Bistable Threshold Sensor With Mechanically Nonlinear Self-Limiting Suspension and Electrostatic Actuation

2011 ◽  
Author(s):  
Shila Rabanim ◽  
Emil Amir ◽  
Slava Krylov
Keyword(s):  
Dynamic Range ◽  
Electrostatic Force ◽  
Silicon On Insulator ◽  
Stable Configuration ◽  
Curved Beams ◽  
Suggested Approach ◽  
Deep Reactive Ion Etching ◽  
Electrostatically Actuated ◽  
Contact Devices

We report on the operational principle, modeling, fabrication and characterization of an electrostatically actuated force/acceleration sensor with mechanically nonlinear stiffening suspension. The suspension incorporates initially curved beams oriented in such a way that both the electrostatic and inertial forces applied to the beam’s ends are directed predominantly along the beam. Since the stiffness of the curved beam is significantly lower than that of the straightened beam, the force-displacement dependence of the suspension is of the self-limiting type while the suspension itself serves as a compliant constraint. Application of a softening electrostatic force, provided by a parallel-plate transducer, results in pull-in instability followed by the steep increase in the suspension stifftness and the appearance of an additional stable configuration of the device. In accordance with the model results the dependence between the acceleration and the shift of the pull-in voltage induced by the acceleration is nearly linear and the pull-in voltage monitoring can be used for the measurement of the acceleration. Model results show that using the suggested approach significantly improves device resolution, extends dynamic range, and improves reliability by eliminating contact. Devices of several configurations were fabricated from a silicon on insulator (SOI) substrate using a deep reactive ion etching (DRIE) based process. Preliminary experimental results imply that the suggested approach is feasible.

Toward MEMS Displacement Sensor Based on Resonant Frequency Monitoring of Slightly Curved Beams

2015 ◽  
Author(s):  
Naftaly Krakover ◽  
Bojan R. Ilic ◽  
Slava Krylov
Keyword(s):  
Electrostatic Force ◽  
Single Crystal Silicon ◽  
Displacement Sensor ◽  
Design Parameters ◽  
Curved Beams ◽  
Crystal Silicon ◽  
Suggested Approach ◽  
Electrostatically Actuated ◽  
Frequency Monitoring ◽  
Post Buckling

In this work we report on operational principle, design and characterization of a generic electrostatically actuated micro displacement/acceleration sensor based on frequency monitoring of an initially curved double-clamped microbeam actuated by a close gap electrode. The displacement of the electrode attached to a proof mass results in varying electrostatic force and changing effective stiffness and frequency of the beam. The sensitivity is improved by choosing the working configurations in the vicinity of the critical snap-through buckling points of the beam. Reduced order model of the device was built by means of Gelerkin decomposition and was used for the feasibility study, evaluation of the design parameters and comparison with the experimental data. Devices of several configurations, which included initially straight as well as curved beams were fabricated from single crystal silicon and operated in open air environment. The responses were registered optically by laser Doppler vibrometry (LDV). Consistently with the model prediction, significant reduction in the frequency in the vicinity of the critical point followed by an increase of the frequency in the post-buckling configurations was observed in the experiments. Our theoretical and experimental results collectively demonstrate the feasibility of the suggested approach.

Parametric Excitation of Flexural Vibrations of Micro Beams by Fringing Electrostatic Fields

2010 ◽  
Author(s):  
Slava Krylov ◽  
Nicola Molinazzi ◽  
Tsvi Shmilovich ◽  
Uri Pomerantz ◽  
Stella Lulinsky
Keyword(s):  
Electric Fields ◽  
Parametric Excitation ◽  
Electrostatic Force ◽  
Nonlinear Differential Equations ◽  
Three Dimensional ◽  
Ambient Air ◽  
Silicon On Insulator ◽  
Suggested Approach ◽  
Base Functions ◽  
Fringing Fields

We report on an approach for efficient excitation of large amplitude flexural out-of-plane vibrations of micro beams and present results of theoretical and experimental feasibility study of the suggested principle. An actuating electrode is located symmetrically at the two sides of the beam and is fabricated from the same layer of the wafer. The electrostatic force is engendered by the asymmetry of the fringing fields in the deformed state and acts in the direction opposite to the deflection therefore increasing the effective stiffness of the system. The time-varying voltage applied to the electrode results in the modulation of this electrostatic stiffness and consequently in the parametric excitation of the structure. The device may exhibit large vibrational amplitudes not limited by the pull-in instability common in close-gap actuators. In contrast to previously reported devices excited by the fringing fields, the force considered here is of distributed character. The reduced order model was built using the Galerkin decomposition with linear modes as base functions and the resulting system of nonlinear differential equations was solved numerically. The electrostatic forces were approximated by means of fitting the results of three-dimensional numerical solution for the electric fields. The devices fabricated from a silicon on insulator (SOI) substrate using deep reactive ion etching (DRIE) based process were operated in ambient air conditions and the responses were registered by means of Laser Doppler Vibrometry. The experimental resonant curves were consistent with those predicted by the model. Theoretical and preliminary experimental results illustrated the feasibility of the suggested approach.

A SOI-MEMS-Based Single Axis Active Probe for Cellular Force Sensing and Cell Manipulation

2010 ◽  
Author(s):  
Li Zhang ◽  
Jingyan Dong
Keyword(s):  
Stage Structure ◽  
Silicon On Insulator ◽  
Cell Manipulation ◽  
Force Sensing ◽  
Deep Reactive Ion Etching ◽  
Active Probing ◽  
Comb Drives ◽  
Active Probe ◽  
Fabrication And Characterization

This paper presents the design, analysis, fabrication, and characterization of an electrostatically driven single axis active probing device for cellular force sensing and cell manipulation applications. The active probe is actuated by linear comb driver to create the motion in the probing direction. Both actuation and sensing comb drives are designed for the probing stage. The sensing comb structures enable us to sense the probe displacement when it is actuated, which enables application of force balanced sensing. The designed active probing device has an overall size of 5 mm × 4.5 mm, is fabricated on a silicon-on-insulator (SOI) substrate through surface micromachining technologies and deep reactive-ion etching (DRIE) process. The probe stage structure is fabricated on the 10-μm-thick device layer of SOI wafer. The handle layer beneath probe stage is etched away by DRIE process to decrease the film damping between the stage and the handle wafer thus achieving high quality factor. The proposed single axis probe is aimed at sensing cellular force which ranges from pN to μN and cell manipulation applications.

SiGeC Cantilever Micro Cooler

2003 ◽  
Vol 793 ◽  
Author(s):  
Gehong Zeng ◽  
Ali Shakouri ◽  
Edward Croke ◽  
Yan Zhang ◽  
James Christofferson ◽  
...  
Keyword(s):  
Integrated Circuit ◽  
Room Temperature ◽  
Molecular Beam ◽  
Silicon On Insulator ◽  
Device Performance ◽  
Deep Reactive Ion Etching ◽  
Temperature Modeling ◽  
Cantilever Structure ◽  
Lattice Matched

ABSTRACTThe fabrication and characterization of SiGeC cantilever microcoolers are described. Silicon on insulator (SOI) was used as the substrate, and two layers of 3 μm p-SiGe0.07C0.0075 and 1.14 μm n-SiGe0.07C0.0075 lattice matched to silicon were grown using molecular beam epitaxy. The uni couple cooler was fabricated using conventional integrated circuit (IC) processing, and the cantilever structure was finally formed by removing the backside Si of SOI substrate by deep reactive ion etching. Devices with different n- and p-side length ratios were characterized. Cooling by 1.2K has been measured at room temperature. Modeling showed that the device performance was dominated by the smaller cooling temperature of the p-SiGeC leg of the cantilever structure. Parasitic heat conduction through the Si buffer layer is the main limitation to the device performance.

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.

scholarly journals A Low-g MEMS Accelerometer with High Sensitivity, Low Nonlinearity and Large Dynamic Range Based on Mode-Localization of 3-DoF Weakly Coupled Resonators

Micromachines ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 310
Author(s):  
Muhammad Mubasher Saleem ◽  
Shayaan Saghir ◽  
Syed Ali Raza Bukhari ◽  
Amir Hamza ◽  
Rana Iqtidar Shakoor ◽  
...  
Keyword(s):  
Microelectromechanical Systems ◽  
Dynamic Range ◽  
Proof Mass ◽  
Amplitude Ratio ◽  
Silicon On Insulator ◽  
Coupled Resonators ◽  
Mode Localization ◽  
Mems Accelerometer ◽  
Weakly Coupled ◽  
Input Acceleration

This paper presents a new design of microelectromechanical systems (MEMS) based low-g accelerometer utilizing mode-localization effect in the three degree-of-freedom (3-DoF) weakly coupled MEMS resonators. Two sets of the 3-DoF mechanically coupled resonators are used on either side of the single proof mass and difference in the amplitude ratio of two resonator sets is considered as an output metric for the input acceleration measurement. The proof mass is electrostatically coupled to the perturbation resonators and for the sensitivity and input dynamic range tuning of MEMS accelerometer, electrostatic electrodes are used with each resonator in two sets of 3-DoF coupled resonators. The MEMS accelerometer is designed considering the foundry process constraints of silicon-on-insulator multi-user MEMS processes (SOIMUMPs). The performance of the MEMS accelerometer is analyzed through finite-element-method (FEM) based simulations. The sensitivity of the MEMS accelerometer in terms of amplitude ratio difference is obtained as 10.61/g for an input acceleration range of ±2 g with thermomechanical noise based resolution of 0.22 and nonlinearity less than 0.5%.

Reduced Order Model of MEMS Sensors Near Natural Frequency

2011 ◽  
Author(s):  
Dumitru I. Caruntu ◽  
Jose C. Solis Silva
Keyword(s):  
Natural Frequency ◽  
Nonlinear Response ◽  
Casimir Effect ◽  
Electrostatic Force ◽  
Reduced Order Model ◽  
Mass Detection ◽  
Order Model ◽  
Reduced Order ◽  
First Order ◽  
Electrostatically Actuated

The nonlinear response of an electrostatically actuated cantilever beam microresonator sensor for mass detection is investigated. The excitation is near the natural frequency. A first order fringe correction of the electrostatic force, viscous damping, and Casimir effect are included in the model. The dynamics of the resonator is investigated using the Reduced Order Model (ROM) method, based on Galerkin procedure. Steady-state motions are found. Numerical results for uniform microresonators with mass deposition and without are reported.

Characterization of a Non-Interdigitated Comb Drive

2018 ◽  
Author(s):  
Mary Gopanchuk ◽  
Mohamed Arabi ◽  
N. Nelson-Fitzpatrick ◽  
Majed S. Al-Ghamdi ◽  
Eihab Abdel-Rahman ◽  
...  
Keyword(s):  
Quality Factor ◽  
Fundamental Frequency ◽  
High Quality Factor ◽  
Silicon On Insulator ◽  
Comb Drive ◽  
High Quality ◽  
Sensor Applications ◽  
Fabrication And Characterization

This paper reports on the design, fabrication, and characterization of non-interdigitated comb drive actuators in Silicon-on-Insulator (SOI) wafers, using a single mask surface microma-chining process. The response of the actuator is analyzed numerically and experimentally. The results show at the fundamental frequency; it behaves as a longitudinal comb drive actuator. At a higher frequency, it exhibits a high-quality factor which is appropriate for sensor applications.

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