Gallium Nitride (GaN) MEMS Lamb Wave Resonators Operating At High Temperature Up To 800°C

We report on the first experimental demonstration of gallium nitride microelectromechanical Lamb wave resonators operating at high temperature up to 800°C, while retaining robust electromechanical resonances at ~32MHz and good quality factor of Q=450 at 800°C. The resonance frequency decreases linearly as temperature is being increased, demonstrating an excellent temperature coefficient of resonance frequency of -10 to -20 ppm/°C. The quality factor gradually decreases from ~2000 to ~300 as temperature increases from room temperature to 700°C, then slightly increases to Q=450 as temperature reaches 800°C. Measured resonances exhibit clear repeatability and consistency during heating and cooling processes, without observable hysteresis. This study helps pave the way for advancing gallium nitride electromechanical transducers into high-temperature and hostile environments.