A Planar Gyroscope Using a Standard Surface Micromachining Process

Alper, Said Emre
Akın, Tayfun
This paper presents a planar gyroscope based on a standard three-layer polysilicon surface micromachining process. Structural geometry is designed to minimize the effects of limitations coming from the standard surface micromachining. Finite element simulations are carried out, and mismatches of resonant frequencies of the drive and sense mode vibrations are reduced down to 0.5% in order to achieve increased performance. The third polysilicon layer on top of outer gimbal is used for feedback control and for tuning of the resonant frequency. The drive and sense capacitance values are 2.48 pF and 0.58 pF, respectively. The device measures about 900μmx550μm area with a 2μm thick structural layer. The fabricated structures are tested and their resonant frequencies are measured as 5119 Hz and 4889 Hz for the drive and sense vibration modes, respectively. The frequency mismatch is 4.65% for these two modes and the resonant frequencies can be adjusted by varying the dc bias voltage applied to the proof mass. A capacitive readout circuit was developed in a 0. 8 μm CMOS process to be hybrid connected to the gyroscope. The fabricated readout circuit can detect capacitance changes smaller than 0.1fF and provide a sensitivity of 45mV/fF.
Citation Formats
S. E. Alper and T. Akın, “A Planar Gyroscope Using a Standard Surface Micromachining Process,” presented at the The 14th European Conf. on Solid-State Transducers (Eurosensors XIV), (27 - 30 Ağustos 2000), Kobenhavn, Danimarka, 2000, Accessed: 00, 2021. [Online]. Available: https://hdl.handle.net/11511/74944.