Showing papers on "Thin film published in 1970"
TL;DR: The morphology of porous anodic oxide films formed on aluminium in phosphoric acid electrolytes at constant current density or voltage, and under changing electrical or electrolytic conditions, has been studied quantitatively by electron microscopy.
Abstract: The morphology of porous anodic oxide films formed on aluminium in phosphoric acid electrolytes at constant current density or voltage, and under changing electrical or electrolytic conditions, has been studied quantitatively by electron microscopy. Replicas from film sections and from both film interfaces have been prepared, as well as transmission micrographs of thin films, produced under accurately defined conditions. During formation at constant current density, pore initiation occurs by the merging of locally thickening oxide regions, which seem related to the substructure of the substrate, and the consequent concentration of current into the residual thin areas. The pores grow in diameter and change in number until the steady-state morphology is established. The film barrier layer thickness has been measured directly for the first time. The steady-state barrier-layer thickness, cell diameter and pore diameter are all observed to be directly proportional to the formation voltage. It becomes evident that the barrier-layer thickness, decided largely by an equilibrium established between oxide formation in the barrier-layer and field-assisted dissolution (probably thermally enhanced) at the pore bases, determines the cell and pore sizes by a simple geometrical mechanism. Anion incorporation into the film and its hydrogen-bonded structure play secondary roles to these factors in determining the actual film morphology, although not its subsequent properties. A consequence of the mechanism is that, at constant current density, relatively non-aggressive electrolytes give thicker barrier layers, larger cells and larger pores next to the barrier layer than aggressive media, although subsequent pore widening at the outer surface of the film by simple chemical dissolution is more severe in aggressive electrolytes.
1,117 citations
TL;DR: In this paper, a new method of coupling a laser beam to thin-film optical guided waves was proposed, which utilizes an optical grating that is made from photoresist and fabricated directly on the film.
Abstract: We report a new method of coupling a laser beam to thin‐film optical guided waves which utilizes an optical grating that is made from photoresist and fabricated directly on the film. High efficiency coupling (∼40 %) into a single mode in a glass film is observed.
242 citations
IBM1
01 Mar 1970-Metallurgical and Materials Transactions B-process Metallurgy and Materials Processing Science
TL;DR: In this article, the feasibility of depositing aluminum thin films by means of rf sputtering has been investigated, and film characteristics compatible with the requirements of conductive stripes in integrated circuits have been obtained.
Abstract: The feasibility of depositing aluminum thin films by means of rf sputtering has been investigated. Film characteristics compatible with the requirements of conductive stripes in integrated circuits have been obtained. The rate of film deposition has been related to rf power dissipation, argon pressure, geometry, and magnetic field. Film characteristics such as electrical resistivity, stress, grain size, and orientation have been studied and compared to the characteristics of films deposited by means of evaporation. The effects of annealing on some of these characteristics have been determined.
239 citations
TL;DR: In this article, the Schottky barriers existing at the metal insulator interfaces, which arise due to the autodoping of the insulator, occurring during deposition of the films, by excess molybdenum, were investigated.
Abstract: Thin film capacitors of MoO3 are found to be extremely temperature and frequency dependent Changes in capacitance are reported as high as 60:1 over a temperature range of 100°C (at constant frequency) and over a two‐decade frequency range (at constant temperature) At lower temperatures and higher frequencies the capacitance corresponds to the geometric capacitance, but at higher temperatures and lower frequencies the capacitance is independent of the film thickness Conductance and quality factor of the films are also observed to be extremely frequency and temperature sensitive The results are explained in terms of Schottky barriers existing at the metal‐insulator interfaces, which arise due to the autodoping of the insulator, occurring during deposition of the films, by excess molybdenum Excellent agreement is found to exist between the experimental data and the theory developed in the previous paper, and this correlation permits determination of the doping density (≃1018 cm−3), the donor depth (≃02
139 citations
TL;DR: In this article, the coupling of a gaussian beam into thin films was investigated utilizing a full wave analysis and the maximum coupling efficiency for a planar structure was found to be 75% and is independent of the phase velocity of the waveguide mode in the film.
Abstract: The coupling of a gaussian beam into thin films is investigated utilizing a full wave analysis. Maximum coupling efficiency for a planar structure is found to be 75% and is independent of the phase velocity of the waveguide mode in the film. Measured coupling values of up to 57% are reported. Coherence properties of the coupling procedure are discussed and optimization of physical parameters is outlined.
94 citations
IBM1
TL;DR: In this article, the authors describe a process for fabricating thin-film recording heads with gaps 2 μm wide in Permalloy film which is 2.5 μm thick.
Abstract: Fabrication of thin-film recording heads with 30-μm wide gaps in 25-μm thick Permalloy have been reported previously. Formation of narrow gaps by chemical etching was limited by undercutting. This paper describes a process for fabricating thin-film recording heads with gaps 2 μm wide in Permalloy film which is 2.5 μm thick. The process makes use of electroplating, photoetching, and electron beam technologies. The narrow gaps with vertical walls are made possible by the use of electron sensitive resist, electron beam exposure of 2-μm wide strips, and electroplating of 2.5-μm thick films of Permalloy on each side of the narrow strip of the electron sensitive resist.
83 citations
TL;DR: In this paper, the effect of applying a rounded stylus to thin metallic films on glass substrates has been investigated using diamond and steel styli with tip radii of approximately 25 μm and loadings of up to 230 g.
Abstract: The effect of applying a rounded stylus to thin metallic films on glass substrates has been investigated using diamond and steel styli with tip radii of approximately 25 μm and loadings of up to 230 g. The films were vacuum-deposited indium, tin, lead, gold, copper, aluminium, nickel, chromium and molybdenum of various thicknesses up to 32 μm. Scanning electron microscope and optical interference microscope observations showed that the process of scratch formation was generally very complex and varied with the film material, indicating that it is not possible to deduce absolute values of adhesion forces using a simple general theoretical model. The method can, however, be used with caution for qualitative comparisons under certain restricted conditions.
79 citations
TL;DR: In this paper, it was shown that ZnO films with resistivities from 108-1013'Ωcm have been obtained by reactively dc sputtering metallic zinc or rf sputtering ZnOs in an argon-oxygen mixture or in pure oxygen.
Abstract: Zinc oxide (ZnO) is a material which, under ordinary circumstances, has a small oxygen deficiency. This lack of chemical makes ZnO an n-type semiconductor with a typical resistivity of 1–100 Ωcm. In this work crystalline ZnO films with resistivities from 108-1013 Ωcm have been obtained by reactively dc sputtering metallic zinc or rf sputtering ZnO in an argon-oxygen mixture or in pure oxygen. Films were deposited on metallic substrates such as gold or zinc or insulating substrates such as quartz or sapphire maintained at temperatures from −100 °–+200 °C. The high resistivity is thought to result from a decrease in the normal oxygen deficiency of ZnO. Three mechanisms are likely to be involved hi the enhanced oxygen incorporation: (1) oxygen atoms in the discharge, (2) dissociation of oxygen ions on impact with the surface, and (3) implantation of oxygen ions in the film. Although quantitative data are not available at this time it is clear that the effect of oxygen atoms is large since they are formed bot...
TL;DR: In this paper, flash evaporation was used to produce homogeneous amorphous nickel-phosphorus alloy thin films, which were observed by electron microscopy and found to proceed, depending on composition, either by crystallite coarsening or nucleation and growth.
TL;DR: In this paper, the role of classical optics in the process of photoemission from thin films is analyzed, and expressions for the reflectance, transmittance, and divergence of the Poynting vector in the film are valid for all angles of incidence and arbitrary values of the dielectric functions of the nonabsorbing initial medium, film, and substrate.
Abstract: The role of classical optics in the process of photoemission from thin films is analyzed. The generation of excited electrons throughout the film is assumed to be proportional to the divergence of the Poynting vector in the film. The film and substrate are allowed uniaxial optical anisotropy, with the optic axis normal to the plane of the film. The main results of the analysis, expressions for the reflectance, transmittance, and divergence of the Poynting vector in the film, are valid for all angles of incidence and arbitrary values of the dielectric functions of the nonabsorbing initial medium, film, and substrate. Expressions for the quantum yield are obtained with the aid of a simple function that describes the diffusion and escape of the excited electrons. Some applications to photoemission from metals in the vacuum-ultraviolet region are discussed.
TL;DR: In this article, the process of forming and rupturing a thin liquid film at a solid surface is described thermodynamically for both high and low energy solid surfaces, and new experimental evidence of the critical rupture thickness of thin liquid films on low energy surface is presented.
Abstract: The process of forming and rupturing a thin liquid film at a solid surface is described thermodynamically for both high and low energy solid surfaces. In part 1 the build-up of thin films on high-energy surfaces from the first monolayer is considered and reviewed. Components of the surface free energy of formation of the thin film (disjoining pressure) are defined. For curved surfaces the disjoining forces should be combined with the Laplace capillary pressure to give a correct form of the Kelvin equation. It is suggested from the early work of Bangham and Deryaguin that thin liquid layers have anomalous physical properties. These studies are discussed in relation to the thickness of the liquid films.In part 2, new experimental evidence of the critical rupture thickness of thin liquid films on low energy surface is presented. A number of pure liquids rupture spontaneously on low energy surfaces such as wax or polytetrafluoroethylene at very great thicknesses (0.01 cm). The effects of aqueous salt and surfactant solutions suggest these long-range forces are electrical in origin.
TL;DR: The dielectric films formed by evaporating Y2O3 in vacuum have been identified with sesquioxide by infrared transmission, electron and X-ray diffraction studies as mentioned in this paper.
Abstract: The dielectric films formed by evaporating Y2O3 in vacuum have been identified with sesquioxide by infrared transmission, electron and X-ray diffraction studies. Thin film capacitors using this dielectric material exhibit excellent electric stability in high termperature and can be reproduced easily in a closed-cycle process with electron beam equipment. The dielectric constant is 13 and dissipation factor, tan δ, is 0.003 at room temperature with a breakdown field strength of 3×106 V/cm. The temperature coefficient of Y2O3 film capacitor is about 300 ppm/°C.
TL;DR: In this paper, the suitability of reactive and rf sputtering for preparation of stoichiometric films has been investigated, using Bi-rich targets, which were obtained by depositing at substrate temperatures (typically in the range of 500°°-700°C) high enough to prevent inclusion of the more volatile bismuth oxide in excess of the Bi4Ti3O12 composition.
Abstract: Single crystals of ferroelectric Bi4Ti3O12 are known to possess novel optical properties with potential use in optical memory or display applications. There is interest in duplicating these properties in thin films. Suitability of reactive and rf sputtering for preparation of stoichiometric films has been investigated. Films from stoichiometric targets were Bi deficient. Using Bi-rich targets stoichiometric films were obtained by depositing at substrate temperatures (typically in the range of 500 °–700 °C) high enough to prevent inclusion of the more volatile bismuth oxide in excess of the Bi4Ti3O12 composition. Good quality epitaxial growth has been achieved on MgO and epitaxial Pt substrates.
Patent•
21 Oct 1970
TL;DR: In this paper, a beam gun is provided having an anode and a cathode and is supplied with current of such magnitude as to cause an arc discharge to occur between the anodes and cathode to emit the beam.
Abstract: A deposition process comprising emitting a beam of particles consisting of atoms and ions of source material, each particle having a kinetic energy between about 10 and 100 electron volts. The particles are deposited onto an object to coat the object with a thin film of source material. A beam gun is provided having an anode and a cathode and is supplied with current of such magnitude as to cause an arc discharge to occur between the anode and cathode to emit the beam.
TL;DR: In this article, the authors measured the stress in thin films of chemical-vapor-deposited (CVD) glass on Si substrates by the Newton-ring method and found that the initial tensile stress in CVD films changed into compressive stress after heat treatments at 600°-900°C.
Abstract: The stress in thin films of chemical‐vapor‐deposited (CVD) glass on Si substrates was measured by the Newton‐ring method. The CVD films studied were Silane‐oxidized SiO2, phosphosilicate glass and borosilicate glass deposited at 400°–450°C. Stress reduction due to moisture absorption was observed in the CVD films, but it was not observed in the sputtered SiO2 and the thermally grown SiO2 films. The initial tensile stress in the CVD films changed into compressive stress after heat treatments at 600°–900°C. By measuring the stress at elevated temperatures, the intrinsic stress was reduced from the total stress. From the thermal stress measurement, the thermal‐expansion coefficient and the elastic constant of the CVD glass films were estimated.
TL;DR: In this paper, the authors measured the thickness of thin, discontinuous silver sulfide tarnish films on a rough metal surface and found that the effect of the thin film should be the same as that of a continuous film whose thickness is the average thickness of the discontinuous film.
Abstract: The strong coupling between photons and surface plasmons that occur on rough metal surfaces permits optical measurements of the shift of the surface plasma resonance frequency when the metal surface is covered with a thin film Thin, discontinuous silver sulfide tarnish films on silver shift the resonance to lower frequencies and also damp the resonance, in agreement with surface plasmon dispersion theory The wavelength of the dominant surface plasma wave is large compared to the size of the discontinuities, so the effect of the thin film should be the same as that of a continuous film whose thickness is the average thickness of the discontinuous film On this basis, the thicknesses of several silver sulfide films are calculated from the measured frequency shift of the resonance peak and are found to be in excellent agreement with values determined from independent ellipsometric measurements
TL;DR: In this paper, the preparation and properties of thin polyethylene films deposited by vacuum evaporation were described. But the results were limited to a single crystal orthorhombic structure with lattice parameters a = 7.40 A and b = 4.95 A.
TL;DR: In this paper, thin films of amorphous ZrO2 suitable for transmission electron microscopy were prepared by sputtering anodized Zr with 6-keV Kr or O2 ions and collecting the deposit on unheated KC1.
TL;DR: In this paper, different mechanisms of evaporation leading to the observed differences in characteristics of thin films are discussed, and the crystallinity, morphology and the chemical composition of the produced thin films have been examined by various analytical methods.
Abstract: Thin films of several III–V and II–VI compounds as well as of some dielectrics have been vacuum-deposited using a focused beam of a CO2 or ruby laser to evaporate these materials. The crystallinity, morphology and the chemical composition of the produced thin films have been examined by various analytical methods. Films produced by the ruby laser were in most cases polycrystalline and stoichiometric, while films produced by the CO2 laser were amorphous and non-stoichiometric. Different mechanisms of evaporation leading to the observed differences in characteristics of thin films are discussed.
TL;DR: In this article, the effect of adsorbate gases on the nucleation and growth characteristics of gold thin films on glass surfaces was studied using resistance measurements and electron microscopy techniques, and it was found that the adsorption of hydrogen, nitrogen and oxygen on the glass substrates after glow discharge cleaning was found to influence the island structure and coalescence of discontinuous gold films.
TL;DR: In this article, the optical and electrical properties of thin films of amorphous germanium are investigated as a function of the conditions of deposition, and the results are compared with the results of annealing experiments and interpreted in terms of varying amounts of imperfections.
TL;DR: In this article, the authors used a simple free-electron picture for the phase shift experienced by electrons traversing the film, giving an effective inner potential of 16 eV for Au.
Abstract: Retarding field measurements were taken on thin films (10–−‐100 A) of Au evaporated on an Ir (111) surface. In the range of 0–5 eV the current‐vs‐voltage plots exhibited a decaying periodic variation in amplitude. The amplitude and period of the variations both decreased with film thickness. This interference phenomenon is interpreted as being due to electron reflection occurring at both the film‐vacuum and the film‐substrate interfaces. Measurements of the period as a function of film thickness agree well with a simple free‐electron picture for the phase shift experienced by electrons traversing the film, giving an effective inner potential of 16 eV for Au. From the temperature dependence of the energy at which maxima and minima occur the thermal expansion coefficient for the films is determined. Also, estimates of the mean‐free path for electrons in the film are obtained from the decay of the variation amplitude with thickness. Values obtained for both these quantities are consistent with previously published values.
TL;DR: In this article, the effect of temperature and shelf-life on the threshold and sustaining voltages has been studied in amorphous thin films of boron, silicon and germanium.
Abstract: Electrical switching phenomenon in amorphous thin films of boron, silicon and germanium is described. The effect of temperature and shelf-life on the threshold and sustaining voltages has been studied. The threshold voltage decreases with increasing temperature while the sustaining voltage is approximately independent of temperature. Both the voltages do not vary significantly with shelf-life. A memory effect is observed in amorphous silicon.