Full thermal characterization of AlGaN/GaN high electron mobility transistors on silicon, silicon carbide, and diamond substrates using a reverse modeling approach

Abstract

Gallium Nitride (GaN) high electron mobility transistors (HEMTs) are thermally-critical devices that require advance thermal characterization, both experimental and numerical, and innovative thermal management strategies. Thermal numerical analysis of microelectronics faces challenges of complex physics and uncertain thermophysical properties which leads to inaccurate and numerically expensive models. Using an innovative reverse modeling approach to overcome the above challenges, this work presents the full thermal characterization of GaN power devices with different substrates aimed at managing the excessive self-heating. The approach develops and optimizes a numerical thermal model to match the results to experimentally-obtained thermal maps of the represented test devices. The experimentally-optimized simulation model can then be used to extract full 3D temperature distributions, infer in-situ thermal properties, and provide a numerical platform that can be used to conduct further parametric studies and design iterations. The presented analysis provides a full thermal characterization of different GaN HEMT devices and compares the thermal performance of different substrates.The extracted thermal properties for the SiC and Diamond substrate HEMTs are compared and a set of conclusions are presented to guide further developments in GaN HEMT thermal management strategies.