Electron mobilities in strained Si-1 C-x(x) layers grown on a Si substrate and relaxed alloys are calculated as functions of carbon content, alloy scattering potential, and doping concentration at room temperature. The electron mobility model is backed by experimental data. In the case of doped strained Si-1 C-x(x), the results of our electron mobilitymodel indicates that for systems with a doping concentration greater than 10(18) cm (3), there is no substantial decrease in the in-plane mobility with an increase in the carbon mole fraction. However, for low doping concentrations, the mobility decreases with a decrease in the carbon mole fraction. (C) 2008 Elsevier B. V. All rights reserved.