A new design and a fabrication approach to realize a high performance three axes capacitive MEMS accelerometer

Aydemir, Akin; Terzioğlu, Yunus; Akın, Tayfun

doi:10.1016/j.sna.2016.04.007

Cited by 67 publications

(29 citation statements)

References 13 publications

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“…In this context, the following relation can be expressed with a good approximation. (25) This relation shows that in the original displacements (as long as the amount of displacement relative to the original air distance is small), a linear relation exists between the capacitor changes and displacement in the z axis direction. Therefore, by replacing equations 17 and 25 into equation 5, the sensor sensitivity in the z axis direction can be achieved:…”

Section: Extraction Of Output Relations For the Z Axismentioning

confidence: 97%

A Design and Optimization of a New, Three-Axis MEMS Capacitive Accelerometer with High Dynamic Range and Sensitivity

2020

Informacije MIDEM

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In this paper a three-axis capacitor accelerometer has been designed, analyzed and optimized using microelectromechanical systems technology. The accelerometers are generally divided into three categories of single axis, two axes, and three axes in terms of their ability to measure acceleration. In the suggested structure, acceleration measurements are carried out on all three axes simultaneously using a mass and spring system, which makes it possible to achieve a high sensitivity at a low occupancy level without losing other accelerator factors. By taking difference in this structure, it is shown that each axis acceleration has a very low impact on the measured acceleration of the other two axes. If any external factor changes the value of a single capacitor, the original output of the capacitor does not change for detecting acceleration. In other words, the acceleration of any of these three axes, due to its designing features, does not influence the other two axes and the system performance cannot be disrupted by external factors. The other important characteristics of the accelerometers are dynamic range, operating frequency and sensitivity. This study covers a dynamic range up to 1000g and an operating frequency up to 20 kHz. The accelerometer sensitivity is 4 fF/g in the z axis direction while it is 9 fF/g in the x and y axes directions. In this paper, the simulation of the structure is performed using Intellisuite software. Moreover, a multi-objective genetic optimization algorithm has been used to determine the dimensions of the constituents of the spring and the weight.

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Section: Extraction Of Output Relations For the Z Axismentioning

confidence: 97%

A Design and Optimization of a New, Three-Axis MEMS Capacitive Accelerometer with High Dynamic Range and Sensitivity

2020

Informacije MIDEM

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“…An accelerometer is a micromechanical sensor which measures various modes of accelerations whether they are constant (gravity), time-varying (vibrations), or quasi-static (tilt) [6][7][8][9][10]. To date, a variety of accelerometer solutions and sensitive principles have emerged and have been successfully commercialized for different fields [11][12][13][14][15][16]. However, many factors, including small proof mass, weak signals, low detection sensitivity and high noise interference, limit further improvement of MEMS accelerometers in performance [17,18].…”

Section: Introductionmentioning

confidence: 99%

A Novel Micromachined Z-axis Torsional Accelerometer Based on the Tunneling Magnetoresistive Effect

Yang

Gao

2020

Micromachines

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A novel micromachined z-axis torsional accelerometer based on the tunneling magnetoresistive effect is presented in this paper. The plane main structure bonded with permanent magnetic film is driven to twist under the action of inertial acceleration, which results in the opposite variation of the magnetic field intensity. The variation of the magnetic field is measured by two differential tunneling magnetoresistive sensors arranged on the top substrate respectively. Electrostatic feedback electrodes plated on the bottom substrate are used to revert the plane main structure to an equilibrium state and realize the closed-loop detection of acceleration. A modal simulation of the micromachined z-axis tunneling magnetoresistive accelerometer was implemented to verify the theoretical formula and the structural optimization. Simultaneously, the characteristics of the magnetic field were analyzed to optimize the layout of the tunneling magnetoresistance accelerometer by finite element simulation. The plane main structure, fabricated with the process of standard deep dry silicon on glass (DDSOG), had dimensions of 8000 μm (length) × 8000 μm (width) × 120μm (height). A prototype of the micromachined z-axis tunneling magnetoresistive accelerometer was produced by micro-assembly of the plane main structure with the tunneling magnetoresistive sensors. The experiment results demonstrate that the prototype has a maximal sensitivity of 1.7 mV/g and an acceleration resolution of 128 μg/Hz0.5 along the z-axis sensitive direction.

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“…Basically, their behavior can be simply described as a planar capacitor (i.e., C = ε·A/d, being ε the relative dielectric constant, A the active surface, and d the distance between capacitor metal plates) whose mechanical features (i.e., A and/or d) are temporarily changed by the physical phenomena to be detected. Furthermore, in several sensory systems, differential capacitive sensing configurations also provide a suitable reduction of the common-mode noise and the parasitic component effects [4][5][6][7][8][9][10][11][12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

A Capacitance-to-Time Converter-Based Electronic Interface for Differential Capacitive Sensors

2019

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In this paper we present an oscillating conditioning circuit, operating a capacitance-to-time conversion, which is suitable for the readout of differential capacitive sensors. The simple architecture, based on a multiple-feedbacks structure that avoids ground noise disturbs and system calibrations, employs only three Operational Amplifiers (OAs) and a mixer implementing a square wave oscillator that provides an AC sensor excitation voltage. It performs a Period Modulation (PM) and a Pulse Width Modulation (PWM) of the output signal proportionally to the sensor differential capacitance values. The sensor variation range and the detection sensitivity can be easily set through the additional resistors. Preliminary PSpice simulation results have shown a good agreement with theoretical calculations as well as a linear response with a high detection sensitivity of differential capacitive sensors having a baseline in the range [2.2 ÷ 180 pF]. Moreover, different experimental measurements have been also performed by implementing the circuit on a laboratory breadboard using commercial discrete components so validating the idea and providing the circuit performances with different kind of differential capacitive sensors achieving detection resolutions of about 0.1 fF in an overall differential capacitive variation range that is equal to ±15.8 pF. The achieved results demonstrate that the proposed interface solution is suitable for on-chip integration with different kinds of differential capacitive sensing devices, such as Micro-Electro-Mechanical-System (MEMS), force/position, and humidity sensors in biomedical and robotics applications.

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A new design and a fabrication approach to realize a high performance three axes capacitive MEMS accelerometer

Cited by 67 publications

References 13 publications

A Design and Optimization of a New, Three-Axis MEMS Capacitive Accelerometer with High Dynamic Range and Sensitivity

A Design and Optimization of a New, Three-Axis MEMS Capacitive Accelerometer with High Dynamic Range and Sensitivity

A Novel Micromachined Z-axis Torsional Accelerometer Based on the Tunneling Magnetoresistive Effect

A Capacitance-to-Time Converter-Based Electronic Interface for Differential Capacitive Sensors

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