scholarly journals A Resonant Pressure Microsensor Based on Double-Ended Tuning Fork and Electrostatic Excitation/Piezoresistive Detection

Sensors ◽  
2018 ◽  
Vol 18 (8) ◽  
pp. 2494 ◽  
Author(s):  
Xiaoqing Shi ◽  
Yulan Lu ◽  
Bo Xie ◽  
Yadong Li ◽  
Junbo Wang ◽  
...  
Keyword(s):  
Tuning Fork ◽  
Single Crystal Silicon ◽  
Open Loop ◽  
Quality Factors ◽  
Accuracy Rate ◽  
Crystal Silicon ◽  
Piezoresistive Sensors ◽  
Pressure Sensitive ◽  
Tuning Forks ◽  
Stress Buildup

This paper presents a resonant pressure microsensor relying on electrostatic excitation and piezoresistive detection where two double-ended tuning forks were used as resonators, enabling differential outputs. Pressure under measurement caused the deformation of the pressure sensitive membrane, leading to stress buildup of the resonator under electrostatic excitation with a corresponding shift of the resonant frequency detected piezoresistively. The proposed microsensor was fabricated by simplified SOI-MEMS technologies and characterized by both open-loop and closed-loop circuits, producing a quality factor higher than 10,000, a sensitivity of 79.44 Hz/kPa and an accuracy rate of over 0.01% F.S. In comparison to the previously reported resonant piezoresistive sensors, the proposed device used single-crystal silicon as piezoresistors, which was featured with low DC biased voltages, simple sensing structures and fabrication steps. In addition, the two double-ended tuning forks were used as resonators, producing high quality factors and differential outputs, which further improved the sensor performances.

scholarly journals A Double-Ended Tuning Fork Based Resonant Pressure Micro-Sensor Relying on Electrostatic Excitation and Piezoresistive Detection

Proceedings ◽  
2018 ◽  
Vol 2 (13) ◽  
pp. 875
Author(s):  
Xiaoqing Shi ◽  
Yulan Lu ◽  
Bo Xie ◽  
Chao Xiang ◽  
Junbo Wang ◽  
...  
Keyword(s):  
Pressure Sensor ◽  
Single Crystal Silicon ◽  
Open Loop ◽  
Differential Sensitivity ◽  
Crystal Silicon ◽  
Resonant Frequencies ◽  
Piezoresistive Sensors ◽  
Pressure Sensitive ◽  
Micro Sensor ◽  
Stress Variations

This study proposes a microfabricated resonant pressure sensor based on electrostatic excitation and low-impedance piezoresistive detection in which a pair of double-ended tuning forks were utilized as resonators for differential outputs. In operations, targeted pressures deforms the pressure-sensitive membrane, resulting in stress variations of two resonators, leading to shifts of the intrinsic resonant frequencies, which were then measured piezoresistively. The developed microfabricated resonant pressure sensor was fabricated using simple SOI-MEMS processes and quantified in both open-loop and closed-loop manners, where the quality factor, differential sensitivity and linear correlation coefficient were quantified as higher than 10,000, 79.4 Hz/kPa and 0.99999, respectively. Compared to previous resonant piezoresistive sensors, the developed device leveraged single-crystal silicon as the piezoresistor, with advantages in simple sensing structures and fabrication steps. Furthermore, the differential setup was adopted in this study which can further improve the performances of the developed sensors.

scholarly journals A Resonant Pressure Sensor Based upon Electrostatically Comb Driven and Piezoresistively Sensed Lateral Resonators

Micromachines ◽  
2019 ◽  
Vol 10 (7) ◽  
pp. 460 ◽  
Author(s):  
Xiaoqing Shi ◽  
Sen Zhang ◽  
Deyong Chen ◽  
Junbo Wang ◽  
Jian Chen ◽  
...  
Keyword(s):  
Pressure Sensor ◽  
Pressure Sensors ◽  
Single Crystal Silicon ◽  
Open Loop ◽  
Quality Factors ◽  
Crystal Silicon ◽  
Pressure Sensitive ◽  
Lower Temperature ◽  
Silicon Based ◽  
Stress Variations

This study proposes a microfabricated resonant pressure sensor in which a pair of double-ended tuning forks were utilized as resonators where comb electrodes and single-crystal silicon-based piezoresistors were used for electrostatic excitation and piezoresistive detection, respectively. In operations, pressures under measurements deform the pressure-sensitive diaphragm to cause stress variations of two resonators distributed on the central and side positions of the pressure-sensitive diaphragm, where the corresponding changes of the intrinsic resonant frequencies are then captured piezoresistively. The developed resonant pressure sensors were fabricated based on MEMS with open-loop and closed-loop characterizations conducted. Key sensing parameters including quality factors, differential pressure/temperature sensitivities and fitting errors were quantified as higher than 17,000, 48.24 Hz/kPa, 0.15 Hz/°C and better than 0.01% F.S. (140 kpa), respectively. In comparison to previously reported resonant pressure sensors driven by parallel-plate electrodes, the developed sensor in this study is featured with a lower temperature sensitivity and a higher stability.

scholarly journals Resonant Pressure Micro Sensors Based on Dual Double Ended Tuning Fork Resonators

Micromachines ◽  
2019 ◽  
Vol 10 (9) ◽  
pp. 560
Author(s):  
Lu ◽  
Zhang ◽  
Yan ◽  
Li ◽  
Yu ◽  
...  
Keyword(s):  
High Efficiency ◽  
Tuning Fork ◽  
Barometric Pressure ◽  
Open Loop ◽  
Anodic Bonding ◽  
Deep Reactive Ion Etching ◽  
Pressure Cycling ◽  
Pressure Sensitive ◽  
Key Steps ◽  
Electrical Connections

This paper presents resonant pressure micro sensors based on dual double ended tuning fork (DETF) resonators, which are electrostatically excited and piezoresistively detected. In operation, the barometric pressure under measurement bends the pressure sensitive diaphragm functioning as the anchor of DETF resonators and therefore produces eigenfrequency shifts of the resonators. Theoretical analyses and finite element analyses (FEA) were conducted to optimize the key geometries of the DETF resonators with enhanced signal to noise ratios (SNRs). In fabrications, key steps including deep reactive ion etching (DRIE) and anodic bonding were used, where sleeve holes were adopted to form electrical connections, leading to high-efficiency structure layout. Experimental results indicate that the presented micro sensors produced SNRs of 63.70 ± 3.46 dB in the open-loop characterizations and differential sensitivities of 101.3 ± 1.2 Hz/kPa, in the closed-loop characterizations. In addition, pressure cycling tests with a pressure range of 5 to 155 kPa were conducted, revealing that the developed micro sensors demonstrated pressure shifts of 83 ± 2 ppm, pressure hysteresis of 67 ± 3 ppm, and repeatability errors of 39 ± 2 ppm. Thus, the developed resonant pressure micro sensors may potentially function as an enabling tool for barometric pressure measurements.

Binary Excitation of a High-Q Bulk Acoustic Microresonator by Actuation Polarity Inversion

2008 ◽  
Author(s):  
Joshua E.-Y. Lee ◽  
Ashwin A. Seshia
Keyword(s):  
Actuation Voltage ◽  
Single Crystal Silicon ◽  
Quality Factors ◽  
Crystal Silicon ◽  
Polarity Inversion ◽  
High Q ◽  
Resonant Modes ◽  
Bulk Mode ◽  
Silicon Bulk ◽  
Modes Of Vibration

We present a technique for independently exciting two resonant modes of vibration in a single-crystal silicon bulk mode microresonator using the same electrode configuration through control of the polarity of the DC actuation voltage. Applications of this technique may include built-in temperature compensation by the simultaneous selective excitation of two closely spaced modes that may have different temperature coefficients of resonant frequency. The technique is simple and requires minimum circuit overhead for implementation. The technique is implemented on square plate resonators with quality factors as high as 3.06 × 106.

Implementing Inductor Function with Vibrating Capacitor Structures

2013 ◽  
Vol 2013 (1) ◽  
pp. 000354-000360
Author(s):  
Thomas F. Marinis ◽  
Joseph W. Soucy
Keyword(s):  
Power Supply ◽  
Eddy Currents ◽  
Single Crystal Silicon ◽  
Buck Converter ◽  
Beam Deflection ◽  
Dissipated Energy ◽  
Quality Factors ◽  
Crystal Silicon ◽  
Element Analysis ◽  
Essential Components

One of the most common uses of inductors is in filtering electrical signals to remove oscillations over selected frequency ranges. In this application, they are combined with capacitors to build resonant circuits to either block or dissipate signals at the unwanted frequencies. Similar, but larger current capacity filters are used to eliminate oscillatory ripple voltages from DC power supply outputs. Inductors are also essential components in buck converter type power supplies in which they store energy supplied by an oscillatory source to power a circuit, which generates a constant voltage. Inductors of various constructions have proven highly successful in all of these applications, but their performance is not ideal. For one, they dissipate the energy that is stored in them via a number of mechanisms. The conductivity of the wire comprising their windings is finite, so they suffer Ohmic losses. Their magnetic fields induce eddy currents within their cores and dissipative currents in surrounding circuit elements. Inductors also exhibit parasitic capacitance between their windings, which can give rise to dielectric losses. Because of these loss mechanisms, the quality factor of an inductor, which is its time average ratio of stored to dissipated energy, is typically less than a few hundred. By contrast, mechanical resonators, fabricated from single crystal silicon, attain quality factors that are orders of magnitude higher. Hence, mechanical filters could be made with sharper roll offs and smaller bandwidths than inductor based filters. They would also be more efficient in power supply applications. Inductors are also relatively heavy components, when compared to capacitors, resistors and integrated circuits, due to their high content of copper and iron. A mechanical oscillator could be made significantly lighter than an inductor that is capable of storing the same amount of energy. We have been investigating mechanical oscillators that use flat beams, suspended at both ends above substrates with electrode patterns that form a capacitive dive to excite oscillations in the beam. We are examining a number of configuration variables, including beam geometry, mass distribution and excitation loading. We use finite element analysis and lumped parameter models to characterize beam deflection and MatLab scripts to predict performance in electrical circuits. We are also preparing to fabricate our first design for testing.

Calibration Systems and Techniques for Automated Microassembly

2003 ◽  
Author(s):  
K. Tsui ◽  
A. Geisberger ◽  
M. Ellis ◽  
G. Skidmore
Keyword(s):  
Single Crystal Silicon ◽  
Cost Effective ◽  
Open Loop ◽  
Calibration Technique ◽  
Crystal Silicon ◽  
Vision Sensing ◽  
Sensing System ◽  
Pick And Place ◽  
Calibration Device ◽  
Calibration Techniques

A calibration technique is presented here that facilitates automated calibration of a robotic system used for open loop MEMS assembly. A micromechanical calibration device was fabricated in a 20 μm thick electro-plated nickel process as well as a 50 μm thick single crystal silicon, deep reactive ion etched (DRIE) process. This device uses a vision sensing system to detect end-effector position. Results obtained using the calibration device, are presented using a microgripper for pick and place assembly. The relative position of the microgripper and die-site was calibrated to an accuracy of ±1 μm using the described techniques. Microgripper geometry obtained using this technique is also ≤ 3.1 μm of the direct measurement. By utilizing these calibration techniques, the assembly system can be automated to yield a cost-effective microassembly solution.

Implementing Inductor Function with Vibrating Capacitor Structures

2014 ◽  
Vol 11 (2) ◽  
pp. 57-63
Author(s):  
Thomas F. Marinis ◽  
Joseph W. Soucy
Keyword(s):  
Power Supply ◽  
Eddy Currents ◽  
Single Crystal Silicon ◽  
Buck Converter ◽  
Beam Deflection ◽  
Dissipated Energy ◽  
Quality Factors ◽  
Crystal Silicon ◽  
Element Analysis ◽  
Essential Components

One of the most common uses of inductors is in filtering electrical signals to remove oscillations over selected frequency ranges. In this application, they are combined with capacitors to build resonant circuits to either block or dissipate signals at the unwanted frequencies. Similar, but larger current capacity filters are used to eliminate oscillatory ripple voltages from DC power supply outputs. Inductors are also essential components in buck converter type power supplies in which they store energy supplied by an oscillatory source to power a circuit, which generates a constant voltage. Inductors of various constructions have proven highly successful in all of these applications, but their performance is not ideal. For one, they dissipate the energy that is stored in them via a number of mechanisms. The conductivity of the wire comprising their windings is finite, so they suffer Ohmic losses. Their magnetic fields induce eddy currents within their cores and dissipative currents in surrounding circuit elements. Inductors also exhibit parasitic capacitance between their windings, which can give rise to dielectric losses. Because of these loss mechanisms, the quality factor of an inductor, which is its time average ratio of stored to dissipated energy, is typically less than a few hundred. By contrast, mechanical resonators, fabricated from single crystal silicon, attain quality factors that are orders of magnitude higher. Hence, mechanical filters could be made with sharper roll offs and smaller bandwidths than inductor based filters. They would also be more efficient in power supply applications. Inductors are also relatively heavy components, when compared with capacitors, resistors, and integrated circuits, due to their high content of copper and iron. A mechanical oscillator could be made significantly lighter than an inductor that is capable of storing the same amount of energy. We have been investigating mechanical oscillators that use flat beams, suspended at both ends above substrates with electrode patterns that form a capacitive dive to excite oscillations in the beam. We are examining a number of configuration variables, including beam geometry, mass distribution and excitation loading. We use finite element analysis and lumped parameter models to characterize beam deflection and MatLab scripts to predict performance in electrical circuits. We are also preparing to fabricate our first design for testing.

Effect of Thin Aluminum Coatings on Structural Damping of Silicon Microresonators

2009 ◽  
Vol 1222 ◽  
Author(s):  
Guruprasad Sosale ◽  
Sairam Prabhakar ◽  
Luc Frechette ◽  
Srikar Vengallatore
Keyword(s):  
High Performance ◽  
Single Crystal Silicon ◽  
Thermoelastic Damping ◽  
Quality Factors ◽  
Crystal Silicon ◽  
Micromechanical Resonators ◽  
Aluminum Films ◽  
Aluminum Coatings ◽  
Thin Aluminum ◽  
Silicon Beams

AbstractQuantifying the effects of thin metallic coatings on the damping factors of micro- and nanomechanical resonators is important for the design of high-performance devices for sensing and communications. This study presents experimental results for the increase in damping caused by aluminum films coated on cantilevered single-crystal silicon beams. The monolithic silicon beams (100 to 125 microns thick) can operate at the ultimate limits of dissipation established by thermoelastic damping with quality factors ranging from 104 to 105. However, coating these beams with 60 to 100 nm of aluminum can increase the damping by factors of three to five. These results provide guidelines for designing composite micromechanical resonators, and establish the foundation of a new approach for accurate measurement of internal friction in substrate-bonded thin films.

Surface effects and high quality factors in ultrathin single-crystal silicon cantilevers

2000 ◽  
Vol 77 (23) ◽  
pp. 3860-3862 ◽  
Author(s):  
Jinling Yang ◽  
Takahito Ono ◽  
Masayoshi Esashi
Keyword(s):  
Single Crystal ◽  
Single Crystal Silicon ◽  
Surface Effects ◽  
Quality Factors ◽  
High Quality ◽  
Crystal Silicon
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