SMALL-SIGNAL PARAMETERS AND THERMAL NOISE OF THE 4-TERMINAL MOSFET IN NON-QUASI-STATIC OPERATION

The behavior of MOS transistors from d.c. to frequencies where the operation is non-quasistatic is investigated, with emphasis on four-terminal operation and including the substrate effect. The aspects considered are: (a) development of expressions for the y parameters, with closed-form expressions for the associated series terms of any order; and (b) development of expressions for the induced thermal noise currents at the drain, gate, and substrate as well as the drain thermal noise voltage. The results presented are verified through extensive comparisons to measured results, and to results obtained by simulation of a many-segment device. Such comparisons extend up to frequencies two orders of magnitude above the intrinsic cutoff frequency with positive results. © 1990.