Electron mobility in InxGa1-xN channel HEMTs

TL;DR

This paper provides a theoretical analysis of electron mobility in InxGa1-xN channel HEMTs, highlighting alloy scattering as a key mobility limit and offering insights for optimizing device design in next-generation electronics.

Contribution

It is the first to analyze the mobility limitations in InxGa1-xN HEMTs and guides device layout optimization for high-performance applications.

Findings

Mobility limited by alloy scattering rather than phonon scattering.

At 30% indium, mobility is approximately 500 cm²/Vs.

Sheet resistance at 30% indium is about 700 ohms per square.

Abstract

In this letter, we report on the theoretical investigations of electron mobility in practically viable designs of InxGa1-xN channel high electron mobility transistors (HEMT). Carriers in such devices are expected to exhibit a higher velocity and hence higher cut-off frequencies (fT) for highly scaled architectures. We estimate that the mobility of two dimensional electron gas (2DEG) is limited by alloy scattering rather than phonon scattering unlike in conventional GaN-channel HEMTs. For indium composition of 0.30, the mobility and sheet resistance are found to be 500 cm2/Vs and 700 ohm per sq. respectively, which can severely affect the parasitic voltage drop in access regions. The results presented here are believed to significantly guide the practical exploration of InxGa1-xN channel HEMTs towards next-generation electronics by enabling careful design of device layouts in highly scaled transistors to minimize parasitic access region voltage drop which results due to significant degradation of 2DEG mobility.