Demonstration of hydrogen sensing operation of AlGaN/GaN HEMT gas sensors in extreme environment

Abstract

Extreme environment operation of hydrogen gas sensing was demonstrated by AlGaN/GaN high electron mobility transistor (HEMT) sensors under the condition of high temperature and energetic irradiation. The HEMT type gas sensors were fabricated on AlGaN/GaN-on-Si platform and the gate area was functionalized with platinum (Pt) as a floating electrode for hydrogen sensing. AlGaN/GaN HEMTs maintained stable current-voltage (I-V) characteristics up to 350 degrees C before and after they were exposed to proton-irradiation with a total dose of 10(15)/cm (2) at 5 MeV. Pt-functionalized GaN HEMT sensors demonstrated excellent hydrogen-sensing performance in the temperature range of 200-350 degrees C. The sensors were able to operate with 30% of hydrogen sensitivity at 350 degrees C even after proton irradiation. This result suggests that gas sensors based-on AlGaN/GaN HEMT structure should be a strong candidate for harsh environment electronics.