Thermal Visualization of Buried Interfaces Enabled by Ratio Signal and Steady-State Heating of Time-Domain Thermoreflectance

Zhe Cheng, Fengwen Mu, Xiaoyang Ji, Tiangui You, Wenhui Xu, Tadatomo Suga, Xin Ou, David G. Cahill, Samuel Graham

Research output: Contribution to journalArticlepeer-review


Thermal resistances from interfaces impede heat dissipation in micro/nanoscale electronics, especially for high-power electronics. Despite the growing importance of understanding interfacial thermal transport, advanced thermal characterization techniques that can visualize thermal conductance across buried interfaces, especially for nonmetal-nonmetal interfaces, are still under development. This work reports a dual-modulation-frequency time-domain thermoreflectance (TDTR) mapping technique (1.61 and 9.3 MHz) to visualize the thermal conduction across buried semiconductor interfaces for β-Ga2O3-SiC samples. Both the β-Ga2O3 thermal conductivity and the buried β-Ga2O3-SiC thermal boundary conductance (TBC) are visualized for an area of 200 × 200 μm simultaneously. Areas with low TBC values (≤20 MW/m2·K) are identified on the TBC map, which correspond to weakly bonded interfaces caused by high-temperature annealing. Additionally, the steady-state temperature rise induced by the TDTR laser, usually ignored in TDTR analysis, is found to be able to probe TBC variations of the buried interfaces without the typical limit of thermal penetration depth. This technique can be applied to detect defects/voids in deeply buried heterogeneous interfaces nondestructively and also opens a door for the visualization of thermal conductance in nanoscale nonhomogeneous structures.

Original languageEnglish (US)
Pages (from-to)31843-31851
Number of pages9
JournalACS Applied Materials and Interfaces
Issue number27
StatePublished - Jul 14 2021
Externally publishedYes


  • TDTR
  • gallium oxide
  • steady-state heating
  • thermal boundary conductance
  • thermal management
  • thermal visualization

ASJC Scopus subject areas

  • General Materials Science


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