Experimental Assessment of Self-heating in AlGaN/GaN HEMTs for Microwave Application

Self-heating effects in AlGaN/GaN high-electron mobility transistors grown on SiC have been evaluated from room temperature to 200 degrees C. The channel temperature was extracted by a fast and simple electrical method combined dc with double-pulsed measurements, which was based on the difference in drain current between two measurements. To validate this technique, the experimental results have been compared with two other electrical methods. FEM thermal simulation has also been applied to demonstrate its accuracy. The thermal contribution of the complex interfacial issue was approximated by an effective TBR layer, which thermal conductivity is temperature dependent and tuned to match the experimental results.