bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cavitation in Unfired Ceramic Sheets by Pulsed Nd:YAG Laser
Authors: Louh Rong-Fuh , Buchanan Relva C. 
Published: March 2011

ABSTRACTSingle shot pulses from a Nd:YAG laser were used to generate different sized holes and patterns in tape-cast ceramic sheets for electronic packaging applications. The ceramic sheets were based on formulations in the BaTiO3 and MgO-Al2O3-SiO2 systems. The single shot laser pulses were targeted using a computer controlled mirror deflection system and a programmed (cavitation) pattern which could readily be modified. Morphology and structure of the drilled holes before and after sintering were examined by SEM. The surface radial temperature profile resulting from the laser pulse was directly mapped using a lacquer thermocoat. Effects of the laser pulse energy and beam spot size on laser/ceramic interactions and cavitation process were also explored.
Excimer Laser Induced Damage in Stressed Polyimide Films Exposed in Air
Authors: Tonyali K. , Jensen L. C. , Dickinson J. T. 
Published: March 2011

ABSTRACTIn earlier work we reported the consequences of simultaneous exposure of polymers to mechanical stress and electron bombardment. In this study we examine the response of highly stressed polyimide films to excimer laser radiation (20 ns pulses @ 248 nm wavelength) in air. The exposed surfaces show evidence of surface and near surface damage, crack initiation, and eventually crack growth over a wide range of applied stress and laser fluence. These results show that the morphology of the stressed material has a significant influence on the resulting damage and suggest that the regions of highest damage are those experiencing the highest local stress. A growth of nodules on the polyimide surface are also observed which are missing when exposed in vacuum.
Ion Beam Modification of Film Stress and the Effectiveness of Thin Film Encapsulants on GaAs
Authors: Haynes T. E. , Picraux S. T. , Lee S. R. , Chu W. K. 
Published: March 2011

ABSTRACTIon implantation has been used to modify the initial stress in thin (40 nm) SiO2 films on G a As, and to condition the SiO2-G a As interface to pro mote adhesion. The effectiveness of these implanted films as caps to suppress decomposition of GaAs during rapid thermal processing has been studied, and this provides an indicator of the mechanical stability of the films. Measurements of the initial film stress, as well as stress changes caused by implantation and annealing, have been made to help interpret the implantation results. Our results indicate that ion implantation does not have a strong effect on the performance of thin film SiO2 encapsulants on GaAs.
On the Contacts Formed in Ni-Al-Si System Due to Localized Melting by Means of Rapid Thermal Processing
Authors: Katz A. , Komem Y. 
Published: March 2011

ABSTRACTLocalized rapid melting of an intermediate Al film in the Ni(30nm)/Al(10nm)/<100>n-Si system was successfully carried out by means of rapid thermal processing at temperatures higher than 580°C. This rapid melting resulted in the formation of a unique metal-silicon contact composed of three separated layers and has the following structure: Ni(Al0.5,Si0.5)/Al3 Ni/NiSi / <100>n-Si.
It was found on the basis of quenching treatments after subsequent rapid thermal processings that an eutectic melting initiated at the Al-Si interface at 580°C, propagated towards the Ni layer and then formed a localized melt zone confined mainly to the region of the intermediate Al layer. The formation of the nickel silicides took place at the silicon surface after Ni diffusion through the melt zone, while the Al compounds were formed during a solidification process of the eutectic liquid. The eutectic melting at 580°C led to the decrease of the sheet resistance of the formed films from 3.2 to 2.6 / and to the increase of the Schottky barrier height of the contact from 0.6 to 0.76 eV.
Interfacial Reactions of Mo with Al: Ion mixing Versus Thermal Annealing
Authors: Ma E. , Brunner A. J. , Workman T. W. , Nieh C. W. , Zhao X.-A. , Nicolet M-A. 
Published: March 2011

ABSTRACTInterfacial reactions induced by ion beam mixing and furnace annealing in Al/Mo bilayers are investigated. The amount of interfacial ion m'xing, 4Dt, follows a linear dose dependence for irradiation temperatures ≤80 C. Below room temperature, the mixing efficiency, defined as d(4Dt)/dø, is temperature independent, and agrees fairly well with the prediction of the phenomenological model based on chemically biased diffusion in thermal spike. We conclude that thermal spike mixing dominates for Xe irradiation of Al/Mo at low temperatures. The mixing efficiency becomes temperature-dependent above room temperature with an apparent activation enthalpy of about 0.17±0.02eV. A layer of 15–20 at.% Mo forms by ion mixing, while oAl12 Mo forms upon thermal annealing in a nonuniform fashion starting at 500°C. Reaction of Mo with large-grained Al substrates shows the same nonuniform characteristics as in evaporated Al/Mo bilayers, implying a minor role of grain boundary effects. Oxygen gettered in the Mo film could be an important factor that influences the interfacial reaction.
Formation of Metastable Structures and Amorphous Phases in cu-w Alloys Using the Triode Sputtering Technique
Authors: Rizzo H. F. , Tanner L. E. , Wall M. A. , Massalski T. B. , McClanahan E. D. 
Published: March 2011

ABSTRACTThe triode sputtering technique and a “split-target” arrangement were used to produce metastable crystalline and amorphous phases in the Cu-W system under essentially oxygen-free conditions. Large metastable extensions of solid solubility were observed both from the Cu (fcc) and W (bcc) sides of the phase diagram, and a wide range of metallic glass formation was observed, approximately between 30 and 65 at.% W. The thickness of the amorphous Cu-W phase (40–160 pm) that can be deposited without the formation of the metastable bcc phase appears to be dependent on the Cu-W alloy composition. On heating, the crystallization temperature of the amorphous alloys was higher than 350°C. The behavior of the lattice parameter and near-neighbor distance has been studied with x-ray diffraction, showing small positive deviations from an assumed Vegard's Law. Hardness measurements indicate that the metastable crystalline phases are relatively harder than the amorphous phase.
Interfacial Reactions of Titanium Thin Films on P+-Implanted (001)Si
Authors: Wan M. H. , Lur W. , Cheng H. C. , Chen L. J. 
Published: March 2011

ABSTRACTInterfacial reactions of titanium thin films on P+-implanted silicon have been studied by transmission electron microscopy.The presence of titanium thin films on P+-implanted silicon was found to alter the defect configuration in the recrystallized layer. Interfacial reactions of titanium thin films on silicon were also found to be influenced by the presence of dopants as well as changes in the microstructures of the substrate. The results are compared with those found in previous studies of Ti thin films on ion-implanted silicon as well as on unimplanted samples. The mechanisms for the chaiiges in defect configuration and phase formation are discussed.
Optical Considerations for Excimer Projection Systems
Authors: Rothschild M. , Ehrlich D. J. 
Published: March 2011

ABSTRACTExcimer laser projection systems are expected to become widely used photolithographic tools, capable of high throughputs at resolution well below 0.5 iffli. The design of practical devices must overcome several challenges which are specific to the short wavelength, the laser performance and the photoresist response of such systems. This paper addresses the issues of UV optical materials, the effects of laser bandwidth on optical design, and the interrelationship between resist response, resolution, and laser pulse-to-pulse stability. It is shown how the various parameters are interconnected, and directions for further technological improvements are outlined.
Xps, Ups, and Hreels Studies of Excimer-Laser-Induced Dissociation of Al2(Ch3) Adsorbed on Si(100) Surfaces
Authors: Lubben D. , Motooka T. , Greene J.E. , Wendelken J.F. , Sundgren J.-E. , Salaneck W.R. 
Published: March 2011

ABSTRACTArF (193 nm) and KrF (248 nm) laser-induced dissociation of Al2(CH3)6 (TMA) adsorbed on Si(100) surfaces have been investigated using x-ray photo-electron, ultraviolet photoelectron, and high-resolution electron energy loss spectroscopies (XPS, UPS, and HREELS). UPS and XPS valence spectra from the adlayer contained three broad peaks near 4.5, 7.5, and 14.5 eV below the Fermi level whose positions were in agreement, based upon molecular orbital calculations, with those expected for TMA dimers. Angle-resolved XPS measurements indicated a splitting in both the Al 2p and Si 2p levels which was interpreted as evidence for TMA dimer molecules being adsorbed with the long (i.e. Al-Al) axis perpendicular to the surface. The HREELS adlayer spectrum consisted of three clusters of peaks located near 86 meV (methyl rocking and Al-C stretch), 170 meV (methyl deformation), and 362 meV (C-H stretch). Changes in the XPS, UPS, and HREELS spectra were monitored as a function of ArF and KrF laser irradiation. No-changes were observed for KrF irradiation with intensities up to 200 mJ-cm . However, ArF laser irradiation resulted in changes in both the XPS and HREELS spectra which indicated TMA dissociation and the desorption of methyl groups. Nevertheless, even after 104 20 mJ-cm-2 ArF pulses most of the carbon-containing species remained. Higher intensities, up to 200 mJ-cm-2, resulted in the formation of compounds which were stable on the surface.
Low Temperature UV Photodeposition of Aluminum from TMA: Characterization and Control of Deposit Composition
Authors: Orlowski T.E. , Mantell D.A. 
Published: March 2011

ABSTRACTLaser processing conditions have been discovered which provide high-quality aluminum deposits from the photodecomposition of TMA (trimethylaluminum). Using an ArF excimer laser, AI can be deposited on Si and glass in well defined patterns at high rates (600 A/min) at low TMA pressure (≤ 30 mtorr) if substrate temperature is kept low (≤ 25C). Deposit composition is characterized by x-ray photoelectron spectroscopy (XPS) which shows that deposit carbon content depends upon laser pulse intensity varying nearly quadratically from < 1% at 8 mJ/cm2 to nearly 25% at 80 mJ/cm2. Mass spectroscopie analysis during laser processing identifies methane, ethylene and ethane as primary hydrocarbon photoproducts. Thermal desorption measurements indicate that many adlayers of adsorbed TMA leave the sample surface with only slight heating (35C) providing an explanation for observing higher growth rates at room temperature. Because of the high deposition rate and deposit quality observed, this low temperature process provides an attractive processing alternative for interconnect repair on Si and glass.
XPS Surface Composition Analysis During UV Laser Photodeposition of Al From Tiba on Si (100) Substrates: Direct Observation of the Prenucleation Regime
Authors: Mantell David A. , Orlowski T.E. 
Published: March 2011

ABSTRACTAn in situ XPS study is made of the AI film growth from TIBA using an ArF pulsed laser on Si (100) substrates. It is found that the film is formed by the photochemical decomposition of the organometaliic on the surface. A metallic film is formed by island growth. These islands are covered with an organometaliic fragment layer of partially decomposed TIBA. The consequences of these observations toward understanding how laser processing can create prenucleation regions that catalyze film growth at temperatures below standard CVD temperatures are discussed.
Thermal Stability of Metal Films Deposited by Ionized Cluster Beams
Authors: Yamada I. , Usui H. , Harumoto H. , Takagi T. 
Published: March 2011

ABSTRACTOur previous experiments have shown that Al and Au films deposited on Si substrates by ionized cluster beams (ICB) exhibit high thermal stability and .long electromigration life time. To understand these characteristics, in-situ XPS measurements during ICB deposition of Au on Si(111) substrate have been made. The results show that at low coverages, the splitting between the two prominent structures in the Au-5d peaks in the valence band becomes closer to those of pure bulk gold when a film is deposited at high acceleration voltages. In contrast to this an appreciable change of the binding energy of the Si-2p state at low coverage and high acceleration voltage could not be observed. These results suggest that a high density layer is formed and any Au-Si interaction is suppressed at the initial stage of film deposition. This could be one of the reasons why ICB-deposited films exhibit high thermal stability.
Laser-Assisted Deposition of Fe and W: Photodecomposition of Fe(CO)5, and W(CO)6 on Si(111)-(7×7)
Authors: Swanson Jon R. , Friend C.M. , Chabal Y.J. 
Published: March 2011

ABSTRACTThe laser-assisted chemical vapor deposition (LCVD) of Fe and W on Si(lll)-(7×7) was investigated under ultrahigh vacuum conditions at 120 K. Multiple internal reflection Fourier transform infrared and Auger electron spectroscopies and temperature programmed desorption and low energy electron diffraction were used to study the adsorption and decomposition of Fe(C0)5 and w(C0)6 on the surface. Neither of the molecules thermally reacts in temperature programmed desorption experiments. Reversible molecular desorption is exclusively observed. Decomposition of both molecules via electronic excitation was induced by ultraviolet, but not visible photons. This was shown by measuring the photodecomposition yield as a function of wavelength. Visible photolysis (λ=720 nm) had no observable effect on either molecule. No surface stable, partially decarbonylated, Fe(C0), x<5, fragments observable with infrared spectroscopy were produced by photolysis. Also, no new features were observed in temperature programmed desorption experiments and only iron was detected on the surface after photolysis. In contrast, initial results indicate that photolysis of W(C0)fi does produce surface stable, W(C0), x<6, fragments.
Soft Vacuum, Pulsed Electron Beam Processing of Polyimides
Authors: Krishnaswamy J. , Li L. , Collins G. J. , Hiraoka H. , Ann Caolo Mary 
Published: March 2011

ABSTRACTWe report on the successful patterning of polyamic acid over wide areas using 28 kV pulsed electron beams produced in 30 mTorr air. The pattern degradation during the 350°C, 1/2 hr, imidizing thermal cure is prevented by pulsed, flood electron beam hardening of the developed polyamic acid patterns using the same soft vacuum, pulsed electron beam apparatus. It is also shown that a CW, low voltage, 1 to 3 kV electron beam sustained oxygen discharge can be used to completely strip the hardened, imidized material which is difficult to remove by wet methods. We also present, dose versus thickness remaining characteristics as a function of electron source to substrate distance and some examples of polyimide patterning.
Laser Ablation-Molecular Beam System. Reactions of Electrons or Ions From Metal Substrates With Organometallic, Metal Carbonyl and Organic Molecules
Authors: Toya Kenzo , Oka Tadashi , Kawasaki Masahiro , Sato Hiroyasu 
Published: March 2011

ABSTRACTLaser light (the second or third harmonics from an Nd:YAG laser) was focussed on the metal substrate in vacuum. A pulsed molecular beam of an organometallic compound, a metal carbonyl, or an organic molecule was introduced in the entrance region (the region in front of the ion-lens assembly) of a quadrupole mass filter which was located near the metal substrate. The reaction of the molecules in the beam with either the electrons or ions from the metal substrate was studied by monitoring the product ions by the mass spectrometer.
Laser Enhanced Selective Epitaxy of ιii-V Compounds
Authors: Karam N.H. , Liu H. , Yoshida I. , Katsuyama T. , Bedair S.M. , El-Masry N. , Jaing B. , Salih A.S.M. , Rozgonyi G. 
Published: March 2011

ABSTRACTSelective epitaxial growth of III-V compounds based on GaAs has been achieved using Ar+ ion laser assisted chemical vapor deposition (LCVD) on GaAs substrates. The growth rate, at carefully selected growth conditions, can be controlled to a few Å/s at bias temperatures as low as 250°C by conventional LCVD multi-scan technique. Typical Gaussian thickness profiles are achieved by this growth technique. On the other hand, flat top thickness profiles are achieved with direct writing of GaAs mono-layers by laser assisted atomic layer epitaxy (LALE). X-ray topography is demonstrated as a powerful tool for characterizing the grown films and photoluminescence shows that the quality of the grown films are comparable with those grown by conventional MOCVD or ALE.
Photodissociation Dynamics of Alkyltellurides
Authors: Brewer P.D. , Jensen J.E. , Olson G.L. , Tutt L.W. , Zinck J.J. 
Published: March 2011

ABSTRACTThe UV photodissociations of dimethyltelluride (CH3)2Te and diethyltelluride (C2Hs)2Te have been investigated by state-selective detection. Nascent populations of Te(5p Pjw) atoms produced by the photodissociation process were monitored using laser-induced fluorescence following excimer laser (248 nm and 193 nm) photolysis. Experimental results for both molecules indicate that the photolysis at 248 nm produces Te atoms via a single photon process and that the liberated Te atoms populate only the 5p3P2 state. The photolysis of diethyltelluride at 193 nm has also been found to be a single photon process producing Te atoms distributed over the 3P2, 3P1, and Pø states in a ratio of 13:2:1, respectively.
Low-Coverage Laser Desorption of Ions on Chlorinated Copper Surfaces
Authors: Chen L. , Liberman V. , O'Neill J.A. , Osgood R.M. 
Published: March 2011

ABSTRACTExperiments were performed to investigate the pulsed excimer laser etching of a chlorinated copper substrate. Time-of-flight mass spectrometric techniques were employed to characterize the mass and velocity distributions of both neutral and ionic species that desorb at laser fluences less than that required to melt bulk Cu or CuCl substrates. The presence of positively charged ions in this work is examined in terms of both photon and electron mediated desorption mechanisms.
Limiting Steps at Low Temperature in Direct Writing of Al on Si From Tma
Authors: Flicstein J. , Bouree J.E. , Bresse J.F. , Pougnet A.M. 
Published: March 2011

ABSTRACTThe rates of aluminum line growth, assisted by photolysis, in the normal direction to the Si (100) substrate, indicate that, in a trimethyl-aluminum + hydrogen mixture, only the change in the TMA flux and the UV laser power can play a determinant role. Possible explanation is based on the generated methyl radical “blocking” action leading to a self-limiting deposition rate, as opposed to the enhancement of methyl desorption by hydrogenation to methane. It is shown that dilution by hydrogen decreases the carbon contamination in aluminum line.
ZNSE/III–V Heterostructures Grown in a Multichamber MBE System
Authors: Tamargo M. C. , de Miguel J. L. , Hwang D. M. , Skromme B. J. , Meynadier M. H. , Nahory R. E. , Farrell H. H. 
Published: March 2011

ABSTRACTWe have grown ZnSe epitaxial layers on bulk GaAs substrates and on GaAs epitaxial layers, with both As-rich and Ga-rich surface terminations. We have also grown ZnSe on AlAs epitaxial surfaces with different As to Al ratios. In all cases, abrupt, layer-by-layer growth is observed on the As-rich surfaces, while 3-dimensional nucleation is observed on the group III-rich surfaces. GaAs was also grown on ZnSe layers. In this case, microtwins form at the interface whose density diminishes as the layer is made thicker. A growth model is proposed consistent with these results which requires over-all electronic balance at the interface.
Asymmetric Cracking in Znse/ZnSxSel−x Superlattices Grown by Molecular Bean Epitaxy
Authors: Dalby Richard J. , Petruzzello John 
Published: March 2011

ABSTRACTOptical and transmission electron microscopy have been used to study cracks appearing in ZnSe/ZnSxSe1−x (x ∼ 0.38) superlattices grown by Molecular Beam Epitaxy. It Is shown that when a fracture occurs it is confined, in most cases, to the superlattice and propagates along <011> cleavage directions in these <001> oriented epilayers. Cracks were not observed in all superlattices and their onset is discussed in relation to sulfur concentration, overall superlattice height, individual superlattice layer thicknesses, and stress, tensile or compressive, due to lattice mismatch and thermal expansion differences between buffer layer and superlattice. It was found that by adjusting the controllable parameters, cracks in the superlattices could be eliminated. Orientation and density of these features have been related to asynnmetric cracking associated with the zincblende structure of these II-VI materials. Experimental results are shown to be in agreement with theoretical predictions of critical heights for the onset of cracking.
Interface Recombination Velocities in Layered GaAs and AlGaAs/GaAs Structures Grown by OMVPE
Authors: Bothra S. , Venkatasubramanian R. , Ghandhi S.K. , Borrego J.M. 
Published: March 2011

ABSTRACTThe interface recombination velocity at n+ GaAs/n GaAs and n+ Al15 Ga85 As/n GaAs are reported for various dopings. It is seen that with an n+ GaAs cap layer it is possible to reduce the interface recombination velocity to ∼ 4.4 × 103 cm/s. This can be further reduced by employing an AlGaAs cap, due to the increased barrier caused by the valence band discontinuity.
Interfacial Reactions Between Ni and GaAs
Authors: Lin J. C. , Zheng X. -Y. , Hsieh K. -C. , Chang Y. A. 
Published: March 2011

ABSTRACTInterfacial reactions between Ni and GaAs have been studied using bulk diffusion couples of Ni(∼0.5mm thick)/GaAs and thin-film Ni (∼40nm) on GaAs (100) in addition to phase diagram determination at 600° C. On the basis of the phase diagram and the bulk diffusion couples, the ternary phase which forms first in the thin-film couples is Ni3 GaAs. Thinfilm studies show that the epitaxial growth of equilibrium contact phases, i.e., NiAs and β-GaNi, on a GaAs (100) substrate is possible.
Misoriented Epitaxial Growth of (111)CoSi 2 on Offset (111)Si Substrates
Authors: Bai Gang , Jamieson David N. , Nicolet Marc-A. , Vreeland Thad 
Published: March 2011

ABSTRACTSingle crystal epitaxial films of CoSi2 were grown by MBE on various (111)Si single crystal substrates, whose surfaces were purposely tilted towards the < 110>>g, direction by small angles ϕg,†, 0°, ≤ϕg, ≤, 4° measured between the surface normal and the < 111>>g, direction of Si. The actual offset angle, .ϕ8,, was determined by back Laue reflection method. The average perpendicular strain of the CoSi2 epilayer, ε┵, and the < 111 >f orientation of the epitaxial CoSi2 film were determined by double crystal diffractometry. We find that the misorientation angle, a, measured between the Si < 111>g, and CoSi2 < 111>f directions, increases linearly with the offset angle, ϕg, up to ϕg, = 4°. A simple geometrical model is developed which predicts that α = ε┵ × tan ϕg,. The model agrees quantitatively with the experimental data. The equivalent strain energy associated with the misorientation is approximated by that of a low angle tilt boundary. The misorientation angle α of the equilibrium state, determined by minimizing the total strain energy of the epitaxial film, is nonzero in general.
Epitaxial Growth of Thick Ag/Si(111) Films
Authors: Park K.-H. , Jin H.-S. , Luo L. , Gibson W.M. , Wang G.-C. , Lu T.-M. 
Published: March 2011

ABSTRACT600∼4000Å thick Ag films grown on 3∼4· misoriented Si(111) substrates by molecular beam epitaxy (MBE) technique have been studied by using x-ray pole-figure analysis and MeV He+ Rutherford Backscattering Spectrometry (RBS)/channeling technique. X-ray pole-figure measurements revealed that despite the large lattice mismatch (∼25%) between Ag and Si, Ag films with epitaxial relationship Ag(111)//Si(111):Ag[011]//Si[011] were grown with a small quantity (15∼20%) of twin structure. The <111> axial channeling minimum yield (Xmin) is reduced at the Ag surface as the Ag film thickness increases. These films were thermally stable up to 500°C annealing but the twinning disappeared after annealing