Thermal boundary resistance reduction by interfacial nanopatterning for GaN-on-diamond electronics applications

Ji, Xiaoyang, Vanjari, Sai Charan, Francis, Daniel, Cuenca, Jerome A. ORCID: https://orcid.org/0000-0003-1370-1167, Nandi, Arpit, Cherns, David, Williams, Oliver A. ORCID: https://orcid.org/0000-0002-7210-3004, Ejeckam, Felix, Pomeroy, James W. and Kuball, Martin 2025. Thermal boundary resistance reduction by interfacial nanopatterning for GaN-on-diamond electronics applications. ACS Applied Electronic Materials 7 (7) , 2939–2946. 10.1021/acsaelm.5c00119

PDF - Published Version Download (4MB)

Abstract

GaN high electron mobility transistors (HEMTs) on SiC substrates are the highest performing commercially available transistors for high-power, high-frequency applications. However, Joule self-heating limits the maximum areal power density, i.e., operating power is derated to ensure the lifetime of GaN-based devices. Diamond is attractive as a heat sink due to its record-high thermal conductivity combined with its high electrical resistivity. GaN-on-diamond devices have been demonstrated, bringing the diamond as close as possible to the active device area. The GaN/diamond interface, close to the channel heat source, needs to efficiently conduct high heat fluxes, but it can present a significant thermal boundary resistance (TBR). In this work, we implement nanoscale trenches between GaN and diamond to explore new strategies for reducing the effective GaN/diamond TBR (TBReff). A 3× reduction in GaN/diamond TBReff was achieved using this approach, which is consistent with the increased contact area; thermal properties were measured using nanosecond transient thermoreflectance (ns-TTR). In addition, the SiNx dielectric interlayer between the GaN and diamond increased its thermal conductivity by 2× through annealing, further reducing the TBR. This work demonstrates that the thermal resistance of heterogeneous interfaces can be optimized by nanostructured patterning and high-temperature annealing, which paves the way for enhanced thermal management in future device applications.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Schools > Physics and Astronomy
Additional Information:	License information from Publisher: LICENSE 1: URL: https://creativecommons.org/licenses/by/4.0/, Start Date: 2025-03-27
Publisher:	American Chemical Society
ISSN:	2637-6113
Date of First Compliant Deposit:	8 April 2025
Date of Acceptance:	21 March 2025
Last Modified:	08 Apr 2025 11:00
URI:	https://orca.cardiff.ac.uk/id/eprint/177475

Actions (repository staff only)

Edit Item