scholarly journals An Electret-Augmented Low-Voltage MEMS Electrostatic Out-of-Plane Actuator for Acoustic Transducer Applications

Micromachines ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 267 ◽  
Author(s):  
Chikako Sano ◽  
Manabu Ataka ◽  
Gen Hashiguchi ◽  
Hiroshi Toshiyoshi
Keyword(s):  
Sound Pressure ◽  
Low Voltage ◽  
Input Voltage ◽  
Plane Motion ◽  
Silicon On Insulator ◽  
Electrostatic Actuators ◽  
Microelectromechanical System ◽  
Acoustic Transducer ◽  
Out Of Plane ◽  
Dc Bias

Despite the development of energy-efficient devices in various applications, microelectromechanical system (MEMS) electrostatic actuators yet require high voltages to generate large displacements. In this respect, electrets exhibiting quasi-permanent electrical charges allow large fixed voltages to be integrated directly within electrode structures to reduce or eliminate the need of DC bias electronics. For verification, a − 40   V biased electret layer was fabricated at the inner surface of a silicon on insulator (SOI) structure facing a 2 μm gap owing to the high compatibility of silicon micromachining and the potassium-ion-electret fabrication method. A − 10   V electret-augmented actuator with an out-of-plane motion membrane reached a sound pressure level (SPL) of 50 dB maximum with AC input voltage of V i n = 5   V pp alone, indicating a potential for acoustic transducer usage such as microspeakers. Such devices with electret biasing require only the input signal voltage, thus contributing to reducing the overall power consumption of the device system.

scholarly journals Low Voltage Electrostatic Actuation and Displacement Measurement Through Resonant Drive Circuit

2012 ◽  
Author(s):  
Sangtak Park ◽  
Eihab Abdel-Rahman
Keyword(s):  
Measurement Method ◽  
Low Voltage ◽  
Supply Voltage ◽  
Numerical Models ◽  
Actuation Voltage ◽  
Input Voltage ◽  
Electrostatic Actuators ◽  
Mems Technology ◽  
Drive Circuit ◽  
The Impact

Most electrostatic actuators fabricated by MEMS technology require high actuation voltage and suffer from the pull-in phenomenon that limits the operation range. We present an amplitude-modulated resonant drive circuit to drive electrostatic actuators at much lower supply voltage than that of conventional actuators to extend their operation range. Analytical and numerical models facilitate stability analysis of electrostatic actuators coupled with the resonant drive circuit. We study the impact of parasitic capacitance and the quality factor of the resonant drive circuit on the operation range of electrostatic actuators. Furthermore, we present a new method to measure the displacement of electrostatic actuators by sensing the phase delay of the actuation voltage with respect to the input voltage. This measurement method allows us to easily incorporate feedback control into existing electrostatic actuators without any modification to the actuator itself.

Optimization of Electrode Structures of PZT Acoustic Energy Harvesters Fabricated on SOI Substrate

2013 ◽  
Vol 683 ◽  
pp. 933-936
Author(s):  
Kazuki Tomii ◽  
Shungo Tomioka ◽  
Satoshi Iizumi ◽  
Kyohei Tsujimoto ◽  
Yusuke Uchida ◽  
...  
Keyword(s):  
Power Generation ◽  
Sound Pressure ◽  
Energy Harvester ◽  
Acoustic Energy ◽  
Silicon On Insulator ◽  
Microelectromechanical System ◽  
Energy Harvesters ◽  
Central Surface ◽  
Peripheral Surface ◽  
Central Energy

This paper reports on the power generation performances of a PZT microelectromechanical system (MEMS) acoustic energy harvester having dual top electrodes to utilize the different polarizations of charges on the surface of a vibrating PZT diaphragm at first resonance. The PZT acoustic energy harvester was fabricated on a silicon-on-insulator (SOI) substrate, and had a diaphragm with a diameter of 2 mm consisting of Al (0.1 μm)/PZT (1 μm)/Pt (0.1 μm)/Ti (0.1 μm)/Si (1.0μm)/ (0.5 μm), and the diaphragm vibrations were excited by sound pressure. The top Al electrodes independently cover the peripheral surface and the central surface of the PZT diaphragm. The peripheral energy harvester generated a power of W, and the central energy harvester generated a power of W at an SPL of 100 dB at 9.95 kHz.

Nano-Manipulation Device With Parallel Kinematic Micro-Positioning Stage and Integrated Active Cantilever

2009 ◽  
Author(s):  
Jingyan Dong ◽  
Placid M. Ferreira
Keyword(s):  
Plane Motion ◽  
Silicon On Insulator ◽  
Three Dimensions ◽  
Driving Voltage ◽  
Ambient Conditions ◽  
Positioning Stage ◽  
Out Of Plane ◽  
Motion Range ◽  
High Bandwidth ◽  
Parallel Kinematic

This paper discusses the design, analysis, fabrication and characterization of a MEMS device for nano-manufacturing and nano-metrology applications. The device includes an active cantilever as its manipulator that is integrated with a high-bandwidth two degree-of-freedom translational (XY) micro positioning stage. The cantilever is actuated electrostatically through a separate electrode that is fabricated underneath the cantilever. Torsion bars that connect the cantilever to the rest of the structure provide the required compliance for cantilever’s out-of-plane rotation. The active cantilever is carried by a micro-positioning stage, which enables high-bandwidth scanning to allow manipulation in three dimensions. The design of the MEMS (Micro-Electro-Mechanical Systems) stage is based on a parallel kinematic mechanism (PKM). The PKM design decouples the motion in the X and Y directions and restricts rotations in the XY plane while allowing for an increased motion range with linear kinematics in the operating region (or workspace). The truss-like structure of the PKM also results in increased stiffness and reduced mass of the stage. The integrated cantilever device is fabricated on a Silicon-On-Insulator (SOI) wafer using surface micromachining and deep reactive ion etching (DRIE) processes. The actuation electrode of the cantilever is fabricated on the handle layer, while the cantilever and XY stage are at the device layer of the SOI wafer. Two sets of electrostatic linear comb drives are used to actuate the stage mechanism in X and Y directions. The cantilever provides an out-of-plane motion of 7 microns at 4.5V, while the XY stage provides a motion range of 24 microns in each direction at the driving voltage of 180V. The resonant frequency of the XY stage under ambient conditions is 2090 Hz. A high quality factor (∼210) is achieved from this parallel kinematics XY stage. The fabricated stages will be adapted as chip-scale manufacturing and metrology devices for nanomanufacturing and nano-metrology applications.

A Study on the Thermal Behavior of Electrothermal Microactuators Due to Various Voltage Inputs.

2006 ◽  
Author(s):  
Mohammad Mayyas ◽  
Panos Shiakolas
Keyword(s):  
Temperature Profile ◽  
Thermal Stresses ◽  
Low Voltage ◽  
Input Voltage ◽  
Silicon On Insulator ◽  
Temperature Profiles ◽  
Femtosecond Laser Micromachining ◽  
Steady State Temperature ◽  
Structural Stresses ◽  
Sinusoidal Temperature

The steady state temperature profiles of U- and I-shaped electrothermal microactuators are analytically derived. The temperature profiles could be used to evaluate the performance sensitivity of the microactuator due to various parameter changes. In this work, the analysis assumes an unpackaged silicon microactuator with an air gap between the actuator and substrate and the profiles are evaluated for various input voltage amplitudes. It was found that at low voltage inputs the temperature profile is exponential in nature with the failure being due to thermo-structural stresses and/or structure melting. At voltages larger than a critical value, a combined sinusoidal and exponential temperature profile is observed with the failure being strongly due to structural melting as well. However, higher voltage excitation causes a fully distributed sinusoidal temperature profile. In this mode, failures occur at different locations and due to high localized thermal stresses causing the temperature to exceed the material melting point. The behavior of U- and I-shaped microactuators based on silicon on insulator (SOI) fabrication and femtosecond laser micromachining was experimentally examined with the results corroborating the conclusions drawn from the analysis.

scholarly journals A Study on Parametric Amplification in a Piezoelectric MEMS Device

Micromachines ◽  
2018 ◽  
Vol 10 (1) ◽  
pp. 19 ◽  
Author(s):  
Miguel Gonzalez ◽  
Yoonseok Lee
Keyword(s):  
Quality Factor ◽  
Parametric Excitation ◽  
Fold Increase ◽  
Plane Motion ◽  
Silicon On Insulator ◽  
Atmospheric Conditions ◽  
Concentrated Mass ◽  
Micro Electro Mechanical Systems ◽  
Out Of Plane ◽  
Quality Factor Q

In various applications, damping from the surrounding fluid severely degrades the performance of micro-electro-mechanical systems (MEMS). In this paper, mechanical amplification through parametric resonance was investigated in a piezoelectrically actuated MEMS to overcome the effects of damping. The device was fabricated using the PiezoMUMPS process, which is based on a Silicon-on-Insulator (SOI) process with an additional aluminum nitride (AlN) layer. Here, a double-clamped cantilever beam with a concentrated mass at the center was excited at its first resonance mode (out-of-plane motion) in air and at atmospheric conditions. A parametric signal modulating the stiffness of the beam was added at twice the frequency of the excitation signal, which was swept through the resonance frequency of the mode. The displacement at the center of the device was detected optically. A four-fold increase in the quality-factor, Q, of the resonator was obtained at the highest values in amplitude used for the parametric excitation. The spring modulation constant was obtained from the effective quality-factor, Q e f f , versus parametric excitation voltage curve. This study demonstrates that through these methods, significant improvements in performance of MEMS in fluids can be obtained, even for devices fabricated using standard commercial processes.

Kinematically Excited Large Angle Tilting Actuator

2010 ◽  
Author(s):  
Assaf Ya’akobovitz ◽  
Slava Krylov
Keyword(s):  
Parallel Plate ◽  
Actuation Voltage ◽  
Large Angle ◽  
Single Layer ◽  
Plane Motion ◽  
Silicon On Insulator ◽  
Deep Reactive Ion Etching ◽  
Micro Actuator ◽  
Tilting Angle ◽  
Out Of Plane

We report on a novel architecture and operational principle of a large angle kinematically excited tilting micro actuator. The device transforms and amplifies small linear out-of-plane motion of a parallel-plate electrostatic transducer into a tilting motion of a plate. The device characterized by robust single layer architecture was fabricated using a silicon on insulator (SOI) wafer and common deep reactive ion etching (DRIE) based fabrication process. Experimental and model results collectively illustrate the feasibility and efficiency of the suggested actuation approach. The optical tilting angle of 37.5° was experimentally registered under relatively low actuation voltage of 100 V.

Resistless Patterning of Magnetic Storage Media Using Ion Projection Structuring

2001 ◽  
Vol 705 ◽  
Author(s):  
A. Dietzel ◽  
R. Berger ◽  
H. Grimm ◽  
C. Schug ◽  
W. H. Bruenger ◽  
...  
Keyword(s):  
Process Development ◽  
Ion Beam ◽  
Silicon On Insulator ◽  
Magnetic Storage ◽  
Magnetic Islands ◽  
Superlattice Structure ◽  
Head Positioning ◽  
Out Of Plane ◽  
Set Up ◽  
The Impact

AbstractCo/Pt thin film multilayers with strong perpendicular anisotropy and out-of-plane coercivities of 5-11 kOe were magnetically altered in areas of local ion beam interaction. The ion irradiations were performed by ion projection through silicon stencil masks fabricated by silicon on insulator (SOI) membrane technology. The ion projector at the Fraunhofer Institute for Silicon Technology (ISiT) was operated at 73 keV ion energy and with a 8.7- fold demagnification. After exposure to 3 × 1014Ar+/ cm2 magnetic islands smaller than 100 nm in diameter were resolved in the Co/Pt multilayersby means of magnetic force microscopy. The impact of different ion species (He+, Ar+ and Xe+) and ion energies (10 – 200 keV) on the multilayer structure was evaluated using Monte Carlo simulations. The ballistic interface intermixing was used to predict magnetic coercivity changes for various irradiation conditions. The simulations revealed that with 73 keV Ar+ and Xe+ ions the irradiation dose could be reduced by a factor of 100 and 400 respectively in comparison to 73 keV He+which was verified in the experiments. X-ray reflectivity measurements confirmed that the Co/Pt superlattice structure is slightly weakened during the irradiation and that the surface smoothness of the media is preserved. Using the Ion Projection Process Development Tool (PDT) at IMS-Vienna concentric data tracks including head positioning servo informations were patterned onto a 1” IBM microdrive™ glass disk which was coated with Co/Pt multilayers. In a single exposure step several tracks within an exposure field of 17 mm in diameter were structured by 2 × 1015He+/ cm2 at 45 keV using a 4- fold demagnification set-up.

LOW-NOISE SILICON-ON-INSULATOR HALL DEVICES

2004 ◽  
Vol 04 (02) ◽  
pp. L345-L354 ◽  
Author(s):  
Y. HADDAB ◽  
V. MOSSER ◽  
M. LYSOWEC ◽  
J. SUSKI ◽  
L. DEMEUS ◽  
...  
Keyword(s):  
Noise Level ◽  
Low Voltage ◽  
Silicon Layer ◽  
Electrical Current ◽  
Low Noise ◽  
Silicon On Insulator ◽  
Technological Parameters ◽  
Wide Range ◽  
Hall Sensors ◽  
Soi Technology

Hall sensors are used in a very wide range of applications. A very demanding one is electrical current measurement for metering purposes. In addition to high precision and stability, a sufficiently low noise level is required. Cost reduction through sensor integration with low-voltage/low-power electronics is also desirable. The purpose of this work is to investigate the possible use of SOI (Silicon On Insulator) technology for this integration. We have fabricated SOI Hall devices exploring the useful range of silicon layer thickness and doping level. We show that noise is influenced by the presence of LOCOS and p-n depletion zones near the edges of the active zones of the devices. A proper choice of SOI technological parameters and process flow leads to up to 18 dB reduction in Hall sensor noise level. This result can be extended to many categories of devices fabricated using SOI technology.

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