MODELING DRAIN AND GATE DEPENDENCE OF HEMT 1-50-GHZ, SMALL-SIGNAL S-PARAMETERS, AND DC DRAIN CURRENT

We present refinements to a previously validated HEMT model that impro ves the model's accuracy as a function of drain bias for simulating d. c. drain current and 1-50 GHz, small-signal S-parameters. By comparing simulation data with experimental data for a 0.4-mu m-gate pseudomorp hic HEMT, we have been able to establish the accuracy of the refined m odel, which predicts the device's d.c. current and S-parameters as a f unction of the applied drain and gate biases to within an accuracy of similar to 5%. The core of the model and, in particular, its bias depe ndence, are directly dependent on the HEMT wafer structure and the phy sical gate length.