Drift diffusion and hydrodynamic simulations of Si/SiGe p-MOSFETs

The interest in SiGe for MOSFET applications has grown continuously, following recent experimental and theoretical demonstrations that the hole mobility in strained SiGe can be considerably higher than in Si. Strained SiGe p-MOSFETs are particularly attractive for CMOS applications as the hole mobility starts to be comparable with that of the electron mobility. This may reduce the asymmetry in the channel widths of the n and p-channel MOSFETs required for efficient CMOS operation, leading to an increase in the packing density. However, optimising the design of SiGe p-MOSFETs will require efficient models for device simulations, with known confidence limits. In this paper, we present simulation results for submicron Si/SiGe p-MOSFETs using drift diffusion and hydrodynamic commercial simulators, with transport parameters extracted from Monte Carlo transport simulations. The Monte Carlo is used to establish confidence limits for the drift diffusion and hydrodynamic models. The role of velocity overshoot for the enhancement of the performance potential in the SiGe devices is also investigated.