Self-consistent full band two-dimensional Monte Carlo two-dimensional Poisson device solver for modeling SiGe p-channel devices

Abstract

Even now there are no device simulators that can model hole carrier transport in p-channel Si or SiGe metal-oxide-semiconductor field-effect transistors (MOSFETs), by properly addressing the issues of hole band-structure and quantum confinement effects. The purpose of this work is to remedy this situation by presenting an approach to modeling p-channel devices using a two-dimensional (2D) Monte Carlo transport kernel that is coupled self-consistently to a 2D Poisson equation solver and to a six band k∙p band-structure module. The need for full band solver for hole transport is especially true in the case of surface channel strained Si and buried channel strained SiGe p-MOSFETs investigated here. We have paid special attention on properly implementing and investigating the role of interface roughness on the operation of these device structures. We find that SiGe p-channel MOSFETs show performance improvement only for low gate and drain biases; i.e., when the device is operated in subthreshold and weak inversion regime and carrier spillover into the surface channel and surface roughness do not play significant role on the device operation.