bluuebunny/crossref_metadata_2025_split huggingface dataset:
Lead Zirconate Titanate Films Produced by Pulsed Laser Deposition
Authors: Saenger K. L. , Roy R. A. , Etzold K. F. , Cuomo J. J. 
Published: March 2011

ABSTRACTThe synthesis of ferroelectric lead zirconate titanate (PZT) films by pulsed laser deposition at 248 nm is described. This study has focused on producing thin (≲ 0.6μm) PZT films on bare and platinum coated MgO < 100 > substrates. Deposition was in an oxygen gas ambient (30 mTorr) at temperatures typically ∼ 525 °C. Rutherford Backscattering Spectroscopy (RBS) was used to evaluate film composition. Film lead content was found to decrease both with increasing laser fluence, and increasing substrate temperature. Film microstructure was evaluated by x-ray diffraction. Electrical measurements were made on the films before and after annealing to determine the dielectric constant and polarization. Properties after annealing were substantially improved, with dielectric permittivity values comparable to bulk PZT.
Lead Zirconate-Titanate Thin Films Prepared by the Laser Ablation Technique
Authors: Chiang C. K. , Cook L. P. , Schenck P. K. , Brody P. S. , Benedetto J. M. 
Published: March 2011

ABSTRACTLead zirconate-titanate (PZT) thin films were prepared by the laser ablation technique. The PZT (Zr/Ti=53/47) target was irradiated using a focused q-switched Nd:YAG laser (15 ns, 100 mJ at 1.064 μ;m). The as-deposited films were amorphous as indicated by X-ray powder patterns, but crystallized readily with brief annealing above 650°C. The dielectric constant and the resistivity of the crystallized films were studied using a parallel-plate type capacitor structure.
Ferroelectric Film Synthesis, Past and Present: A Select Review
Authors: Roy R. A. , Etzold K. F. , Cuomo J. J. 
Published: March 2011

ABSTRACTA review of the history of ferroelectric (FE) thin film synthesis is given covering the period of the 1960's to the present. Early methods, materials and applications are discussed. An assessment of the recent upsurge in activity takes note of current targeted applications, including nonvolatile memory, piezoelectric actuators, capacitors, and electro-optic devices. Focus is placed on similarities and differences in the most common film deposition processes. Comparison of microstructure and composition variation seen in films deposited by sputtering, laser ablation, and solution deposition is made. More detailed understanding of process-microstructure relations is stressed as necessary for film property control. Also discussed are the roles of substrate interactions and interface layers in thin film growth.
Preparation and Characterization of Sol-Gel Derived PbTiO3 Thin Layers on GaAs
Authors: Schwartz R. W. , Xu Z. , Payne D. A. , DeTemple T. A. , Bradley M. A. 
Published: March 2011

ABSTRACTPbTiO3 thin layers were deposited onto GaAs by sol-gel processing. The GaAs substrates were encapsulated with Si3N4 or SiO2 to minimize diffusion problems. Gel layers were heat treated to 350°C for removal of organic species and for the densification of the amorphous gel structure. Rapid thermal processing at 600°C was used to crystallize PbTiO3 into the perovskite structure. SIMS analysis determined limited diffusion of Ga and As into PbTiO3. The fine grain microstructure contained domains.
Grain-Oriented Lithium Niobate Thin-Layers Prepared by Sol-Gel Methods
Authors: Hagberg Daniel S. , Payne D. A. 
Published: March 2011

ABSTRACTThin-layers of lithium niobate were deposited on polycrystalline platinum and (001) sapphire. Preferred orientation was observed by x-ray diffraction measurements, and confirmed by x-ray rocking curve studies. The orientation was [006] LiNbO3 with [111] Pt and [001] Al2O3. Dielectric data are reported for grain oriented LiNbO3 as a function of frequency for layer thicknesses from 0.15 to 0.70 μm.
Plasma Etching of PLT Thin Films and Bulk PLZT Using Fluorine- and Chlorine-Based Gases
Authors: Poor M. R. , Hurd A. M. , Fleddermann C. B. , Wu A. Y. 
Published: March 2011

ABSTRACTPotential applications for ferroelectric thin films include both electronic and optoelectronic devices. In order to integrate a large number of devices on a single ceramic film or to incorporate ceramic devices with silicon-based integrated circuits, suitable film patterning techniques must be developed. In this study, the use of plasma etching for device patterning of PLT thin films has been explored using a dc hollow cathode discharge with HCl and CF4 etching gases. At room temperature, no etching of material is discernable. As the substrate temperature is increased, however, relatively rapid etching takes place. Etch rates for PLT thin films as high as 6500 Å/hour were measured. Etching occurred in both chlorinated and fluorinated plasmas, but at considerably different rates. The etch rate is enhanced by a factor of six by using a combination of HCl and CF4 in the plasma. After etching, the stoichiometry of the film, measured by energy dispersive spectroscopy (EDS), varied greatly with changes in substrate temperature. Although the removal rate for each element is different, all traces of lead, titanium, and lanthanum can be removed from the substrate over a wide range of plasma etching conditions.
Physical Characterization of Thin Films of Lithium Niobate Deposited on Silicon Substrates
Authors: Baumann Robert C. , Rost Timothy A. , Rabson Thomas A. 
Published: March 2011

ABSTRACTThin films (.1-.6 μm) of LiNbO3 have been deposited on silicon substrates by reactive rf sputtering. Under optimized deposition conditions the resulting thin films of LiNbO3 were optically transparent, adhered well to the silicon substrates, and were found to be polycrystalline and uniaxial with the c axis oriented normal to the silicon surface. Optical microscopy and scanning electron microscopy were used to examine film morphology. Both methods indicated that the films were smooth and contained no gross irregularities. The ratio of oxygen to niobium in these films was measured by Rutherford backscattering to be approximately 3 to 1. Auger electron spectroscopy depth profiling revealed that the films had the expected ratio of Li, Nb, and O. This information, together with Bragg x-ray diffraction data, indicates that the thin films deposited on silicon were stoichiometric, crystalline LiNbO3.
Computer Simulation Study of the Effect of Defects on Switching in Ferroelectric Thin Films
Authors: Pugh Robert D. , Sabochick Michael J. , Luke Theodore E. 
Published: March 2011

ABSTRACTA new computational method for simulating the dynamics of switching in ferroelectric materials is presented. The new method is shown to be more realistic for dynamic simulations and computationally more efficient than the traditional Monte Carlo method. The method is used to investigate the effect of polar defects on switching behavior. The results are in qualitative agreement with experimental observations of fatigue.
PbTiO3 Thin Films by Chemical Beam Deposition
Authors: Kingon A.I. , Hsieh K.Y. , King L.L.H. , Rou S.H. , Bachmann K.J. , Davis R.F. 
Published: March 2011

ABSTRACTThe feasibility of chemical beam deposition of PbTiO3 thin films is demonstrated. The method utilizes chemical (molecular) beams of metalorganic precursors in a high vacuum chamber. Pyrolysis reactions of the metalorganics at the substrate surface are facilitated by presence of active oxygen from an ozone source. Fine grained, smooth polycrystalline PbTiO3 films have been deposited at substrate temperatures as low as 325°C.
Plasma Assisted Low Temperature OMVPE of GaAs Utilizing Trimethylgallium and Trimethylarsenic Feedstock Gases
Authors: Pihlstrom B. G. , Thompson L. R. , Asher S. , Collins G. J. 
Published: March 2011

AbstractA spatially confined disk shaped hydrogen plasma is used for plasma assisted organometallic vapor phase epitaxy (PAOMVPE) of GaAs at substrate temperatures from 245–430°C. Feedstock gases, trimethylgallium (TMGa) and trimethylarsenic (TMAs), are introduced downstream from the disk shaped plasma in the near afterglow. Dissociation of the organometallics is dominated by VUV photons and metastable species energy transfer reactions rather than non-selective electron impact. At the temperatures employed no thermal CVD occurs. An Arrhenius plot of the growth rate shows a low activation of 3 Kcal/mole for surface mobility. The transitional temperature from amorphous to homoepitaxial growth (300°C) is determined via electron diffraction patterns from deposited films versus substrate temperature. Increases in the feedstock gas V-III ratio resulted in decreases in absolute carbon concentration in the deposited films.
Anisotropic ArF Laser-Assisted Cl2 Etching of GaAs
Authors: Tejedor Paloma , Briones Fernado 
Published: March 2011

AbstractArF laser etching of n-GaAs (100) in Cl2 gas ambient has been investigated as a function of laser fluency and the main thermodynamical parameters of the process (pressure, temperature and gas phase composition). Experimental results indicate that GaAs laser etching in the presence of Cl2 occurs by a combination of thermally and photochemically initiated reaction steps. The etch rate was found to be kinetically controlled by the surface reaction between photogenerated CI adatoms and GaAs, with an activation energy of 6.3 Kcal/mol. Vertical etch profiles with smooth bottom surfaces were obtained at substrate temperatures above 150°C, low Cl2 partial pressures (≤ 1.5 m Torr), and low laser fluences (≤ 25 mJ/cm2) for etch masks parallel to the | 01 1 | direction.
Novel Process for Ceramic Epitaxy Using Laser Mbe
Authors: Yoshimoto Mamoru , Nagata Hirotoshi , Tsukahara Tadashi , Gonda Satoshi , Koinuma Hideomi 
Published: March 2011

AbstractAn ArF excimer laser MBE system specially designed for the deposition of ceramic thin films was used to construct atomi-cally defined epitaxial SrCuO2−x films. According to XPS analysis, Cu valence was evaluated to be 2+ in the film as-grown in the presence of 10−7 Torr NO2, but it was less than 2+ in the film prepared in the presence of 10−7Torr 02. In situ XPS depth analysis of as-grown SrCuO2−x film on SrTiO3 substrate revealed the band profile at the interface of the film and substarte. Ceramic superlattices composed of metallic SrCuO2−x (3∼8nm thick) and insulative SrTiO3 (8nm thick) were prepared by sequential heteroepitaxial growth.
Growth and Properties of Ceramic thin Films Processed by In-Situ Laser Deposition Technique
Authors: Kanetkar S. M. , Sharan S. , Tiwari P. , Matera J. , Narayan J. 
Published: March 2011

AbstractGood quality ceramic thin films of yttria-stabilized zirconia (YSZ), MgO, BN and TiN were grown on single crystal silicon with (100) orientation using in-situ pulsed laser physical vapor deposition (LPVD) technique.Laser deposition parameters were optimized and the resulting thin films were characterized by X-ray diffraction ,Rutherford backscattering spectrometry and transmission electron microscopy (plan and cross section). All the films were found to be polycrystalline with a texture. The absence of interfacial reaction and smooth interface on the atomic scale are the main features observed in these oxides and nitrides thin films on Si (100) substrate.
Ductility Enhancement and Mechanical Properties of Ibad Ceramic thin films
Authors: Hirvonen J. K. , Tetreault T. G. , Parker G. , McHargue C. J. 
Published: March 2011

AbstractThin ceramic films (A12O3 ZrO2, Si3N4, and BN) have been prepared by ion beam assisted deposition (IBAD) and their mechanical properties examined. The films exhibit extreme ductility and adhesion, with the former property possibly attributed to the very fine grained, quasi-amorphous grain structure noted for low temperature IBAD coatings.
Effects of Excimer Laser Ablation on the Surface of Hexagonal Boron Nitride
Authors: Doll G. L. , Perry T. A. , Sell J. A. 
Published: March 2011

AbstractThe laser-induced changes in the hexagonal boron nitride targets that are used in the deposition of pulsed laser-deposited cubic boron nitride films are examined. Although the structure of the hexagonal boron nitride in the irradiated areas is unaltered, the surface morphology changes considerably. Boron-rich spheroids were found to cover the irradiated area. Their origin is consistent with the hydrodynamic sputtering of the hexagonal boron nitride targets, and a liberation of nitrogen atoms to the gas phase.
High-Energy Low-Dose Implanted Silicon Annealed by Transient RTA
Authors: BÁrsony IstvÁn , Heideman Jean-Luc , Middelhoek Jan , Wallinga Hans 
Published: March 2011

AbstractTransient RTA performed in the sub-second time range has been applied for low-thermal-budget post-implantation anneal of low-dose, high-energy P and B implanted wafers. This very rapid thermal step not only accomplished full activation and minimum profile motion but was also effective in reducing the resident damage-associated lifetime problems compared to conventional annealing. The generation lifetime and velocity depth-profiling used for process characterization shed light on the role of metallic impurities in the high-energy B and P implanted samples during the fast-quenching operations in determining the electrical behavior.
Ion-Irradiation Study of the “Exotic” Mineral Neptunite: LiNa2K(Fe,Mg,Mn)2Ti2Si8O24
Authors: Eby Ray K. , Wang L. M. , Arnold G. W. , Ewing R. C. 
Published: March 2011

AbstractSingle crystals of the silicate neptunite were irradiated with 600 keV Ar2+ and 1.5 MeV Kr+ and analysed by transmission electron microscopy. Amorphization was observed in a surface layer several hundred angstroms thick following Ar2+ irradiations up to 5.0×l013 Ar/cm2, yet the Ar2+ ions travelled an average of 1/2 μm in depth. The microstructure of the amorphous surface layer depends on the ion fluence, but the amorphous layer thickness remained constant. At the highest fluence, a narrow region below the amorphous layer shows a brittle-to-ductile strain transition, due to tensional volume-expansion of the adjacent ductile amorphous layer. With 1.5 MeV Kr1+, amorphization of the electron transparent region was completed after a fluence of 1.7×l014 Kr+/cm2, and no further damage was observed up to 5.1×1015 Kr+/cm2. However, following a low fluence of 2.0×1011 Kr+/cm2, a single crystal of neptunite became a polycrystalline aggregate (grain size 10 nm) within 7 days of room temperature aging.
Molecular Beam Induced Dissociative Chemisorption at Surfaces
Authors: Madix Robert J. 
Published: March 2011

AbstractThe application of supersonic nozzle beams to the study of the dynamics of gas-surface scattering is discussed. Examples are chosen to illustrate the use of such beam sources in synthesizing surface compounds otherwise unaccessible under normal ambient conditions in ultrahigh vacuum and the role of trapping and direct collisional activation in adsorption on surfaces.
Implantation Doping and Stimulated Emission of Er3+ in LinbO3:Ti Optical Waveguides
Authors: Buchal Ch. , Brinkmann R. , Sohler W. , Suche H. 
Published: March 2011

AbstractWe have implanted Nd and Er ions into x- and z-cut LiNbC3 single crystals and investigated the recrystallization of the host and the rare earth solubility and diffusion. The diffusion is substitutional, fastest parallel to c-axis and characterized by an activation energy of 3.6 eV. Optical fluorescence experiments of Er3+ in a waveguide configuration show stimulated emission and amplification at 1.53, 1.55 and 1.56 μm wavelength.
Electrical and Optical Properties of Si+ and P+ Implanted InP:Fe
Authors: Shen Honglie , Yang Genqing , Zhou Zuyao , Xia Guanqun , Zou Shichang 
Published: March 2011

AbstractDual implantations of Si+ and P+ into InP:Fe were performed both at 200°C and room temperature. Si+ ions were implanted by 150keV with doses ranging from 5×1013 /cm2 to 1×1015 /cm2, while P+ ions were implanted by 110keV. 160keV and 180keV with doses ranging from 1×l013 /cm2 to 1×1015 /cm2. Hall measurements and photoluminescence spectra were used to characterize the silicon nitride encapsulated annealed samples. It was found that enhanced activation can be obtained by Si+ and P+ dual implantations. The optimal condition for dual implantations is that the atomic distribution of implanted P overlaps that of implanted si with the same implant dose. For a dose of 5×l014 /cm2, the highest activation for dual implants is 70% while the activation for single implant is 40% after annealing at 750°C for 15 minutes. PL spectrum measurement was carried out at temperatures from 11K to 100K. A broad band at about 1.26eV was found in Si+ implanted samples, of which the intensity increased with increasing of the Si dose and decreased with increasing of the co-implant P+ dose. The temperature dependence of the broad band showed that it is a complex (Vp-Sip) related band. All these results indicate that silicon is an amphoteric species in InP.
On the Amorphization of Silicon by Light Ion Implantation: Ion Flux and Substrate Temperature Effects
Authors: Claverie A. , Roumili A. , Gessinn N. , Beauvillain J. 
Published: March 2011

AbstractIn this work, we have observed by cross-sectional electron microscopy (XTEM) and high resolution electron microscopy (HREM) the kinetics of silicon amorphization during nitrogen and helium bombardments for various dose rates and substrate temperatures. It is shown that the progression of the cla interfaces can be accurately described by the “Critical Damage Energy Density” (CDED) model for both ions at 100°K. At this temperature however, dose rate effects are unimportant. When increasing the substrate temperature up to 300°K, the amorphization efficiency is lowered. At 300°K dose rate effects are important and we show that for higher dose rates, the efficiency of the amorphization process is improved. In this case, the amorphous layers created by helium implantation are situated in the near surface region in apparent contradiction with damage calculations. The present experimental study demonstrates the competition which exists between the generation rate of point defects and the anihilation rate of these defects. Therefore, it is shown that the position of the a-layers created by light ion implantation at room temperature can be predicted by using a three-dimensional damage energy calculation.
In Situ

Study of the Effects of Heavy-Ion Irradiation on Co-Evaporated Cosi2 Films
Authors: Allen Charles W. , Smith David A. 
Published: March 2011

AbstractThe in situ ion irradiation capability of Argonne’s HVEM-Tandem User Facility has been employed to study effects of 1.5 MeV Kr+ irradiation and 300 kV electron irradiation on the crystallization of as-deposited and of partially crystallized 40 nm thick films of CoSi2. Ion fluxes ranged from 8.5×1014 to 6.8×1015 m−2s−1 for which beam heating effects may be neglected. The maximum electron flux at 300 kV was 0.8×1023 m−2S−1. The maximum temperature at which crystalline CoSi2 is amorphized by the ion irradiation of flux = 6.8×1015 m−2s−1 is between 250 and 280 K. At higher temperatures amorphous material crystallizes by growth of any preexisting crystals and by classical nucleation and growth, with radial growth rates which are proportional to ion flux. The average degree of transformation per ion is 4×10−26 m3 per ion. Thermally induced crystallization of as-deposited films occurs above approximately 420 K. For ion doses at least as low as 3.4×1016 m−2 ion irradiation at 300 K promotes thermal crystallization at 450 K, by virtue of enhanced apparent nucleation and at large doses, by enhanced growth rate.
CoSi2Precipitate Coarsening During Formation of Buried Epitaxial Cosi2Layers By Ion Beam Synthesis
Authors: Jebasinski R. , Mantl S. , Radermacher K. , Fichtner P. , Jăger W. , Buchal Ch. 
Published: March 2011

AbstractThe coarsening of CoSi2precipitates and the microstructural evolution of (111) Si implanted with 200 keV Co+ions at 350°C and fluences of 1×1016cm−2and 6×1016cm−2were investigated as a function of depth, annealing temperature and annealing time using Rutherford Backscattering Spectroscopy (RBS) and Transmission Electron Microscopy (TEM). After annealing cross-section TEM micrographs show a layered array of platelet-shaped precipitates with preferred facets on {111} planes. The fraction of Co-atoms, that were redistributed during the different annealing temperatures and times, has been used to determine an activation energy for the precipitate coarsening. By applying the Meechan-Brinkman and the change-of-slope methods, we obtained activation energies in the range of 3.2 – 3.6 eV.
Laser-Target Interactions and its Effect on Surface Morphology of Laser Deposited thin films
Authors: Singh R. K. , Bhattacharya D. , Narayan J. 
Published: March 2011

AbstractThe laser-target interactions during pulsed laser evaporation (PLE) of materials have been investigated in detail. Sub-surface temperatures have been calculated to be higher than the surface temperatures during planar surface evaporation of the target material. While the evaporating surface is being cooled due to the latent heat of vaporization, sub-surface superheating occurs due to the finite absorption depth of the laser beam. Detailed computer simulations have been carried out to understand the evaporation characteristics of different targets (Si, YBa2Cu3O7 ) as a function of laser and target variables. For silicon targets irradiated with 25 nanosecond laser pulses (energy density of 10J/cm2, absorption coefficient of 105 cm−1), the sub-surface temperatures were found to be more than 2000°C above the surface evaporation temperatures. The sub-surface superheating increased with increasing energy density and absorption depth. This internal superheating effects may lead to volume evaporation of the target where a solid material in form of particles may be ejected from the target surface. Based on the above understanding, parameters required to reduce the particle density in PLE films are predicted.
Selective Surface Modification of a Fluorocarbon Resin Into Hydrophilic Material Using an Excimer Laser
Authors: Okoshi M. , Murahara M. , Toyoda K. 
Published: March 2011

AbstractSelective surface modification of fluorocarbon resin has been demonstrated by using an ArF excimer laser beam and an ammonia complex which was made from NH3 and B2H6 gases. The fluorocarbon resin was set in the atmosphere of NH3 gas. NH3 molecules which were adsorbed on the surface reacted quickly with the B2H6 molecules, and an ammonia complex was produced. As a result, the complex was adsorbed on the surface. The resin surface was selectively irradiated by ArF laser beam. The complex and C-F bonds of this resin were excited by the laser beam, and the surface was selectively modified to be hydrophilic property. The modified samples were evaluated by XPS analysis, measuring the contact angles of the water and the SEM image on the surface.
Excimer-Laser-Assisted Etching of Gallium Arsenide: The Effect of Substrate Temperature
Authors: Berman Michael R. 
Published: March 2011

AbstractThe excimer-laser-assisted etching of GaAs in Cl2 at 308 nm has been studied as a function of substrate temperature in the range of 23 to 150°C. Rectangular channels were etched into (100)-oriented, undoped GaAs wafers. The fluence from the xenon chloride excimer laser at the GaAs surface was 175 mJ/cm2. At temperatures below 75°C, the etch rate was independent of substrate temperature and the etch rate increased with Cl2 pressure from 0.4 to 2.0 Torr. At substrate temperatures above 75°C, the etch rate increased with increasing substrate temperatures and was independent of Cl2 pressure. Analysis of the temperature dependence of the total etch rate above 75°C according to an Arrhenius expression gave an activation energy of 11.8 kcal/mol, which is consistent with the enthalpy of vaporization of GaCl3. The onset of the temperature dependent region coincides with the melting point of GaCl3.