InAlN/GaN HEMTs for Operation in the 1000 degrees C Regime: A First Experiment

GaN-based heterostructures, and here, particularly, the lattice matched InAlN/GaN configuration, possess high chemical and thermal stability. Concentrating on refractory metal contact schemes, HEMT devices have been fabricated allowing high-temperature 1-MHz large-signal operation at 1000 degrees C ( in vacuum) for 25 h. Despite slow gate contact degradation, major degradation of the heterostructure could not be observed. Extrapolation of the RF characteristics suggests that operation up to gigahertz frequencies at this temperature may be feasible.