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 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.

Assembly and Testing of Surface Micromachined, Piezoresistive Polysilicon Pressure Sensors

1999 ◽  
Author(s):  
Todd F. Miller ◽  
David J. Monk ◽  
Gary O’Brien ◽  
William P. Eaton ◽  
James H. Smith
Keyword(s):  
Pressure Sensor ◽  
Microelectromechanical Systems ◽  
Pressure Sensors ◽  
Single Crystal Silicon ◽  
Surface Micromachining ◽  
Process Technology ◽  
Crystal Silicon ◽  
Noise Characteristics ◽  
Testing Techniques ◽  
Piezoresistive Pressure Sensors

Abstract Surface micromachining is becoming increasingly popular for microelectromechanical systems (MEMS) and a new application for this process technology is pressure sensors. Uncompensated surface micromachined piezoresistive pressure sensors were fabricated by Sandia National Labs (SNL). Motorola packaged and tested the sensors over pressure, temperature and in a typical circuit application for noise characteristics. A brief overview of surface micromachining related to pressure sensors is described in the report along with the packaging and testing techniques used. The electrical data found is presented in a comparative manner between the surface micromachined SNL piezoresistive polysilicon pressure sensor and a bulk micromachined Motorola piezoresistive single crystal silicon pressure sensor.

Design and Optimization of a Highly Sensitive and Linearity Piezoresistive Pressure Sensor Based on a Combination of Cross Beam-Peninsula-Membrane Structure

2017 ◽  
Author(s):  
Tran Anh Vang ◽  
Xianmin Zhang ◽  
Benliang Zhu
Keyword(s):  
Pressure Sensor ◽  
Pressure Sensors ◽  
Single Crystal Silicon ◽  
High Sensitivity ◽  
Crystal Silicon ◽  
Nonlinearity Error ◽  
Trade Off ◽  
Design And Optimization ◽  
Piezoresistive Pressure Sensor ◽  
Piezoresistive Pressure Sensors

The sensitivity and linearity trade-off problem has become the hotly important issues in designing the piezoresistive pressure sensors. To solve these trade-off problems, this paper presents the design, optimization, fabrication, and experiment of a novel piezoresistive pressure sensor for micro pressure measurement based on a combined cross beam - membrane and peninsula (CBMP) structure diaphragm. Through using finite element method (FEM), the proposed sensor performances as well as comparisons with other sensor structures are simulated and analyzed. Compared with the cross beam-membrane (CBM) structure, the sensitivity of CBMP structure sensor is increased about 38.7 % and nonlinearity error is reduced nearly 8%. In comparison with the peninsula structure, the maximum non-linearity error of CBMP sensor is decreased about 40% and the maximum deflection is extremely reduced 73%. Besides, the proposed sensor fabrication is performed on the n-type single crystal silicon wafer. The experimental results of the fabricated sensor with CBMP membrane has a high sensitivity of 23.4 mV/kPa and a low non-linearity of −0.53% FSS in the pressure range 0–10 kPa at the room temperature. According to the excellent performance, the sensor can be applied to measure micro-pressure lower than 10 kPa.

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.

Design and Fabrication of a High Temperature Pressure Sensor

2007 ◽  
Author(s):  
Libo Zhao ◽  
Yulong Zhao ◽  
Zhuangde Jiang
Keyword(s):  
High Temperature ◽  
Single Crystal ◽  
Strain Gage ◽  
Pressure Sensor ◽  
Silicon Substrate ◽  
Single Crystal Silicon ◽  
Sio2 Layer ◽  
Silicon On Insulator ◽  
Crystal Silicon ◽  
Mobile Industry

Based on Silicon on Insulator (SOI) and Micro Electro Mechanical System (MEMS) technology, a single-crystal silicon piezoresistive strain gage was fabricated and constituted by silicon substrate, a thin SiO2 layer by Separation by Implantation of Oxygen (SIMOX), an optimized boron ion implantation doping layer photo lithographed to discrete piezoresistors, stress matching Si3N4 layer, and metallization scheme of Ti/Pt/Au as beam lead layer for connecting piezoresistors to be Wheatstone bridge configuration. A special buried SiO2 layer with the thickness of 367 nm was fabricated by the SIMOX technology, which replaced p-n junction to isolate the piezoresistors from the bulk silicon substrate, so this kind of single-crystal silicon strain gage can be used in many harsh fields under high temperature up to 350°C. By the single-crystal silicon strain gage packaged on the metallic circular flat diaphragm, and along with other thermal treatments and compensating methods, a high temperature pressure sensor has been developed with the pressure range of 0–120 MPa under high temperature above 200°C. The testing results show that the sensor has good static performances under 200°C and fine dynamic characteristics to meet the requirements of the modern industry, such as petroleum and chemistry, mobile industry, military industry, wind tunnels, materials processing.

A Novel Process for Fabricating Force Sensors for Atomic Force Microscopy

1992 ◽  
Vol 276 ◽  
Author(s):  
M. M. Farooqui ◽  
A. G. R. Evans
Keyword(s):  
Single Crystal Silicon ◽  
Force Sensing ◽  
Precise Location ◽  
Crystal Silicon ◽  
Resonant Frequencies ◽  
Force Microscopy ◽  
Atomic Force ◽  
Highly Sensitive ◽  
Mask Design ◽  
Alignment Errors

ABSTRACTThe new technique of scanned force microscopy which enables imaging surface features with sub nanometre resolution has been made possible by the development of highly sensitive, hysteresis free force sensing cantilevers and the availability extremely sharp probing tips. Such cantilevers with integral tips can be micromachined using IC compatible technology, and several processes have been described in literature for their fabrication. These are based on different etching schemes, and require two or more masking stages. A novel process using a single mask is described here for the fabrication of single crystal silicon cantilevers with integral sensing tips. The cantilever thickness can be tailored to provide a range of force constants and resonant frequencies, and the tip profile can be varied from pyramidal to highly cusped. As only a single mask is used in the fabrication, there are no mask alignment errors and precise location of the tip is thereby achieved. This eliminates any twist in the cantilever during scanning which could give rise to distorted imaging. The complete fabrication process and the mask design is described together with SEM photographs of the first batch of devices, which have been evaluated by retrofitting to a commercial atomic force microscope.

Structure Design, Fabrication and Characteristics of Polysilicon Nano-Thin Films Resistances Pressure Sensor Based on MEMS Technology

2011 ◽  
Vol 483 ◽  
pp. 200-205
Author(s):  
Xiao Feng Zhao ◽  
Dian Zhong Wen ◽  
Yang Li ◽  
Yuan Xin Hou ◽  
Chun Peng Ai ◽  
...  
Keyword(s):  
Thin Films ◽  
Pressure Sensor ◽  
Single Crystal Silicon ◽  
Wheatstone Bridge ◽  
Structure Design ◽  
Constant Current ◽  
Bridge Structure ◽  
Crystal Silicon ◽  
Mems Technology ◽  
Single Crystal Silicon Substrate

A polysilicon nano-thin films pressure sensor was designed and fabricated on single crystal silicon substrate by MEMS technology in this paper, and the sensor is composed by Wheatstone bridge structure with four polysilicon nano-thin films resistances fabricated on squared silicon membrane. The experiment result shows that, under constant current power supply of 0.875mA , full scale output is 24.05 mV at room temperature, sensitivity is 0.15 mV/kPa, when the temperatures are from -20 to 80°C, the coefficient of zero temperature and sensitivity temperature is –960 ppm/°C and –820 ppm /°C respectively.

HREM observation of dislocations near room temperature fractures in silicon

1988 ◽  
Vol 46 ◽  
pp. 892-893
Author(s):  
M. H. Rhee ◽  
W. A. Coghlan
Keyword(s):  
Cross Section ◽  
Room Temperature ◽  
Single Crystal Silicon ◽  
Dislocation Nucleation ◽  
Back Side ◽  
Ion Milling ◽  
Crystal Silicon ◽  
Flat Surfaces ◽  
Induced Fractures ◽  
Vicker’S Microhardness

Silicon is believed to be an almost perfectly brittle material with cleavage occurring on {111} planes. In such a material at room temperature cleavage is expected to occur prior to any dislocation nucleation. This behavior suggests that cleavage fracture may be used to produce usable flat surfaces. Attempts to show this have failed. Such fractures produced in semiconductor silicon tend to occur on planes of variable orientation resulting in surfaces with a poor surface finish. In order to learn more about the mechanisms involved in fracture of silicon we began a HREM study of hardness indent induced fractures in thin samples of oxidized silicon.Samples of single crystal silicon were oxidized in air for 100 hours at 1000°C. Two pieces of this material were glued together and 500 μm thick cross-section samples were cut from the combined piece. The cross-section samples were indented using a Vicker's microhardness tester to produce cracks. The cracks in the samples were preserved by thinning from the back side using a combination of mechanical grinding and ion milling.

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