scholarly journals A Temperature-Insensitive Resonant Pressure Micro Sensor Based on Silicon-on-Glass Vacuum Packaging

Sensors ◽  
2019 ◽  
Vol 19 (18) ◽  
pp. 3866 ◽  
Author(s):  
Pengcheng Yan ◽  
Yulan Lu ◽  
Chao Xiang ◽  
Junbo Wang ◽  
Deyong Chen ◽  
...  
Keyword(s):  
Thermal Stress ◽  
Vacuum Packaging ◽  
Silicon On Insulator ◽  
Pressure Measurements ◽  
Element Analysis ◽  
Pressure Sensitive ◽  
Order Of Magnitude ◽  
Micro Sensor ◽  
Q Factors ◽  
Fitting Error

This paper presents a temperature-insensitive resonant pressure sensor, which is mainly composed of a silicon-on-insulator (SOI) wafer for pressure measurements and a silicon-on-glass (SOG) cap for vacuum packaging. The variations of pressure under measurement bend the pressure sensitive diaphragm and regulate the intrinsic frequencies of the resonators in the device layer. While, variations of temperature cannot significantly change the intrinsic frequencies of the resonators, due to the SOG cap to offset generated thermal stress. Numerical simulations, based on finite element analysis, were conducted to calculate the residual thermal stress and optimize the sensing structures. Experimental results show that the Q-factors of the resonators are higher than 16,000, with a differential pressure sensitivity of 11.89 Hz/kPa, a nonlinearity of 0.01% F.S and a low fitting error of 0.01% F.S with the pressure varying from 100 kPa to 1000 kPa. In particular, a temperature sensitivity of ~1 Hz/°C was obtained in the range of −45 °C to 65 °C, which is one order of magnitude lower than the previously reported counterparts.

High and Moderate-Level Vacuum Packaging of Vibratory MEMS

2013 ◽  
Vol 2013 (1) ◽  
pp. 000705-000710 ◽  
Author(s):  
Igor P. Prikhodko ◽  
Brenton R. Simon ◽  
Gunjana Sharma ◽  
Sergei A. Zotov ◽  
Alexander A. Trusov ◽  
...  
Keyword(s):  
Vacuum Packaging ◽  
Moderate Level ◽  
Silicon On Insulator ◽  
Quality Factors ◽  
High Q ◽  
Hermetic Sealing ◽  
Hemispherical Resonator ◽  
Q Factors ◽  
Grade Performance

We report vacuum packaging procedures for low-stress die attachment and versatile hermetic sealing of resonant MEMS. The developed in-house infrastructure allows for both high and moderate-level vacuum packaging addressing the requirements of various applications. Prototypes of 100 μm silicon-on-insulator Quadruple Mass Gyroscopes (QMGs) were packaged using the developed process with and without getters. Characterization of stand-alone packaged devices with no getters resulted in stable quality factors (Q-factors) of 1000 (corresponding to 0.5 Torr vacuum level), while devices sealed with activated getters demonstrated Q-factors of 1.2 million (below 0.1 mTorr level inside the package). Due to the high Q-factors achieved in this work, we project that the QMG used in this work can potentially reach the navigation-grade performance, potentially bridging the gap between the inertial silicon MEMS and the state-of-the-art fused quartz hemispherical resonator gyroscopes.

scholarly journals A Piezoresistive Pressure Sensor with Optimized Positions and Thickness of Piezoresistors

Micromachines ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 1095
Author(s):  
Qinggang Meng ◽  
Yulan Lu ◽  
Junbo Wang ◽  
Deyong Chen ◽  
Jian Chen
Keyword(s):  
Pressure Sensor ◽  
Good Accuracy ◽  
High Sensitivity ◽  
Silicon On Insulator ◽  
Pressure Measurements ◽  
Pressure Sensitive ◽  
Piezoresistive Pressure Sensor ◽  
Different Temperatures ◽  
Good Repeatability ◽  
Electrical Connections

In this paper, a piezoresistive pressure sensor based on silicon on insulator (SOI) was presented, which was composed of an SOI layer with sensing elements and a glass cap for a hermetic package. Different from its conventional counterparts, the position and thickness of the four piezoresistors was optimized based on numerical simulation, which suggests that two piezoresistors at the center while the other two at the edge of the pressure-sensitive diaphragm and a thickness of 2 μm can produce the maximum sensitivity and the minimum nonlinearity. Due to the use of silicon rather than metal for electrical connections, the piezoresistive pressure sensor was fabricated in a highly simplified process. From the experimental results, the fabricated piezoresistive pressure sensor demonstrated a high sensitivity of 37.79 mV·V−1·MPa−1, a high full-scale (FS) output of 472.33 mV, a low hysteresis of 0.09% FS, a good repeatability of 0.03% FS and a good accuracy of 0.06% FS at 20 °C. A temperature coefficient of sensitivity of 0.44 mV·MPa−1·°C−1 and a low zero drift were also shown at different temperatures. The piezoresistive pressure sensor developed in this study may function as an enabling tool in pressure measurements.

Method of Detecting Trace Metal Contamination in Thick-Film SOI Device

2005 ◽  
Author(s):  
Yasunori Goto ◽  
Hiroomi Eguchi ◽  
Masaru Iida
Keyword(s):  
Trace Metal ◽  
Thick Film ◽  
Metal Contamination ◽  
Semiconductor Device ◽  
Trace Element Analysis ◽  
Silicon On Insulator ◽  
Element Analysis ◽  
Trace Metal Contamination ◽  
Trace Metal Elements ◽  
Output Characteristics

Abstract In the automotive IC using thick-film silicon on insulator (SOI) semiconductor device, if the gettering capability of a SOI wafer is inadequate, electrical characteristics degradation by metal contamination arises and the yield falls. At this time, an automotive IC was made experimentally for evaluation of the gettering capability as one of the purposes. In this IC, one of the output characteristics varied from the standard, therefore failure analysis was performed, which found trace metal elements as one of the causes. By making full use of 3D perspective, it is possible to fabricate a site-specific sample into 0.1 micrometre in thickness without missing a failure point that has very minute quantities of contaminant in a semiconductor device. Using energy dispersive X-ray, it is possible to detect trace metal contamination at levels 1E12 atoms per sq cm. that are conventionally detected only by trace element analysis.

scholarly journals A Resonant Pressure Microsensor with a Wide Pressure Measurement Range

Micromachines ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 382
Author(s):  
Chao Xiang ◽  
Yulan Lu ◽  
Chao Cheng ◽  
Junbo Wang ◽  
Deyong Chen ◽  
...  
Keyword(s):  
Chemical Mechanical Planarization ◽  
Measurement Range ◽  
Silicon On Insulator ◽  
Anodic Bonding ◽  
Pressure Measurements ◽  
Quality Factors ◽  
Deep Reactive Ion Etching ◽  
Wide Range ◽  
Form Pressure ◽  
Silicon Islands

This paper presents a resonant pressure microsensor with a wide range of pressure measurements. The developed microsensor is mainly composed of a silicon-on-insulator (SOI) wafer to form pressure-sensing elements, and a silicon-on-glass (SOG) cap to form vacuum encapsulation. To realize a wide range of pressure measurements, silicon islands were deployed on the device layer of the SOI wafer to enhance equivalent stiffness and structural stability of the pressure-sensitive diaphragm. Moreover, a cylindrical vacuum cavity was deployed on the SOG cap with the purpose to decrease the stresses generated during the silicon-to-glass contact during pressure measurements. The fabrication processes mainly contained photolithography, deep reactive ion etching (DRIE), chemical mechanical planarization (CMP) and anodic bonding. According to the characterization experiments, the quality factors of the resonators were higher than 15,000 with pressure sensitivities of 0.51 Hz/kPa (resonator I), −1.75 Hz/kPa (resonator II) and temperature coefficients of frequency of 1.92 Hz/°C (resonator I), 1.98 Hz/°C (resonator II). Following temperature compensation, the fitting error of the microsensor was within the range of 0.006% FS and the measurement accuracy was as high as 0.017% FS in the pressure range of 200 ~ 7000 kPa and the temperature range of −40 °C to 80 °C.

Three Turnaround Heat Treating Studies

2003 ◽  
Author(s):  
Jaan Taagepera ◽  
Marty Clift ◽  
D. Mike DeHart ◽  
Keneth Marden
Keyword(s):  
Heat Treatment ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Thermal Stress ◽  
Thermal Stresses ◽  
Heat Treating ◽  
Element Analysis ◽  
Stress Profiles ◽  
Insight Into

Three vessel modifications requiring heat treatment were analyzed prior to and during a planned turnaround at a refinery. One was a thick nozzle that required weld build up. This nozzle had been in hydrogen service and required bake-out to reduce the potential for cracking during the weld build up. Finite element analysis was used to study the thermal stresses involved in the bake-out. Another heat treatment studied was a PWHT of a nozzle replacement. The heat treatment band and temperature were varied with location in order to minimize cost and reduction in remaining strength of the vessel. Again, FEA was used to provide insight into the thermal stress profiles during heat treatment. The fmal heat treatment study was for inserting a new nozzle in a 1-1/4Cr-1/2Mo reactor. While this material would ordinarily require PWHT, the alteration was proposed to be installed without PWHT. Though accepted by the Jurisdiction, this nozzle installation was ultimately cancelled.

Finite Element Analysis of Thermal Stress Distribution in Planar SOFC

2019 ◽  
Vol 7 (1) ◽  
pp. 1977-1986 ◽  
Author(s):  
Chih-Kuang Lin ◽  
Tsung-Ting Chen ◽  
An-Shin Chen ◽  
Yau-Pin Chyou ◽  
Lieh-Kwang Chiang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Thermal Stress ◽  
Stress Distribution ◽  
Element Analysis ◽  
Thermal Stress Distribution

scholarly journals Surface Pressure Measurements on Supercritical Airfoil Employing Pressure -Sensitive Paint

2012 ◽  
Vol 31 ◽  
pp. 1160-1167
Author(s):  
Qiang Zhou ◽  
Jian Xiong ◽  
Liusheng Chen ◽  
Husheng Ma ◽  
Yang Tao
Keyword(s):  
Surface Pressure ◽  
Pressure Measurements ◽  
Pressure Sensitive Paint ◽  
Supercritical Airfoil ◽  
Pressure Sensitive

Study on the Influence of Deformation of the Slipper of Axial Piston Pump under High Pressure on Oil Film Structure

2014 ◽  
Vol 900 ◽  
pp. 734-737 ◽  
Author(s):  
Huai Chao Wu ◽  
Yun Liu Yu
Keyword(s):  
High Pressure ◽  
Film Structure ◽  
Piston Pump ◽  
Axial Piston Pump ◽  
Working Pressure ◽  
Element Analysis ◽  
Oil Film ◽  
The Finite Element Analysis ◽  
Order Of Magnitude ◽  
Axial Piston

The stress and strain of the slipper of 35 MPa high pressure axial piston pump are analyzed by the finite element analysis method, and the following facts are revealed: in spite of the fact that the slipper can satisfy the use requirement in the aspect of stress, whereas, in the aspect of strain, the deformation of the bottom of the slipper increases with the pressure increase, and the deformation of the slipper has reached the order of magnitude of the oil film thickness under 35 MPa working pressure. Therefore, when the slipper pair of 35 MPa high pressure axial piston pump is designed and its oil film performances are studied, the influence of deformation of the slipper on the oil film structure must be considered comprehensively. The results of this study can provide some guides for developing 35 MPa high pressure axial piston pump.

scholarly journals Accurate Measurements of Wall Shear Stress on a Plate with Elliptic Leading Edge

Sensors ◽  
2018 ◽  
Vol 18 (8) ◽  
pp. 2682 ◽  
Author(s):  
Guang-Hui Ding ◽  
Bing-He Ma ◽  
Jin-Jun Deng ◽  
Wei-Zheng Yuan ◽  
Kang Liu
Keyword(s):  
Shear Stress ◽  
Wind Tunnel ◽  
Wall Shear Stress ◽  
Leading Edge ◽  
Reynold Number ◽  
Micro Electro Mechanical System ◽  
Flow Speed ◽  
Silicon On Insulator ◽  
Micro Sensor ◽  
Wall Shear

A micro-floating element wall shear stress sensor with backside connections has been developed for accurate measurements of wall shear stress under the turbulent boundary layer. The micro-sensor was designed and fabricated on a 10.16 cm SOI (Silicon on Insulator) wafer by MEMS (Micro-Electro-Mechanical System) processing technology. Then, it was calibrated by a wind tunnel setup over a range of 0 Pa to 65 Pa. The measurements of wall shear stress on a smooth plate were carried out in a 0.6 m × 0.6 m transonic wind tunnel. Flow speed ranges from 0.4 Ma to 0.8 Ma, with a corresponding Reynold number of 1.05 × 106~1.55 × 106 at the micro-sensor location. Wall shear stress measured by the micro-sensor has a range of about 34 Pa to 93 Pa, which is consistent with theoretical values. For comparisons, a Preston tube was also used to measure wall shear stress at the same time. The results show that wall shear stress obtained by three methods (the micro-sensor, a Preston tube, and theoretical results) are well agreed with each other.

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