Issues associated with the design, fabrication and testing of a crystalline silicon ring gyroscope with electromagnetic actuation and sensing

The design of a single-crystal silicon ring with electromagnetic actuation and sensing, for the purpose of producing a gyroscope, is presented which t akes into account the anisotropic nature of silicon. Ring structures are fa bricated using a reactive ion etching process which is compatible with CMOS fabrication technology. Three methods of reducing electrical coupling betw een the drive and the sense are considered. The modes of vibration of the r ing are measured as a function of frequency and drive amplitude and interpr eted in terms of the modes of an ideal structure. Unwanted asymmetry in the ring structure resulting from the fabrication process is responsible for b oth a frequency mismatch and a large mechanical coupling between the princi pal modes of the ring and this limits the response as a gyroscope. Improvem ents to the fabrication of the ring are identified.