An improved but reliable model for MESFET parasitic capacitance extraction

The conventional parasitic capacitance extraction always produces bias-dependent C_pd, even though from the underlying physic, the parasitic capacitance is known to be bias-independent. In this paper, an improved model is thus proposed to evaluate the parasitic capacitances of GaAs MESFET transistor from the cold-FET S-parameters measurement. The resulting C_pd is found to be independent of V_gs when V_gs < V_p. In our approach, model parameters can be uniquely determined by using only two sets of cold-FET S-parameters under different Vgs biasing condition.