluated via…”

Electron Transport and Microwave Noise in MBE- and MOCVD-Grown AlGaN/AlN/GaN

“…An essentially better performance at mm-waves is expected from the electron drift velocity measured [4] for a low-electron-density GaN pin diodes and calculated [5] for a two-dimensional AlGaN/GaN channel * corresponding author; e-mail: matulionis@pfi.lt (361) with hot phonons ignored. However, hot phonons are known to reduce the electron drift velocity [6]. The calculated drift velocity is higher if hot-phonon lifetime is shorter [7] and the electron three-dimensional density is lower [8].…”