Investigation of local heating effect for 14nm Ge pFinFETs based on Monte Carlo method

FinFET is regarded as one of the most promising device structure for future scaling-down demands. However, heat dispassion is a severe problem for the device performance and reliability in nano-scale FinFETs. Germanium (Ge) is a novel channel material with its high carrier mobility, especially for PMOSFET. However, the bulk thermal conductivity of Ge (52.98Wm-1K-1) is almost 3 times smaller than that of Si (148.6Wm-1K-1)[1], which will lead to more serious heat dispassion problems in Ge devices. What's more, the phonon mean free path is largely decreased in nano-device structure due to increased surface scatterings, which leads to a largely reduced thermal conductivity. Hence, heat dissipation problems will have a large impact on the performance of Ge FinFETs. In this paper, we use 3D Full Band Self-consistent Ensemble Monte Carlo Simulator and 3D Fourier Heat Conduction Solver to study the local heating effects (LHE) and its impact on 14nm Ge SOI pFinFETs. The heat dissipation path is also evaluated. From the simulation results, we find that 14nm Ge SOI FinFETs will experience severe heating problems and heat effects will seriously affect the device performance.