Integrated Raman - IR Thermography on AlGaN/GaN Transistors

We report on the integrated Raman-IR thermography analysis of AlGaN/GaN heterostructure field effect transistors (HFETs). IR thermography provides fast temperature overviews while micro-Raman enables accurate peak temperature determination with high spatial resolution in selected device areas. Excellent agreement between Raman determined device temperatures and finite difference simulations was achieved in the active device region. IR provided temperature determination over large device areas, and complemented the Raman thermal data. In IR thermography, lateral averaging of temperature in the small active device region resulted in an underestimation of device peak temperature and an overestimation of temperature profile linewidth. Dependent on device layout, depth averaging of device temperature occurs in IR thermography. The developed novel approach opens unique possibilities for the thermal screening of MMICs and reliability optimization