Graphene-Graphite Quilts for Thermal Management of High-Power GaN Transistors

TL;DR

This paper introduces graphene-graphite quilts as an innovative heat management solution for high-power GaN transistors, significantly reducing device temperature and enhancing performance.

Contribution

The study demonstrates the effective use of few-layer graphene as lateral heat spreaders in GaN transistors, improving thermal management beyond existing methods.

Findings

Temperature reduction of ~20°C in operating devices

Effective heat removal at ~13 W/mm power density

Potential for enhanced performance on thermally resistive substrates

Abstract

Self-heating is a severe problem for high-power GaN electronic and optoelectronic devices. Various thermal management solutions, e.g. flip-chip bonding or composite substrates have been attempted. However, temperature rise still limits applications of the nitride-based technology. Here we demonstrate that thermal management of GaN transistors can be substantially improved via introduction of the alternative heat-escaping channels implemented with few-layer graphene - an excellent heat conductor. We have transferred few-layer graphene to AlGaN/GaN heterostructure field-effect transistors on SiC substrates to form the "graphene-graphite quilts" - lateral heat spreaders, which remove heat from the channel regions. Using the micro-Raman spectroscopy for in-situ monitoring we have shown that temperature can be lowered by as much as ~ 20oC in such devices operating at ~13-W/mm power density. The simulations suggest that the efficiency of the "graphene quilts" can be made even higher in GaN devices on thermally resistive sapphire substrates and in the designs with the closely located heat sinks. Our results open a novel application niche for few-layer graphene in high-power electronics.