Abstract

For the first time, we report direct on-wafer noninvasive temperature distribution measurements of AlGaN/GaN HFETs grown on Si substrates under microwave large-signal conditions. An infrared camera and a load-pull measurement system coupled to a probe station enable us to produce surface temperature maps with micronic resolution. Results include the impact of the RF drive, differences between RF and DC drive, as well as impact of reduced power added efficiency on the surface temperature of the device.