Charge transfer and low-temperature electron mobility in a strained Si layer in relaxed Si_1-xGe_x

Calculated results for charge transfer and low-temperature electron mobility in strained silicon grown epitaxially on relaxed Si 1-xGex are presented versus the thickness of an undoped spacer layer and other structural and materials parameters. The indicated conduction band offset for Si on relaxed Si0.7Ge0.3 is 180±15 meV. Scattering by the remote doping impurities that supply the carriers is found to be the dominant scattering mechanism in high-mobility samples. Samples with enhanced interface scattering are expected to have a stronger temperature dependence of mobility.