Self-Temperature-Compensated GaN MEMS Resonators through Strain Engineering up to 600 K

Intrinsically, MEMS resonators have a large temperature coefficient of frequency (TCF) more than -20 ppm/K. Although several methods were developed to reduce the TCF, the quality (Q) factors of the resonators are markedly degraded. Here, we demonstrate a novel self-temperature-compensated strategy for GaN-based MEMS resonator with an ultra-low TCF without losing the Q factors up to 600 K by using elastic strain engineering. Different from the conventional flexural modes, the internal thermal stress improves the TCF of the GaN MEMS resonator by over 10 times to be as low as ~ ppm/K even at 400 K, without losing the highest Q factor of 10
⁵
even up to 600 K.