bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mechanical Properties of Sputtered Silicon Oxynitride Films by Nanoindentation
Authors: Liu Yan , Lin I-Kuan , Zhang Xin 
Published: April 2011

AbstractSilicon oxynitride (SiON) films with different oxygen and nitrogen content were deposited by RF magnetron sputtering. Fourier-transform infrared (FT-IR) spectroscopy study revealed that co-sputterred SiON films were composed of one homogeneous phase of random bonding O-Si-N network. Time-dependent plastic deformation (creep) of SiON films were investigated by depth-sensing nanoindentation at room temperature. Results from nanoindentation creep indicated that plastic flow was relatively less homogenous with increasing nitrogen content in film composition. A deformation mechanism based on atomic bonding structure and shear transformation zone (STZ) plasticity theory was proposed to interpret creep behaviors of sputtered SiON films.
Indentation of Nonlinearly Viscoelastic Solids
Authors: Oyen Michelle L 
Published: April 2011

AbstractMuch recent attention has been focused on the indentation of linearly viscoelastic solids, and analysis techniques have been developed for polymeric material characterization. However, there has been relatively little progress made in the development of analytical approaches for indentation of nonlinearly viscoelastic materials. Soft biological tissues tend to exhibit responses which are nonlinearly viscoelastic and are frequently modeled using a decomposition of the relaxation or creep function into a product of two functions, one time-dependent and the other stress- or strain-level dependent. Consideration here is for soft biological tissue-like responses, exhibiting approximately quadratic stress-strain behavior, which can be alternatively cast as linear dependence of elastic modulus on strain level. An analytical approach is considered in the context of indentation problems with flat punch, spherical and conical indenter shapes. Hereditary integral expressions are developed and solved for typical indentation experimental conditions including indentation creep, load-relaxation and monotonic constant load- or displacement-rate tests. Primary emphasis is on the deconvolution of material and geometrical nonlinearities during an indentation experiment. The simple analytical expressions that result from this analysis can be implemented for indentation characterization of soft biological tissues without the need for computationally- intensive inverse finite element approaches.
Instrumented Indentation Contact with Sharp Probes of Varying Acuity
Authors: Morris Dylan J. 
Published: April 2011

AbstractWhile elastic and plastic material property extraction from instrumented indentation tests has been well-studied, similarly-based fracture property measurement remains difficult. Furthermore, estimation of the fracture toughness requires measurement of the crack lengths from a micrograph, which makes nano-scale indentation toughness measurement expensive and difficult. Initiation and propagation of cracks on the nano-scale requires a more acute indenter than a Berkovich or sphere, such as the cube-corner pyramid. Experiments described here were performed on a range of elastic, plastic and brittle materials with diamond indenters of acuity varying between the Berkovich and the cube-corner. These experiments reveal some of what is changed and what remains the same, when the acuity of the probe is changed, when fracture is initiated at the contact, or both. A preliminary model for the physical origin of the extra crack-driving power of acute probes is presented in light of these, and complementary macro-scale in-situ indentation experiments. This work provides the basis for development of instrumented indentation-based nano-scale toughness measurement.
Viscoelastic Behavior of a Centrally Loaded Circular Film Being Clamped at the Circumference
Authors: Oyen Michelle L , Liu Kuo-kang , Wan Kai-tak 
Published: April 2011

AbstractA new theoretical model is constructed for the viscoelastic response of a clamped circular membrane deformed by a spherical indenter, using the classical Maxwell and Standard Linear Solid (SLS) constitutive equations. Preliminary stress-relaxation experiments are performed for a hydrogel membrane and the corresponding data fitted to the SLS-based viscoelastic model.
Emerging Nanomaterials for Nuclear Radiation Detectors
Authors: Osinski Marek 
Published: April 2011

AbstractNanosize devices have attracted tremendous interest over the last few years for a wide range of biomedical, biochemical sensing, and optoelectronic applications. So far, however, their potential has largely eluded the nuclear detection community. In this paper, the current status of the emerging nanomaterials for nuclear detection applications is reviewed. Recent preliminary data are presented, and the potential improvements in the detector cost, reliability, and performance the nanosize devices have to offer are discussed.
MEMS Lubrication: An Atomistic Perspective of a Bound + Mobile Lubricant
Authors: Irving Douglas Lee , Brenner Donald W 
Published: April 2011

AbstractThe adhesive pressure needed to separate two ocatdecyltrichlorosilane (ODTS) coated surfaces both with and without the addition of tricresyl phosphate (TCP) as a function of separation rate is characterized using molecular dynamics simulation. The simulations predict that when TCP is added between surfaces the adhesive pressure needed for separation is reduced compared to the system containing ODTS only. Both the adhesive pressure and the break up of the TCP layers exhibit a separation rate dependence that appears unrelated to the rate of diffusion of TCP on the ODTS. The ability of the TCP to remain localized to defected areas of the ODTS layer upon normal separation of the contact is also characterized. It is found that the TCP remains localized to defect sites, which effectively coats the damaged area.
Indentation Characterization of Fracture Toughness and Interfacial Strength of PECVD Nitrides after Rapid Thermal Annealing
Authors: Yan H-Y , Ou K-S , Chen K-S 
Published: April 2011

AbstractThis work presents the result of mechanical characterization of the fracture toughness and interfacial strength of PECVD silicon nitride films deposited on silicon subjected to rapid thermal annealing (RTA) processing between 200 and 800 °C. Both micro- and nano-indentation techniques are employed to perform the experiments. In conjunction with the model proposed by Marshall and Lawn for data reduction, the fracture toughness of un-heat treated nitride is obtained as 2.2 MPa√m based on a series of Vickers micro-indentation tests and this value is essentially unchanged if the RTA temperatures are below 400°C. Further increase in RTA temperature would significantly enhance the fracture toughness. On the other hand, using nanoindentation testing in conjunction with the model proposed by Marshall and Evans, the interfacial strength between the nitride and silicon is determined as 17.2 J/m2 for un-heat treatment nitrides and it could also be significantly enhanced by RTA processes with temperatures exceeding 400°C. These results should be useful for related MEMS or IC structure fabrication for the concerns of maintaining the structural integrity and improve fabrication performance in related applications.
A Novel Micro Tensile Testing Instrument with Replaceable Testing Specimen by Parylene Passivation Technique
Authors: Lau Yung-Dong , Chang Tso-Chi , Hocheng Hong , Chen Rongshun , Fang Weileun 
Published: April 2011

AbstractThis study has successfully demonstrated a novel tensile testing approach to mount the thin film test specimen onto the MEMS instrument using microfabrication process. The MEMS instrument consists of thermal actuator, differential capacitance sensor, supporting spring. The thermal actuator applies tensile load on the test specimen to characterize the Young's modulus and the residual stress of thin films. As compare with the existing approaches, the problems and difficulties resulting from the alignment and assembly of thin film test specimens with the testing instrument can be prevented. Furthermore, the parylene passivation technique of MEMS fabrication process allows the changing of testing film materials easily. In application, the present approach has been employed to determine the Young's modulus and the residual stress of Al films.
Elastic and Viscoelastic Characterization of Polydimethylsiloxane (PDMS) for Cell-Mechanics Applications
Authors: Lin I-Kuan , Liao Yen-Ming , Liu Yan , Chen Kuo-Shen , Zhang Xin 
Published: April 2011

AbstractThe mechanical properties of polydimethylsiloxane (PDMS) were characterized by using uniaxial compression, dynamic mechanical analysis (DMA), and nanoindentation tests as well as finite element simulation methods. A five-parameter linear solid model was used to emulate the behavior of PDMS. The study results indicated that the effect of viscoelasticity affected the PDMS pillar arrays significantly. The traditional approach for calculating the cell force basing on the linear elastic mechanics could result in considerable errors.
Modification of Conductivity and of Mechanical Properties of Electroactive Polymer (EAP) Thin Films by Titanium Ion Implantation
Authors: Niklaus Muhamed , Rosset Samuel , Dadras Massoud , Dubois Philippe , Shea Herbert R. 
Published: April 2011

AbstractWe present a study of the influence on Young's modulus, stress and electrical conductivity of poly-dimethylsiloxane membranes implanted with titanium ions at energies from 5 to 35 keV, with doses up to 8×1016 ions/cm2. The motivation for this study was to find the optimum implantation conditions to create electrodes for microfabricated dielectric electroactive polymer actuators, which must combine low resistivity with low stiffness. Two implantation techniques are used, Filtered Cathodic Vacuum Arc (FCVA) and the more conventional Low Energy broad beam Implanter (LEI). Of the two, it is found that the FCVA implanter is much better suited to create compliant electrodes.
Optically Actuated Deformable Micro-Mirrors for Adaptive Optics
Authors: Ribaudo Troy , Li Jin , Haji-saeed Bahareh , Khoury Jed , Goodhue William 
Published: April 2011

AbstractIn this paper we report on our latest efforts to fabricate and characterize optically actuated deformable micro mirrors for wavefront correction in an adaptive optics system. The optically actuated DMM device consists of a Silicon Nitride (Si3N4) thin film patterned into a spring plate array, an SU-8 photoresist supporting structure that provides the space through which the mirror is allowed to deform, and a PIN photodiode which allows an optical control signal to actuate the DMM.
Compliant MEMS Motion Characterization by Nanoindentation
Authors: Choueifati Joseph , Lusk Craig , Pang Xialou , Volinsky Alex A. 
Published: April 2011

AbstractLarge out-of-plane displacements can be achieved when compliant mechanisms are utilized in MEMS. While mathematical and macroscopic modeling is helpful in building original designs, the actual MEMS device motion needs to be characterized in terms of the forces and displacements. A nanoindentation apparatus equipped with Berkovich diamond tip was used in an attempt to actuate and characterize the motion of the Bistable Spherical Compliant Micromechanism with a nonlinear (approximately cubic) mechanical response. Based on the obtained lateral force-displacement data it was concluded that the Berkovich diamond tip was too sharp, thus cutting through the polysilicon material of the MEMS device.
Protection Layer Influence on Capacitive Micromachined Ultrasonic Transducers Performance
Authors: Jeanne Edgard , Meynier Cyril , Teston Franck , Certon Dominique , Felix Nicolas , Roy Mathieu , Alquier Daniel 
Published: April 2011

AbstractFor MEMS technology, reliability is of major concern. The implementation of a protection and passivation layer, that may easily enhance reliability of capacitive Micromachined Ultrasonic Transducers (cMUTs) must be done without degrading device performance. In this work, realization, simulation and characterization of passivated cMUT are presented. Two materials, SiNx and Parylene C, were selected with regard to their mechanical and physical properties as well as their compatibility with device processing. Particular attention was paid on layer deposition temperature to avoid a structural modification of the top aluminium electrode and, hence, a membrane bulge. The characterization results are in good agreement with the simulations. The SiN passivation layer clearly impact device performance while Parylene C effectiveness is clearly pointed out even through ageing characterizations. If SiNx layer can be used for passivation with particular precautions, Parylene is definitely an interesting material for cMUT passivation and protection.
Relationship between film stress and dislocation microstructure evolution in thin films
Authors: Fertig Ray Stuart , Baker Shefford P. 
Published: April 2011

AbstractMetals with one or more dimensions in the submicron regime are widely used in MEMS devices. Device stresses often exceed the strength of the corresponding bulk material by an order of magnitude and can lead to a variety of mechanical failures. At moderate temperatures, high stresses occur because dislocations are unable to move to relax the stress. This is partly because of an elastic dimensional constraint, but complex dislocation behavior, such as junction formation, annihilation, and nucleation, are also observed. In this report, we present results from analytical models, cellular automata simulations, and large-scale dislocation dynamics simulations of submicron films to examine the relationship between dislocation interactions and material strength. Our results reveal a complex relationship between dislocation interactions and stress inhomogeneity that arises from the stress fields of the dislocations. We show that the stress inhomogeneity increases both the likelihood of interactions and acts to increase the strain hardening rate.
Optical Waveguides Embedded in PCBs - A Real World Application of 3D Structures Written by TPA
Authors: Houbertz Ruth , Wolter Herbert , Schmidt Volker , Kuna Ladislav , Satzinger Valentin , Wüchter Christoph , Langer Gregor 
Published: April 2011

ABSTRACTThe integration of optical interconnects in printed circuit boards (PCB) is a rapidly growing field worldwide due to a continuously increasing need for high-speed data transfer. There are any concepts discussed, among which are the integration of optical fibers or the generation of waveguides by UV lithography, embossing, or direct laser writing. The devices presented so far require many different materials and process steps, but particularly also highly-sophisticated assembly steps in order to couple the optoelectronic elements to the generated waveguides. In order to overcome these restrictions, an innovative approach is presented which allows the embedding of optoelectronic components and the generation of optical waveguides in only one optical material. This material is an inorganic-organic hybrid polymer, in which the waveguides are processed by two-photon absorption (TPA) processes, initiated by ultra-short laser pulses. In particular, due to this integration and the possibility ofin situpositioning the optical waveguides with respect to the optoelectronic components by the TPA process, no complex packaging or assembly is necessary. Thus, the number of necessary processing steps is significantly reduced, which also contributes to the saving of resources such as energy or solvents. The material properties and the underlying processes will be discussed with respect to optical data transfer in PCBs.
Micro/Nano Fabrication of Surface Architectures on Polymers and Copolymers Using Direct Laser Interference Patterning
Authors: Acevedo Diego , Lasagni Andrés , Barbero Cesar , Muecklich Frank 
Published: April 2011

ABSTRACTNovel surface engineering techniques of polymeric materials are essential to produce advanced topographies which could for example serve to modulate cell and tissue response in bio-materials. Direct Laser Interference Patterning (DLIP) permits the fabrication of repetitive arrays and microstructures by irradiation of the sample surface with coherent beams of light. Furthermore, the most important advantage of this method is that no additional process steps are required in comparison with other top-down or bottom-up techniques. In this study, we report a novel method for the advanced design of architectures in polymers using a single step process, as well as photo-activation of polymers with low absorption coefficient using a second polymer with relative high absorption coefficient. Previously calculated interference patterns using the well known interference theory could be directly produced on polymeric surface. Moreover, the cross-section of the structured polymers changes depending on the intensity of the laser beams, and photomachinability of polymers is highly influenced by laser wavelength. High absorbance of the polymeric materials at specific wavelengths allows the reduction of the laser intensity required to achieve a determined structure depth. For (60:40 %) polymethylmetacrylate/polystyrene copolymer substrate, different structures types were observed depending on the laser intensity including swelling and ablation of the material.
Atomic Layer Deposition on Quantities of Multiwalled Carbon Nanotubes
Authors: Cavanagh Andrew S. , Wilson Christopher A. , Weimer Alan W. , George Steven M. 
Published: April 2011

ABSTRACTAtomic layer deposition (ALD) was performed on quantities of multiwalled carbon nanotubes (MWCNTs) in a rotary reactor. Because of nucleation difficulties, Al2O3 ALD grew as nanospheres on the MWCNTs. After a NO2 nucleation treatment, Al2O3 ALD films grew conformally and noncovalently functionalized the surface of the MWCNT. This Al2O3 ALD film served as a platform for the growth of W ALD metal. The uncoated and ALD-coated MWCNTs were characterized with transmission electron microscopy and x-ray photoelectron spectroscopy. This study demonstrates that ALD can be performed on quantities of very high surface area MWCNT substrates.
EBI Joining Between Different Polymers Without Adhesive Materials
Authors: Sato Hironori , Iwata Keisuke , Tonegawa Akira , Nishi Yoshitake 
Published: April 2011

ABSTRACTJoining between Nylon-film and Silicone-rubber was successfully developed. Effects of EB-irradiation on joining strength of different polymers without adhesive materials were investigated by using homogeneous EB irradiation. The EB irradiation increased the joining strength of the joining sample between Nylon-film and Silicone-rubber. Excess EB-irradiation more than 0.3 MGy apparently decreased the joining strength. To discuss the influences of electron beam irradiation on the joining strength, ESR signals related to dangling bonds were observed. Since the EB irradiation produced detectable dangling bonds on Nylon-film, using dangling bonds probably joined the different polymers.
Effect of Crystallographic Structure of Substrate on Texture in Electrodeposited Ni Layers
Authors: Shimada Takafumi , Shibata Akinobu , Ishiyama Chiemi , Sone Masato , Higo Yakichi 
Published: April 2011

ABSTRACTEffect of substrate on the texture of electrodeposited Ni layer was investigated by using various substrates; Ni-P alloy (amorphous), pure Cu (fcc) and pure Ni (fcc). In the case of Ni-P and Cu substrates, deposited Ni layer shows the (115) fiber texture and its formation was not biased by substrate. On the other hand, the formation of texture is not independent of Ni substrate because its texture is not ideal fiber.Near the interface between deposited Ni layer and Ni-P or Cu substrates, fine columnar grains were observed. In contrast, on Ni substrate there are coarse columnar grains ahead of continuous epitaxial region. It is considered that texture of deposited Ni layer is not independent of Ni substrate due to the fact that these columnar grains satisfy a certain orientation relationship with respect to substrate.
Specific Surface Free Energy of Ruby Thin Film Grown on Sapphire Single Crystals Studied by Contact Angle of Liquid Droplet
Authors: Suzuki Takaomi , Sugane Shintaro , Hidaka Miki , Teshima Katsuya , Oishi Shuji 
Published: April 2011

ABSTRACTRuby thin film was grown on sapphire substrate by evaporation method of MoO3 flux. Small amount of Na2CO3 was added in order to decrease the evaporation rate of flux. The contact angles of liquids and crystal surfaces were measured for water and formamide droplets, and the specific surface free energy of each face of the crystal was calculated using Fowkes approximation and Wu's mean equations. The growth hillocks on the synthesized thin film were observed. The addition of Na2CO3 incrased the density of hillocks and the specific surface free energy was larger for the ruby thin film, which has larger number of hillocks.
New method of photochemical adhesion of fused silica glasses by using Xe2 excimer lamp
Authors: Funatsu Takayuki , Sato Yuji , Okamoto Yoshiaki , Murahara Masataka 
Published: April 2011

ABSTRACTA strong adhesion of two silica glasses or a silica glass and a different glass that creates properties of heatproof, no adhesive strain, and high transmittance in the region of ultraviolet [UV] was demonstrated with photochemical reaction by vacuum-ultraviolet [V-UV] light. It was confirmed that the adhesive strength of the silicone oil between the two silica glasses enhanced to 18 [MPa] after irradiation from 0 [MPa] before irradiation, that of the SiO2 and BK7 to 12.3 [MPa], and that of the SiO2 and TEMPAX®, to 10 [MPa], and that of the SiO2 and CLEARCERAM® to 7.4 [MPa]. Furthermore, the adhesive strain of the bonded sample was measured by 3-dimension roughness meter (ZYGO), and the results showed no adhesive strain. This sample had the bonding strength at 500 degrees Celsius.
Controlled Modification of Erbium Lifetime in Silicon Dioxide Film with Chromium or Titanium Coatings
Authors: Yu Nanfang , Bao Jiming , Belyanin Alexey , Mates Thomas , Troccoli Mariano , Capasso Federico 
Published: April 2011

ABSTRACTWe report systematic measurements of the lifetime of the 1.54 μm transition of erbium implanted at different energies in SiO2films coated with titanium or chromium. The lifetime shows a strong reduction up to a factor of 20 with decreasing distance between the erbium and the metal coating. Our experiments combined with rigorous theoretical modeling demonstrate that a high degree of control over the radiative properties of erbium can be achieved in erbium-implanted materials.
A Simple Method to Self-Assemble Two-dimensional and Three-dimensional Superlattices of Gold Nanoparticles
Authors: Fu Tao , Qin Hai-Yan , Li Wen-Jiang , He Sailing 
Published: April 2011

ABSTRACTCitrate-capped gold nanoparticles with narrow diameter distribution were prepared by the reduction of chloroauric acid with borohydride. After the gold nanoparticles were transferred to toluene solution through ligand conformation change, close-packed two-dimensional nanocrystal lattices were obtained on transmission electron microscopy (TEM) copper grids by evaporating approximately 10 μL of concentrated particle dispersion. The formation of the thiolate gold nanoparticles was investigated by UV-visible absorption spectroscopy and FTIR spectra. The 2D Fourier transform power spectra of the monolayer confirmed the supperlattices' hexagonal symmetry. Furthermore, long-range-ordered bilayer superlattices, of which the nanoparticles in the top layer piled on the ones in the bottom layer, could also be observed by transmission electron microscopy.