An improved C-infinity-continuous small-geometry MOSFET modeling for analog applications
The purpose of this work is to present a new MOSFET model suitable for circuit simulation and valid from the deep-submicron range to long-channel devices. This model is derived from the physics of the device, but explicit expressions are finally obtained by making some reasonable approximations, and they are valid and continuous through all operating regimes. The suitability of the new model for analog applications is due to the use of explicit expressions with an infinite order of continuity. This implies the use of smoothening functions requiring a larger computation time than simpler functions used by the piecewise models currently available in circuit simulators. Nevertheless, this increase in complexity is compensated with an improvement in the convergence when employed in circuit simulation and with a better accuracy of the transistor currents and charges (especially of their derivatives, the conductances and the capacitances, respectively). Furthermore, the use of physically-based expressions makes the model more suitable to be extended in the deep-submicron range and eases parameter extraction.
mosfet physics and modeling analog design