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

Abstract

This paper presents, what is to the authors' knowledge, the smallest MEMS gyroscope reported to date. With a footprint of only 0.5 mm2, 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.