image: The design and fabrication of the proposed MEMS accelerometer. a Schematic diagram of the accelerometer with two-layered proof mass. The upper layer has flexures, stiffness tuning electrodes, and stopper structure; the lower layer has displacement sensing and FTR electrodes. the proof mass is attached to the glass substrate through flexures and anchors. b Front-side SEM image of the fabricated accelerometer. c SEM image of the back-side of the fabricated proof mass. d Fabricating process of the accelerometer. (1) silicon cleaning, (2) 1st silicon patterning, (3) 2nd silicon patterning, (4) 3rd silicon patterning, (5) glass cleaning, (6) metal patterning, (7) anodic bonding, (8) silicon thinning, (9) structure releasing
Credit: Microsystems & Nanoengineering
MEMS accelerometers, critical in high-precision fields, have historically faced issues with temperature drift and stability, limiting their broader application. The recent study addresses these challenges by introducing a MEMS accelerometer that utilizes advanced self-centering and stiffness control mechanisms. This innovation enhances both precision and temperature stability, making the device suitable for more demanding applications. The research opens new doors for the use of MEMS accelerometers in areas where accuracy and consistency are of utmost importance.
MEMS accelerometers, essential for various high-tech applications, face challenges with temperature-induced accuracy drifts. Despite their widespread use in electronics, navigation, and monitoring systems, their performance is compromised by temperature effects on mechanical and electronic components, leading to inaccuracies. Traditional solutions involve designing temperature-insensitive structures and improving manufacturing processes, but these have limited success.
A recent study (doi: 10.1038/s41378-023-00647-4) led by a team of experts from Zhejiang University, published on January 18, 2024, in the journal Microsystems & Nanoengineering, has introduced an innovative MEMS accelerometer based on stiffness tuning with enhanced precision and stability. This device, notable for its self-centering and stiffness control capabilities, represents a significant advance in accelerometer technology.
The study showcases a MEMS accelerometer equipped with a novel dual closed-loop system, integrating DC/AC electrostatic tuning for effective stiffness adjustment and geometric offset calibration. This system counters the common problem of temperature drift, improving the device's precision and reliability. The accelerometer's design employs a self-centering closed-loop for accurately determining the optimal reference position and a stiffness closed-loop to maintain effective stiffness despite temperature variations. Real-time adjustments of the reference position and tuning voltage enable the compensation of residual temperature drift, achieving a temperature drift coefficient of approximately 7 μg/°C and an Allan bias instability of less than 1 μg.
Lead researcher, Dr. Zhipeng Ma, states, "Our study marks a substantial step forward in MEMS technology, offering remarkable improvements in both precision and temperature stability for a quasi-zero stiffness-based instrumentation of acceleration."
This innovation not only addresses longstanding challenges of temperature drift but also paves the way for more reliable and accurate applications in critical areas like space exploration and environmental monitoring, promising to revolutionize high-precision measurement and control systems.
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References
DOI
10.1038/s41378-023-00647-4
Original Source URL
https://doi.org/10.1038/s41378-023-00647-4
Funding information
The National Natural Science Foundation of China (Grant No. 62104211).
About Microsystems & Nanoengineering
Microsystems & Nanoengineering is an online-only, open access international journal devoted to publishing original research results and reviews on all aspects of Micro and Nano Electro Mechanical Systems from fundamental to applied research. The journal is published by Springer Nature in partnership with the Aerospace Information Research Institute, Chinese Academy of Sciences, supported by the State Key Laboratory of Transducer Technology.
Journal
Microsystems & Nanoengineering
Subject of Research
Not applicable
Article Title
A self-centering and stiffness-controlled MEMS accelerometer
Article Publication Date
18-Jan-2024
COI Statement
The authors declare that they have no competing interests