Extraction of the Thermal Resistance and the Thermal Capacitance of GaN Power HEMTs by Using Pulsed I-V Measurements

This work presents an extraction method for the thermal resistance and the thermal capacitance of GaN power high-electron mobility transistors (HEMTs). An electro-thermal analytic model is derived describing the current drain degradation in the linear region of the transistor, which is caused by self-heating. This model function is fit to pulsed I-V measurement data, and the fitting parameters provide the required thermal parameters. A parameter analyzer and a thermal chuck are used as setups to perform the measurements. A quasi-transient drain current response signal is composed of the measured data, which is used for parameter extraction. The new method is used to extract the thermal parameters of a 650 V class GaN power transistor. The transistor features an integrated temperature sensor. This allows a cross-validation of the results, which are obtained by the new method, with the results which are measured by the temperature sensor. The new extraction method can be easily performed with typical equipment, that is commonly available in labs for electrical characterization of GaN power transistors.