Comprehensive understanding of surface roughness and Coulomb scattering mobility in biaxially-strained Si MOSFETs

We have experimentally found that tensile biaxial strain enhances the surface roughness scattering limited mobility (mu_sr) of electrons, while degrades that of holes slightly, for the first time. It is also found that tensile biaxial strain enhances the Coulomb scattering mobility of holes induced by interface states (mu_it) thanks to the enhancement of the averaged distance between the holes and scattering centers at the Si/SiO₂ interface (Z_inv), while degrades that induced by substrate impurity (mu_sub) due to the enhancement of interband scattering. These impacts of tensile strain on mu_it and mu_sub of holes are opposite to the trend of electron ones.