Thermal effects of substrates on the performance of AlGaN/GaN HFETs

摘要

In this paper, we report on the analytical thermal modeling and temperature measurement of AlGaN/GaN HFETs fabricated using the sapphire and SiC substrates. The thermal modeling was conducted by the unit temperature profile approach and the thermal measurement was made using the nematic liquid crystal thermogrphic method. The calculated data and the measured results were found out to agree well and exhibited the linear relationship of peak temperature and input power. For the same drive condition at gate voltage, V_(gs) = 0 V, it was found out that the AlGaN/GaN HFET built on SiC delivers twice more current comparing to its sapphire counterpart. Under the input power of 0.63 W, the device with the sapphire substrate exhibits the peak temperature of 110 °C, but the peak temperature of the device built on the SiC substrate is measured to be about 40 °C.