A closed-loop evaluation and validation of a method for determining the scattering limited carrier velocity in MOSFETs

A closed-loop evaluation of a saturation transconductance (g _msat⁽ⁱ⁾) based method for determining the scattering limited carrier velocity (ν_sat) in enhancement MOSFETs was performed with the use of a 2-D device simulator. Consistency in the extracted ν_sat over a wide range of gate oxide thickness (T_ox), channel doping concentration, and bias condition was tested and verified. Also analyzed are the appropriate measurement condition, the significance of the parasitic effect due to the source and drain resistances, the applicability of the method used for compensating this parasitic effect, and the expected accuracy of the extracted ν_sat under ideal conditions. A plausible explanation is provided for the inconsistency between ν_sat determined from g_msat⁽ⁱ⁾(0), the extrapolated transconductance, and ν_sat determined from the slope of [ g_msat⁽ⁱ⁾(0)]^-1 versus T _ox characteristics observed in published results. The g_msat ⁽ⁱ⁾-based method for extracting ν_sat has been applied to MOSFETs fabricated with three vastly different technologies, and the experimentally-based ν_sat of electrons at 300 K ranges from 7.37×10⁶ to 7.92×10⁶ cm/s, which shows its independence of technology