Design and fabrication of high-performance polysilicon vibrating ring gyroscope

This paper presents a detailed analysis on the design and scaling limits of vibrating ring gyroscopes and their implementation using a combined bulk and surface micromachining technology. A high aspect-ratio p++/polysilicon trench-refill fabrication technology has been used to realize the 30-40 μm thick polysilicon ring structure with 0.9 μm ring-to-electrode gap-spacing. The theoretical analysis of the ring gyroscope shows that by taking advantage of the high quality factor of polysilicon, sub-micron ring-to-electrode gap spacing, high aspect ratio polysilicon ring structure produced using deep dry-etching, and the all-silicon feature of this technology, tactical grade vibrating ring gyroscopes with random walk as small as 0.05 deg/√h can be realized, providing several orders of magnitude improvement in performance