Design and Fabrication of a lateral axis Gyroscope with Asymmetric Comb-Fingers as Sensing Capacitors

A novel comb capacitor, the fixed and movable fingers of which have different positions but the same height, is proposed. The comb capacitor can be used to measure out-of-plane movement through differential method and has low air damping. Using this kind of comb capacitor, a bulk micromachined y-axis gyroscope is designed, whose structure is doubly decoupled. The gyroscope is fabricated by silicon/glass wafer bonding and deep reactive ion etching process, in which composite etching mask technique is used twice to realize the novel comb structure. The process is compatible with previous reported fabrication process of lateral accelerometers and z-axis gyroscopes.