Mobility of holes and density of states at Si-SiO2 interfaces

An investigation was made of the Hall and conductivity mobilities of holes in an inversion channel, and the C-V as well as G-V characteristics of Al-SiO2-Si structures were recorded. It was established that the technology of fabrication of MIS structures influenced the parameters of the Si-SiO2 interface. It was found that chemodynamic polishing of silicon plates before oxidation improved significantly the properties of the Si-SiO2 interface. A relationship was found between the density of the surface states (Nss) and the mobility of holes in an inversion channel. It was found that the high mobility of holes at the channel opening threshold was mainly due to a reduction in Nss at the Si-SiO2 interface and in the insulator near this Si-SiO2 interface. In addition to the phonon scattering mechanism, the scattering by the charge in the surface states at the Si-SiO2 interface also played an important role.