Uncertainty estimation and optimal extraction of intrinsic FET small signal model parameters

In this paper, analytical expressions for the sensitivities in the parameters of a standard intrinsic FET small signal model are derived with respect to variations in the S-parameters. The sensitivities are used to estimate the uncertainty in extracted model parameters. The theories are applied to measurements made on a commercial HEMT device. Using models for the measurement uncertainties allows the model parameter uncertainties to be studied versus frequency and bias. As a result, optimal, minimum uncertainty parameter extraction can be performed independent of the bias voltage and without prior knowledge of the FET device characteristics. Thus making it suitable for implementation in automatic multi-bias extraction programs.