Extracting transistor changes from device simulations by gradient fitting

The results of small-signal or transient analyses from a conventional device simulator (or measured data) can be combined with gradient-fitting techniques to produce smooth spline-based MOSFET charge models for circuit simulation. These techniques are also applicable to shape-from-shading problems. Results based on simulations of some small devices are presented. The comparative efficiencies of the small-signal and transient approach are discussed as well as the relation between the so-called small- and large-signal charges. The role of spline-based table models as against compact analytical models is considered.>