High Thermal Boundary Conductance across Bonded Heterogeneous GaN-SiC Interfaces.

High-power GaN-based electronics are limited by high channel temperatures induced by self-heating, which degrades device performance and reliability. Increasing the thermal boundary conductance (TBC) between GaN and SiC will aid in the heat dissipation of GaN-on-SiC devices by taking advantage of the high thermal conductivity of SiC substrates. For the typical growth method, there are issues concerning the transition layer at the interface and low-quality GaN adjacent to the interface, which impedes heat flow. In this work, a room-temperature bonding method is used to bond high-quality GaN to SiC directly, which allows for the direct integration of high-quality GaN with SiC to create a high TBC interface. Time-domain thermoreflectance is used to measure the GaN thermal conductivity and GaN-SiC TBC. The measured GaN thermal conductivity is larger than that of grown GaN-on-SiC by molecular beam epitaxy. High TBC is observed for the bonded GaN-SiC interfaces, especially for the annealed interface (∼230 MW m