Quantitative assessment of mobility degradation by remote Coulomb scattering in ultra-thin oxide MOSFETs: measurements and simulations

In this paper, we report measurements of electron effective mobility (/spl mu//sub eff/) in ultra-thin (UT) pure SiO/sub 2/ bulk MOSFETs. A low substrate doping was intentionally used to better detect a possible /spl mu//sub eff/ degradation at small T/sub ox/. New quantitative criteria were developed and used to obtain /spl mu//sub eff/ measurements unaffected by either gate doping penetration or gate oxide leakage. Mobility simulations, based on an improved and comprehensive remote Coulomb scattering (RCS) model, exhibit a good agreement with the experimentally observed mobility reduction at small T/sub ox/. Our results indicate that polysilicon screening is an essential ingredient to reconcile the RCS models with the experiments.