bluuebunny/crossref_metadata_2025_split huggingface dataset:
Operating Frequency of Thin Film NiTi in Fluid Media
Authors: Shin Daniel D. , Carman Gregory P. 
Published: November 2021

Abstract
For the present paper, the operating frequencies for thin film Nickel-Titanium (NiTi) shape memory alloy were investigated. The results thus far have shown that careful delivery of power to NiTi membrane increased the operating frequency by an order of magnitude. The method of power delivered to the membrane seemed to depend on the thermal conductivity of the fluid in contact. Stagnant air and mineral oil required shorter heating times and less power due to then-low conducting characteristics. De-ionized water on the other hand required greater power and longer heating time. Although heat dissipation to the surrounding was inevitable, it was determined that delivering large bursts of energy in a short heating time can minimize such loss. This way, more energy was used to heat the membrane rather than dissipating to the surroundings. While only 60Hz was measured using the thin film membrane, higher operating frequencies are achievable if power delivery to the membrane is carefully controlled.
Electrothermal Linear Micromotors Fabricated From Deep Reactive Ion Etching of Single Crystal Silicon
Authors: Maloney John M. , Schreiber David S. , DeVoe Don L. 
Published: November 2021

Abstract
Electrothermal linear motors with heights of 50 μm have been fabricated by using deep reactive ion etching (DRIE) on silicon-on-insulator (SOI) wafers. The motors are powered by V-beam thermal actuators that deflect laterally when current is applied. Synchronized arrays of actuators are used to position and clamp a slider through frictional contact only, improving positioning resolution. These high-aspect-ratio motors produce significantly larger forces than similar polysilicon electrothermal or electrostatic devices. Forces of 6.7 mN have been demonstrated at a voltage of 12 V, making these motors well suited for positioning compliant mechanisms. Motors measuring 2.5 mm by 2.1 mm in die area have been run at speeds of up to 1 mm/s over a range in excess of 2 mm.
Micromachined Fabry-Perot Interferometers for the Demodulation of Fiber Optic Strain Sensors
Authors: Rosenberger Frederick F. , Schreiber David S. , DeVoe Don L. 
Published: November 2021

Abstract
Two types of micromachined Fabry-Perot interferometers have been developed to serve as adjustable read-out interferometers for an optical fiber strain sensor system. The fabricated micromirror serves as one reflective surface of the Fabry-Perot cavity, with the cleaved, coated end of the input optical fiber acting as the second surface. Electrostatic and thermal actuators allow adjustment of the cavity spacing. Due to the particular system requirements, the micromotors used to position the mirror must provide large displacements (over 50μm) with sub-micron positioning accuracy. Two different embodiments of the interferometer design, including integrated micromotors, have been achieved. The first design, fabricated using the Cronos MUMPs 2.5-layer polysilicon process, consists of a pop-up mirror mounted on a slider that is positioned in front of the fiber by an electrothermal stepper motor. The second design, fabricated using Deep Reactive Ion Etching (DRIE) of single crystal silicon, uses a bulk etched silicon mirror that is positioned in front of the fiber by an electrostatic comb drive. Design, fabrication, and characterization of the interferometers are discussed.
Development of a Program for Predicting Residual Stress Distribution in Multi-Stacked Film
Authors: Choi Hyeon Chang , Park Jun Hyub , Park Yong Soo 
Published: November 2021

Abstract
The mean stresses of the single and multi-stacked film are experimentally investigated. After stacking several layers on a wafer, we measure the curvature on the wafer. Followed by peeling each layer stacked, we measure the curvature on the wafer, again. Mean residual stresses are calculated from radiuses of the curvatures using the Stoney’s equation[1]. Microcantilever beams is constructed by removing substrate and the deflection at the end of a beam is measured.
Finite element method for determining residual stress distribution in multi-stacked films with a multi-step doping process is studied for use in micromachining applications. We propose a finite element program for residual stress analysis (RESA) in multi-stacked polysilicon film. The distribution of residual stress field in multi-stacked films is predicted using RESA. And it is established for the prediction method determining the deflection in a cantilever beam using finite element method (FEM).
Through-Wafer Electrical Interconnects for MEMS Sensors
Authors: Chandrasekaran Venkataraman , Chow Eugene M. , Kenny Thomas W. , Nishida Toshikazu , Sheplak Mark 
Published: November 2021

Abstract
The fabrication and characterization of p-type silicon electrical through-wafer interconnects (pETWI) on a silicon wafer is presented. Together with previously developed n-type ETWI [1], the pETWI enables complementary ETWI (CETWI) for maximum flexibility of through-wafer interconnects for MEMS sensors and semiconductor devices. Deep reactive ion etching using the Bosch process is employed to create high aspect ratio 20 μm vias through the wafer. The interconnects are electrically isolated from the bulk silicon substrate by a 2 μm thermal oxide layer. Electrical conduction is achieved by depositing several layers of boron-doped polysilicon. Details of the fabrication process as well as results of the pETWI characterization are presented. Interconnects with various polysilicon doping concentrations were fabricated to investigate the effect on the resistance, capacitance and noise. Average resistance values between 10 Ω and 14 Ω were obtained for each interconnect depending on the doping levels. This resistance is suitable for many MEMS applications. High frequency capacitance versus voltage (C-V) characteristics and the noise power spectral density (PSD) were also measured.
Metal-Induced Laterally Crystallized Polycrystalline Silicon for Micro-Systems: Mechanical and Etching Characteristics
Authors: Wang Mingxiang , Yeung Wan Lap , Zohar Yitshak , Wong Man 
Published: November 2021

Abstract
It is determined that for metal-induced laterally crystallized (MILC) polycrystalline silicon (poly-Si), the mechanical and etch properties compare favorably with and the sensing and electrical properties are better than those of conventional low-pressure chemical vapor deposited (LPCVD) poly-Si. The etching characteristics of MILC poly-Si in tetra-methyl ammonium hydroxide (TMAH) solution have been studied. A unified model based on preferential grain boundary (GB) etching has been proposed to explain the etching behavior of poly-Si in TMAH.
Fabrication of Micropipes for Optical Interconnects Using Electroless Processes
Authors: Cheng Yu-Ting , Sambucetti Carlos , Teh K. S. 
Published: November 2021

Abstract
A novel process for low cost fabrication of metallic micropipes has been successfully developed. This method requires only selective surface activation of a single mode optical fiber followed by electroless plating. Concentrated HF and sulfuric acid solutions are used to remove the glass core and the polymer buffer of the fiber with a rate of 500 μm/hr and 500 μm/min respectively. These micropipes can have different inner diameter (i.d.) such as 125 or 250 μm, depending on the size of the optical fiber, and hence they are very suitable for high precision splicing of single mode optical fibers as well as for optical switches used in fiber-optical systems. The fabrication process holds great promise to evolve into an inexpensive manufacturing process for mass production of micropipes and also it can be integrated with Silicon Optical Benches metallurgical techniques.
A Novel Testing Machine for Characterization of Materials for MEMS Applications
Authors: Gudlavalleti Sauri , Anand Lallit 
Published: November 2021

Abstract
We have developed a novel uniaxial testing machine for testing small samples in the load range 25 μN – 1.5 N and specimen size/displacement range μm - mm, which are typically encountered in microtensile testing of free standing thin films and foils, micro-beam bending, and ultramicro-indentation. The machine is based on the use of compound flexures (in an integrated frame) as precision guides for actuation and as linear springs for force measurement. Results are presented from tests in different regimes of the machine’s force and displacement ranges to demonstrate its capabilities. The tests include (a) micro-tensile tests on free-standing gold thin films, rolled copper foils and elastomeric fibers, and (b) micro-indentation tests on aluminum samples. The machine yields consistent high quality data at a very high resolution.
Piezoelectric Bimorph Microphone With Serial Electrical Connection
Authors: Yi Seung Hwan , Kim Eun Sok 
Published: November 2021

Abstract
This paper describes a piezoelectric bimorph microphone built on Parylene-D diaphragm with two ZnO films of opposite c-axis orientations. The highest sensitivity of fabricated microphone is about 74.22 μV/μbar with proper serial electrical connections, which is about twice higher than that of individual segmented electrode. The piezoelectric bimorph microphone is very attractive since it can be fabricated low temperature under 250 °C except the first low stress nitride deposition.
Surface Micro-Machined Mirrors Using Simple Floating and Fixed Hinge Designs for Three-Layer Process
Authors: Mahatvaraj Alpha , Vora Nirav D. , Bush Jimmy , Cunningham Glenn , Biernacki Joseph J. , Frolik Jeffrey 
Published: November 2021

Abstract
Micro-mirrors and other hinged microstructures have numerous MEMS applications. Such micro-mirrors can be used in laser-interferometry, laser beam modulation, fiber-optical switching, laser scanners and printers and a variety of other optical applications.
A pop-up mirror device is proposed which consist of a hinged polysilicon mirror mounted on a silicon substrate. The folding mirror, with one fixed hinge and two floating hinges, is designed such that the mirror is lifted off the substrate by the linear movement of a shaft from an actuating system. The assembly uses a simple three-layer process such as MUMPS (Multi User MEMS Process). The fixed hinge is constructed in all three structural layers. The mirror lifting arm and the mirror arm are designed in both the second and the third structural layers and the floating hinge, linking them, is formed by cross members of the second and third structural layers.
The motion of the mirror for different mirror lengths was simulated. Based on these predictions the geometry of the mirror was determined and then the components were simulated for various mechanical loads. The initial simulations of the device involved analyzing the stresses and displacements of the mirror and the mirror lift arm. The stress on the components was found to be acceptable for preliminary fabrication prototyping.
The Knudsen Compressor As an Energy Efficient Micro-Scale Vacuum Pump
Authors: Young M. , Vargo S. , Shiflett G. , Muntz E. P. , Green Amanda 
Published: November 2021

Abstract
The low-pressure pumping limit of the MEMS Knudsen Compressor, a thermal transpiration pump, is identified and discussed. The practical low-pressure limit is due to a requirement for an approach to continuum flow in the connector section, it is roughly 10mTorr. A previously developed transitional flow model was used to size several Knudsen Compressor cascades that operate down to the low-pressure limit. Designs based on previous experimental Knudsen Compressors do not provide the necessary pumping efficiency. A design, employing carefully sized capillaries etched in aerogel transpiration membranes, is shown to result in a viable device. A cascade incorporating this design provides a gas flow rate of 3E16 mol/sec, while pumping from a pressure of 10mTorr to 1 atm. It requires a volume of 73 cm3 and 2.0 W. Design considerations are outlined for MEMS Knudsen Compressors operating at their lower pressure limit. A primary concern, efficiently transitioning from the capillary section to the connector at constant temperature is discussed.
The Fabrication and Test of a Phase-Change Micropump
Authors: Yoon Hyeun Joong , Sim Woo Young , Yang Sang Sik 
Published: November 2021

Abstract
This paper presents the fabrication and test of a phase-change type micropump with two aluminum flap valves. This micropump consists of a pair of Al flap valves and a phase-change type actuator. The actuator is composed of a heater, a silicone rubber diaphragm and a working fluid chamber. The diaphragm is actuated by the vaporization and the condensation of the working fluid. The micropump is fabricated by the anisotropic etching, the boron diffusion and the metal evaporation. The dimension of the micropump is 8.5 mm × 5 mm × 1.7 mm. The forward and the backward flow characteristics of the flap valve illustrate the appropriateness as a check valve. Also, the flow rate of the micropump is measured. When the square wave input voltage of 10 V is applied to the heater, the maximum flow rate of the micropump is 6.1 μl/min at 0.5 Hz and the duty ratio of 60% for zero pressure difference.
Shear-Induced Arching of Particle-Laden Flows in Microtubes
Authors: Sharp Kendra V. , Adrian Ronald J. 
Published: November 2021

Abstract
Despite the growing interest in microfluidic systems, the study of two-phase flows in such systems thus far has been somewhat limited in scope. Examples of recent studies of two-phase flows in microchannels include flows containing liquid and gas (Tran, 1998; Stanley, 1997), the dispersion of laminar fluid streams (Galambos, 1998), and the flow of very dilute particle suspensions through micropumps (Jang et al., 1999).
The present experiments identify ‘shear-induced arching’ as a new mechanism causing microtube blockage. This mechanism is most likely to occur when 0.33D &lt; dp &lt; 0.46D, where dp is the particle diameter and D is the microtube diameter, and was observed for flows of particle-laden fluids with concentration, ϕ, as low as 0.5%. Following a simple geometrical analysis, for 0.33D &lt; dp &lt; 0.46D, it can be shown that once the particles are in the arching configuration, lateral forces induced by the shear on the arch can hold the particles in place and stabilize the arch. Experiments were performed over a range of particle-to-rube diameter ratios. As predicted, if enough of the particles in any given experiment had a diameter of 0.33D–0.46D, blockages occurred in the microtube.
An Electrokinetic Instability Micromixer
Authors: Oddy Michael H. , Santiago Juan G. , Mikkelsen James C. 
Published: November 2021

Abstract
We present the design, fabrication, and characterization of a micromixer that uses an electrokinetic instability (EKI) as the stirring mechanism. We have observed that microchannel liquid flows subjected to sinusoidally alternating electric fields exhibit, under certain electric field strengths and geometries, a flow instability capable of rapidly stirring micro- and nanoliter volume solutions [1]. We have performed a fluorescein dilution experiment to observe the rapid dispersion of dyed and undyed buffers within the mixing chamber as a result of EKI stirring. The flow field was imaged using an inverted, epifluorescent microscope fitted with a 12 bit, cooled CCD camera. We have initially characterized the mixer performance by computing ensemble-averaged probability density functions (PDF’s) and power spectra of the instantaneous, spatial fluorescence intensity fields. This novel stirring mechanism has the potential for significantly improving the functionality of microfluidic, bioanalytical devices.
Design of a Microfin Array Heat Sink Using Flow-Induced Vibration to Enhance the Heat Transfer Rate in the Laminar Flow Regime
Authors: Go Jeung Sang , Lim Geunbae , Yun Hayong , Kim Sung Jin , Song Inseob 
Published: November 2021

Abstract
This paper presented design guideline of the microfin array heat sink using flow-induced vibration to increase the heat transfer rate in the laminar flow regime. Effect of the flow-induced vibration of a microfin array on heat transfer enhancement was investigated experimentally by comparing the thermal resistances of the microfin array heat sink and those of a plain-wall heat sink. At the air velocities of 4.4m/s and 5.5 m/s, an increase of 5.5% and 11.5% in the heat transfer rate was obtained, respectively. The microfin flow sensor also characterized the flow-induced vibration of the microfin. It was determined that the microfin vibrates with the fundamental natural frequency regardless of the air velocity. It was also shown that the vibrating displacement of the microfin is increased with increasing air velocity and then saturated over a certain value of air velocity. Based on the numerical analysis of the temperature distribution resulted from microfin vibration and experimental results, a simple heat transfer model (heat pumping model) was proposed to understand the heat transfer mechanism of a microfin array heat sink. Under the geometric and structural constraints, the maximum heat transfer enhancement was obtained at the intersection of the minimum thickness of the microfin and constraint of the bending angle.
Electroosmotic Flow in a Grooved Micro-Channel Configuration: A Comparative Study of μ-PIV Measurements and Numerical Simulations
Authors: Dutta Prashanta , Kim Min Jun , Kihm Kenneth D. , Beskok Ali 
Published: November 2021

Abstract
This paper presents global and point-wise comparisons of experimental measurements and numerical simulation results of electroosmotically driven flows in grooved micro-channels. The micro-channels are made by photolithography using poly-dimethyl-siloxane (PDMS), a type of silicon product, which is transparent, permeable to a variety of liquids and vapors. Experiments are performed using a micro-scale particle image velocimetry (μ-PIV) system developed for measurement of flows in micro-channel geometries. Full field velocity distributions are measured in Eulerian viewpoint by tracking the fluorescence images. The numerical algorithm is based on the spectral element formulation of incompressible Navier-Stokes equations with electroosmotic forcing. The algorithm utilizes modal expansions in mixed quadrilateral and triangular meshes, enabling complex geometry discretizations with spectral accuracy. Comparisons of experimental and numerical results show good agreements, validating both numerical and experimental methodologies.
Infrared Diagnostics for the Measurement of Fluid and Solid Motion in Micromachined Devices
Authors: Breuer Kenneth S. , Bird James C. , Han Gengxin , Westin K. Johan A. 
Published: November 2021

Abstract
A new velocimetry system has been developed for use in microdevices that incorporate silicon as their structural material. The system is designed to illuminate and measure particle and surface motions using infrared wavelengths, taking advantage of the fact that silicon is largely transmissive to light with wavelength above 1 micron. The system allows us to observe motion inside silicon-based microdevices, which are otherwise opaque to light at visible wavelengths. By analyzing these images using both time-of-flight and phase-locked techniques, we can make quantitative measurements about the position and speed of internal surfaces and the motion of fluids inside complex microfabricated devices.
Molecular Tagging Velocimetry Measurements in Supersonic Micro Jets
Authors: Lempert Walter R. , Jiang Naibo , Sethuram Subin , Samimy Mo 
Published: November 2021

Abstract
Acetone-based Molecular Tagging Velocimetry (MTV) is demonstrated in high sub-sonic and supersonic (Mach 1.8) nitrogen and air free jets produced by nozzles with exit dimensions of order 1 mm. Measurements are performed in the static pressure range 1–110 torr, with spatial resolution of approximately 10 microns. The statistical uncertainty (2σ) in velocity is found to be of order 6–10 m/sec, approximately independent of flow field pressure. Spectral emission scans indicate that under some circumstances, the CH radical is formed in the flow, which is believed to be the primary light emitting species in air flows.
Solder-Assembled MEMS Flaps to Enhance Fluid Mixing
Authors: Ma Zhichun , Peacock T. , Bradley E. , Lee Y. C. 
Published: November 2021

Abstract
Thermal actuator-based MEMS flaps with a length scale of 1,000 μm were developed for the enhancement of fluid mixing. These flaps were much larger than typical MEMS devices, and the experiment required an array of 10 flaps to be soldered onto a ceramic substrate with precision assembly. As a result, in the initial fabrication it was difficult to achieve good assembly yields capable of providing large deflections. To improve the yields and deflections, we have modified the flap design by reducing the size of solder pads, removing sharp corners, changing the number and the width of the actuator’s hot arms, and strengthening the support beams. In addition, we have developed a controllable process to reflow tin/lead solder on gold pads. Numerical simulations were used in the design process to assist in improving performance. The deflection was increased from 6.4 to 11.1 μm under a 5-V apply and the maximum von Mises stress reduced from 2000 to 500 Mpa. The simulated deflection-vs.-voltage relationship was verified by experimental characterizations.
Flexible Circuit-Based RF MEMS Switches
Authors: Wang Chunjun , Ramadoss Ramesh , Lee Simone , Gupta K. C. , Bright Victor M. , Lee Y. C. 
Published: November 2021

Abstract
This paper describes a new microelectromechanical systems (MEMS) switch fabricated using flexible circuit technologies. Hundreds of such switches can be laminated onto a large-area printed circuit board (PCB) with other RF devices and circuits. The switches are fabricated using low-cost, low-loss flexible circuit material Kapton-E polyimide film. Switches with actuation voltages as low as 73 V are reported.
A Simple Method for Determination of Thermal Conductivity Coefficients of Thin Films
Authors: Pan Chi Hsiang , Tung Chien Li 
Published: November 2021

Abstract
In this paper, we present a simple method to determine thermal conductivity coefficients (TCC) of thin films with a compact characterization microstructure and by using common measuring apparatus. The microstructure can be fabricated by a simple surface micromachining technique and in situ along with active devices on the same chip. Analytical expressions are derived to calculate the thermal conductivity coefficients of thin films from the experimental data. Experimental results with a heavily n-doped LPCVD poly crystalline silicon film are used herein to demonstrate the effectiveness of the proposed method. The obtained thermal conductivity coefficient seems to decrease a little as temperature increase and the average is around 39 Wm−1 °C−1 at 400°C below.
Noncontact Physical Removal of Nano-Scale Particles From Surfaces
Authors: Busnaina Ahmed A. , Lin Hong 
Published: November 2021

Abstract
With the International Technology Roadmap for Semiconductors decreasing the particle removal requirements from 125nm (0.3–0.75/cm2) in 1997 to 25nm (0.01–0.15/cm2) in 2011, an era of the most challenging cleaning applications in semiconductor manufacturing is upon us [1. Megasonic cleaning is a widely used non-contact cleaning technique. In megasonic cleaning, wafers are immersed in a cleaning liquid medium to which sonic energy is applied. High intensity sound waves generate pressure fluctuations and acoustic streaming which detach the particles from the surface and remove them. Busnaina et al [2–3 studied megasonic particle removal and the effect of acoustic streaming on the cleaning process especially in post-CMP applications. It is important to know the advantage and the limitation of megasonic cleaning technique in nano-scale particles removal.