Surface optical phonon scattering in N-polar GaN quantum well channels

TL;DR

This paper presents theoretical calculations of surface optical phonon scattering in N-polar GaN quantum wells, highlighting its impact on electron mobility, especially in ultra-thin channels with high-k dielectrics.

Contribution

It provides the first detailed analysis of SO phonon scattering effects on 2-DEG mobility in N-polar GaN channels with various dielectrics.

Findings

SO phonon scattering has minimal impact for channels thicker than 5 nm.

In 3 nm channels, SO scattering significantly reduces mobility.

High SO phonon energy dielectric (SiNx) results in negligible scattering.

Abstract

N-polar GaN channel mobility is important for high frequency device applications. In this Letter, we report the theoretical calculations on the surface optical (SO) phonon scattering rate of two-dimensional electron gas (2-DEG) in N-polar GaN quantum well channels with high-k dielectrics. The effect of SO phonons on 2-DEG mobility was found to be small at >5 nm channel thickness. However, the SO mobility in 3 nm N-polar GaN channels with high-k dielectrics is low and limits the total mobility. The SO scattering for SiNx dielectric GaN was found to be negligible due to its high SO phonon energy.