Thermal transport mechanism of 4H–SiC/SiO2 heterostructures: a molecular dynamics study

Abstract Silicon carbide (SiC) is widely used in high-frequency, high-speed, and high-power applications such as power electronics, rail transportation, new energy vehicles, and aerospace. However, the thermal properties of the SiC/SiO 2 interface, which is commonly found in SiC-based devices, are not yet fully understood. This study aims to investigate the influence of temperature and interface coupling strength on the interface thermal resistance (ITR) of 4H-SiC/SiO 2 using non-equilibrium molecular dynamics simulations. Both crystalline and amorphous SiO 2 , as well as two interface contact modes (Si-terminated and C-terminated), have also been considered. The results reveal that the ITR of 4H-SiC/SiO 2 is significantly affected by the interface coupling strength and contact modes. Under strong interface coupling conditions, the ITR for Si-terminated and C-terminated contacts modes of 4H-SiC/SiO 2 interfaces are 8.077 × 10 −10 m 2 KW −1 and 6.835 × 10 −10 m 2 KW −1 , respectively. However, under weak interface coupling conditions, these values increase to 10.142 × 10 −10 m 2 KW −1 and 7.785 × 10 −10 m 2 KW −1 , respectively. Regardless of whether SiO 2 is crystalline or amorphous, the ITR of the 4H-SiC/SiO 2 interface exhibits a similar trend with increasing temperature (from 300 to 700 K). Additionally, the ITR of the amorphous SiO 2 interface is smaller than that of the crystalline SiO 2 interface under both strong and weak coupling conditions. To gain insights into the heat transport mechanism, the phonon density of states was analyzed to examine the phonon spectral characteristics under varying coupling strengths. These findings have implications for enhancing the thermal management and heat dissipation of SiC devices, providing a framework for controlling interface phonon scattering, and informing the thermal design of nanodevices.