Accurate Temperature Estimation for Each Gate of GaN HEMT With n-Gate Fingers

Abstract

An analytical approach based on the thermoelectrical analogy to calculate the maximum channel temperature of multifinger AlGaN/GaN HEMT transistor is presented. The model is capable of predicting the maximum channel temperature, including the impact of the nonlinearity of thermal conductivity for every single gate with excellent accuracy. The model remains invariant under device scaling up and down and gives an accurate estimation for any number of gate fingers. Furthermore, the temperature field fluctuation due to the interaction between gates and variation in the number of gate fingers can be easily identified by the model. The validity of the proposed approach has been testified by comparing the results with those from infrared spectroscopy and numerical simulations for different AlGaN/GaN HEMT transistors with a different number of gates. The significance of models is justified by its ability to evaluate the temperature of any gate finger with high accuracy. Such an ability is particularly highly important while optimizing the structure layout and cooling system for high-power AlGaN/GaN HEMT transistors. The model can serve as a powerful tool for power devices and microwave IC designers and can be easily incorporated into SPICE empirical or physical-based models.