Temperature assessment of AlGaN/GaN HEMTs: A comparative study by Raman, electrical and IR thermography

The accuracy of different thermography techniques for the determination of AlGaN/GaN HEMT channel temperature was investigated. Micro-Raman thermography, a novel electrical testing method, and IR thermography were applied to measure the temperature in the active region of AlGaN/GaN HEMTs with different device geometries. Due to its accepted accuracy, micro-Raman thermography was performed on different devices in order to validate thermal simulation results. When compared to the validated thermal model, pulsed I-V measurements underestimated channel temperature to some degree, while IR thermography determined unrealistically low device temperatures.