How to invent (or not invent) the first silicon MEMS gyroscope

Weinberg, Marc S.

doi:10.1109/isiss.2015.7102372

Cited by 9 publications

(4 citation statements)

References 6 publications

(6 reference statements)

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“…Hence, it is essential to investigate the origin of ZRO drift, uncover the drift mechanisms and explore an effective method to relieve the ZRO drift. Many studies have discussed the mechanisms of ZRO drift in the past decades, and it is believed that the ZRO drift of gyroscopes mainly results from their inherent sensitivity to temperature variations [21,22]. To investigate the correlations between temperature and the ZRO drift, elaborate measurements of the device temperature and f drive at the thermal start-up stage are conducted.…”

Section: Research On the Zro Drift Of Tfgsmentioning

confidence: 99%

ZRO Drift Reduction of MEMS Gyroscopes via Internal and Packaging Stress Release

Wei

Jia

et al. 2021

Micromachines

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Zero-rate output (ZRO) drift induces deteriorated micro-electromechanical system (MEMS) gyroscope performances, severely limiting its practical applications. Hence, it is vital to explore an effective method toward ZRO drift reduction. In this work, we conduct an elaborate investigation on the impacts of the internal and packaging stresses on the ZRO drift at the thermal start-up stage and propose a temperature-induced stress release method to reduce the duration and magnitude of ZRO drift. Self-developed high-Q dual-mass tuning fork gyroscopes (TFGs) are adopted to study the correlations between temperature, frequency, and ZRO drift. Furthermore, a rigorous finite element simulation model is built based on the actual device and packaging structure, revealing the temperature and stresses distribution inside TFGs. Meanwhile, the relationship between temperature and stresses are deeply explored. Moreover, we introduce a temperature-induced stress release process to generate thermal stresses and reduce the temperature-related device sensitivity. By this way, the ZRO drift duration is drastically reduced from ~2000 s to ~890 s, and the drift magnitude decreases from ~0.4 °/s to ~0.23 °/s. The optimized device achieves a small bias instability (BI) of 7.903 °/h and a low angle random walk (ARW) of 0.792 °/√ h, and its long-term bias performance is significantly improved.

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Section: Research On the Zro Drift Of Tfgsmentioning

confidence: 99%

ZRO Drift Reduction of MEMS Gyroscopes via Internal and Packaging Stress Release

Wei

Jia

et al. 2021

Micromachines

View full text Add to dashboard Cite

show abstract

“…Hence, it is essential to study the ZRO drift, understand the drift mechanism and find an effective method to shorten the duration and magnitude of ZRO drift. Research on the mechanism of ZRO drift has been conducted for many years, the ZRO drift of gyroscopes mainly sources from its inherent sensitivity to temperature variations [17,18]. To investigate the correlation between temperature and ZRO drift, a detailed measurement of the device temperature and drive frequency (fdrive) at the thermal stage is adopted.…”

Section: Research On the Zro Drift Of Tfgsmentioning

confidence: 99%

ZRO Drift Reduction of MEMS Gyroscopes via Internal and Packaging Stress Release

Xu¹,

Wei²,

Jia³

et al. 2021

Preprint

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Zero-rate output (ZRO) drift induces deteriorated micro-electromechanical system (MEMS) gy-roscope performances, severely limiting its practical applications. Hence, it is vital to explore an effective method toward ZRO drift reduction. In this work, we conduct an elaborate investigation on the impacts of the internal and packaging stresses on the ZRO drift at the thermal start-up stage, and propose a temperature-induced stress release method to reduce the duration and magnitude of ZRO drift. Self-developed high-Q dual mass tuning fork gyroscopes (TFGs) are adopted to study the correlations between temperature, frequency and ZRO drift. Furthermore, a rigorous finite element simulation model is built based on the actual device and packaging structure, revealing the temperature and stresses distribution inside TFGs. Meanwhile, the relationship between temperature and stresses are deeply explored. Moreover, we introduce a temperature-induced stress release process to generate thermal stresses and reduce the temperature-related device sensitivity. By this way, the ZRO drift duration is drastically reduced from ~2000 s to ~890 s, and the drift magnitude decreases from ~0.4 °/s to ~0.23 °/s. This stress release method achieves a small bias instability (BI) of 7.903 °/h and a low angle random walk (ARW) of 0.792 °/√h, and the long-term bias performance is significantly improved.

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“…Since the introduction of first MEMS rate gyroscopes and accelerometers thanks to the work of miniaturization of inertial systems carried out by Draper Laboratory in the late 1980s [ 9 , 10 ], the precision of MEMS gyroscopes has improved a lot in the last decades, from a bias of few hundred degrees per hour [ 9 , 11 ] to few degrees per hour [ 12 , 13 , 14 , 15 ]. Moreover, as a result of all of these years of research in MEMS gyroscope mechanical design and to the unceasing improvements in microfabrication, silicon, high-quality packaging, and electronics technology, MEMS gyroscopes with

bias and

ARW (angular random walk) are now a reality [ 16 , 17 , 18 , 19 ].…”

Section: Introductionmentioning

confidence: 99%

The Effect of the Bending Beam Width Variations on the Discrepancy of the Resulting Quadrature Errors in MEMS Gyroscopes

et al. 2022

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In this paper, we develop a new approach in order to understand the origin of the quadrature error in MEMS gyroscopes. As the width of the flexure springs is a critical parameter in the MEMS design, it is necessary to investigate the impact of the width variations on the stiffness coupling, which can generate a quadrature signal. To do so, we developed a method to determine the evolution of the stiffness matrix of the gyroscope springs with respect to the variation of the bending beams width of the springs through finite element analysis (FEA). Then, a statistical analysis permits the computation of the first two statistical moments of the quadrature error for a given beam width defect. It turns out that even small silicon etching defects can generate high quadrature level with up to a root mean square (RMS) value of 1220°/s for a bending beam width defect of 0.9%. Moreover, the quadrature error obtained through simulations has the same order of magnitude as the ones measured on the gyroscopes. This result constitutes a great help for designing MEMS gyroscopes, as the consideration of the bending beams width defects is needed in order to avoid high quadrature error.

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How to invent (or not invent) the first silicon MEMS gyroscope

Cited by 9 publications

References 6 publications

ZRO Drift Reduction of MEMS Gyroscopes via Internal and Packaging Stress Release

ZRO Drift Reduction of MEMS Gyroscopes via Internal and Packaging Stress Release

ZRO Drift Reduction of MEMS Gyroscopes via Internal and Packaging Stress Release

The Effect of the Bending Beam Width Variations on the Discrepancy of the Resulting Quadrature Errors in MEMS Gyroscopes

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