A 0.5 mm2 7-mhz capacitive bulk acoustic wave gyroscope in (100) silicon with large dynamic range

This paper presents, what is to the authors' knowledge, the smallest MEMS gyroscope reported to date. With a footprint of only 0.5 mm
²
, the device consists of a high frequency bulk acoustic wave (BAW) disk resonator (408 um diameter) with robust performance to environmental disturbances, and a large dynamic range of more than 6,000 °/s. The device utilizes nano-transduction capacitive gaps provided by the HARPS S process, which enable an extremely small footprint without sacrificing other specifications, such as sensitivity and noise. Moreover, due to the inherently stiff structure, the presented BAW gyro has a significantly reduced sensitivity to shock and vibration [1]. The device exhibits a measured angle-random walk (ARW) of 1 °/√h and a bias instability of 15 °/h, which are dominated by the thermal and flicker noise of the interface electronics. The gyro element itself is capable of reaching 5–10X lower noise levels.