On surface roughness-limited mobility in highly doped n-MOSFET's

Based on a numerical study of Ando's model for surface roughness scattering, we assess the links between the functional dependencies of the electron surface roughness-limited mobility and the morphology of the interface. The results are summarized in an analytical expression that can be implemented into device simulators. Our results also highlight that as the channel doping increases, the surface roughness-limited mobility features a roll-off in the low effective field region, similar to the one due to the Coulomb-limited mobility. This physical effect is discussed.