Theoretical prediction of universal curves for carrier transport in Si/SiO2(100) interfaces

Atomic structure dependence of carrier transport in Si/SiO2 interface has been extensively studied. It is shown by first-principles calculations that a strong Si-O dipole is formed at the interface, and the polarized interface Si-O dipole becomes the origin of the dipole scattering. A physics-based dipole scattering model, which considers the inelastic scattering due to the vibrated dipole as well as the elastic scattering, is proposed. In particular, it is found that Si atom that forms the Si-O dipole vibrates parallel to the interface and becomes the origin of the inelastic dipole scattering. By performing the mobility calculation based on relaxation-time approximation, it is shown that the interface Si-O dipole has a significant influence on the carrier mobility in the inversion layer, and that the interface Si-O dipole scattering is one of the main scattering components that limit the carrier transport in the inversion layer, in addition to the conventional scattering components: the substrate impurity scattering, the bulk phonon scattering, and the surface roughness scattering. Upon incorporation of the Si-O dipole scattering, universal curves have been fully predicted.