A micro-electro-mechanical accelerometer based on gallium nitride on silicon

Abstract

We report on an accelerometer micro-sensor based on epitaxial gallium nitride and silicon. The device is a vibrating beam accelerometer fabricated with a micro-electro-mechanical-system technology starting from an AlGaN/GaN heterostructure grown on silicon. The vibrating GaN beam has integrated high electron mobility transducers, whereas a high aspect ratio proof mass is engineered in the silicon substrate. The sensor response was investigated for several modes and features a scale factor up to 160 Hz/g, with unconventional dependence vs the mode number. To account for this, we propose an analytical model of the accelerometer scale factor that takes into account the built-in stress during epitaxy. This proof-of-concept device opens perspectives for inertial sensors taking advantage of GaN properties.