Influence and regulation of amorphous layers on phonon transport at SiC/Si interface

Y Zhang and HP Zhu and FY Liu and J Zhong and WE Lu and CC Wang and L Wang and ZP Wu and B Li, INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER, 252, 127407 (2025).

DOI: 10.1016/j.ijheatmasstransfer.2025.127407

Silicon-on-silicon carbide (SiC/Si) wafers offer superior thermal transport, representing a critical technological approach to addressing heat dissipation challenges in traditional silicon-on-insulator (SOI) wafers. To improve interface quality, an amorphous layer of silicon oxide (a-SiO2) or silicon (a-Si) is typically introduced between SiC and Si. Understanding the amorphous layer thermal transport mechanisms is crucial for effective thermal management in SiC/Si devices. Using non- equilibrium molecular dynamics (NEMD), we studied how a-SiO2 and a-Si layers affect the thermal transport across the SiC/Si interface. Our results show that interfacial thermal conductance (ITC) decreases with increasing thicknesses of a-SiO2 and a-Si. However, a significant regulatory effect of the a-SiO2 layer on ITC is observed. Specifically, an a-SiO2 layer of 0.3 nm can enhance the ITC to 994.7 MW/m2K, which is 54.4% higher than that of the Sharp-SiC/Si interfaces without amorphous layer. Analysis revealed that this enhancement stems from increased overlap in vibrational densities of states between SiC and Si and new transport channels created by high-frequency phonons converting to low- frequency phonons. In contrast, introducing an a-Si layer increases inelastic phonon scattering, significantly reducing ITC. This study also examines the temperature-dependent behavior of ITC for Sharp-SiC/Si and SiC/Si interfaces with varying a-SiO2 and a-Si thicknesses. These findings offer theoretical support for the development of SiC/Si wafer materials with enhanced thermal management performance.

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