Showing papers on "Thin film published in 1984"

Thin‐layer element for interfaces and joints

Abstract: The idea of using a thin solid element, called a thin-layer element, in soil-structure interaction and rock joints is proposed. A special constitutive model is used and various deformation modes such as no slip, slip, debonding and rebonding are incorporated. The shear stiffness is found from special laboratory tests and the normal stiffness is assumed to be composed of participation of the thin-layer element and the adjoining solid elements. A parametric study shows that the thickness of the thin-layer element can be such that the ratio of thickness to (mean) dimension of the adjacent element is in the range of 0.01 to 0.1. A number of simple and practical problems are solved to illustrate the success of the thin-layer element for soil-structure interaction problems.

Ink-belt bubble propulsion printer

Abstract: A printing machine is provided, comprising a thin film having first and second surfaces connected by a plurality of hole or recess portions and movably positioned; an ink tank for supplying ink to the hole or recess portions; a thermal head member having a plurality of thermal head elements in contact with the first surface of the film; a driving circuit for selectively driving the thermal head elements; and a recording paper feeding mechanism to feed recording paper adjacent the second surface of the film. The ink fills the holes or recess portions, and the thermal head element is selectively driven by the driving circuit when one thermal head element corresponds to a plurality of holes or recesses of the film, whereby ink is sprouted or jetted from a plurality of the holes or recesses onto the recording paper by bubble pressure caused by heat from the thermal head element. Color printing is also possible with the apparatus of the invention.

Thin film transistor

Abstract: PURPOSE:To obtain a transparent thin film transistor having a large ON-current and a memorizing property by a method wherein a transition metal oxide is used as a semiconductor layer. CONSTITUTION:A gate 2 is formed on a substrate 1, then an SiO2 film 3 is deposited on the whole surface, a semiconductor layer 4 is formed, and a source electrode 5 and a drain electrode 6 are formed. Then, an SiO2 film 7 is provided in such a manner that it will not be formed on the electrode 6, and a thin film transistor TFT is formed. In this constitution, a transition metal oxide which is WO3 in other words is used. When WO3 is used for the film 4, its ON-current is approximately two figures higher when compared with the TFT whereon an amorphous semiconductor layer is used. Also, as the WO3 is transparent, a transparent TFT is obtained when a transparent electrode is used for electrodes 2, 5 and 6. Besides, a WO3 thin film can maintain the donor position in the film and the width of a depletion layer for a fixed period even after voltage is cut off, and a memorizing property can also be given to the film.

Highly Conductive and Transparent Aluminum Doped Zinc Oxide Thin Films Prepared by RF Magnetron Sputtering

Abstract: Highly conductive films of Al-doped ZnO have been prepared by rf magnetron sputtering of a ZnO target with Al2O3 dopant of 1–2 wt% in content added. Films with resistivity as low as 2×10-4 Ωcm and transmittance above 80% at the wavelength between 400 and 800 nm can be produced on low temperature substrate with a relatively high deposition rate. It is shown that a stable resistivity for use in various ambients at high temperature can be attained for the films. The characteristic features of Al-doped ZnO films are their high carrier concentration and low mobility in comparison with non-doped ZnO films.

The preparation of cross‐section specimens for transmission electron microscopy

Abstract: The structure and chemistry of thin solid films are best studied by transmission electron microscopy (TEM) when they are viewed in cross-section—that is, when the surface normal of the film is made perpendicular to the electron beam. In this orientation, the substrate, the thin film layers, and the interfaces between them can be imaged either simultaneously or individually. Further, information from each of these regions remains distinct from that obtained from the others, eliminating the problems of superimposition that are a consequence of viewing a layered structure in the conventional manner (i.e., parallel to the surface normal). A technique for fabricating TEM specimens that can be viewed in cross-section is described here. Although the majority of our work is with silicon-based materials, the technique can be readily adapted to the study of other systems.

Semiconducting transparent thin films: their properties and applications

Abstract: The present state of the art of transparent, electrically conducting films, with special reference to In2O3, SnO2 and Cd2SnO4, has been reviewed. Various production techniques currently in use, and typical parameters used in the processes have been discussed in detail. Electrical and optical properties of these films have been reported as a function of various parameters, e.g. substrate temperature, doping, oxygen pressure, etc. Finally, the applications of these films in research and industry have been discussed in detail.

Coatings on glass

Abstract: Introduction and history composition, structure and properties of inorganic and organic glasses nature of a surface cleaning of substrate surfaces glass and thin films film formation methods film thickness properties of thin films applications of coatings on glass.

Modification of the optical and structural properties of dielectric ZrO2 films by ion‐assisted deposition

Abstract: Low‐energy bombardment by argon and oxygen ions has been used in the deposition of thin dielectric films of ZrO2. The film packing density has been improved from 0.83 to unity with a corresponding increase in the refractive index from 1.84 to 2.19. The highest stable refractive index measured was 2.23 for oxygen ion‐assisted deposition of ZrO2 on a substrate heated to 300 °C. Ion bombardment during condensation of evaporated ZrO2 on a room temperature substrate results in crystallization into the cubic phase which is consistent with previous studies of ion impact crystallization by thermal‐spike processes. At elevated substrate temperatures the monoclinic phase is also present.

Formation of thin films of NiSi: Metastable structure, diffusion mechanisms in intermetallic compounds

Abstract: The formation of NiSi films from the reaction of Ni2Si with (100) and (111) silicon substrates was found to be controlled by a lattice diffusion process with an activation energy of 1.70 eV. In order to correlate kinetic information obtained by Rutherford backscattering with x‐ray diffraction data, ‘‘standard’’ diffraction powder patterns for both Ni2Si and NiSi have been established. The existence of a metastable hexagonal form of NiSi has been confirmed. Observations on the formation of Ni2Si confirm previous investigations. The diffusion process at work during the formation of NiSi is discussed in terms of the crystalline anisotropy of this compound and compared to what is known about diffusion in other silicides.

Multiple determination of the optical constants of thin-film coating materials

Abstract: The seven participating laboratories received films of two different thicknesses of Sc2O3 and Rh. All samples of each material were prepared in a single deposition run. Brief descriptions are given of the various methods used for determination of the optical constants of these coating materials. The measurement data are presented, and the results are compared. The mean of the variances of the Sc2O3 refractive-index determinations in the 0.40–0.75-nm spectral region was 0.03. The corresponding variances for the refractive index and absorption coefficient of Rh were 0.35 and 0.26, respectively.

Electrical and optical properties of zinc oxide thin films prepared by rf magnetron sputtering for transparent electrode applications

Abstract: Zinc oxide films were prepared on unheated glass substrates by rf magnetron sputtering under an applied external dc magnetic field in pure argon gas, and electrical and optical properties of the deposited films were investigated. Highly transparent films with resistivity as low as 10−4 Ω cm, which were weakly oriented perpendicular to the substrate surface(c‐axis orientation), could be produced with a relatively high deposition rate on the substrate suspended perpendicular to the target surface by controlling the sputtering gas pressure and the external dc magnetic field, without any postdeposition preparative treatment. The Hall mobility of the film with the highest conductivity was about 120 cm2/V sec, which was the highest yet reported for thin films on ZnO. The increase in the conductivity was related to the increase in Hall mobility which was caused by the decrease of carrier scattering from grain boundaries due to the grain growth resulting from the improvement of crystallization. The improvement of...

Pseudomorphic growth of GexSi1−x on silicon by molecular beam epitaxy

Abstract: GexSi1−x layers are grown on Si substrates over the full range of alloy compositions at temperatures from 400–750 °C by means of molecular beam epitaxy. At a given growth temperature films grow in a smooth, two‐dimensional manner up to a critical germanium fraction xc. Beyond xc growth is rough. xc increases from 0.1 at 750 °C to 1.0 at ∼550 °C. Rutherford ion backscattering measurements indicate good crystallinity over a wide range of growth conditions. Transmission electron microscopy reveals that in thin films, the lattice mismatch between the GexSi1−x and Si layers can be accommodated by lattice distortion rather than by misfit dislocation formation. This pseudomorphic growth condition can persist to alloy thicknesses as large as l/4 μm.

Supercritical fluid molecular spray film deposition and powder formation

Abstract: Solid films are deposited, or fine powders formed, by dissolving a solid material into a supercritical fluid solution at an elevated pressure and then rapidly expanding the solution through a short orifice into a region of relatively low pressure. This produces a molecular spray which is directed against a substrate to deposit a solid thin film thereon, or discharged into a collection chamber to collect a fine powder. Upon expansion and supersonic interaction with background gases in the low pressure region, any clusters of solvent are broken up and the solvent is vaporized and pumped away. Solute concentration in the solution is varied primarily by varying solution pressure to determine, together with flow rate, the rate of deposition and to control in part whether a film or podwer is produced and the granularity of each. Solvent clustering and solute nucleation are controlled by manipulating the rate of expansion of the solution and the pressure of the lower pressure region. Solution and low pressure region temperatures are also controlled.

Diffusion of silicon in gallium arsenide using rapid thermal processing: Experiment and model

Abstract: Rapid thermal processing was used to diffuse Si into GaAs from a thin elemental source. Several encapsulants were applied. The diffusion was found to be dependent on the type of encapsulant. A model is developed based on the formation and rapid diffusion of Si nearest neighbor donor‐acceptor pairs. Results from the codiffusion of Si and Ge support this model.

Influence of chemical driving forces in ion mixing of metallic bilayers

Abstract: The effective interdiffusion coefficient of metallic bilayers under ion irradiation has been correlated with the heat of mixing of corresponding binary alloys. The results are interpreted according to Darken's theory of chemically enhanced diffusion.

Thin film photoelectrochemistry: Iron oxide

Abstract: Fe/sub 2/O/sub 3/ photoelectrodes offer advantages in respect to simplicity. However, at normal thickness, the efficiency is low. In this paper, the consequences of reducing the thickness of the oxide below that of the space-charge region is investigated. Allowing the light transmitted through the first electrode to be incident on further semitransparent electrodes should give a gain over a normal (ca. 1 ..mu..m thick) electrode of ca. three times for ten successive electrodes. The theory is experimentally tested. It is quantitatively in agreement with experiment for values of the hole-solution transferrate constant (for water oxidation) of 6 x 10/sup -2/ cm s/sup -1/ M/sup -1/ and a model in which 1/4 of any change in applied p.d. occurs across the Helmholtz layer.

High‐efficiency electroplated heterojunction solar cell

Abstract: Over 9% efficiency is demonstrated in electroplated CdS/CdTe thin film solar cells. Processing of the devices is described. A brief heat treatment step first anneals out the deep lifetime killer centers in the material then converts the originally n‐type film into solar cell grade p‐CdTe.

Ion–surface interactions during thin film deposition

Abstract: The interactions of ion beams with surfaces are strongly dependent on the incident kinetic energy and the amount of ionic charge. Fundamental effects of ion bombardment by atomic and cluster ion beams have been elucidated in terms of kinetic energy of the ion beams. These fundamental effects include enhancement of adatom migration, desorption of physically absorbed atoms, displacement of the surface atoms, sputtering, shallow ion implantation, and trapping of impinging atoms. The importance of low energy ion beams for film formation is shown by taking into account the binding energies of the atoms in a solid. Emphasis has been placed on interactions of ionized cluster beams (ICB) during film formation because ICB offers unique capabilities for deposition due to the properties of the clusters and also to characteristic low energy ion beam transport over a range from thermal energy to a few hundred eV.

Structural and morphological investigation of the development of electrical conductivity in ion-irradiated thin films of an organic material

Abstract: Thin films of 3,4,9,10‐perylenetetracarboxylic dianhydride (PTCDA) develop low electrical resistivity ( 5×1...

Preparation of ferroelectric PZT films by thermal decomposition of organometallic compounds

Abstract: Transparent PZT thin films with perovskite structure were successfully obtained by thermal decomposition of organometallic compounds at the temperatures of 500 to 700° C. The films deposited on platinum substrates were smooth and uniform, but microcrackings were observed in the films deposited on fused silica substrates. The ratio of metal composition in the PZT film agreed with that in the mixture of starting materials. Films obtained at 700° C on platinum substrate showed a hysteresis loop. A spontaneous polarization was 35.65μC cm−2, a saturation remanent polarization was 30.56μC cm−2 and a coercive field was 45 kV cm−1. Dielectric constant and dielectric loss angle were about 300 and 0.05, respectively.

Impurity trapping, interface structure, and luminescence of GaAs quantum wells grown by molecular beam epitaxy

Abstract: A correlation has been demonstrated between impurity trapping and the interface structure in GaAs quantum well (QW) superlattices and single quantum well structures grown by molecular beam epitaxy (MBE) on (100) GaAs. Using low‐temperature cathodoluminescence, photoluminescence, and transmission electron miscroscopy, we have shown that interface roughness in QW superlattices is related to trapped impurities at interfaces. We have observed that impurities originate from either the substrate or from the GaAlAs MBE layers. A new getter smoothing effect associated with QW structures is shown to produce efficient impurity trapping and yield higher quality GaAs QW with atomically smooth interfaces.

Electrocatalytic oxidation and determination of arsenic(III) on a glassy carbon electrode modified with a thin film of mixed-valent ruthenium(III, II) cyanide

Abstract: Le courant de pic voltammetrique a balayage lineaire obtenu est directement proportionnel a la concentration en As(III) dans le domaine 5 μM-2 mM avec une limite de detection de 3,5 μM

Preparation and structure of carbon film deposited by a mass‐separated C+ ion beam

Abstract: Carbon films were deposited using mass‐separated C+ ions of 300 and 600 eV. The films have diamond‐like characteristics such as transparency in the visible spectral region with wavelengths longer than about 650 nm and in the infrared, and high electrical resistivity. Transmission electron diffraction analysis shows that the film is amorphous and does not contain graphitically bonded carbon atoms. Kα x‐ray emission spectrum of the carbon in the film agrees well with that of diamond. In the x‐ray photoemission spectrum of the film, no characteristic energy loss due to π plasmon was observed. The atomic density of the film calculated from the energy loss due to the plasma oscillation of valence electrons is 1.7×1023 atoms/cm3, which is in good agreement with that of diamond. These results indicate that the film deposited using C+ ion beam consists of tetrahedraly bonded carbon atoms.

Ferrite plating in aqueous solution: New technique for preparing magnetic thin film

Abstract: This paper describes the principle and performance of a new technique which facilitates the formation of crystalline spinel film at low temperature (T<80 °C) without a heat treatment. For a substrate, not only a metal but also oxides and organic compounds can be used. Various transition metals (M=Ni, Co, Mn, Cu, Zn, etc.) are incorporated into the spinel. Hydrolyzed metal ions FeOH+ and MOH(n−1)+ in an aqueous solution (pH=6∼11,T=40∼80 °C) are adsorbed on a substrate surface which react into spinel film associated with anodic or air oxidation of the FeOH+ ion. We have plated Fe3O4 and CoFe2O4 films on a substrate of Cu, polyethylene terephthalate, and stainless steel. They are polycrystalline with no preferred orientation, and exhibit no magnetic anisotropy. The polar Kerr rotation of these films has been measured.

Comparison of MOCVD‐Grown with Conventional II‐VI Materials Parameters for EL Thin Films)

Abstract: A brief description is given of the growth of MOCVD ZnSe and ZnS, contrasted with alternative growth techniques. The general physical properties of these layers, grown as single crystals on GaAs or GaP and as polycrystalline layers on glass, are described; particularly smoothness, crystal structure, and doping by donors and by Mn luminescence activators. Techniques of optical characterization and the general optical properties are discussed. Radiative recombination processes involve shallow donor species, and shallow acceptors when present, and these spectra are used to identify residual donor species. Effects of strain associated with heteroepitaxial growth of ZnSe on GaAs and GaP are evident and provide quantitative estimates of the lattice mismatch-induced strain provided this is relatively small. The spectra contain a variety of low energy luminescence bands, weak in well-prepared MOCVD layers. Some of these bands seem particularly characteristic of the MOCVD growth technique. Amongst these, two bands Y and Z have very unusual aspects of spectral form. A speculative model is offered, of recombinations within extended defects involving a non-central force electronic system. Strong variations in the form and intensity of photoluminescence spectra are described for very thin single crystal layers and attributed to the influence of electric fields on distant donor acceptor pair processes, particularly at the heteroepitaxial interface. These results and variations in the deep centre luminescence observed as a function of deliberate doping by shallow donors, D suggest the strong influence of (DZn–Vzn–Dzn) associates at high D concentrations or high electric fields. Some properties of dead layers in thin film electroluminescence are briefly discussed. Es wird das Wachstum von MOCVD-ZnSe und -ZnS diskutiert und anderen Wachstumstechniken gegenubergestellt. Dabei werden die allgemeinen physikalischen Eigenschaften dieser Schichten, die als Einkristalle auf GaAs oder GaP und als polykristalline Schichten auf Glas wachsen, beschriebeu, insbesondere Ebenheit, Kristallstruktur und Dotierung mit Donatoren und Mn-Lumineszenzaktivatoren. Die Methoden zur optischen Charakterisierung und die allgemeinen optischen Eigenschaften werden diskutiert. Der Prozes der strahlenden Rekombination schliest flache Donatorarten und, wenn vorhanden, flache Akzeptoren ein, und diese Spektren werden benutzt, um die Restdonatoren zu identifizieren. Spannungseffekte, die mit dem heteroepitaktischen Wachstum von ZnSe auf GaAs und GaP zusammenhangen, werden aufgezeigt und liefern quantitative Ergebnisse der durch Gitterfehlanpassung induzierten Spannung, vorausgesetzt, das diese relativ klein ist. Die Spektren enthalten eine Vielzahl von niederenergetischen Lumineszenzbanden, die in gut hergestellten MOCVD-Schichten schwach sind. Einige dieser Banden scheinen fur die MOCVD-Wachstumsmethode besonders charakteristisch zu sein. Von diesen haben zwei Banden, Y und Z, sehr ungewohnliche Aspekte der Linlenform. Ein spekulatives Modell von Rekombinationen innerhalb ausgedehnter Defekte, die ein Elektronensystem ohne Zentralkraft enthalten, wird vorgeschlagen. Starke Variationen der Form und Intensitat der Photolumineszenzspektren von sehr dunnen Einkristallschichten werden dem Einflus von elektrischen Feldern auf Rekombination zwischen entfernten Donator-Akzeptorpaare, insbesondere an den heteroepitaktischen Grenzflachen, zugeschrieben. Diese Ergebnisse und Aderungen der Lumineszenz tiefer Zentren, die in Abhangigkeit von der Dotierung mit flachen Donatoren D, beobachtet werden, weisen auf den starken Einflus von (DZn–VZn–DZn) -Assoziaten bei hohen D-Konzentrationen oder hohen elektrischen Feldern hin. Einige Eigenschaften von Totschichten bei der Dunnschicht-Elektrolumineszenz werden kurz diskutiert.

Frequency Shifts of an Electric-Dipole Resonance near a Conducting Surface

Abstract: The resonance frequency of an electric dipole placed near a conducting surface is shifted by the dipole-surface interaction. The observation and measurement of these shifts at optical frequencies is reported for an experimental system that consists of a metal-island film spaced a distance d from a continuous Ag film. The dependence of the shift in the frequency of the island resonance on d shows good agreement with that predicted by a classical theory of the dipole-surface interaction.