Design of Ga2O3 Modulation Doped Field Effect Transistors

TL;DR

This paper presents a comprehensive model and design considerations for beta-Ga2O3-based MODFETs, emphasizing self-heating effects, thermal management, and secondary channel formation, to improve device performance.

Contribution

It introduces a temperature- and doping-dependent electron mobility model and proposes a simple thermal management solution for beta-Ga2O3 MODFETs.

Findings

Self-heating reduces drain current via mobility decrease.

Thermal management through source contact improves heat dissipation.

Secondary channel formation affects transconductance characteristics.

Abstract

The design of beta-Ga2O3-based modulation doped field effect transistors (MODFETs) is discussed with a focus on the role of self-heating and resultant modification of the electron mobility profile. Temperature- and doping-dependent model of the electron mobility as well as temperature- and orientation-dependent approximations of the thermal conductivity of beta-Ga2O3 are presented. A decrease in drain current was attributed to a position-dependent mobility reduction caused by a coupled self-heating mechanism and a high electric-field mobility reduction mechanism. A simple thermal management solution is presented where heat is extracted through the source contact metal. Additionally, it is shown that an undesired secondary channel can form at the modulation doped layer that is distinguished by an inflection in the transconductance curve.