Thermal management and device failure assessment of high-power AlGaN/GaN HFETs

Self-heating effects limit the performance of high-power AlGaN/GaN HFETs. Knowledge of the temperature in the active area of AlGaN/GaN HFETs is essential for optimizing device design, performance and reliability, however, direct measurement of this temperature is not readily achieved by IR techniques. Improved temperature information can be obtained by micro-Raman spectroscopy allowing temperature measurements with 1 /spl mu/m spatial resolution, important for local device geometries in the micron/sub-micron dimension range. This novel approach allows fast temperature measurements with minimal influence on device performance. We illustrate the use of micro-Raman spectroscopy for thermal management and device failure assessment by studying effects of device design and substrate on temperature in active high-power AlGaN/GaN HFETs. Temperature evolution up to device failure was investigated.