A Polysilicon Microhemispherical Resonating Gyroscope

This letter reports, for the first time, an integrated polysilicon microhemispherical resonating gyroscope (μHRG) with selfaligned drive, sense, and tuning electrodes, all fabricated using a single wafer process. The polysilicon hemispherical shell is 700 nm in thickness and 1.2 mm in diameter, resulting in a 1:3000 aspect ratio three-dimensional (3-D) microstructure. The quality factor of the wineglass mode is measured to be 8500 at 6.7 kHz with an as-fabricated frequency mismatch of 105 Hz between the two m = 2 degenerate modes. The modes are electrostatically matched and aligned using the tuning electrodes with a resulting mode-matched quality factor of 11100. Initial characterization of the sensitivity of the μHRG shows a scale factor of 4.4 mV/o/s.