Estimation of the effects of remote charge scattering on electron mobility of n-MOSFETs with ultrathin gate oxides

The effects of remote charge scattering on the electron mobility of n-MOSFETs with ultrathin gate oxides from 1.5 nm to 3.2 nm have been estimated. By calculating the scattering rate of the two-dimensional (2-D) electron gas at the Si/silicon dioxide interface due to the ionized doping impurities at the poly-Si/silicon dioxide interface, the remote charge scattering mobility has been calculated. Electron mobility measured from the n-MOSFETs with ultrathin gate oxides has been used to extract several known mobility components. These mobility components have been compared to the calculated remote charge scattering mobility. From these comparisons, it is clear that the overall electron mobility is not severely degraded by remote charge scattering for the oxide thickness studied.