Charge-controlled GaN FET modeling by displacement current integration from frequency-domain NVNA measurements

We propose an efficient procedure for the extraction of a charge-controlled nonlinear model of a 1-mm gallium nitride on silicon carbide field-effect transistor (L = 0.25μm) from nonlinear vector network analyzer acquisitions. A fast, single-shot measurement technique is described, in which the two device-under-test (DUT) ports are excited by single-tone sources at carefully selected tone frequencies, acquiring calibrated waveforms at the on-wafer DUT ports with an almost complete coverage of the voltages domain. The gate and drain charge functions identification is executed by the integration of the displacement currents in the frequency domain. A suitable approach for separating the conductive and displacement drain current components is provided. The presence of thermal self-heating and charge trapping phenomena is empirically evaluated, and accounted through an equivalent voltage approach. Experimental validation is provided at 2.5 and 5 GHz for a continuous-wave excitation, and at 2.5 GHz for a two-tone excitation.