A Drain–Source Connection Technique: Thermal Resistance Measurement Method for GaN HEMTs Using TSEP at High Voltage

In the article, a new thermal resistance measurement method for GaN high electron mobility transistor (HEMTs) is proposed based on temperature sensitive electrical parameter (TSEP) with the use of MOS switches to connect the drain-source at the beginning of the measurement processes. Compared with traditional methods, the connection of the source and drain reduces the delay caused by the matching circuit. In our experiments, we measured a GaN HEMT at 48 V with a power consumption of 5.28 W. The delay time was less than ${2}~\mu \text{s}$ , and the thermal resistance was 9.85 °C/W. We also measured the thermal resistance at the same current-different voltages and different voltages-same power. The results show that the thermal resistance of the GaN HEMT increases with the increase of the power and voltage. Furthermore, the results have been verified by infrared (IR) and simulation methods. Compared with Raman thermography and IR, this method can conveniently measure the thermal resistance of GaN HEMTs without breaking the package, and the temperature accuracy was ±2 °C or better. And the thermal resistance information of each layer of structure, such as the chip-solder-carrier, can be extracted by structural function method to improve the thermal design of GaN HEMTs.