Utilizing Diode Characteristics for GaN HEMT Channel Temperature Prediction

Measuring channel temperature in GaN high-electron mobility transistors (HEMTs) is challenging due to the submicrometer dimensions of the gate fingers. The HEMT characteristics are electrically and thermally dependent. The channel temperature is measured using the Schottky gate-diode forward characteristics and compared with results of simulation, theory, and experimental evidence. The pulsed gate-diode forward resistance and threshold voltage predict channel temperatures that agree well with other methods. The technique presented provides a fast, easily implementable methodology for estimating channel temperature.