Parameters Extraction And Sensitivity Analysis For GaN High Electron Mobility Transistor

The GaN (gallium nitride) high electron mobility transistor (HEMT) has attracted a huge attention for high-power and high-temperature applications at microwave and millimeter-wave frequencies due to wide bandgap of GaN. It should be noted, that any successful system level design of power amplifiers, oscillators, or mixers requires accurate empirical device modeling. Clearly, the validity of device modeling is dependent on the accuracy of the parameter extraction method.Many techniques have been proposed for GaN HEMT small-signal parameter extraction which usually utilize optimization or direct extraction method. The optimization techniques, which aim to determine the value of parameters by fitting the measured and modeled S-parameters versus frequency, may result in nonphysical and nonunique values of the equivalent circuit parameters. Direct extraction method is faster than optimization method, but it often requires a subsequent step to improve the fitting between the measured and modeled S-parameters. The Monte Carlo-based sensitivity analysis will be useful to find the optimum values. Parameter sensitivity analysis can be used to decide which parameters should be optimized or determined more accurately through further modeling or experimental studies.In this paper, the extraction techniques and sensitivity analysis of GaN HEMT equivalent circuit are researched, the main contents include:1) the process of RF devices modeling and de-embedding techniques during extraction procedure; 2) present an improved linear modeling technique with sensitivity analysis for GaN HEMT small-signal equivalent circuit which is a combination of the test structure and sensitivity analytical method; 3) give the analytical expressions for the relative sensitivities with respect to deviations in the measured scattering (S) parameters are to improve the precision of the intrinsic elements; 4) the 2×100 μm gatewidth (number of gate fingers×unit gatewidth) GaN HEMT with 0.25-μm gatelength have been characterized using proposed method. The validity of the approach is proven by comparison with measured and modeled S parameters in the frequency range of 100 MHz-40 GHz over a wide range of bias points; 5) parameter extraction technologies of the EEHEMT nonlinear equivalent circuit model of GaN HEMT are studied in this paper, and the modeling results are also given.