Advanced Characterization Techniques and Analysis of Thermal Properties of AlGaN/GaN Multifinger Power HEMTs on SiC Substrate Supported by Three-Dimensional Simulation

In this paper, several methods suitable for real time on-chip temperature measurements of power AlGaN/GaN-based high-electron mobility transistor (HEMT) grown on a SiC substrate are presented. The measurement of temperature distribution on HEMT surface using Raman spectroscopy is presented. The second approach utilizes electrical I–V characteristics of the Schottky diode neighboring to the heat source of the active transistor under different dissipated power for temperature measurement. These methods are further verified by measurements with microthermistors. The features and limitations of the proposed methods are discussed. The thermal parameters of materials used in the device are extracted from the temperature distribution in the structure with the support of three-dimensional thermal simulation of the device. Thermal analysis of the multifinger power HEMT is performed. The effects of the structure design and fabrication processes from semiconductor layers, metallization, and packaging up to cooling solutions are investigated. The influence of individual layer properties on the thermal performance of different HEMT structures under different operating conditions is presented. The results show that the proposed experimental methods supported by simulation have a potential for the design, analysis, and thermal management of HEMT.