Electron mobility in SOS films

Mobility of electrons in various thickness thin silicon films grown on two different high-temperature pre-epitaxial growth annealed sapphire substrates was measured as a function of the depth from the Si-SiO2 interface and the gate bias voltage at-50 to 120°C temperature range. The mobility is larger for electrons in thicker SOS films and in those films grown on higher temperature pre-epitaxial growth annealed sapphire substrates. Crystal defects, edge dislocations, and deep traps are found to play major roles of limiting the mobility of electrons in thin SOS films. For very thin SOS films the surface scattering process may not be an important factor which affects the electron mobility even when the surface is strongly accumulated.