Above 500 °C operation of InAlN/GaN HEMTs

Due to their ceramic-like thermal/chemical stability GaN-based HEMTs are expected to be of high robustness and may also be a prime candidate for reliable high temperature operation. In gas sensing AlGaN/GaN heterostructures have been investigated up to 800 °C [1]. In a simple proof-of-concept experiment InAlN/GaN HEMTs have been operated at 1000 °C for a short period of time in vacuum [2]. However in respect to continuous operation most tests have been limited to a temperature range below 500 °C. Here a continuous test is described operating devices under 1 MHz large signal conditions for 250 hrs at a given temperature increased in steps of 100 °C (in vacuum), concentrating on the temperature range above 500 °C, until failure.