Electrothermal Mapping of AlGaN/GaN HEMTs Using Microresistance Thermometer Detectors

Abstract

Self-heating effects in AlGaN/GaN high-electron mobility transistors (HEMTs) can notably reduce electron mobility and produce reliability concerns. Electrothermal characterization and appropriate thermal management are required to address this situation. This letter presents the measurement of channel temperature (T <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ch</sub> ) of GaN HEMTs in multiple bias conditions with a good accuracy. The measurements are executed using the integrated microresistance thermometer detector (μRTD) technique in AlGaN/GaN HEMTs on SiC and sapphire substrates. The integrated Ti/Pt μRTD sensor with linear resistance-temperature characteristic is used to obtain an I <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ds</sub> -V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ds</sub> -T <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ch</sub> map for each device. Thermal resistances are compared for similar operation conditions, obtaining RTH = 34.7 °C · W <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> for the HEMT on SiC and RTH = 157.2 °C · W <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> for the HEMT on sapphire.