Interfacial fracture toughness of GaN film on diamond substrate for application in ultra-high power RF devices

Dong Liu*, Stephen Fabes, Daniel Francis, Martin Kuball

*Corresponding author for this work

Research output: Contribution to conferenceConference Paperpeer-review

Abstract

Achieving a mechanically stable interface with low thermal boundary resistance in GaN-on-diamond is crucial for reliable operation of high-power devices . As one cannot grow diamond directly to GaN due to crystallographic restrictions, an interlayer of SiNx is usually introduced between GaN and diamond. This layer not only affects the thermal resistance of the heterogeneously integrated GaN-on-diamond material, but also impact its mechanical strength. In this work, a series of GaN-on-diamond materials with varying SiNx thicknesses were studied. First of all, the GaN/diamond interfacial toughness was measured by nanoindentation. Secondly, the effective thermal boundary resistance was evaluated by transient thermoreflectance method. In addition, to understand the complex stress-strain field at the interface, a 2D axisymmetric finite element model has been established and validated by experimental results. It was found that the reduction in SiNx interlayer thickness benefits the thermal properties of GaN-on-diamond without compromising its mechanical stability.

Original languageEnglish
Publication statusPublished - 1 Jan 2019
Event2019 International Conference on Compound Semiconductor Manufacturing Technology, CS MANTECH 2019 - Minneapolis, United States
Duration: 29 Apr 20192 May 2019

Conference

Conference2019 International Conference on Compound Semiconductor Manufacturing Technology, CS MANTECH 2019
CountryUnited States
CityMinneapolis
Period29/04/192/05/19

Keywords

  • GaN-on-diamond
  • Interfacial toughness
  • Nanoindentation
  • Thermal boundary resistance
  • Transient thermoreflectance

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