Silicon MOS transconductance scaling into the overshoot regime

Simulations incorporating velocity overshoot are used to derive the dependence of deep-submicrometer MOS transconductance on low-field mobility mu /sub eff/ and channel length L/sub ch/. In contract to strict velocity saturation, saturated transconductance departs from a strict mu /sub eff//L/sub ch/ dependence when overshoot is considered. Constraints on mu /sub eff/ derived from conventional scaling laws together with strong mu /sub eff/ dependencies in these regimes indicate the importance of low-field inversion layer control and optimization. Transconductance in saturation is shown to approach a well-defined limit for very high mu /sub eff/.<>