Characterization of Electro-Thermal Effects in GaN Based HEMTs

This paper presents a new method for characterizing electro-thermal effects in GaN based HEMTs. The proposed method characterizes the thermal and bias dependence of the current through the 2-DEG individually. The temperature dependence is characterized by TLM measurements versus ambient temperature, showing an increasing sheet resistivity with temperature. The thermal impedance is determined from low frequency impedance measurements, indicating thermal response up to at least 100 MHz. The isothermal bias dependence is measured above the thermal cut-off with a LSNA, showing a nonlinear current versus voltage characteristic.