Reducing GaN-on-diamond interfacial thermal resistance for high power transistor applications

Huarui Sun, Roland B. Simon, James W Pomeroy, Daniel Francis, Firooz Faili, Daniel J. Twitchen, Martin H H Kuball

Research output: Contribution to journalArticle (Academic Journal)peer-review

93 Citations (Scopus)
468 Downloads (Pure)


Integration of chemical vapor deposited polycrystalline diamond offers promising thermal performance for GaN-based high power radio frequency amplifiers. One limiting factor is the thermal barrier at the GaN to diamond interface, often referred to as the effective thermal boundary resistance (TBReff). Using a combination of transient thermoreflectance measurement, finite element modeling and microstructural analysis, the TBReff of GaN-on-diamond wafers is shown to be dominated by the SiNx interlayer for diamond growth seeding, with additional impacts from the diamond nucleation surface. By decreasing the SiNx layer thickness and minimizing the diamond nucleation region, TBReff can be significantly reduced, and a TBReff as low as 12 m2K/GW is demonstrated. This enables a major improvement in GaN-on-diamond transistor thermal resistance with respect to GaN-on-SiC wafers. A further reduction in TBReff towards the diffuse mismatch limit is also predicted, demonstrating the full potential of using diamond as the heat spreading substrate.
Original languageEnglish
Article number111906
Number of pages4
JournalApplied Physics Letters
Issue number11
Early online date17 Mar 2015
Publication statusPublished - 17 Mar 2015

Structured keywords

  • CDTR


  • Diamond
  • Nucleation
  • Thermal conductivity
  • Elemental semiconductors
  • III-V semiconductors


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