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 (μeff) in Ultra-Thin (UT) pure SiO2 bulk MOSFETs. A low substrate doping was intentionally used to better detect a possible μeff degradation at small Tox. New quantitative criteria were developed and used to obtain μeff 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 Tox. Our results indicate that the Polysilicon Screening is an essential ingredient to reconcile the RCS models with the experiments.