High field transport in strained Si/GeSi double heterostructure: A Fokker–Planck approach

We report calculations of high electric field transport for the case of a strained Si/GeSi double heterostructure (DHS) considering transport along the Si channel and by applying the analytical Fokker-Planck approach (FPA), where the process is modeled as drift diffusion in energy space. We limit ourselves to electronic transport in the conduction band of the strained Si, where an energy shift between the otherwise degenerate six energy valleys characterizes the band alignment in the DHS. Inter-valley phonon scatterings are considered while intra-valley acoustic phonon scattering is ignored, leading to results valid for high enough temperatures. Our results are compared to previous theoretical work where Monte Carlo simulations were applied. A reasonable agreement between the two approaches is obtained in the high electric field regime.