Enhancing interfacial thermal conductance of an amorphous interface by optimizing the interfacial mass distribution

Thermal management challenges arise from interfacial thermal resistance as modern semiconductors are miniatured to nanoscale. Authors of previous studies have found that graded mass distribution in the interface can maximumly enhance the interfacial thermal conductance (ITC) of crystalline interface; however, whether this strategy is effective for amorphous interface is less explored. In this paper, a graded mass distribution in the amorphous interface between crystalline Si and crystalline Ge is optimized to increase ITC by the extended atomistic Green's function method. The results show that atomic mass of 26 amu for one type of atomic mass and 24 and 31 amu for two types of atomic mass in the amorphous interface can maximumly increase ITC. Therefore, the strategy of graded mass distribution is still effective when only considering the atoms in the amorphous interface. In addition, applying the value of the smaller atomic mass of the two contacts to the amorphous interface can largely enhance interface thermal conductance, which is only 0.9% smaller than the maximum value. Further analyses show that atomic mass of 26 amu can increase the phonon modal transmission at large frequency $(>2\mathrm{THz})$ for most phonons, and the phonon spectral transmissions are almost the same at low frequency $(<2\mathrm{THz})$ for different distributions of atomic mass in the amorphous interface in this paper. The findings in this paper are expected to be valuable for optimizing ITC of amorphous interfaces for semiconductor devices.