A high-performance silicon-on-insulator MEMS gyroscope operating at atmospheric pressure

This paper presents a new, high-performance silicon-on-insulator (SOI) MEMS gyroscope with decoupled oscillation modes. The gyroscope structure allows it to achieve matched-resonance-frequencies, large drive-mode oscillation amplitude, high sense-mode quality factor, and low mechanical cross-talk. The gyroscope is fabricated through the commercially available SOIMUMPS process of MEMSCAP Inc. The fabricated gyroscope has minimum capacitive sense gaps of 2.6m and a structural silicon thickness of 25m, and it fits into a chip area smaller than 3m m× 3 mm. The fabricated gyroscope is hybrid connected to a CMOS capacitive interface ASIC chip, which is fabricated in a standard 0.6m CMOS process. The characterization of the hybrid-connected gyroscope demonstrates a low measured noise-equivalent rate of 90 ◦ /h/Hz 1/2 at atmospheric pressure, eliminating the need for a vacuum package for a number of applications. R 2 -non-linearity of the gyroscope is measured to be better than 0.02%. The gyroscope has a low quadrature signal of 70 ◦ /s and a short-term bias stability of 1.5 ◦ /s. The angular rate sensitivity of the gyroscope is 100V/( ◦ /s) at atmospheric pressure, which improves 24 times to 2.4 mV/( ◦ /s) at vacuum. The noise-equivalent rate of the gyroscope at 20 mTorr vacuum is measured to be 35 ◦ /h/Hz 1/2 , which can be improved further by reducing the electromechanical noise.

[1]  Tayfun Akin,et al.  Symmetrical and decoupled nickel microgyroscope on insulating substrate , 2004 .

[2]  Said Emre Alper,et al.  A symmetric surface micromachined gyroscope with decoupled oscillation modes , 2002 .

[3]  Farrokh Ayazi,et al.  Micromachined inertial sensors , 1998, Proc. IEEE.

[4]  S. E. Alper,et al.  High-Performance SOI-MEMS Gyroscope with Decoupled Oscillation Modes , 2006, 19th IEEE International Conference on Micro Electro Mechanical Systems.

[5]  S. Sherman,et al.  Single-chip surface micromachined integrated gyroscope with 50°/h Allan deviation , 2002, IEEE J. Solid State Circuits.

[6]  Guohong He,et al.  A single-crystal silicon vibrating ring gyroscope , 2002, Technical Digest. MEMS 2002 IEEE International Conference. Fifteenth IEEE International Conference on Micro Electro Mechanical Systems (Cat. No.02CH37266).

[7]  S. Sherman,et al.  Single-chip surface-micromachined integrated gyroscope with 50/spl deg//hour root Allan variance , 2002, 2002 IEEE International Solid-State Circuits Conference. Digest of Technical Papers (Cat. No.02CH37315).

[8]  T. Akin,et al.  A single-crystal silicon symmetrical and decoupled MEMS gyroscope on an insulating substrate , 2005, Journal of Microelectromechanical Systems.

[9]  M. Offenberg,et al.  A surface micromachined silicon gyroscope using a thick polysilicon layer , 1999, Technical Digest. IEEE International MEMS 99 Conference. Twelfth IEEE International Conference on Micro Electro Mechanical Systems (Cat. No.99CH36291).