bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optical and Magnetic Properties of Silica Implanted with N+ and Fe+
Authors: Isobe T. , Weeks R.A. , Zuhr R.A. 
Published: April 2011

AbstractSilica platelets (Corning 7940) were implanted sequentially with N at 52 keV to different doses ranging from 0 to 1.2×l017 ions cm2 and then with Fe at 160 keV to a dose of 6×10 ions cm2. The optical absorption decreased with increasing N1 dose at photon energies ranging from 1.4 eV to 6.5 eV. The relative intensity, S(0°), of the ferromagnetic resonance absorption and its resonance field, H(0°), at θ = 0° were larger than S(90°) and H,(90°) at 0 = 90°, where Θ is the angle between the applied magnetic field and the normal to the implanted surface. The maximum values of S(0°) and S(90°) were observed near the N/Fe atomic ratio of 0.2. At the similar atomic ratio, the differential relative intensity, S(0°)- S(90°), and the differential resonance field, H,(0°)-H,(90°). associated with the degree of magnetic interaction between the produced compounds, also showed maxima. We conclude that sequential ion-implantation of N1 and Fe1 into silica causes a chemical interaction to produce iron nitrides.
Materials Science Issues of Plasma Source Ion Implantation
Authors: Nastasi M. , Elmoursi A.A. , Faehl R.J. , Hamdi A.H. , Henins I. , Malaczynski G.W. , Mantese J.V. , Munson C. , Qui X. , Reass W.A. , Rej DJ. , Scheuer J.T. , Speck CE. , Walter K.C. , Wood B.P. 
Published: April 2011

AbstractIon beam processing, including ion implantation and ion beam assisted deposition (IBAD), are established surface modification techniques which have been used successfully to synthesize materials for a wide variety of tribological applications. In spite of the flexibility and promise of the technique, ion beam processing has been considered too expensive for mass production applications. However, an emerging technology, Plasma Source Ion Implantation (PSII), has the potential of overcoming these limitations to become an economically viable tool for mass industrial applications. In PSII, targets are placed directly in a plasma and then pulsed-biased to produce a non-line-of-sight process for intricate target geometries without complicated fixturing. If the bias is a relatively high negative potential (20-100kV) ion implantation will result. At lower voltages (50-1200V), deposition occurs. Potential applications for PSII are in low-value-added products such as tools used in manufacturing, orthopedic devices, and the production of wear coatings for hard disk media. This paper will focus on the technology and materials science associated with PSII.
New Developments in Metal Ion Implantation by Vacuum Arc Ion Sources and Metal Plasma Immersion
Authors: Brown I.G. , Anders A. , Anders S. , Dickinson M.R. , MacGill R.A. , Monteiro O.R. , Oks E.M. , Raoux S. , Wang Z. , Yushkov G. 
Published: April 2011

AbstractIon implantation by intense beams of metal ions can be accomplished using the dense metal plasma formed in a vacuum arc discharge embodied either in a vacuum arc ion source or in a ‘metal plasma immersion’ configuration. In the former case high energy metal ion beams are formed and implantation is done in a more-or-less conventional way, and in the latter case the substrate is immersed in the plasma and repetitively pulse-biased so as to accelerate the ions at the high voltage plasma sheath formed at the substrate. A number of advances have been made in the last few years, both in plasma technology and in the surface modification procedures, that enhance the effectiveness and versatility of the methods, including for example: controlled increase of the ion charge states produced; operation in a dual metal-gaseous ion species mode; very large area beam formation; macroparticle filtering; and the development of processing regimes for optimizing adhesion, morphology and structure. These complementary ion processing techniques provide the plasma tools for doing ion surface modification over a very wide parameter regime, from ‘pure’ ion implantation at energies approaching the MeV level, through ion mixing at energies in the ∼1 to ∼100 keV range, to IBAD-like processing at energies from a few tens of eV to a few keV. Here we review the methods, describe a number of recent developments, and outline some of the surface modification applications to which the methods have been put.
Dual Ion Beam Sputtering of Carbides for EUV Reflectance
Authors: Schwarcz Dan , Keski-Kuha R.A.M. 
Published: April 2011

AbstractThere is a need for thin optical coatings that can be produced at low temperatures and have a high reflectance at the extreme ultraviolet (EUV), λ < 1200 Å. Currently, the best such materials are silicon carbide (SiC) and boron carbide sputtered onto optical surfaces. The EUV reflectance of sputtered SiC, however, is not as high as that of the sputtered target materials (sintered or CVD -SiC). More significantly, the reflectance of both sputtered films degrades with time. In previous work the reflectance degradation of the SiC films has been quantified, and efforts to ameliorate it via ion-beam assisted deposition (BAD) were described. Further work on sputtered SiC films is reported, including chemical and structural analysis. In addition, the degradation behavior of sputtered boron carbide is discussed.
Depth Profiles of Medium Energy Phosphorus Implants into Silicon
Authors: Lavine J. P. , Zheng L. , Whalen P. M. , Downey D. F. 
Published: April 2011

AbstractSecondary ion mass spectrometry (SIMS) is used to produce depth profiles of ion-implanted phosphorus in silicon. The implant energies are 250, 500, and 750 keV, and there is a 0.06-μm thick oxide on the silicon. The experimental profiles are compared with predictions from a variety of simulation programs, most of which give larger projected ranges than the data. The silicon crystal structure needs to be included in the calculations to produce projected ranges and depth profiles that agree with the present experimental data and with data from the literature.
Controls of Crystallinity and Surface Roughness of Cu Film in Partially Ionized Beam Deposition
Authors: Koh Seok-Keun , Kim Ki-Hwan , Choi Won-Kook , Jang Hong-Gui , Yoon Young-Soo , Han Sung , Jung Hyung-Jin 
Published: April 2011

AbstractChanges of crystallinity and surface roughness are discussed in terms of the average energy per deposited atom in the partially ionized beam(PIB) deposition. The average energy per deposited atom can be controlled by adjusting the ionization potential, Vi and acceleration potential, Va. The ion beam consists of a Cu ion beam and residual gas ion beam and residual gases as well as Cu particles that were ionized and accelerated to provide the film with energy required for film-growth. The relative contribution of residual gas ions and Cu ions to total average energy per deposited atom was varied with the ionization potential. At fixed ionization potentials of Vi=400 V and Vi=450 V, the average energy per deposited atom was varied in the range of 0 to 120 eV with acceleration potential Va, of 0 to 4 kV. The relative intensity ratio, 1(111)/I(200), of the Cu films increased from 6 to 37 and the root mean square(Rms) surface roughness decreased with an increase in acceleration potential at Vi=400 V. The relative intensity ratio, I(lll)/I(200), of Cu films increased up to Va=2 kV at Vi=2 kV, above which a decrease occurred, and the surface roughness of Cu films increased as a funtion of acceleration potential. The degree of preferred orientation was closely related with the average energy per deposited atom. The change of Rms roughness might be affected by ion flux, particle energy and preferred orientation.
Characterization of Defects Created in Silicon Due to Etching in Low-Pressure Plasmas Containing Fluorine and Oxygen
Authors: Buyanova I. A. , Henry A. , Monemar B. , Lindström J. L. , Lamprecht A. , Svensson B. G. , Oehrlein G. S. 
Published: April 2011

AbstractDefect characterization in n-type silicon after the reactive ion etching (RIE) in low-pressure plasmas containing fluorine and oxygen is performed by using photoluminescence (PL) and deep level transient spectroscopies (DLTS). It is shown that RIE treatment results in the formation of (i) luminescence centers giving rise to the C- and G- excitonic lines and broad emission bands related to radiation-induced defect complexes and extended defects and (ii) several electron traps located at 0.16 eV, 0.26 eV, 0.43 eV and 0.58 eV below the conduction band. The addition of oxygen to the SF6 and CF4 plasma is shown to cause nonuniform stress in the near surface region. This stress is responsible for the experimentally observed splitting of the C- and G-excitonic lines, a low energy shift of the phosphorous bound exciton lines, as well as the splitting of the DLTS spectra. It is shown that the stress field is highly inhomogeneous across the wafer, and is rather related to the RIE-induced extended defects than caused by the reaction layer formed on the Si surface.
Role of Interface in Ion Mixing or Thermal Annealing Induced Amorphization in Multilayers in Some Immiscible Systems
Authors: Liu B.X. , Zhang Z.J. , Jin O. , Pan F. 
Published: April 2011

AbstractSix binary metal systems were selected to study the possibility of forming amorphous alloys by ion mixing or thermal annealing in multilayered Films, i.e. the Ta-Cu, Zr-Nb, Zr-Ta, Y-Zr, Y-Mo and Y-Ta systems, featuring positive heats of formation (ΔHf) ranging from +3 to +40 kJ/mol. Firstly, the interfacial free energy consisting of a chemical and an elastic terms was calculated and added to the energetic state of the multilayers. It was found that the excess interfacial free energy increased with increasing the fraction of the interfacial atoms in the multilayers, and could raise the multilayers to an energy level intersecting with or being higher than thai of the amorphous phase possessing a typical convex shape. It is therefore possible to produce amorphous alloys in such systems, if the multilayered filins included enough fraction of the interfacial atoms. The multilayered samples were then designed and prepared accordingly and both ion mixing and thermal annealing under appropriate conditions resulted in the formation of a number of new amorphous alloys, confirming the above prediction based on the interfacial free energy concern. It is noted that the success of synthesising amorphous alloys by solid-state reaction in the immiscible systems develops a new glass forming technique, namely interface-generated spontaneous amorphization, which has a great potential to produce new and relatively thick amorphous films, e.g. a Ta72Cu28 amorphous film of 800 nm thick was obtained.
Properties of Silicon-on-Defect-Layer Material
Authors: Li Jianming , Jones K. W. , Coleman J. H. , Yi J. , Wallace R. , Anderson W. A. 
Published: April 2011

AbstractA new silicon material, silicon-on-defect-layer (SODL), has been measured by secondary ion mass spectrometry (SIMS) and spreading resistivity (SR) measurements. SIMS data show that the buried defect-layer in SODL consists of silicon oxide due to the gettering of intrinsic oxygen by proton-implanted damage. Furthermore, SODL procedure makes a silicon wafer contain much fewer oxygen in surface-layer on the defect-layer, resulting in a purfied surface-layer. Measurements of SR indicate that the surface-layer of n-type silicon wafer was converted to p-type silicon after SODL procedure. A metal oxide semiconductor (MOS) device with a value of the electron mobility in the inversion mode of 714 cm2/(V s) was fabricated on SODL material. Like isolation function of a well in a complementary MOS (CMOS) device, the p-n junction in SODL material could play a role of isolation between the surface-layer and bulk. In addition, by reducing the implantation energy, SODL technology for making p-n junction, in which built-in field separates light-generated electrons and holes, is a candidate to make cheap solar cells by using low-quality low-cost silicon.
Cavity Nucleation and Evolution in He-Implanted Si and GaAs
Authors: Follstaedt D. M. , Myers S. M. , Petersen G. A. , Barbour J. C. 
Published: April 2011

AbstractThe criteria for forming stable cavities by He implantation and annealing are examined for Si and GaAs. In Si, implanting at room temperature requires a minimum of 1.6 at.% He to form a uniformly dense layer of cavities after annealing at 700°C. Near this threshold, cavities are located at dislocations and planar defects. Peak He concentrations just above 1.6 at.% produce narrow layers of cavities at the projected range. In GaAs, room-temperature implantation followed by annealing results in exfoliation of the surface layer. Cavities were formed instead by implanting Ar followed by overlapping He, both at 400°C, with additional annealing at 400°C to outgas the He. This method forms 1.5-3.5 nm cavities that are often on {111} planar defects.
High-Energy Ion-Implantation of a Moderately Deep Acceptor Hg Into Liquid Encapsulated Czochralski Grown GaAs : Formation of New Shallow Emission Bands
Authors: Harada K. , Makita Y. , Shibata H. , Lo B. , Beye A. C. , Halsalic M. P. , Kimura S. , Kobayashi N. , Iida T. , Shima T. , Obara A. 
Published: April 2011

AbstractHg (mercury) in GaAs is known to be a moderately deep acceptor impurity, having a 52 meV activation energy. Optical properties of Hg acceptors in GaAs were systematically investigated as a function of Hg concentration, [Hg]. Samples were prepared by high-energy ion-implantation of Hg+ into GaAs grown by the liquid encapsulated Czochralski (LEC) method. Heat treatment was made by furnace annealing and rapid thermal annealing. Photoluminescence measurements at 2K revealed that the Hg-related so-called “g” line is formed in addition to the well-defined conduction band-to-Hg acceptor transition, (e, Hg). Additionally, three shallow emissions are formed for net hole concentrations INA-NDI greater than 2×1017cm−3 . This is the first demonstration that even Hg in GaAs makes multiple shallow emissions due to acceptor-acceptor pairs and LEC GaAs can be used for the investigations of these emissions.
The Fabrication of Complex Membrane Structures in N-GaAs for Micromechanical Applications
Authors: Miao J. , Weiss B.L. , Hartnagel H.L. , Wilson R.J. , Ruck D. 
Published: April 2011

AbstractA novel process for the fabrication of complex membrane structures in n-GaAs has been developed which utilises high energy nitrogen implantation and annealing to produce a semi-insulating etch stop layer and pulsed anodic etching for the selective removal of material. The process is versatile and can be used to produce complex, single crystal, stress-free, self-supporting membrane structures which are suitable for use as transducers operating up to ∼300°C. The semi-insulating properties of the membrane demonstrates its potential use as a substrate for electronic circuits.
Mev Ion Beam Synthesis of Well-Defined Buried 3C-Sic Layers in Silicon
Authors: Lindner J.K.N. , Götz B. , Frohnwieser A. , Stritzker B. 
Published: April 2011

AbstractWell-defined, homogenous, deep-buried 3C-SiC layers have been formed in silicon by ion beam synthesis using MeV C+ ions. Layers are characterized by RBS/channeling, X-ray diffraction, x-sectional TEM and electron diffraction. The redistribution of implanted carbon atoms into a rectangular carbon depth distribution associated with a well-defined layer during the post-implantation anneal is shown to depend strongly on the existence of crystalline carbide precipitates in the as-implanted state.
Electrical and Structural Properties of Annealed Epitaxial Ceo2 Films on Si(111) Substrates
Authors: Morshed A. H. , Tomita M. , El-Masry N. , Mclarty P. , Parikh N. P. , Bedair S. M. 
Published: April 2011

AbstractEpitaxial CeO2 films were grown on Si(111) substrates by laser ablation of CeO2 targets under UHV conditions. The as-grown films were found to have poor electrical properties due to the presence of a large amount of defects near the oxide-silicon interface. Improved MOS electrical characteristics were obtained by annealing in an O2 environment. This however resulted in the growth of a SiO2 layer that can be 10 nm thick at the silicon interface which will thus reduce the capacitance of the grown structure. Annealing in argon and argon followed by oxygen environments were investigated as means to reduce the defects while minimizing the intermediate SiO2 layer thickness. The annealed films were compared based on their RBS yields, breakdown voltages and capacitance-voltage characteristics. Growth and annealing conditions were optimized to achieve device quality MOS structures.
Defects and Their Origin in Thin Films of (001) Alkaline Earth Oxides
Authors: Walker F. J. , Mckee R. A. , Pennycook S. J. , Thundat T. G. 
Published: April 2011

AbstractMgO is used as an optical isolation layer for waveguides epitaxially grown on silicon. The crystalline perfection of MgO is a critical issue because it serves as a substrate for the single crystal, perovskite guiding layer. Imperfections in the MgO will result in imperfections in the guiding layer and lead to large optical losses for the planar waveguide structure. We show that the most common defect to form in thin films of MgO are twin boundaries between {111}-type planes. The highest density of twins is observed when (001) MgO is grown directly on silicon/MgO interlayers containing barium. Twinning is shown to accommodate the large size of barium impurities incorporated in the MgO films through the formation of internal grain boundaries and open surfaces other than the growing (001) of MgO.
Thermodynamics of Epitaxial Ferroelectric Films.
Authors: Desu S. B. , Dudkevich V. P. , Dudkevich P. V. , Zakharchenko I. N. , Kushlyan G. L. 
Published: April 2011

AbstractThe problem of phase transitions and physical properties of the BaTiO3-type films on the (001) single-crystal substrates of the cubic syngony was solved in the limits of the Landau- Devonshire thermodynamics. The thermoelastic film-substrate interaction caused by the difference between thermal expansion coefficients was strictly taken into consideration. The model was based on the following assumptions: 1) the film is closely conjugated with the substrate; 2) the film is sufficiently “thick”to find itself unstrained at the growth temperature Ts, ( growth stresses were compensated by misfit dislocations ), and 3) the film is sufficiently “thin, and the stresses arising at the temperatures T>Ts may be considered to be uniform.
Atomic Scale Control of Epitaxial Growth and Interface in Oxide Thin Films for Advanced Oxide Lattice Engineering
Authors: Yoshimoto M. , Maeda T. , Ohnishi T. , Lee G. H. , Koinuma H. 
Published: April 2011

AbstractAdvanced thin film technology based on laser MBE has enabled us to control the molecular layer-by-layer epitaxial growth and interface structure of oxide thin films in an atomic scale. Molecular layer epitaxy of oxide thin film growth was verified from in situ monitoring of intensity oscillation in reflection high energy electron diffraction (RHEED). Advanced oxide thin film technology was applied to form oxide superlattices for quantum functional oxides and to achieve lattice-matched heteroepitaxy in oxide films on silicon substrate for all epitaxial oxide/silicon hybrid devices. The key factors to develop oxide lattice engineering are discussed with respect to not only in situ monitoring of growth process using RHEED but also atomic regulation of the substrate surface by atomic force microscopy and ion scattering spectroscopy.
Epitaxial Niobate Thin Films and Their Nonlinear Optical Properties
Authors: Wessels B. W. , Nystrom M. J. , Chen J. , Studebaker D. , Marks T. J. 
Published: April 2011

AbstractFerroelectric oxide thin films show considerable potential as electro-optic and non-linear optical materials. Of particular interest are the niobates such as strontium barium niobate and potassium niobate. The growth of these epitaxial oxide films by metal-organic chemical vapor deposition (MOCVD) has been investigated. This technique has yielded epitaxial thin films with excellent non-linear optical properties. Issues concerning the epitaxy of these thin films and its relationship to their optical and nonlinear optical properties are discussed.
Hetero-Epitaxial Structures of Litao3 Thin Films
Authors: Hung L.-S. 
Published: April 2011

AbstractWe have grown epitaxial thin films of LiTaO3 on various substrates. LiTaO3 grows epitaxially on (111) GaAs and forms a waveguide with its underlying buffer layer of MgO, providing a desirable structure for monolithic integration. LiTaO3 grows on LiNbO3 with a buffer layer of magnesium niobate or magnesium tantalate to form an optical waveguide structure having good lattice matching and pronounced differences in refractive index. This heterostructure has the potential for reducing crystal imperfection of waveguides and improving optical confinement. We also describe a multilayer structure using an epitaxial conducting layer as a bottom electrode to grow a nonlinear optical waveguide on LiNbO3 for waveguide switching and modulation. Both light-absorbing metals and transparent metallic oxides are employed. Ion channeling and x-ray diffraction reveal high crystalline quality of the hetero-epitaxial structures. The influence of surface polarity, thermal expansion, and lattice matching on waveguiding LiTaO3 thin films is addressed.
Afm Study of CeO2 Growth on Sapphire as a Buffer Layer for YBa2Cu3O7
Authors: Denhoff M. W. , Mason B. F. , Tran H. T. , Grant P. D. 
Published: April 2011

AbstractThe structure of CeO2 films grown on (1102) sapphire and on YBCO thin films was investigated. The films reported on here were grown by pulsed excimer laser deposition and their surface structure was probed using atomic force microscopy. We found that CeO2 films grown on sapphire were epitaxial with a granular structure which is smooth on an atomic scale. We see evidence of a surface reconstruction on a very smooth CeO2 (100) oriented surface. At higher growth temperatures, three dimensional islands begin to form. When a CeO2 film is grown on top of a YBCO film, the growth mode is two dimensional. The steps in this layer by layer growth are a surprisingly large 2 nm. This is about equal to 4 times the CeO2 lattice constant. This step height appears to be temperature dependent.
The High Resolution Magneto-Optical Faradayeffect as a Research Tool to Investigate Details of Current and Magnetic Flux Distribution in Y-Ba-Cu-O Thin Films
Authors: Forkl A. , Kronmüller H. , Habermeier H.-U. , Leibold B. 
Published: April 2011

AbstractThe magneto-optical Faradayeffect [MOFE] is known to be an excellent tool for the spatially resolved analysis of the flux distribution in superconductors. We use three examples to demonstrate the power of this technique for device oriented investigations. It is shown that homogeneous Yba2Cu3O7 thin films with different shape show a flux pattern strongly depending on the geometry of the sample; model calculations for the flux distribution are in excellent agreement with the experimental results. Furthermore, we show, that crystallographic defects as well as imperfections due to pattern delineation are affecting the flux pattern on macroscopic scale. In a third example we use the MOFE to demonstrate that pulsed laser irradiation of Yba2Cu3O7 thin films with UV photons of moderate flux causes an enhancement of the critical current.
New Substrate/Buffer Layer Compounds for Epitaxial HTSC Film Growth
Authors: Tauber A. , Tidrow S. C. , Wilber W. D. , Finnegan R. D. 
Published: April 2011

AbstractA series of compounds in the system A4MeSb13O12 where A=Ba, Sr and Me=Li, Na &K were prepared by solid state reaction at elevated temperature. A new form of Sr4NaSb3O12 was prepared. The compounds were characterized with regard to their lattice parameters, density and dielectric properties. Thin films were prepared by PLD from dense targets and epitaxial relationships identified between YBCO and these compounds.