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, it was shown that Lifshitz' theory can be used to calculate dispersion forces across a triple-layer soap film in air, and numerical estimates were obtained specifically for soap films in air.
Abstract: It is shown that Lifshitz' theory can be used to calculate dispersion forces across a triple‐layer film. The general expression is derived and numerical estimates obtained specifically for soap films in air. The theory predicts clear deviation from single‐film behavior for very thin films and a marked solute effect. This may explain “anomalies” observed in experimental studies.
202 citations
TL;DR: In this article, the absorption coefficient of thin films of free base, copper, and zinc phthalocyanines was measured for photon energies between 0.5 and 11.8 eV and several new discrete transitions were observed in the ultraviolet spectra, in addition to a strong continuum component of absorption.
158 citations
TL;DR: In this paper, a technique has been developed for automatically counting etched tracks that pass through a thin film, where a spark, passing through the film along a damage track, evaporates a hole in the Al. A second spark is prevented from starting through the same hole, so that the discharge passes successively along each track.
Abstract: The low background of damage track detectors allows them to measure low integrated fluxes of charged particles or neutrons. When good statistical accuracy is desired, the long times required for visual track counting under the microscope may seriously limit the number of measurements, particularly when the track density is low. A technique has been developed for automatically counting etched tracks that pass through a thin film. Very simple and inexpensive equipment is required. The insulating film is placed between a plane, high-voltage electrode and a thin layer of Al. A spark, passing through the film along a damage track, evaporates a hole in the Al. A second spark is prevented from starting through the same hole, so that the discharge passes successively along each track and then stops. Sparks are counted with a scaler. The pattern of holes in the Al provides a visible replica of the pattern of tracks. Track densities from background level to 3000 tracks/cm2 can be measured. Areas up to 100 ...
154 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 paper, the authors present a review of the performance and limitations of narrow-band interference filters for dielectric thin-film applications, with a brief history of the subject and the reasons for continuing interest in it.
Abstract: This review is divided into seven sections entitled "Introduction", "Basic theoretical framework", "Readily available materials", "Applications", "Performance and limitations of narrow band interference filters", "Problems in the preparation of optical coatings" and "Probable future developments". In the introductory section the scope of the review is presented and a survey is given of already published reviews which are relevant to the subject. A brief history of the subject is also presented and the reasons for continuing interest in it are discussed. The introduction is concluded by mention of problems which are currently engaging the attention of workers in the field. In the next section the matrix theory relating the optical properties of single or multilayer dielectric thin films to the basic film parameters (refractive index and thickness) is developed with particular reference to the assumptions that are made in establishing this theoretical framework. It is emphasized that the conditions implied in these assumptions are not always satisfied in practice, and that differences between observed and predicted optical performance are therefore to be expected. In addition, the basic matrix formulation is used to derive other useful expressions for the optical properties of multilayers, e.g. the reiterative amplitude reflectance formula usually associated with multiple-beam calculations, the generalized Airy formula associated with the `two effective interfaces' approach, and the method of equivalent layers for symmetrical systems. The calculation of Poynting flux and the concept of `potential transmittance' are also discussed. The section on readily available materials consists basically of a table listing the relevant physical properties of commercially available materials suitable for the vacuum deposition of dielectric thin films. A brief description of such practical detail is necessary as a prelude to the following section. In the section on applications, details are given of the design and application of filters consisting of single or multilayer dielectric thin films. The term `filters' is used here in its widest sense and the term includes antireflection coatings, mirrors, edge filters, beam splitters and narrow band filters. Magneto-optical applications of dielectric films are also described briefly. The fifth section is devoted to a more detailed examination of the properties of narrow band interference filters, specifically their performance and limitations. This choice of emphasis is made for two reasons. Firstly, the advantage of narrow band interference filters over other means of spectral selection such as prism or grating monochromators is marked and can be discussed on a quantitative basis. Secondly, the structural `defects' of layers which afflict all thin film devices produce the most easily measurable effects in narrow band filters. These effects are discussed under the subheading "Limitations". The section on problems in the preparation of optical coatings is concerned with the precise control of the optical thickness of individual films, since this is usually crucial to the performance of the complete filter. This subject is divided into two separate parts, one concerned with the uniformity of thickness of the film over a relatively large substrate area, and the other with the control of optical thickness during the deposition of the film, commonly referred to as `thickness monitoring'. In both cases the limitations of the available techniques are emphasized. The review is concluded with comments on probable future developments of the subject.
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.
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.
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.
Patent•
04 Nov 1970
TL;DR: In this article, a surface in relief is formed by scanning coherent radiation over a surface defined by a thin film supported upon a plastic substrate, and the wave length of the coherent radiation is chosen so that it is absorbed by the film and hence removes portions of the film exposing the substrate.
Abstract: A surface in relief is formed by scanning coherent radiation over a surface defined by a thin film supported upon a plastic substrate. The wave length of the coherent radiation is chosen so that it is absorbed by the film and hence removes portions of the film exposing the substrate. The coherent radiation for removing the film may be switched on and off or otherwise modified so as to write information on the surface. Thereafter, the surface is again scanned by coherent radiation of a wave length that is reflected by the film but absorbed by the plastic substrate thereby removing portions of the plastic exposed by the coherent radiation. The film may or may not then be completely removed leaving a pattern in relief upon the surface of the substrate.
TL;DR: In this paper, it was shown that the formation of electromigration-induced open circuits in polycrystalline aluminum thin film conductors is caused predominantly by diffusion along grain boundaries.
Abstract: Electrical open circuits can be produced in current‐carrying polycrystalline aluminum thin film conductors as a result of electromigration phenomena. In this study, attempts have been made to induce such open circuits in comparable single‐crystal aluminum thin‐film conductors. It has not been possible to do so even after subjecting the latter to relatively high current densities for more than 10 000h. This observation adds strong support to the previous inference that the formation of electromigration‐induced open circuits in polycrystalline aluminum thin film conductors is caused predominantly by diffusion along grain boundaries.
TL;DR: In this paper, the authors derived expressions for the field induced in a thin-film waveguide by plane waves incident upon an adjacent frustrated total reflecting interface, and deduced an expression for the coupling coefficient for a Gaussian TEM 00 beam into such a guide as a function of the guide and beam parameters.
Abstract: We have derived expressions for the field induced in a thin-film waveguide by plane waves incident upon an adjacent frustrated total reflecting interface. From these, we have deduced an expression for the coupling coefficient for a Gaussian TEM 00 beam into such a guide as a function of the guide and beam parameters.
TL;DR: The morphology of glassy amorphous thin polycarbonate film cast from solution is affected by thermal treatments as mentioned in this paper, which results in an increase in the size of the ordered regions, nodules, up to several hundred Angstroms.
Abstract: The morphology of glassy amorphous thin polycarbonate film cast from solution is affected by thermal treatments. Annealing above 80° C and below Tg results in an increase in the size of the ordered regions, nodules, up to several hundred Angstroms. The crystallization process from the glass, taking place at 145° C, is divided into three major steps. At first the nodules merge into patches which aggregate to form lamellar planar structures. In some cases the planar structures are well-formed single crystals. Following this, spherulitic arms develop from the planar structures as centers. These arms at first consist of aggregates of large nodules which recrystallize to form lamellae; the final morphology is spherulitic in nature. The effect of film thickness and of several substrates on the morphology has been observed. Applying stress at room temperature to the crystalline film results in a breaking up of the lamellae into small blocks.
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: In this article, a model extending the Lennard-Jones and Devonshire cell model to surface environments is described, where the frequency spectrum and various correlation functions are decomposed into contributions from the bulk, surface and edge of a particle.
Abstract: Measurements on thin films and surfaces have generated a need for a technique whereby one can calculate the phonon properties of small particles containing only a few hundred atoms. We have used moleculardynamic techniques to calculate the frequency distribution and various moments for five different particle configurations. Results are compared with the bulk solid. A model extending the Lennard-Jones and Devonshire cell model to surface environments is described. It is shown that this model replicates features of the more exact calculation. The frequency spectrum and various correlation functions are decomposed into contributions from the bulk, surface, and edge of a particle. The differences can be explained in terms of the local environment.
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.