bluuebunny/crossref_metadata_2025_split huggingface dataset:
Investigation of Oxide/Metal Multilayers for Soft X-Ray Optics Fabricated by Ion Beam Sputterinc
Authors: Kataoka I. , Yoneiitsu T. , Sekine K. , Yaiada I. , Etoh K. , Ito K. , Hoshi N. 
Published: March 2011

ABSTRACTThe dependence of the ordering factor and surface roughness of aiorphous SiO2 and Ni filis fabricated by Dual Ion Beai Sputtering(DIBS) assisted by Ar+ ion boibardient were evaluated. The ordering factor tas defined as a quantity which shows the degree of aiorphousness froi ris value of correlation function of the RHEED pattern. The surface roughness was leasured with a Talystep systei and STM, and the data was evaluated with respect to the spatial wavelength.For aiorphous SiO2 filis, the surface roughness is strongly correlated with the ordering factor as a parameter of the assisting Ar+ ion energy, and it depends on the fill structure. Siiilar relationship was not observed for Ni filis, because of the traced surface roughness of substrate in the energy region investigated.
Freezing in Silicon at Large Undercooling
Authors: Stolk P.A. , Polman A. , Sinke W.C. 
Published: March 2011

ABSTRACTPulsed laser irradiation is used to induce epitaxial explosive crystallization of amorphous silicon layers buried in a (100) oriented crystalline matrix. This process is mediated by a self-propagating liquid layer. Time-resolved determination of the crystallization speed combined with numerical calculation of the interface temperature shows that freezing in silicon saturates at 16 m/s for large undercooling (> 130 K). A comparison between data and different models for melting and freezing indicates that the crystallization behavior at large undercooling can be described correctly if the rate-limiting factor is assumed to be diffusion in liquid Si at the solid/liquid interface.
Pulsed Laser-Induced Melting of Intermediate Cu-Zn Phases
Authors: Follstaedt David M. , Peercy Paul S. , Perepezko John H. 
Published: March 2011

ABSTRACTWe have discovered that the β and γ brasses of Cu-Zn exhibit clearly resolved increases in reflectance upon melting with a 30 ns ruby laser, which allow their melt durations to be readily measured. This system thus offers potential for obtaining quantitative information about the solidification kinetics of metals. We have also found that a heteroepitaxial layer of β' brass is formed on the surface of (ordered) γ brass with 63 wt.% Zn following pulsed laser-induced melting. The β' layer is interpreted to mean that the metastable β phase (bcc) formed on the liquid-solid interface as the γ substrate attempted to regrow, and that β ordered to β' (B2) during cooling. The β formation implies that undercoolings > 16 K were attained during the attempted regrowth of the γ phase.
Metastable Ge-Sn Alloy Layers Prepared by Pulsed Laser Melting
Authors: Chang I.T.H. , Cantor B. , Cullis A.G. 
Published: March 2011

ABSTRACTGe has a diamond cubic crystal structure (α) while Sn exists in both the diamond cubic (α) and body centred tetragonal (β) allotropic forms. The solid solubilities between Ge and Sn are very small according to the equilibrium phase diagram. This paper describes an investigation into the manufacture of metastable diamond cubic Ge-Sn alloy layers using pulsed laser melting of evaporated thin films . Cross-sectional and plan-view transmission electron microscopy have been used to characterise the microstructures of the Ge-Sn alloy layers, with alloy compositions determined by energy-dispersive X-ray microanalysis. The metastable diamond cubic Ge-Sn alloy microstructures are discussed in detail as a function of processing conditions.
Condensation of Ultrafine Silica from a Laser-Induced Plume
Authors: Chow G.M. , Strutt PR. 
Published: March 2011

ABSTRACTThe different silica-phase morphologies formed in synthesizing silica-metal matrix composites layers have been studied, using a new evaporation technique, involving rapid condensation of silica from a laser beam induced-ceramic plume. This process occurs within a reactive gas environment (98.5% hydrogen, 1.5% methane), with a heated tungsten filament in proximity to the laser beam-material interaction zone. The silica phase in the composite layers deposited on a nickel substrate exhibited different metastable morphologies, namely, nanometer-size amorphous fibers or linear-chain shape aggregates. There appeared to be a correlation between the morphology of the deposits and the position of the heated tungsten filament. When the tungsten filament was absent, silica was deposited in the form of clusters. In this case, depending on the beam-ceramic target interaction times, there was a shift in the Si-O stretching vibration characteristics. The laser beam-ceramic target interaction and the formation of the laser-induced ceramic plume are briefly discussed. Characterization techniques involved FTTR, X-ray diffraction, Auger and microprobe analysis, EDX and WDX analysis, SEM and TEM.
Excimer Laser Induced Crystallization of Amorphous Silicon Near Threshold
Authors: Bachrach R.Z. , Winer K. , Boyce J.B. , Ponce F.A. , Ready S.E. , Johnson R. , Anderson G.B. 
Published: March 2011

ABSTRACTUsing a suitably homogenized excimer laser beam, we have shown that the threshold for crystallization of amorphous silicon is well defined and exhibits a square root dependence on the laser energy density above threshold. This sharp threshold behavior can be exploited in a number of ways.
Influence of Ion Beam Mixing on the Growth of High Temperature Oxide Superconducting Thin Film
Authors: Bordes N. , Rollett A.D. , Cohen M. , Nastasi M. 
Published: March 2011

ABSTRACTThe superconducting properties of high temperature superconductor (HTS) thin films fabricated using the BaF2 process are dependent on the quality of the substrate used to grow these films. In order to maximize the lattice matching between the superconducting film and the substrate, we have used a YBa2Cu3O7, thin film deposited on <100> SrTiO3 as a template. The first film was prepared by co-evaporation of Y, BaF2 and Cu on <100> SrTiO3, followed by an anneal in “wet” oxygen at 850 °C. This film showed a sharp transition at about 90 K. A thicker layer of about 5000 A was then deposited on top of this first 2000 Å film, using the same procedure. After the post anneal at 900 °C, the transition took place at 82 K and no epitaxy of the second film was observed. Ion beam mixing at 400 °C, using 400 keV O ions was done at the interface of the two films (the second one being not annealed). After the post anneal, the film displayed an improved Tc at 88K. Moreover, epitaxial growth was observed to take place at the ion mixed two-layer interface which was dose dependent. These results suggest that the homoepitaxy of the second layer on the first is interface limited and can be enhanced by ion mixing treatments.
The Effect of Ion Induced Damage on the Mechanical Properties of Zirconia
Authors: Fleischer E. L. , Herd W. , Alford T. L. , Børgesen P. , Revesz P. , Mayer J. W. 
Published: March 2011

ABSTRACTMicrohardness measurements were carried out on ion implanted single crystal Y2O3 stabilized cubic ZrO2. Ions were implanted up to fluences of 3×1017 ions/cm2. Comparison of the Knoop micro-hardness values of ZrO2 implanted with various species over a range of fluences showed that the principle variable causing hardness changes for inert ion implantation is damage energy and not the ion fluence nor the ion species. For shallow inert ion implants, the hardness versus damage energy gives a unified plot. Hardnesses rise with increasing deposited damage energy to a value 15% higher than that of unimplanted zirconia. With additional damage the hardness drops to a value 15% lower than that of the unimplanted zirconia. Deep implants showed 50% increases in hardness and significant fracture toughness increases.Friction and wear measurements of the shallow implants in a pin-on-disk assembly showed very different behavior for high dose versus unimplanted ZrO2. The unimplanted samples showed debris with an associated rise in friction. The implanted system showed much less debris and a constant value of friction even after 10,000 cycles.
Synthesis of MOS2 Phase in the Near Surface Region of Al2O3 and ZrO2 by Ion Implantation
Authors: Rai A.K. , Bhattacharya R.S. , Rung S.C. , Patrizio D. 
Published: March 2011

ABSTRACTAl2O3 and ZrO2 substrates were coimplanted with 175 keV Mo+ and 74 keV S+ at doses of 1×10 cm−2 and 2×1017 cm−2 respectively. The energies of Mo+ and S+ ions were chosen to provide a nearly overlapping depth profiles in both substrates. Rutherford backscattering (RBS), Auger electron spectroscopy (AES) and transmission electron microscopy (TEM) techniques were used for characterization. The as implanted surface of Al2O3 became amorphous while as implanted ZrO2 surface remained crystalline. The MoS2 phase was observed in the as implanted ZrO2. The MoS2 phase was observed in the implanted region of Al2O3 and ZrO2 after furnace annealing at 700°C. Thermodynamic calculations were performed to predict the equilibrium binary phase formed in Al2O3 and ZrO2 under the present implant and annealing conditions. The predictions agree with the experimental findings.
Laser Vaporization and Deposition of Lead Zirconate Titanate
Authors: Schenck Peter K. , Cook Lawrence P. , Zhao Jianrong , Hastie John W. , Farabaugh Edward N. , Chiang Chwan-Kang , Vaudin Mark D. , Brody Philip S. 
Published: March 2011

ABSTRACTLaser-induced vaporization of ceramics shows promise as a technique for the deposition of thin films of these materials. Critical to the utility of this technique is an understanding of the laser-material interaction, plume formation and dynamics, material transport and how variations in the vaporization conditions affect the deposited film. Lead zirconate titanate (PZT, Zr/Ti-47/53) targets were irradiated using a q-switched Nd:YAG laser (15 ns, 100 mJ at 1.064 /μm) . The deposition chamber was maintained at a pressure of 100 mTorr oxygen. Material from the plume was collected on silicon wafer substrates, suspended 1.0 - 3.0 cm above the target. The films were characterized by SEM/EDX, TEM, x-ray diffraction and electrical measurements before and after annealing. Very thin films were deposited on carbon coated metal grids for observation in the TEM using a hot stage to study crystallization.
Temporally and spatially resolved spectra of the light emitted by the laser-generated plume were obtained with an optical multichannel analyzer (0MA) to yield information on the plume generation and chemistry of the deposition process. These spectra indicate that under these conditions a plasma is created above the target surface which persists for -100 ns after the laser pulse.
Comparison of the Effect of Boron and Phosphorus Impurities on Solid Phase Epitaxial Regrowth of Amorphous Silicon
Authors: Jeon Young-Jin , Becker M.F. , Walser R.M. 
Published: March 2011

ABSTRACTThis work was concerned with comparing the relative effects of boron and phosphorus impurities on the solid phase epitaxial (SPE) regrowth rate of self-ion amorphized layers in silicon wafers with (100) orientation. We used previously reported data measured by in situ, high precision, cw laser interferometry during isothermal annealing for temperatures from 450°C to 590°C, and concentrations in the range from 7.8×1018 cm-3 to 5×l020 cm-3 for boron (NB), and from 5×l017 cm-3 to 3×1020 cm-3 for phosphorus (Np) impurities. The basis for the comparison was a recently developed model that extends the Spaepen-Turnbull model for silicon recrystallization to include ionization enhanced processes.The experimental data for bom boron and phosphorus exhibited the linear variation in regrowth rate expected for low concentrations of implanted hydrogenic impurities having a concentration-independent fractional ionization in amorphous silicon. In the linear range the relative enhanced regrowth rate produced by these impurities can be expressed as a product of their, relative fractional ionizations, and the relative amount the rate constant for reconstruction is altered by localizing an electron, or a hole, at the reconstruction site. Assuming that a localized hole and electron equally softened the potential barrier for reconstruction, the experimental results indicated that boron had an ?40 meV lower barrier to ionization in amorphous silicon than phosphorus.The variations in the SPE regrowth rates with higher concentrations of both implanted boron and phosphorus were well fit by quadratic equations, but with different curvatures (+ and - for B and P respectively). This result was interpreted to indicate that SPE regrowth was further enhanced by localized hole pairs, but retarded by localized electron pairs.
Irradiation-Induced Amorphization and Elastic Shear Instability in Intermetallic Compounds
Authors: Koike J. , Okamoto P. R. , Rehn L. E. , Bhadra R. , Grimsditch M. H. , Meshh M. 
Published: March 2011

ABSTRACTPreviously we reported a substantial (∼ 50 %) decrease in shear modulus prior to amorphization in Kr irradiated Zr3Al, and proposed that amorphization is triggered when the crystalline lattice becomes unstable against shear stress. In the present work, the relation between amorphization and shear elastic instability has been investigated in two additional compounds (FeTi and NiAl) during room temperature irradiation with 1.7-MeV Kr+. A shear modulus was measured using Brillouin scattering; structural information was obtained in situ in a high voltage electron microscope interfaced to a tandem accelerator.During irradiation of FeTi, chemical disordering and a large (∼40 %) decrease of shear modulus were observed, and an amorphous phase developed subsequently. In contrast, NiAl remained crystalline and chemically ordered during irradiation, and exhibited only a ∼ 10 % decrease in shear modulus. Hence, these two results provide further support that a shear instability triggers irradiation-induced amorphization. The shear instability mechanism may also apply to other solid-state amorphization techniques, e.g. hydrogen charging and mechanical deformation.
Studies of Ion-Assisted Growth and Properties of PbTe Epilayers Deposited by Rf Magnetron Sputtering
Authors: Cook J.G. , Mukherjee G. , Das S.R. 
Published: March 2011

ABSTRACT(111) PbTe // (111) BaF2 epilayers have been prepared by rf magnetron sputtering. A small negative substrate bias voltage (-10 V) enhances the (111) growth habit at reduced substrate temperatures (180 °C) and increased deposition rates (2.5 μ/h–1). Langmuir probe diagnostics is used to determine the energy and flux density of Ar ions incident on the growing film. Hall effect measurements are made to determine the carrier type and mobility as a function of the growth temperature.
Formation of Niobium Carbides in High-Dose Carbon-Ion-Implanted and Annealed Niobium
Authors: Huang J. S. 
Published: March 2011

ABSTRACTPolycrystalline niobium was implanted with 200-keV C+ ions to a total fluence of 7 × 1017 carbon ions per cm2 (C/cm2). Auger electron spectroscopy (AES) analysis showed that the carbon concentration varied from 5 to 50 at.% within a depth of about 4000 Å. Glancing-angle x-ray diffraction analysis (XRDA) and transmission electron microscopy (TEM) analysis indicated that no Nb2C phase was formed and that a buried fee NbC layer was formed in the region where carbon content exceeds about 40 at.%. The absence of Nb2C was attributed to its narrow range of solubility for carbon and the low diffusivity of carbon atoms. The possibility of the NbC precipitation by nucleation and growth or by a diffusionless martensitic transformation is discussed. When the implanted samples were annealed at 1273 K for 1 h, an orthorhombic Nb2C phase formed as spherical precipitates and the implanted carbon redistributed.
Strengthening of Aluminum by Oxygen Implantation: Experimental Results and Mechanical Modeling
Authors: Bourcier Roy J. , Follstaedt David M. , Myers Samuel M. , Polonis Douglas H. 
Published: March 2011

ABSTRACTThe microstructuTe and mechanical properties of high purity aluminum implanted with 20 at.% oxygen to a depth of roughly 500 nm and subjected to various thermal histories have been examined. Transmission electron microscopy and Rutherford-backscattering spectrometry were used to characterize the depth and nature of the implanted zone. As implanted, the material appears to contain a homogeneous distribution of disordered precipitates with sizes of 1.5-3.5 nm. Annealing at 450 or 550ΰC for 1 hour, induces ordering of the precipitates but only causes slight coarsening. Ultra-low load indentation hardness testing was used to probe the mechanical response of the surface-modified material. The data from the hardness tests were interpreted through the use of a finite-element model; the results indicate the flow stresses of an implanted and annealed layer are as high as 1600 MPa. The as-implanted material is much harder, approaching 3300 MPa. The degree of strengthening expected for the as-implanted and post-annealed material on the basis of the observed microstructure was estimated using several micromechanical models, and the results conform to the findings from indentation testing.
Computer Simulation of Ion Beam Enhanced Deposition of Titanium Nitride Films
Authors: Xi Wang , Jiankun Zhou , Youshan Chen , Xianghuai Liu , Shichang Zou 
Published: March 2011

ABSTRACTA Monte-Carlo computer simulation has been performed to describe, at atomic level, the growth of titanium nitride films formed by ion beam enhanced deposition (IBED). The simulation is based on a random target, fixed free path of moving particles and binary collisions. An alternate process of deposition of titanium atoms and implantation of nitrogen ions is applied instead of the actual continuous and synchronous process of IBED. According to the actual conditions, the adsorption of nitrogen gas, which is leaked out from the ion source, at the fresh titanium layer surface has been considered. In addition, the change of the composition profile and the density profile during film growth is taken into account. It is demonstrated that the width of the intermixed region between the film and substrate increases with the increase of the atomic arrival ratio, R, of implanted nitrogen ions to deposited titanium atoms. When the titanium deposition rate is low, the nitrogen concentration of the film is relatively insensitive to R, indicating that a dominant contribution to the nitrogen concentration is derived from the nitrogen gas leaked out from the ion source. The results obtained in this study are in agreement with the experimental measurements.
Low Temperature Interlevel SiO2 Layers by Photoinduced Processing
Authors: Sigmund H. , Klumpp A. , Springholz G. 
Published: March 2011

ABSTRACTPolysiloxane layers were deposited from the gas phase by photoinduced polymerization reaction of tetraethylorthosilicate (TEOS) and 02/N20. The deposition kinetics can be described by a gas phase polymerization and the subsequent condensation of the siloxane molecules. As UV light sources an ArF excimer laser (193 nm) anda 185/253 nm low pressure Hg—discharge lamp were used, the polysiloxane deposition rates are 2000 Å/min or 1200 Å/min respectively. Ina second thermal or combined thermal/ photoinduced process step the as deposited siloxane layers are transformed by hydrolysis and condensation reactions to pure Si02. The composition of the as deposited and transformed polysiloxane layers were investigated by FTIR spectroscopy. Typical examples of the step coverage and planarizing properties of the SiO2 layers for the use as interlevel dielectrics are presented.
X-Ray Photoemission Investigation of Excimer Laser Induced Etching of InP
Authors: Matz R. , Meiler J. , Haarer D. 
Published: March 2011

ABSTRACTArF excimer laser induced etching of InP in various etch gases (HBr, HCI, CI2) is discussed with regard to its spatial resolution capability. X-ray photoemission spectra and large-area etch rate measurements published before lead to fundamental understanding and interpretation of the characteristics of etched test structures. HBr and HCI require gas phase photodissociation. CI2' in contrast, has the advantage to react spontaneously.
Local Laser Induced Etching of Copper Films by Chlorine
Authors: Tang Hua , Herman Irving P. 
Published: March 2011

ABSTRACTA focused argon ion laser was used to induce local thermal etching of copper films in the presence of chlorine gas. Raman scattering was used to follow the transformation of the copper film in situ to CuC1 and CuCl2. In some regimes the laser only induced transformation of copper to copper chloride, while in others the laser produced copper chloride and also desorbed it.
A Process Model for Reactive Ion Etching and Study of the Effects of Magnetron Enhancement
Authors: Meyyappan M. , Buggeln R. C. 
Published: March 2011

ABSTRACTMagnetron reactive ion etching has been receiving much attention since it offers low pressure, and low bias etching conditions with little damage. We have developed a process model for this process and present simulation results for boron trichloride etching of GaAs. The computed etch rates are uniform in the center with higher rates at the edges of the wafer. Flow rates and pressure can be optimized to improve uniformity. The etch rates with the aid of the magnetron are shown to be higher than the rates tor conventional reactive ion etching.
Downstream Etching of GaAs and InP Using Molecular Chlorine and Chlorine Radicals
Authors: Lishan David G. , Hu Evelyn L. 
Published: March 2011

ABSTRACTThe temperature dependent etching of GaAs and InP using both molecular and remote plasma activated Cl2 and HC1 is examined. GaAs etches nearly three times faster in a remotely generated C12 plasma than in a molecular Cl2 environment with plasma off. The temperature dependance from room temperature to 250°C is similar for both cases. Significant etch rates of GaAs are observed for HC1 remotely generated plasma even at room temperature (∼1000 Å/min). Although the etch rate for InP below 150°C is quite low for either C12 or HCl, the relatively fast, temperature independent etch rate above this temperature is comparable to that of GaAs. The results are compared to RIE and a thermodynamic model.
Hollow Cold Cathode Ion Source for Reactive Ion-Beam Etching
Authors: Stognij A.I. , Tokarev V.V. 
Published: March 2011

ABSTRACTA wide-aperture reactive gas ion source has been developed for various ion-beam processings in high vacuum (p < < 5×10−2 Pa). The peculiar feature of the ion source is that two-stage self-maintained low-pressure discharge is used here as a plasma emitter. This provides high operating parameters of the source along with simple diode-type structure.
Generation of Blind Via-Holes for a High Density Multi-Chip-Module Using Excimer Lasers
Authors: Bachmann Friedrich G. 
Published: March 2011

ABSTRACTIn recent years the on-chip delay has gone down much more rapidly than the signal delay in packaged circuits. As a consequence of this the packaging delay times have had to be reduced drastically, which means that a greater packging density had to be implemented. A novel planar packaging technique, used in the new Siemens main frame computer 7500 H 90 has led to considerable progress in solving this problem. An essential part of this system is a multi-chip-module which can hold up to 144 bare chips. The carrier of these IC's is a 16-layer high density multilayer printed circuit board, which is fabricated in a sequential process. Interlayer contacts are formed by 80 µm wide blind via-holes, which are generated by excimer-laser ablation of the dielectric. The process desribed in this paper shows that it is possible to produce blind via-holes with an aspect ratio of about one in an extremely reliable and reproducible way. This process is already being successfully run on a production line. It is to our best knowledge the first time excimer lasers have been used on a large-scale in an industrial environment.