Low temperature mobility improvement in high-mobility strained-Si/Si_1-xGe_x multilayer MOSFETs

Electron density and mobility curves have been simulated for buried strained-Si/SiGe MOSFET. A Monte Carlo simulator including electron quantization, nonparabolicity and a new model for Coulomb scattering has been used at different temperatures. It has been demonstrated that the improved confinement of the electron charge in the strained-Si quantum well at low temperatures greatly reduces Coulomb scattering in these structures. The inversion charge in the superficial channel is reduced in comparison with operation at room temperature. Therefore, apart from lower Coulomb scattering rates, surface-roughness and phonon scattering is also lower.