Thermal Characterization of Field Plated AlGaN/GaN HEMTs

The performance of AlGaN/GaN HEMTs (High Electron Mobility Transistors), frequently used in high voltage and frequency power applications, can be enhanced with the use of field-plate technology. Experimental characterization of the device maximum temperature is extremely important for device reliability, yet it is difficult in devices with the field-plates due to geometrical constraints. To compare the temperature measurement performance and limits of current experimental methods: micro-Raman thermography and Thermoreflectance Thermal Imaging (TTI) when used on field-plated devices, a numerical thermal model is built. The model accounts for the size effects in the channel that occur due to extremely small heat generation region in devices. The peak temperatures of the devices with and without field-plates, at various power densities obtained from micro-Raman and TTI measurements will be simulated using the numerical model. As a result of this, maximum temperature measurement capability of micro-Raman and TTI for field-plated devices will be identified and proper techniques will be suggested.