Title: Z-axis tuning fork gyroscope having a controlled anti-phase and freestanding architecture: design and fabrication

Authors: Minh Ngoc Nguyen; Long Quang Nguyen; Nhat Sinh Ha; Hoang Manh Chu; Hung Ngoc Vu; Trinh Duc Chu

Addresses: International Training Institute for Materials Science (ITIMS), Hanoi University of Science and Technology, No. 1, Dai Co Viet Street, Hai Ba Trung, Hanoi, Vietnam ' International Training Institute for Materials Science (ITIMS), Hanoi University of Science and Technology, No. 1, Dai Co Viet Street, Hai Ba Trung, Hanoi, Vietnam ' International Training Institute for Materials Science (ITIMS), Hanoi University of Science and Technology, No. 1, Dai Co Viet Street, Hai Ba Trung, Hanoi, Vietnam ' International Training Institute for Materials Science (ITIMS), Hanoi University of Science and Technology, No. 1, Dai Co Viet Street, Hai Ba Trung, Hanoi, Vietnam ' International Training Institute for Materials Science (ITIMS), Hanoi University of Science and Technology, No. 1, Dai Co Viet Street, Hai Ba Trung, Hanoi, Vietnam ' Faculty of Electronics and Telecommunications, University of Engineering and Technology, Vietnam National University, 144 Xuan Thuy Street, Cau Giay, Hanoi, Vietnam

Abstract: This paper reports the design and fabrication of a z-axis tuning fork gyroscope (TFG) having anti-phase controlled and freestanding architectures. The gyroscope is designed to suppress the in-phase sensing mode by using a self-rotation ring. To improve the performance of the TFG by limiting the influence of the squeeze-film damping, the driving and sensing parts of the gyroscope were designed to oscillate in plane. Furthermore, by removing the substrate underneath the device, the slide-film damping in the gap between the proof masses and the substrate is eliminated. The proposed architecture is analysed by finite element method using ANSYS software. The simulated frequencies of the driving and sensing modes are 9.788 kHz and 9.761 kHz, respectively, which determines the sensor bandwidth of 27 Hz. The frequency difference between the driving and sensing modes and the parasitic ones is obtained to be 57.5%. The sensing displacement and driving displacement of the gyroscope at resonance are 0.104 μm and 6.034 μm, respectively. The gyroscope was fabricated based on the bulk micromachining technology. It is shown that the quality factor of the gyroscope is 111.2. The measured sensitivity of the sensor is evaluated to be 11.56 mV/°/s.

Keywords: bulk micromachining; vibratory gyroscope; tuning fork; FEM; finite element analysis.

DOI: 10.1504/IJNT.2018.089557

International Journal of Nanotechnology, 2018 Vol.15 No.1/2/3, pp.14 - 23

Available online: 12 Jan 2018 *

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