A high-aspect-ratio and all-silicon wafer-level vacuum encapsulated disk resonant gyroscope

A high-aspect-ratio and all-silicon wafer-level vacuum encapsulated disk resonant gyroscope (DRG) is designed, fabricated and characterized in this paper. The structure of the DRG is constructed with three layers, the middle active layer is sandwiched by the silicon through silicon via (TSV) layer for electrical interconnect and the silicon cap layer for encapsulation. The bulk silicon fabrication technique is used and the DRG is encapsulated by wafer-level vacuum packaging. The 350 mu m height of the (111) silicon wafer is chosen as active layer to increase the pick-off capacitance, the DRG with a high aspect ratio 35:1 is realized by a nonlinear multi-steps silicon deep reactive ion etching (DRIE) recipe. The measured results show the resonant frequency of the DRG for the drive mode and sense mode is 18220.3 Hz and 18228.3 Hz, respectively, with a 8 Hz frequency split. The quality factor is about 17,000 measured by ring-down method. The frequency split and Q value can be further optimized by controlling the fabrication deviation and the encapsulated vacuum level, respectively.