Modeling and simulation of phonon boundary scattering in PDE-based device simulators

In this work, the effect of phonon boundary scattering on the heat transfer in thin silicon layers and close to interfaces was investigated. The modeling is applicable to silicon-on-insulator (SOI) devices as well as to conventional bulk technology. From a linearized Boltzmann transport equation (BTE), anisotropic local thermal conductivities are derived. A separate expression is formulated for the case of a bulk device where only one interface is present. Anisotropy was implemented as a finite element-based operator into the PROPHET device simulator and a demonstration of the new electrothermal modeling was made for a conventional MOSFET. The anisotropic local thermal conductivities lead to a temperature increase ~30% higher at the gate oxide interface compared to conventional modeling