ELECTRON-TRANSPORT IN STRAINED SI LAYERS ON SI1-XGEX SUBSTRATES

Results on the in-plane electron drift velocities and mobilities in strained Si layers grown on Si1-xGex substrates are reported for 300 and 77 K. High-field drift velocities are calculated by Monte Carlo simulations and low-field mobilities by numerical solution of Boltzmann's equation including intra- and intervalley phonon and impurity scattering mechanisms. Significant improvements of drift velocities relative to bulk Si are found for electric fields up to several 10 kV/cm, while saturation occurs at the bulk values for both temperatures. A much stronger mobility enhancement of 74% is obtained at 300 K compared to 36% at 77 K, which is consistent with recent experimental results.