Interface conductance modal analysis of a crystalline Si-amorphous SiO2 interface

Abstract

We studied the modal contributions to heat conduction across an interface between crystalline Si and amorphous SiO2, using the interface conductance modal analysis (ICMA) method. Our results show that >70% of the thermal interface conductance (TIC) arises from the extended modes. Using ICMA, we could also determine the contribution of interfacial modes to the TIC. Interestingly, we observed that although the number of these modes is <5% of all modes, interfacial modes contribute significantly to the TIC (>15%). Such an observation shows the non-negligible role of localized modes in facilitating heat conduction across systems with interfaces between dissimilar materials, specifically in a system that is straightforward to fabricate and study experimentally. Our observations suggest that neglecting the contribution of localized modes would be an oversimplification of the actual mechanisms at play. Determining the individual mode contributions is therefore of vital importance, since these values are directly utilized in predicting the temperature dependent TIC, which is important to silicon on insulator technologies with a myriad of applications within microelectronics and optoelectronics.