Temperature Dependence of the Taylor Series Coefficients and Intermodulation Distortion Characteristics of GaN HEMT

This paper focused on nonlinear distortion modeling and characterization of AlGaN/GaN HEMT on SiC substrate using a two-tone intermodulation measurement. The variation of Taylor series coefficients with temperature: linear terms (Gm, Gds), nonlinear terms (Gm2, Gm3, Gds2, Gds3) and the cross terms (Gmd, Gmd2, Gm2d) are reported. Furthermore, in saturation region the magnitude of Gds related linear, nonlinear and cross terms (Gds, Gds2, Gds3, Gmd, Gmd2, and Gm2d) are found to be minimal. This implies that the nonlinear distortion behavior of the device is transconductance-dependent. A temperature-dependent current based empirical model taking into account of bias, input power and frequency for the nonlinearity of the device has been developed based two-tone measurements. The modeled data are consistent with the two-tone measurements providing an effective means for analyzing these devices.