bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fatigue of Aluminum Films Leading to Melting by Multiple Laser Pulses
Authors: Bernstein Joseph B. , Cohen Simon S. , Wyatt Peter W. 
Published: March 2011

ABSTRACTRepeated laser pulses at a single point on an aluminum thin film can reduce the power needed to melt or damage the surface as compared with CW application. This multi-pulse effect was found to depend on metal thickness and number of pulses, while being weakly dependent on the pulse length. This behavior appears to result from cumulative mechanical fatigue due to cyclic thermal stress in excess of the aluminum yield stress. This principle has been applied to cutting metal wires in microelectronic applications for deletive redundancy. The results suggest a significant advantage over CW laser application since the power needed to cut a metal wire is reduced by more than 70%, and 87% as compared to a single pulse.
XPS and FTIR Study of the Thin Polyimide Films Fabricated by Ionized Cluster Beam Deposition
Authors: Kim K. W. , Chae K. H. , Choi S. C. , Cho S. J. , Vahc Y. W. , Whang C. N. , Jung H. J. , Lee D. H. , LEE J. K. 
Published: March 2011

ABSTRACTThe ionized cluster beam deposition (ICBD) technique has been employed to fabricate high-purity polyimide (PI) films. The pyromellitic dianhydride (PMDA) and oxydianiline (ODA) were deposited using dual ionized cluster beam (ICB) sources. Fourier transform infrared spectroscopy (FT-IR) and X-ray photoemission spectroscopy (XPS) studies show that the bulk and surface chemical properties are very sensitive to the ICBD conditions such as cluster ion acceleration voltage and ionization voltage. At optimum ICBD conditions, the PI films have a maximum imidization and negligible impurities(∼;1% isoimide) probably due to the high surface migration energy and surface cleaning effect.
Atomic Oxygen Plasma Effects on CVD Deposited Diamond-Like Carbon Films
Authors: Hale Jeffrey S. , Synowicki R. A. , Nails S. , Woollam John A. 
Published: March 2011

ABSTRACTCVD deposited diamond-like carbon (DLC) films have been studied for possible use as a secondary standard for Low Earth Orbit materials degradation. Samples of various thicknesses have been exposed to a simulated Low Earth Orbit atomic oxygen (AO) environment using a plasma asher. Mass loss measurements indicate that DLC degrades at a rate of 0.7 mg/hr which is two to three times the rate of currently used Kapton samples which degrade at a rate of.3 mg/hr. Thickness measurements show that DLC thins at a rate of 77 Angstroms/min. Since DLC is not as susceptible to environmental factors such as moisture absorption, it could potentially provide more accurate measurements of AO fluence on short space flights. Adhesion of DLC films to both fused silica and crystalline silicon substrates has been studied under thermal cycling conditions. Film adhesion to fused silica can be enhanced by sputtering a thin layer of silicon dioxide onto the substrate prior to deposition. In addition to the above, the index of refraction and extinction coefficient of various thicknesses of DLC films has been characterized by Variable Angle Spectroscopic Ellipsometry.
Dynamics of Graphite Photoablation
Authors: Murray P. T. , Peeler D. T. , Dempsey D. V. 
Published: March 2011

ABSTRACTSpeed distributions were determined for the ions, ground state and electronically-excited neutrals ejected from a graphite target by 248 nm laser ablation. Mass distributions were measured for the laser-ejected ions. The measurements were carried out normal to the graphite target as well as at an angle of 45°. Significant differences were observed in both the speed and mass distributions at the two angles.
Effects of Fluorine Implantation into Hydrogenated Amorphous Silicon
Authors: Wong S. P. , Peng Shaoqi , Ke Ning , Liu Jingxi 
Published: March 2011

ABSTRACTMultiple-energy implantation of fluorine into rf glow discharge deposited hydrogenated amorphous silicon (a-Si:H) thin films has been performed. It is found that the optical gap decreases with the implanted fluorine concentration CF from 1.56 eV for the unimplanted sample to 1.40 eV for the sample with CF of 3×1021 cm−3. Results of the Staebler-Wronski experiment show that the ratio between the electrical conductivity before and after illumination, as well as the ratio between the photo- and dark conductivity, decrease also with Cp. Electrical measurements show that there is significant decrease in the conductivity activation energy Ea with CF for samples annealed at or below the substrate temperature TS during deposition. But for samples annealed at temperatures higher than TS, Ea was found to change back to values close to that of the unimplanted sample. A large shift to higher energy for one peak in the photoluminescence spectra at 77K has been observed, from 1.34 eV of the unimplanted sample to around 1.6 eV for the implanted samples, though with almost one order of magnitude weakening in intensity. It is also observed that ESR splitting has been induced in the fluorine implanted samples. The g-factors of the two resonances are determined to be 2.003 and 2.006, respectively. For the g=2.006 resonance, the spin density increases markedly after implantation but is essentially independent on CF before annealing and effectively reduced or eliminated after annealing. For the g=2.003 resonance, the spin density increases rapidly with CFp especially in the range from CF = 1×1020 to 1×1021 cm−3 before annealing and reduces only slightly after annealing.
The Role of Hydrogen in Laser Deposition of Diamond-Like Carbon
Authors: Thebert-Peeler D. , Murray P. T. , Petry L. , Haas T. W. 
Published: March 2011

ABSTRACTThin films have been grown on Si (100) substrates by pulsed laser evaporation of graphite using both IR and UV radiation. The character of the resulting film is found to be independent of the presence of H°. Diamond-like films are found to be a result of low (RT) temperature deposition of the higher energy incident particles of the UV (versus IR) laser ablation process.
Growth of BN Thin Films by Pulsed Laser Deposition
Authors: Knapp J. A. 
Published: March 2011

ABSTRACTA new UHV system for pulsed laser deposition of materials is described, together with results from preliminary experiments for depositions of BN on Si. The system is designed to allow for in-situ diagnostics of the ablation plasma, as well as UHV preparation and characterization of clean sample substrates. The room temperature depositions of BN result in amorphous, B-rich films, whose particle content is a strong function of laser wavelength.
Laser Cvd of Tungsten on Silicon Oxynitride
Authors: Izquierdo R. , Lecours A. , Meunier M. 
Published: March 2011

AbstractLaser direct writing of tungsten from WF6 onto 0.6 μm thick films of silicon oxynitride on silicon using an argon-ion laser beam is investigated. XPS studies show that WF6 is chemisorbed on the oxynitride surface and that nitrogen plays a role in this adsorption. Deposits have good adhesion, columnar growth structure and resistivities ranging from 13 to 25 μΩ-cm. The deposition conditions significantly affect the deposit morphology and profile. In particular, increasing the hydrogen pressure increases the linewidth but reduces the thickness. Mass transport phenomena are invoked to explain these effects.
Thermal and Photoinduced Decomposition Pathways of Arsine on GaAs(100)
Authors: Zhu X.-Y. , Wolf M. , Huett T. , White J. M. 
Published: March 2011

AbstractWe have studied the thermal and photoinduced dissociation pathway of AsH3 on the Ga-rich GaAs(100) surface. Arsine adsorbs molecularly at 115 K and dissociates upon either heating to above 140 K or upon irradiation with 3.5 - 6.4 eV photons. The decomposition of arsine is accompanied by the formation of surface Ga-H species, which are thermally and photochemically more stable than surface AsHx. A comparison of the wavelength dependence for adsorbed and gas phase arsine reveals that the excitation mechanism of the AsH3 surface photochemistry is substrate mediated, which probably involves a charge transfer between surface states and the adsorbate.
Laser-Induced Deposition of Buried Insulator Lines in Mn-Zn Ferrite
Authors: Lu Y.F. , Takai M. 
Published: March 2011

AbstractMaskless etching of single crystalline Mn-Zn ferrite (MnO: ZnO: Fe2O3 = 31:17:52) has been investigated in a SiCl4 atmosphere by Ar+ laser irradiation. The ferrite substrate can be thermochemically etched by a single scan of a laser beam. Silicon oxide was deposited simultaneously in the etched groove. The deposited silicon oxide lines were investigated by AES, XPS and RBS. It is found that the deposited lines were stoichiometric SiO2 under specific conditions. The etching and deposition process can be controlled by changing the SiCl4 gas pressure. A planarized SiO2 layer buried in ferrite was found not to affect the magnetic characteristics of the ferrite layer.
GaAs and Si Assisted Etching using a Scanning Tunneling Microscope
Authors: Baba Masakazu , Matsui Shinji 
Published: March 2011

AbstractGaAs etching with Cl2 gas is studied with a scanning tunneling microscope (STM). Both Cl2 gas and tunnel electron assist etching occur under the tip during scanning and the etching profile is found to depend on the gas flow time. GaAs and Si patterns with nanometer dimensions are fabricated by STM assist etching with a very low voltage (-IV). Also atomic layer etching of GaAs is demonstrated by STM assist-etching using a Cl adlayer.
Activation of the Si(100)/Cl2 Etching Reaction at High Cl2 Translational Energies
Authors: Campos Francis X. , Weaver Gabriela C. , Waltman Curtis J. , Leone Stephen R. 
Published: March 2011

AbstractExposing a Si(100) surface to a pulsed beam of neutral Cl2 with high translational energy results in etching at a rate faster than that seen with chlorine at thermal energies. The Cl2 beam used in these experiments is produced by laser vaporization of cryogenic films. It has a broad energy distribution which can be varied by changing laser energy and film thickness. Beams with mean energies as low as 0.4 eV result in etching =10 times faster than etching by thermal Cl2. When Cl2 beams are used which have considerable flux above 3 eV, the etching rate increases by a further factor of 3.6 ± 0.6. This rate increase, which occurs at energies just above the Si-Si bond energy, suggests that kinetic energy can be efficiently utilized to break surface bonds.
Ge Surface Displacements Due to Low Energy Particles
Authors: Picraux S. T. , Horn K. M. , Chason E. , Tsao J. Y. , Bedrossian P. , Klitsner T. , Brice D. K. 
Published: March 2011

AbstractThe production of surface defects by low energy 4He and Xe ions incident on very smooth Ge(001)2x1 surfaces is reported. Roughening at -50°C by 100-500 eV ions is measured by RHEED in real-time using the intensity of the out-of-phase specular beam. For He, the surface displacements per ion range from 0.05 to 0.3 and are comparable to our binary collision calculated surface vacancy production rate for a displacement threshold energy of 11 eV (3/4 of bulk value). For Xe, the displacement rate ranges from 2 to 10 (∼30x higher) and falls between the calculated total vacancy and total defect (vacancy + interstitial) production rates.
Microstructures of Si(111) on Ion Sputtering and Electron Annealing
Authors: Al R. , Savage T. S. , Xu P. , Zhang J. P. , Marks L. D. 
Published: March 2011

AbstractThe microstructure evolution during preparation of thin Si(111) samples for surface sensitive imaging has been studied using ultra-high vacuum (UHV) transmission electron microscopy (TEM). The effects of ion beam sputtering and electron annealing have been investigated. A unique and routine sample preparation method for surface sensitive TEM imaging that combines TEM sample preparations with surface science sample preparation was developed. The microstructure evolution during the sample preparation process was studied in detail.
X-Ray Fluorescence Determination of Low Metal Concentration in Surface Masking Layers on Organic Polymers
Authors: Hutton Richard S. , Taylor Gary N. 
Published: March 2011

AbstractA highly sensitive x-ray fluorescence (XRF) technique has been developed for the determination of low metal concentrations in the etch resistant layer of surface-imaged photoresists. The samples may be analyzed quickly and the method is applicable to a wide variety of surfaceimaging processes. For each metal of interest the XRF spectrometer is easily calibrated using polymer films containing known concentrations of a metal-containing reagent. Examples of the application of this technique to the analysis of Ti, Si and Zr-containing films are described.
Hydrogen in Dielectric Film Formation from an Electron Cyclotron Resonance Plasma
Authors: Barbour J. C. , Stein H. J. 
Published: March 2011

AbstractThe incorporation of hydrogen into silicon nitride films grown downstream from an electron cyclotron resonance (ECR) plasma decreased rapidly with increasing substrate temperature (100-600°C). Fourier transform infra-red (FTIR) spectroscopy showed that the hydrogen in the as-grown material was primarily bonded to nitrogen. However, an applied bias of -200 V caused an increase in the number of Si-H bonds relative to N-H bonds, as a result of increased ion-beam damage. In addition, ion irradiation of an asgrown film with 175 keV Ar+ at room temperature showed that H transferred from N-H bonds to Si-H bonds without a loss of H. Elastic recoil detection (ERD) and FTIR of thermally annealed films showed that the stability of H incorporated during deposition increased with deposition temperature, and that the N-H bond was more stable than the Si-H bond above 700°C. Deuterium plasma treatments, at 600°C, of annealed films caused isotopic substitution with a conservation of bonds. Therefore, hydrogen loss from annealed films is apparently accompanied by a reduction in dangling bonds.
Low Energy Ion Beam Modification of High Performance Polymer
Authors: Jeong Hyo-Soo , White R. C. 
Published: March 2011

AbstractIon beam modification of polyimide (PI) by low energy and surface analysis were performed using XPS. The surface chemistry was monitored as a function of ion dose. The results indicate that even low energy ion beam (LEIB) induces a drastic change in chemical compositions on the PI surface, and the modification begins to occur at the onset of beam treatment, contrary to previous observations. Damage level is severely restricted to surface region. It is also proven that LEIB modification is a direct way to control interface chemistry.
Laser Etching of Ceramics for Defining Slider Air-Bearing Surfaces for Magnetic Recording Heads
Authors: Khan Jamal 
Published: March 2011

AbstractA laser etching process was used to etch air-bearing surface patterns (cavities) on sliders for magnetic recording heads. Results on projection through mask as well as maskless etching of patterns on the TiC-A12O3 ceramic substrate and encapsulant alumina film on the surface are described. Pattern dimensions and location, along with laser operating parameters, are defined via a computer software program in the maskless etching process, and no external hard masks were used. A combination of maskless etching processes, using a Q-switched Nd:YAG laser for most of the ceramic substrate material in the back of the cavity and an excimer laser system for the alumina coating and nearby areas in the front, was found to give the best results.
Large Area Photochemical Dry Etching of Polymers with Incoherent Excimer UV Radiation
Authors: Esrom Hilmar , Zhang Jun-Ying , Kogelschatz Ulrich 
Published: March 2011

AbstractPhotochemical dry etching and surface modification of different polymers, e.g., poly-methylmethacrylate (PMMA), polyimid (PI) and poly-ethylene terephthalate (PET) was achieved with an incoherent excimer UV source. Decomposition and etch rates of PMMA were determined as a function of UV intensity and exposure time at different wavelengths λ = 172 nm (Xe2*), λ = 222 nm (KrCI*) and λ = 308 nm (XeCI*). The morphology of the exposed area of PMMA was investigated with SEM. The etching of the polymers can be explained as a result of extensive photooxidation. The results are compared with data obtained from mercury lamp and excimer laser experiments.
Oxide Phase Formation in Excimer Laser Processed Ti Alloy
Authors: Jervis T. R. , Hubbard K. M. , Zocco T. G. 
Published: March 2011

AbstractExcimer laser surface processing of Ti-6A1-4V results in substantial surface oxygen incorporation as measured by the narrow resonance in the elastic scattering of a particles at 3.05 MeV. Single pulse processing at 1.0 J-cm−2 results in transformation from the original a + β grain structure to a martensite structure. Multiple pulse processing results in oxygen incorporation proportional to the number of pulses during processing, but this is primarily reflected in the depth of the oxygen containing layer. A maximum oxygen to titanium ratio of 1.0 was observed in the surface layer. This was confirmed by transmission electron microscopy (TEM) which showed the development of a fine-grained equiaxed TiO surface layer from a phase mixture of Ti alloy with TiO precipitates. Concentration vs. depth profiles show that this layer is approximately 400 nm thick after 40 pulses. Further processing with a total of 60 pulses results in coarsening of the grains and an increase in the thickness of the layer. The TiO precipitate concentration increases gradually, becoming apparent in electron diffraction patterns after 30 pulses. No other oxide phases are observed, the TiO developing directly from the metallic phases. In particular, we do not observe the formation of Ti2O prior to the formation of the TiO, or the formation of TiO2.
In-Situ Ellipsometry Study of Pulsed Laser Deposited ZnO Films
Authors: Pittal Shakil , Mcconville L.A. , Tanno N.J. , Snyder P.G. 
Published: March 2011

AbstractEllipsometry is normally used to characterize layered structures that have uniform properties laterally across the area of the probe beam. In this study, pulsed laser deposition of ZnO films was found to have highly nonuniform growth properties in the lateral directions. We were able to account for the effects of the nonuniform growth on in-situ ellipsometric data, by considering two dynamic growth models.
Generation of Shock Waves in Confined Excimer Laser Ablation of Polyimide
Authors: Zweig Adrian D. , Deutsch T.F. 
Published: March 2011

AbstractWe study acoustic effects associated with the ablation of polyimide under water confinement. Ablation launches a shock in the target. After the shock propagates into the surrounding water we measure its velocity with an optical probe system. In the water the shocks decay after propagating a few hundred microns. The peak shock pressure scales with the square root of the laser fluence. Our observations can be explained by a simple model that interprets the generated pressures as being due to the heating of a confined ideal gas.
Photophysics of Polyatomic Species Ejection Following Uv Laser Ablation of Single Crystal Bi2Sr2Ca1Cu2O8
Authors: Wiedeman Lawrence , Kim Hyun-Sook , Helvajian Henry 
Published: March 2011

AbstractA series of experiments have been conducted which probe the origin of the polyatomic ions (e.g., Sr2O+, BiCu+) measured following the low fluence, pulsed UV laser irradiation of crystalline Bi2Sr2CaCu2O8 (BiSrCaCuO). The photoejection of polyatomic species presents a problem for the pulsed laser deposition (PLD) technique. The deposition of polyatomic products could limit epitaxial growth during thin film material processing. Our results indicate that the polyatomic species are not the consequence of a gas phase recombination, but are in fact directly produced. All experiments are done at laser fluences below that required for above surface plasma formation. As such, our results do not address the formation of large clusters within the dense plume in high fluence laser ablation.
Photon-Single Phonon Coupling at Polar Crystal Surfaces: Infrared Optical Anisotropy Spectra
Authors: Mochan W. Luis , Recamier Jose , Monsivais Guillermo , Barriga Lucia Diaz 
Published: March 2011

AbstractWe extend a formalism for the calculation of the surface-induced infrared anisotropy spectra of cubic polar crystals, in order to incorporate surface relaxation, reconstruction, and in general, surface modifications to the dynamic matrix. We calculate the reflectance anisotropy of a model (110) GaAs surface. The spectra have a rich structure which can be related to critical points of the phonon dispersion relation, and to coupling to surface states and surface resonances. The results display a very large sensitivity to the surface parameters, indicating that the surface induced anisotropy can be employed as an optical surface probe in the far IR.
Electron, Ion and Photon Beam Processing
Authors: Gamo Kenji 
Published: March 2011

AbstractBeam processing techniques are increasingly important because of their unique capability as nano-device fabrication techniques. These are low temperature processing, high spacial resolution, high material and spacial selectivity and anisotropy, etc. For device fabrication, reduction of processinduced damage is crucial. In the present paper, basic characteristics of electron, ion and photon beam processing for etching and deposition are compared with putting emphasize on the effect of damage and promising techniques to minimize damage.
Slim: a Personal Computer Based Software for Simulation of Laser Interaction with Materials
Authors: Singh Rajiv K. , Viatella John 
Published: March 2011

AbstractA user-friendly, personal computer (PC) based routine called SLIM [Simulation of Laser Interaction with Materials] has been developed to understand the non-equilibrium effects of high intensity, short laser pulses on different materials. By employing an accurate implicit finite difference scheme with varying spatial and temporal node dimensions, the time-dependent thermal history of laser-irradiated material can be accurately and quickly determined. This program can take into account the temperature dependent optical and thermal properties of the solid, time dependent laser pulse intensity, and formation and propagation of the melt and/or vaporization interfaces induced by intense laser irradiation. The program can also simulate thermal effects on multilayer structures exposed to pulsed laser irradiation It is expected that this simulation routine will be indispensable to all researchers working in the area of pulsed laser processing of materials, including rapid heating, melting, annealing, laser doping, laser deposition of thin films and laser solidification processing.
Resistless Etching of SiO2 by Two Color Excimer Lasers
Authors: Obara T. , Murahara M. 
Published: March 2011

AbstractResistless etching of thermal oxide silicon filmes were demonstrated by ArF & KrF excimer lasers, and CC12F2 gases. CC12F2 was decomposed by ArF excimer laser light, and CF2 radicals were produced. These radicals, which have absorption band nearby 250nm, were vary stable. Then the circuit pattarned KrF laser light was irradiated on the SiO2 in an atomsphere of CF2 radicals. As thse result, the etching pattern of 2 μ m width was performed.
Morphological Features of the Solid-Liquid Interface of a Gallium Film
Authors: Robinson Richard D. , Miaoulis Ioannis N. 
Published: March 2011

ABSTRACTThis paper presents a new experimental method to investigate solid-liquid interface morphologies during Zone-Melting-Recrystallization at lower than the typical processing temperatures. Gallium films were used as a substitute for silicon films. In situ preliminary investigation identified three phenomena typically occurring during ZMR of silicon films: a) Transition from planar to dendritic to cellular morphologies was observed for different processing conditions; b) cell period proved to be dependant on scanning velocity; c) instabilities at the solidification interface at low heating strip temperatures were caused by supercooling and optical property variations as the material changed phase.