Study on thermoreflectance-based transient temperature measurement and thermal resistance characterization of GaN HEMT

This study proposes a system for detecting transient temperatures in GaN HEMT devices. The system employs 360 nm laser thermal reflection and leverages the established linear relationship between laser reflectivity and temperature, enabling real-time measurement of transient temperature drops. The system comprises a UV laser, a photodiode, and auxiliary components. The temperature calibration curve of the test system is derived from a thermostatic platform, and the thermal resistance of each layer is determined by integrating RC theory with the structural function method. Device temperatures were further measured using infrared thermography in combination with the electrical temperature-sensitive parameter method to validate the proposed thermal reflection approach. The results demonstrate that this method provides precise measurement outcomes and overcomes the limitations of conventional techniques, which require multiple heating cycles. By integrating the advantages of both thermal reflection and electrical methods, the approach offers technical support for high-resolution measurement of surface temperature distributions and for detailed analysis of thermal resistance composition.