Implementing Inductor Function with Vibrating Capacitor Structures

2014 ◽  
Vol 11 (2) ◽  
pp. 57-63
Author(s):  
Thomas F. Marinis ◽  
Joseph W. Soucy
Keyword(s):  
Power Supply ◽  
Eddy Currents ◽  
Single Crystal Silicon ◽  
Buck Converter ◽  
Beam Deflection ◽  
Dissipated Energy ◽  
Quality Factors ◽  
Crystal Silicon ◽  
Element Analysis ◽  
Essential Components

One of the most common uses of inductors is in filtering electrical signals to remove oscillations over selected frequency ranges. In this application, they are combined with capacitors to build resonant circuits to either block or dissipate signals at the unwanted frequencies. Similar, but larger current capacity filters are used to eliminate oscillatory ripple voltages from DC power supply outputs. Inductors are also essential components in buck converter type power supplies in which they store energy supplied by an oscillatory source to power a circuit, which generates a constant voltage. Inductors of various constructions have proven highly successful in all of these applications, but their performance is not ideal. For one, they dissipate the energy that is stored in them via a number of mechanisms. The conductivity of the wire comprising their windings is finite, so they suffer Ohmic losses. Their magnetic fields induce eddy currents within their cores and dissipative currents in surrounding circuit elements. Inductors also exhibit parasitic capacitance between their windings, which can give rise to dielectric losses. Because of these loss mechanisms, the quality factor of an inductor, which is its time average ratio of stored to dissipated energy, is typically less than a few hundred. By contrast, mechanical resonators, fabricated from single crystal silicon, attain quality factors that are orders of magnitude higher. Hence, mechanical filters could be made with sharper roll offs and smaller bandwidths than inductor based filters. They would also be more efficient in power supply applications. Inductors are also relatively heavy components, when compared with capacitors, resistors, and integrated circuits, due to their high content of copper and iron. A mechanical oscillator could be made significantly lighter than an inductor that is capable of storing the same amount of energy. We have been investigating mechanical oscillators that use flat beams, suspended at both ends above substrates with electrode patterns that form a capacitive dive to excite oscillations in the beam. We are examining a number of configuration variables, including beam geometry, mass distribution and excitation loading. We use finite element analysis and lumped parameter models to characterize beam deflection and MatLab scripts to predict performance in electrical circuits. We are also preparing to fabricate our first design for testing.

Implementing Inductor Function with Vibrating Capacitor Structures

2013 ◽  
Vol 2013 (1) ◽  
pp. 000354-000360
Author(s):  
Thomas F. Marinis ◽  
Joseph W. Soucy
Keyword(s):  
Power Supply ◽  
Eddy Currents ◽  
Single Crystal Silicon ◽  
Buck Converter ◽  
Beam Deflection ◽  
Dissipated Energy ◽  
Quality Factors ◽  
Crystal Silicon ◽  
Element Analysis ◽  
Essential Components

One of the most common uses of inductors is in filtering electrical signals to remove oscillations over selected frequency ranges. In this application, they are combined with capacitors to build resonant circuits to either block or dissipate signals at the unwanted frequencies. Similar, but larger current capacity filters are used to eliminate oscillatory ripple voltages from DC power supply outputs. Inductors are also essential components in buck converter type power supplies in which they store energy supplied by an oscillatory source to power a circuit, which generates a constant voltage. Inductors of various constructions have proven highly successful in all of these applications, but their performance is not ideal. For one, they dissipate the energy that is stored in them via a number of mechanisms. The conductivity of the wire comprising their windings is finite, so they suffer Ohmic losses. Their magnetic fields induce eddy currents within their cores and dissipative currents in surrounding circuit elements. Inductors also exhibit parasitic capacitance between their windings, which can give rise to dielectric losses. Because of these loss mechanisms, the quality factor of an inductor, which is its time average ratio of stored to dissipated energy, is typically less than a few hundred. By contrast, mechanical resonators, fabricated from single crystal silicon, attain quality factors that are orders of magnitude higher. Hence, mechanical filters could be made with sharper roll offs and smaller bandwidths than inductor based filters. They would also be more efficient in power supply applications. Inductors are also relatively heavy components, when compared to capacitors, resistors and integrated circuits, due to their high content of copper and iron. A mechanical oscillator could be made significantly lighter than an inductor that is capable of storing the same amount of energy. We have been investigating mechanical oscillators that use flat beams, suspended at both ends above substrates with electrode patterns that form a capacitive dive to excite oscillations in the beam. We are examining a number of configuration variables, including beam geometry, mass distribution and excitation loading. We use finite element analysis and lumped parameter models to characterize beam deflection and MatLab scripts to predict performance in electrical circuits. We are also preparing to fabricate our first design for testing.

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.

scholarly journals The Effects of Cold Arm Width and Metal Deposition on the Performance of a U-Beam Electrothermal MEMS Microgripper for Biomedical Applications

Micromachines ◽  
2019 ◽  
Vol 10 (3) ◽  
pp. 167 ◽  
Author(s):  
Marija Cauchi ◽  
Ivan Grech ◽  
Bertram Mallia ◽  
Pierluigi Mollicone ◽  
Nicholas Sammut
Keyword(s):  
Microelectromechanical Systems ◽  
Coefficient Of Thermal Expansion ◽  
Numerical Models ◽  
Lateral Displacement ◽  
Single Crystal Silicon ◽  
Silicon On Insulator ◽  
Adhesion Promoter ◽  
Crystal Silicon ◽  
Element Analysis ◽  
Human Red Blood Cells

Microelectromechanical systems (MEMS) have established themselves within various fields dominated by high-precision micromanipulation, with the most distinguished sectors being the microassembly, micromanufacturing and biomedical ones. This paper presents a horizontal electrothermally actuated ‘hot and cold arm’ microgripper design to be used for the deformability study of human red blood cells (RBCs). In this study, the width and layer composition of the cold arm are varied to investigate the effects of dimensional and material variation of the cold arm on the resulting temperature distribution, and ultimately on the achieved lateral displacement at the microgripper arm tips. The cold arm widths investigated are 14 μ m, 30 μ m, 55 μ m, 70 μ m and 100 μ m. A gold layer with a thin chromium adhesion promoter layer is deposited on the top surface of each of these cold arms to study its effect on the performance of the microgripper. The resultant ten microgripper design variants are fabricated using a commercially available MEMS fabrication technology known as a silicon-on-insulator multi-user MEMS process (SOIMUMPs)™. This process results in an overhanging 25 μ m thick single crystal silicon microgripper structure having a low aspect ratio (width:thickness) value compared to surface micromachined structures where structural thicknesses are of the order of 2 μ m. Finite element analysis was used to numerically model the microgripper structures and coupled electrothermomechanical simulations were implemented in CoventorWare ® . The numerical simulations took into account the temperature dependency of the coefficient of thermal expansion, the thermal conductivity and the electrical conductivity properties in order to achieve more reliable results. The fabricated microgrippers were actuated under atmospheric pressure and the experimental results achieved through optical microscopy studies conformed with those predicted by the numerical models. The gap opening and the temperature rise at the cell gripping zone were also compared for the different microgripper structures in this work, with the aim of identifying an optimal microgripper design for the deformability characterisation of RBCs.

Fracture Behavior of Silicon Cut with a High Power Laser

1991 ◽  
Vol 226 ◽  
Author(s):  
C.C. Chao ◽  
R. Chleboski ◽  
E.J. Henderson ◽  
C.K. Holmes ◽  
J.P. Kalejs ◽  
...  
Keyword(s):  
Single Crystal ◽  
Fracture Strength ◽  
High Power ◽  
Single Crystal Silicon ◽  
Strength Distribution ◽  
Power Laser ◽  
Crystal Silicon ◽  
Element Analysis ◽  
Cut Edge ◽  
Basic Hypothesis

AbstractThe fracture twist test is used to obtain the statistical fracture strength distribution for 10-cm square single crystal and polycrystalline silicon wafers cut with a high-power Nd:YAG laser. Tensile wafer edge stresses at fracture are calculated using nonlinear finite element analysis, and the model results are used to examine the limitations of linear torsion and plate theories. The basic hypothesis is that fracture strength of laser-cut wafers is limited by microcracks formed by large residual tensile stresses produced in the cut edge upon cooling after cutting. Differences are found between single crystal CZ and polycrystalline EFG silicon material Weibull parameters characterizing the fracture strength distribution. These indicate that there is a statistical influence of material variables on the fracture strength of the EFG silicon, which lowers its strength and increases the variance of fracture response in comparison to single crystal silicon.

A Study on the Nanoindentation Behaviour of Single Crystal Silicon Using Hybrid MD-FE Method

2008 ◽  
Vol 32 ◽  
pp. 259-262 ◽  
Author(s):  
Akbar Afaghi Khatibi ◽  
Bohayra Mortazavi
Keyword(s):  
Molecular Dynamics ◽  
Finite Element ◽  
Single Crystal ◽  
Material Properties ◽  
Single Crystal Silicon ◽  
Dynamics Simulation ◽  
Fe Method ◽  
Crystal Silicon ◽  
Element Analysis ◽  
Nano Scale

Developing new techniques for the prediction of materials behaviors in nano-scales has been an attractive and challenging area for many researches. Molecular Dynamics (MD) is the popular method that is usually used to simulate the behavior of nano-scale material. Considering high computational costs of MD, however, has made this technique inapplicable as well as inflexible in various situations. To overcome these difficulties, alternative procedures are thought. Considering its capabilities, Finite Element Analysis (FEA) seems to be the most appropriate substitute for MD simulations in most cases. But since the material properties in nano, micro, and macro scales are different, therefore to use FEA methods in nano-scale modeling one must use material properties appropriate to that scale. To this end, a previously developed Hybrid Molecular Dynamics-Finite Element (HMDFE) approach was used to investigate the nanoindentation behavior of single crystal silicon with Berkovich indenter. In this study, a FEA model was developed based on the material properties extracted from molecular dynamics simulation of uniaxial tension test on single crystal Silicon. Eventually, by comparison of FEA results with experimental data, the validity of this new technique for the prediction of nanoindentation behavior of Silicon was concluded.

Binary Excitation of a High-Q Bulk Acoustic Microresonator by Actuation Polarity Inversion

2008 ◽  
Author(s):  
Joshua E.-Y. Lee ◽  
Ashwin A. Seshia
Keyword(s):  
Actuation Voltage ◽  
Single Crystal Silicon ◽  
Quality Factors ◽  
Crystal Silicon ◽  
Polarity Inversion ◽  
High Q ◽  
Resonant Modes ◽  
Bulk Mode ◽  
Silicon Bulk ◽  
Modes Of Vibration

We present a technique for independently exciting two resonant modes of vibration in a single-crystal silicon bulk mode microresonator using the same electrode configuration through control of the polarity of the DC actuation voltage. Applications of this technique may include built-in temperature compensation by the simultaneous selective excitation of two closely spaced modes that may have different temperature coefficients of resonant frequency. The technique is simple and requires minimum circuit overhead for implementation. The technique is implemented on square plate resonators with quality factors as high as 3.06 × 106.

FRACTURE CHARACTERISTICS OF DLC ON SILICON USING NANO-INDENTATION AND FEA

2006 ◽  
Vol 20 (25n27) ◽  
pp. 4213-4218 ◽  
Author(s):  
SEUNG BAEK ◽  
CHANG-SUNG SEOK
Keyword(s):  
Fracture Toughness ◽  
Finite Element ◽  
Single Crystal Silicon ◽  
Chemical Vapor ◽  
Diamond Like Carbon ◽  
Silicon Substrates ◽  
Crystal Silicon ◽  
Element Analysis ◽  
Indentation Tests ◽  
Micro Indentation

In this study, using the nano and micro-indentation tests and finite element analysis (FEA), we investigated the fracture behaviors of diamond like carbon (DLC) on silicon in indentation state. Diamond like carbon coating of 3μm and 1.5μm thickness were deposited on polished (100) single crystal silicon substrates by radio frequency plasma assisted chemical vapor deposition (RF-PACVD), respectively. Fracture toughness of DLC films was calculated from the measured lengths of the cracks formed by nano and micro-indentation on each sample. We used various equations such as Lawn's and Liang's equation to calculate the fracture toughness. The effective fracture toughnesses of these DLC films were 1.2 ~1.3 MPam 0.5, calculated by Lawn's and Liang's equations. The true fracture toughness of DLC on silicon, excluding the portion of fracture toughness due to a substrate, was determined to be 4.0~5.1 MPam 0.5. DLC films with crack initiation and propagation were analyzed by finite element method.

scholarly journals The Effects of Structure Thickness, Air Gap Thickness and Silicon Type on the Performance of a Horizontal Electrothermal MEMS Microgripper

Actuators ◽  
2018 ◽  
Vol 7 (3) ◽  
pp. 38 ◽  
Author(s):  
Marija Cauchi ◽  
Ivan Grech ◽  
Bertram Mallia ◽  
Pierluigi Mollicone ◽  
Nicholas Sammut
Keyword(s):  
Microelectromechanical Systems ◽  
Numerical Models ◽  
Substrate Surface ◽  
Single Crystal Silicon ◽  
Air Gap ◽  
Silicon On Insulator ◽  
Free Standing ◽  
Crystal Silicon ◽  
Element Analysis ◽  
Intrinsic Nature

The ongoing development of microelectromechanical systems (MEMS) over the past decades has made possible the achievement of high-precision micromanipulation within the micromanufacturing, microassembly and biomedical fields. This paper presents different design variants of a horizontal electrothermally actuated MEMS microgripper that are developed as microsystems to micromanipulate and study the deformability properties of human red blood cells (RBCs). The presented microgripper design variants are all based on the U-shape `hot and cold arm’ actuator configuration, and are fabricated using the commercially available Multi-User MEMS Processes (MUMPs®) that are produced by MEMSCAP, Inc. (Durham, NC, USA) and that include both surface micromachined (PolyMUMPs™) and silicon-on-insulator (SOIMUMPs™) MEMS fabrication technologies. The studied microgripper design variants have the same in-plane geometry, with their main differences arising from the thickness of the fabricated structures, the consequent air gap separation between the structure and the substrate surface, as well as the intrinsic nature of the silicon material used. These factors are all inherent characteristics of the specific fabrication technologies used. PolyMUMPs™ utilises polycrystalline silicon structures that are composed of two free-standing, independently stackable structural layers, enabling the user to achieve structure thicknesses of 1.5 μm, 2 μm and 3.5 μm, respectively, whereas SOIMUMPs™ utilises a 25 μm thick single crystal silicon structure having only one free-standing structural layer. The microgripper design variants are presented and compared in this work to investigate the effect of their differences on the temperature distribution and the achieved end-effector displacement. These design variants were analytically studied, as well as numerically modelled using finite element analysis where coupled electrothermomechanical simulations were carried out in CoventorWare® (Version 10, Coventor, Inc., Cary, NC, USA). Experimental results for the microgrippers’ actuation under atmospheric pressure were obtained via optical microscopy studies for the PolyMUMPs™ structures, and they were found to be conforming with the predictions of the analytical and numerical models. The focus of this work is to identify which one of the studied design variants best optimises the microgripper’s electrothermomechanical performance in terms of a sufficient lateral tip displacement, minimum out-of-plane displacement at the arm tips and good heat transfer to limit the temperature at the cell gripping zone, as required for the deformability study of RBCs.

Effect of Thin Aluminum Coatings on Structural Damping of Silicon Microresonators

2009 ◽  
Vol 1222 ◽  
Author(s):  
Guruprasad Sosale ◽  
Sairam Prabhakar ◽  
Luc Frechette ◽  
Srikar Vengallatore
Keyword(s):  
High Performance ◽  
Single Crystal Silicon ◽  
Thermoelastic Damping ◽  
Quality Factors ◽  
Crystal Silicon ◽  
Micromechanical Resonators ◽  
Aluminum Films ◽  
Aluminum Coatings ◽  
Thin Aluminum ◽  
Silicon Beams

AbstractQuantifying the effects of thin metallic coatings on the damping factors of micro- and nanomechanical resonators is important for the design of high-performance devices for sensing and communications. This study presents experimental results for the increase in damping caused by aluminum films coated on cantilevered single-crystal silicon beams. The monolithic silicon beams (100 to 125 microns thick) can operate at the ultimate limits of dissipation established by thermoelastic damping with quality factors ranging from 104 to 105. However, coating these beams with 60 to 100 nm of aluminum can increase the damping by factors of three to five. These results provide guidelines for designing composite micromechanical resonators, and establish the foundation of a new approach for accurate measurement of internal friction in substrate-bonded thin films.

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