High accuracy pressure measurement with a silicon resonant sensor

Greenwood, J. C.; Wray, T. E.

doi:10.1016/0924-4247(93)80017-b

Cited by 46 publications

(29 citation statements)

References 2 publications

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“…The deflection of each tine attributed to the electrostatic force is given in (5) where and are the capacitance and gap between tine and electrode, respectively, and is the second moment of area of the tine (5) Given typical driving voltages V and mV, m and m , the static deflection due to the ac component alone is 1 10 m. Naturally, at resonance, this is multiplied by the -factor of the resonator. Assuming a -factor of 10 000, which is conservative compared to similar devices [4], [5], [14], this would equate to an amplitude of 0.1 m, which is of the desired order of magnitude.…”

Section: B Proposed Excitation and Detection Mechanismsmentioning

confidence: 97%

“…Normalizing so that the deflection at the center of the tine is equal to a peak amplitude of 0.1 m, the longitudinal strain can be calculated from the integral where is a normalization constant. Using Mathcad, the strain is found to be 2.7 10 The change in resistivity is given by (4) where π is the piezoresistive coefficient and σ is the stress. Using values of 72 10 m /N [12] for the piezoresistive coefficient for p-type silicon in the [110] direction and 1.66 10 N/m [13] for the elastic modulus of silicon, the estimated change in resistance is calculated to be 32 ppm, which is detectable with careful design of the associated electronic circuitry.…”

Section: B Proposed Excitation and Detection Mechanismsmentioning

confidence: 99%

“…Resonant devices have more recently been realized in silicon using standard micromachining processes [2], [3] and high-performance pressure sensors based upon this technology are already commercially available [4], [5]. While silicon is an excellent mechanical material for resonant applications and many suitable micromachining processes exist, the design, fabrication and packaging of such devices is far from straightforward.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Micromachined silicon resonant strain gauges fabricated using SOI wafer technology

Beeby

Ensell

Baker

et al. 2000

J. Microelectromech. Syst.

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The optimum mode of double-ended tuning-fork-style resonators is a lateral vibration in the plane of the wafer. Lateral vibrations are typically excited using the comb drive approach, but this requires modification to the resonator structure. This paper reports a simple method for exciting and detecting lateral vibrations without modifying the resonator, thereby enabling the optimum dynamically balanced structure to be used. This approach uses plane electrodes positioned parallel to the resonator's tines to excite the vibrations while the change in resistance along the length of the resonator enables the vibrations to be detected. Test devices have been fabricated in single-crystal silicon using the buried oxide in silicon-on-insulator wafers as a sacrificial layer. The resonators are 340-m long, 3-m thick with tines 2-m wide. The gap between the tines and the electrode is 2 m. Visual inspection in a scanning electron microscope and electrical tests have confirmed the validity of this approach. [475]

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Section: B Proposed Excitation and Detection Mechanismsmentioning

confidence: 97%

Section: B Proposed Excitation and Detection Mechanismsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Micromachined silicon resonant strain gauges fabricated using SOI wafer technology

Beeby

Ensell

Baker

et al. 2000

J. Microelectromech. Syst.

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show abstract

“…Greenwood and Wray (1993) mounted a temperature sensing diode on the carrier to correct the temperature drift. In this method, there were some errors caused by temperature difference as the temperature sensor was far away from the resonator.…”

Section: Introductionmentioning

confidence: 99%

An electrothermally excited dual beams silicon resonant pressure sensor with temperature compensation

et al. 2011

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An electrothermally excited dual beams silicon resonant pressure sensor with temperature compensation is proposed in this paper. One beam locates upon the diaphragm, whose resonant frequency changes with the measured pressure; the other beam is on the fixed edge, isolated from the pressure effect but sensitive to the temperature variation. Taking the difference of the dual beams' resonant frequencies, temperature influence can be corrected. Compensation algorithm with consideration of the fabrication errors is deducted theoretically and implemented by a homemade readout system. Experimental results of the test sample indicates that the maxim pressure measurement residual errors without compensation is up to 53.9 kPa in the working temperature range from -40 to 60°C; while with compensation the maxim residual errors decreased to 1.8 kPa from -40 to 60°C, which is only 3.3% of the uncompensated sensor. The experimental results confirm that the new designed sensor has good temperature compensation ability.

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“…With its significant advantages of high sensitivity, small volume, low price and quasi-digital output, the resonant silicon pressure sensor has been the research focus [1][2][3][4][5] . Two typical kinds of resonant pressure sensors were introduced in reference [1][2] respectively, in which the sensor feature better performance, especially in the best sensitivity. But the complicated processing and packaging make the sensor so expensive as not to be replied in more fields except in precision instruments.…”

Section: Introductionmentioning

confidence: 99%

A novel resonant pressure sensor with boron diffused silicon resonator

Wang¹,

Shi²,

Liu³

et al. 2008

2008 International Conference on Optical Instruments and Technology: MEMS/NEMS Technology and Applications

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To improve the performance of the micro-machined resonant pressure sensor and simplify its fabrication process, a novel structure is proposed in which the boron diffused silicon (up to 15um thickness) and the bulk silicon are used as the resonant beam and pressure membrane respectively. The structural parameters were optimized through FEM to achieve the better sensitivity, and the relationships between the structural parameters and the sensitivity were established. Moreover, the fabrication processes were discussed to increase the product rate and the pressure sensor with the optimal structural parameters was fabricated by the bulk silicon MEMS processes. In order to enhance the signal of the sensor and make the closed-looped control of the sensor easily, electromagnetic excitation and detection was applied. However there is so high noise coming from the distributing capacitances between the diffused silicon layer and electrodes that reduce the signal to noise ratio of the sensor. Through the analysis of the micro-structure of the sensor, the asymmetrical excitation circuit was used to reduce the noise and then the detection circuit was designed for this sensor. The resonator of the sensor was packaged in the low vacuum condition so that the high quality factor (Q) with about 10000 can be achieved. Experimental tests were carried out for the sensor over the range of -80kPa to 100kPa, the results show that the sensitivity of the sensor is about 20kHz/100kPa, the sensitivity is 0.01%F.S. and the nonlinearity is about 1.8%.

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High accuracy pressure measurement with a silicon resonant sensor

Cited by 46 publications

References 2 publications

Micromachined silicon resonant strain gauges fabricated using SOI wafer technology

Micromachined silicon resonant strain gauges fabricated using SOI wafer technology

An electrothermally excited dual beams silicon resonant pressure sensor with temperature compensation

A novel resonant pressure sensor with boron diffused silicon resonator

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