Measurement of MMIC gate temperature using infrared and Thermoreflectance thermography

Thermal characterization of high power microwave devices is important for determining their reliability. Exceeding the optimal temperature will have a detrimental effect on the performance and reliability of these devices. In this paper, the temperature a power amplifier (PA) Monolithic Microwave Integrated Circuit (MMIC) was measured using the traditional Infrared (IR) thermography technique and an emerging technique called Thermoreflectance (TR) thermography. The measured results were compared to those calculated using finite element analysis (FEA). It was found that temperatures measured using TR thermography agreed very well with FEA results, whereas temperatures measured using IR thermography did not. This could be attributed to the presence of reflective and low emissivity surfaces on the PA MMIC and the inadequate spatial resolution of the IR camera.