Actuator for Out-of-Plane MEMS Devices

2001 ◽  
Author(s):  
A. D. Johnson ◽  
Vikas Gupta
Keyword(s):  
Mems Devices ◽  
Out Of Plane

A In Situ Measuring Method for Stress Gradient of a MEMS Film

2009 ◽  
Vol 60-61 ◽  
pp. 357-360 ◽  
Author(s):  
Han Chen ◽  
Hua Rong ◽  
Ming Wang
Keyword(s):  
Thin Film ◽  
Circular Plate ◽  
Stress Gradient ◽  
Measuring Method ◽  
Mechanical Parameter ◽  
Curvature Radius ◽  
Mems Devices ◽  
Out Of Plane

The stress gradient of a deposited thin-film is a mechanical parameter that affects the performance of MEMS devices, so in-situ measuring stress gradient of a thin-film is great significant. A new in-situ measuring method based on a center-anchored circular plate is presented. The Mirau interferometer has been used to measure the out-of-plane height at the edge of circular plate, then the curvature radius of the plate and the stress gradient of the film can be calculated. The measuring method has been verified by CoventorWare. The accuracy of the presented measuring method is ideal. The advantages of the method also have been discussed.

Characterization of the Dynamical Response of a Micromachined G-Sensor to Mechanical Shock Loading

2007 ◽  
Author(s):  
Daniel E. Jordy ◽  
Mohammad I. Younis
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Element Model ◽  
Squeeze Film ◽  
Dynamical Response ◽  
Mems Devices ◽  
Damping Coefficients ◽  
Squeeze Film Damping ◽  
Out Of Plane ◽  
Gap Width

Squeeze film damping has a significant effect on the dynamic response of MEMS devices that employ perforated microstructures with large planar areas and small gap widths separating them from the substrate. Perforations can alter the effect of squeeze film damping by allowing the gas underneath the device to easily escape, thereby lowering the damping. By decreasing the size of the holes, the damping increases and the squeeze film damping effect increases. This can be used to minimize the out-of-plane motion of the microstructures toward the substrate, thereby minimizing the possibility of contact and stiction. This paper aims to explore the use of the squeeze-film damping phenomenon as a way to mitigate shock and minimize the possibility of stiction and failure in this class of MEMS devices. As a case study, we consider a G-sensor, which is a sort of a threshold accelerometer, employed in an arming and fusing chip. We study the effect of changing the size of the perforation holes and the gap width separating the microstructure from the substrate. We use a multi-physics finite-element model built using the software ANSYS. First, a modal analysis is conducted to calculate the out-of-plane natural frequency of the G-sensor. Then, a squeeze-film damping finite-element model, for both the air underneath the structure and the flow of the air through the perforations, is developed and utilized to estimate the damping coefficients for several hole sizes. Results are shown for various models of squeeze-film damping assuming no holes, large holes, and assuming a finite pressure drop across the holes, which is the most accurate way of modeling. The extracted damping coefficients are then used in a transient structural-shock analysis. Finally, the transient shock analysis is used to determine the shock loads that induce contacts between the G-sensor and the underlying substrate. It is found that the threshold of shock to contact the substrate has increased significantly when decreasing the holes size or the gap width, which is very promising to help mitigate stiction in this class of devices, thereby improving their reliability.

scholarly journals High Performance, Continuously Tunable Microwave Filters Using MEMS Devices With Very Large, Controlled, Out-of-Plane Actuation

2018 ◽  
Vol 27 (6) ◽  
pp. 1135-1147 ◽  
Author(s):  
Jackson Chang ◽  
Michael J. Holyoak ◽  
George K. Kannell ◽  
Marc Beacken ◽  
Matthias Imboden ◽  
...  
Keyword(s):  
High Performance ◽  
Microwave Filters ◽  
Mems Devices ◽  
Tunable Microwave ◽  
Out Of Plane

scholarly journals Reduced Order Component & System Level Modelling for Fluid-Solid Interactions in Complex MEMS Devices

Proceedings ◽  
2019 ◽  
Vol 2 (13) ◽  
pp. 937
Author(s):  
Henry Schmidt ◽  
David Kriebel ◽  
Jan Mehner
Keyword(s):  
Synthesis Method ◽  
Optical Measurements ◽  
System Level ◽  
Model Generation ◽  
Mems Devices ◽  
Reduced Order ◽  
Flow Simulations ◽  
Pressure Profiles ◽  
Out Of Plane ◽  
Generation Procedure

The time-efficient and accurate implementation of physics-based fluidic damping effects is still one of the biggest challenges in the simulation of complex MEMS devices. Two modelling approaches utilizing the CRAIG/BAMPTON component mode synthesis method are discussed and compared in context of a highly automated model generation procedure. The first approach uses a modal projection technique with pressure profiles obtained from REYNOLDS flow simulations using the thermal-fluidic analogy. The second approach is based on the representation of the fluidic domain in form of a generalized KIRCHHOFFian lumped flow resistance network model. Both methods are generally suited for the simulation of structures like gyroscopes or accelerometers, but show different behaviors in terms of scaling and complexity during the model generation step and in the final ROM. The methods are demonstrated on examples and are compared to optical measurements of an out-of-plane teeter-totter type accelerometer.

Wide Bandwidth Piezoelectric Energy Harvester With Transverse Movable Mass

2020 ◽  
Author(s):  
Luis A. Rodriguez ◽  
Nathan Jackson
Keyword(s):  
Proof Mass ◽  
Vibrational Energy ◽  
Mems Devices ◽  
Wide Bandwidth ◽  
Energy Harvesters ◽  
Piezoelectric Energy ◽  
Complex Design ◽  
Out Of Plane ◽  
Commercial Applications ◽  
Frequency Sweeping

Abstract High Q-Factor vibrational energy harvesters are ideal as they maximize power generation, but a narrow bandwidth limits the potential use in most commercial applications, and it is a major challenge that has not been resolved. Numerous designs have been investigated to solve this challenge but most of the attempts are based on frequency sweeping mechanism or require complex design/fabrication which are not practical especially for MEMS devices. This paper reports for the first time a transverse vertical moving mass inside the proof mass as a method to widen the bandwidth which is independent of frequency sweeping. The out-of-plane movable mass is achieved by fabricating a vertical cavity in the proof mass and partially filling the cavity with metallic spheres. Ultra-wide bandwidth was achieved for low (0.5g) and high (1g) accelerations with an increase in bandwidth from 3.9 Hz (control) to 56 Hz (movable mass). This transverse method of widening the bandwidth is potentially scalable to MEMS devices.

Laminated Photoresist Sacrificial Layer Process for 3-D Movable Suspension Microstructures in LIGA-Based Surface Micromachining

2010 ◽  
Vol 97-101 ◽  
pp. 2538-2541 ◽  
Author(s):  
Yi Bo Wu ◽  
Gui Fu Ding ◽  
Cong Chun Zhang ◽  
Hong Wang
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Sacrificial Layer ◽  
Low Cost ◽  
Three Dimensional ◽  
Mems Devices ◽  
Metal Structures ◽  
Positive Photoresist ◽  
Out Of Plane ◽  
Freely Moving

The fabrication process of three-dimensional (3D) high-aspect-ratio MEMS devices entirely made of electroplated metals with suspending multilayered microstructures is reported. The technology used is a LIGA-liked micromachining process, called the laminated positive photoresist sacrificial layer process (LPSLP). The LPSLP allows in UV-lithography not only for thick resist mould for electroplating of cascaded metal structures but also for the sacrificial layer for supporting mechanically the suspensions. So far the LPSLP procedure has incorporated with more than five sacrificial layers, which allows for the creation of overhanging structures and freely moving parts like out-of-plane cantilever stacks. A description of the underlying fabrication principle and processing details is discussed in this paper. Thus the proposed procedures open a low-cost route for fabricating micro-components such as cantilevers, bridges, movable electrodes, and freestanding parts.

Integrating SOI and Poly-Si Surface Structures Using a Monolithic Process

2003 ◽  
Author(s):  
Mingching Wu ◽  
Shiunafang Shy ◽  
Weileun Fang
Keyword(s):  
Thin Film ◽  
Self Assembly ◽  
Single Crystal Silicon ◽  
Optical Quality ◽  
Mems Devices ◽  
Crystal Silicon ◽  
High Optical Quality ◽  
Out Of Plane ◽  
Variable Optical Attenuators ◽  
Bimorph Beam

This work has successfully integrated thick SCS and thin film poly-Si microstructures on a SOI wafer using monolithic processes. Thus high optical quality SOI micromirror and large output microactuators are available using the thick SOI wafer. Moreover, the poly-Si thin film microstructures serve as microhinges and stress-induced self-assembly mechanisms. The microstructures will be lifted and assembled by SixNy/Poly-Si bimorph beams after releasing. This work adopted in-plane movable optical stage and out-of-plane pop-up mirror to demonstrate the characteristic of proposed process. Some reliability testing results showed that the SixNy/Poly-Si bimorph beam was reliable for self-assembly applications. In summary, this integrated process can substantially increase the feasibility and extensibility of fabricating MEMS devices using single crystal silicon (SCS) and poly-Si. In applications, various 3-dimesional optical devices, such as optical switches, variable optical attenuators, and micro-scanners, can be developed by proposed process after assembling the SCS micromirror and poly-Si microstructures.

Characterization of the Dynamical Response of a Micromachined G-Sensor to Mechanical Shock Loading

2008 ◽  
Vol 130 (4) ◽  
Author(s):  
Daniel Jordy ◽  
Mohammad I. Younis
Keyword(s):  
Element Model ◽  
Plane Motion ◽  
Squeeze Film ◽  
Dynamical Response ◽  
Mechanical Shock ◽  
Mems Devices ◽  
Squeeze Film Damping ◽  
Out Of Plane ◽  
Gap Width

Squeeze film damping has a significant effect on the dynamic response of microelectromechanical system (MEMS) devices that employ perforated microstructures with large planar areas and small gap widths separating them from the substrate. Perforations can alter the effect of squeeze film damping by allowing the gas underneath the device to easily escape, thereby lowering damping. By decreasing the size of the holes, damping increases and the squeeze film damping effect increases. This can be used to minimize the out-of-plane motion of the microstructures toward the substrate, thereby minimizing the possibility of contact and stiction. This paper aims to explore the use of the squeeze film damping phenomenon as a way to mitigate shock and minimize the possibility of stiction and failure in this class of MEMS devices. As a case study, the performance of a G-sensor (threshold accelerometer) employed in an arming and fusing chip is investigated. The effect of changing the size of the perforation holes and the gap width separating the microstructure from the substrate are studied. A multiphysics finite-element model built using the software ANSYS is utilized for the fluidic and transient structural analysis. A squeeze film damping model, for both the air underneath the structure and the flow of the air through the perforations, is developed. Results are shown for various models of squeeze film damping assuming no holes, large holes, and assuming a finite pressure drop across the holes, which is the most accurate way of modeling. It is found that the threshold of shock that causes the G-sensor to contact the substrate has increased significantly when decreasing the holes size or the gap width, which is very promising to help mitigate stiction in this class of devices, thereby improving their reliability.

Grain separation enhanced magnetic coercivity in Pt/Co multilayers.

1993 ◽  
Vol 51 ◽  
pp. 1038-1039 ◽  
Author(s):  
G.A. Bertero ◽  
R. Sinclair
Keyword(s):  
Remanent Magnetization ◽  
Strong Influence ◽  
Uniaxial Anisotropy ◽  
Magnetic Coupling ◽  
Recording Media ◽  
Magnetic Media ◽  
Signal To Noise ◽  
Out Of Plane ◽  
Longitudinal Recording ◽  
The Relationship

Pt/Co multilayers displaying perpendicular (out-of-plane) magnetic anisotropy and 100% perpendicular remanent magnetization are strong candidates as magnetic media for the next generation of magneto-optic recording devices. The magnetic coercivity, Hc, and uniaxial anisotropy energy, Ku, are two important materials parameters, among others, in the quest to achieving higher recording densities with acceptable signal to noise ratios (SNR). The relationship between Ku and Hc in these films is not a simple one since features such as grain boundaries, for example, can have a strong influence on Hc but affect Ku only in a secondary manner. In this regard grain boundary separation provides a way to minimize the grain-to-grain magnetic coupling which is known to result in larger coercivities and improved SNR as has been discussed extensively in the literature for conventional longitudinal recording media.We present here results from the deposition of two Pt/Co/Tb multilayers (A and B) which show significant differences in their coercive fields.

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