Validation of MOSFET Model Source-Drain Symmetry
Colin C. McAndrew
IEEE TED, Vol. 53, No. 9, Sep. 2006
Abstract: Symmetry around Vds= 0 is a critical requirement for MOSFET models, e.g. as it affects the ability of a model to simulate distortion accurately for some RF CMOS mixers. The Gummel symmetry test (GST) has been the standard test used to evaluate the symmetry of MOSFET models. However, this test is only applicable to DC current, and is only valid when there is negligible gate or substrate current. This paper presents a DC symmetry test that is applicable in the presence of gate and substrate currents, and an AC symmetry test that is simple and effective in verifying symmetry of Cgs and Cgd.
FIG: Biasing scheme for dc symmetry testing.