A universal large/small signal 3-terminal FET model using a nonquasistatic charge-based approach

Abstract

Introduces a charge-based nonquasistatic large/small signal FET model that is extracted from measured small signal S-parameter and DC data and can be applied to an arbitrary three-terminal FET structure. The model is based on general physical principles, and provides consistent topologies for both large and small signal simulations to frequencies above f/sub t/ and over a wide range of node voltages. The procedure for extracting model elements includes deembedding linear parasitic elements and extracting bicubic, B-spline functions, which represent large signal model elements. The spline coefficients are calculated using a constrained least squares fit to a set of small signal parameters and/or DC currents that have been measured at a number of node voltage values. Advantages of this approach include fast parameter extraction for new FET structures, accuracy, computational efficiency, charge conservation, and the requirement of only a single model for all simulation modes. The model can also be used to interface device simulators (e.g., PISCES) with circuit simulators for accurate predictive modeling. >