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The Frequency Domain Thermoreflectance Technique for Thermal Property Measurements
Published on: December 5, 2025
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The role of optical phonons in intermediate layer-mediated thermal transport across solid interfaces
1Department of Aerospace and Mechanical Engineering, University of Notre Dame, Notre Dame, IN 46556, USA. tluo@nd.edu.
Physical Chemistry Chemical Physics : PCCP
|July 6, 2017
Summary
Intermediate layers (ILs) significantly impact thermal transport in power electronics. This study found that atomic mass in ILs, particularly AlN, can optimize thermal conductance across SiC/GaN interfaces by 27%.
Area of Science:
- Materials Science
- Solid-State Physics
- Computational Materials Science
Background:
- Efficient thermal management is crucial for modern power electronics, with solid interface thermal transport being a key factor.
- Silicon carbide (SiC) and gallium nitride (GaN) interfaces are vital in high-power electronic devices.
- Intermediate layers (ILs) are employed to enhance thermal conductance across such interfaces.
Purpose of the Study:
- To systematically investigate the influence of intermediate layer (IL) atomic masses on thermal conductance across SiC/GaN interfaces using non-equilibrium molecular dynamics (NEMD) simulations.
- To identify optimal IL properties for maximizing thermal transport.
- To provide insights for designing effective ILs for thermal management in power electronics.
Main Methods:
- Non-equilibrium molecular dynamics (NEMD) simulations were performed on a model SiC/GaN interface.
- The Tersoff potential was used to model interatomic interactions, with variations solely based on atomic masses of ILs.
- Vibrational power spectra (VPS) of SiC, ILs, and GaN were analyzed to understand phonon transport mechanisms.
Main Results:
- Thermal boundary conductance (TBC) is influenced by both the total primitive cell mass and the relative atomic masses within the IL's unit cell.
- Optical phonons play a significant role in thermal transport across solid/solid interfaces.
- An optimal mass ratio exists for IL atoms to maximize the overlap of VPS with SiC and GaN, enhancing phonon coupling.
Conclusions:
- Aluminum nitride (AlN) was identified as the optimal IL, potentially improving thermal transport across SiC/GaN interfaces by up to 27% by considering only mass effects.
- The study highlights the importance of phonon spectra matching between the IL and the base materials for efficient thermal transport.
- While acknowledging limitations like the absence of strain and quantum effects, the findings offer valuable guidance for designing ILs to enhance thermal management in power electronics.
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