Showing papers on "Evaporation (deposition) published in 1971"

Apparatus for metal evaporation coating

Abstract: An apparatus for metal evaporation coating, comprising an evacuated chamber, an anode made as an envelope of arbitrary shape, a cathode made of the metal being evaporated, the evaporation surface of said cathode facing the space defined by said envelope, a trigger electrode generating a cathode spot on the cathode, means for retaining the cathode spot on the cathode in the form of a shield, and an electric arc supply.

The epitaxial growth of cobalt on copper

Abstract: Single-crystal films of cobalt are grown by evaporation in ultra-high vacuum onto (001) copper substrates held at temperatures between 250°C and 350°C. It is found that the first misfit dislocations appear in the Cu-Co interface when the cobalt film is 13, A thick. Although thicker films are no longer pseudomorphic, the mean strain in the cobalt is still much greater than the equilibrium value predicted by existing theory. A previously established mechanism for the generation of misfit dislocations is used to estimate the magnitude of this discrepancy between the theoretical and measured strains. It is suggested that the existence of large residual strains is inevitable in any film which initially grows as a continuous pseudomorphic layer.

Growth, Texture, and Surface Morphology of SiC Layers

Abstract: Highly oriented layers were grown on (001) and (111) silicon substrates by the reduction of in an excess of hydrogen at a temperature of 1365°C. Layers up to ≈100µ thick were grown at a rate of 4.3 µ/min. The material was predominantly with a resistivity range of 0.5–34.5 ohm‐cm, n‐type. Laue x‐ray analysis indicated that the degree of preferred orientation varied with thickness and that multiple orientations exist on the (001) silicon substrates. A higher degree of preferred orientation was achieved on the (001) compared to the (111) substrates. At various thicknesses, faceted grains on the order of 1–2µ in diameter were visible using the scanning electron microscope. The fact that oriented growth was achieved at higher than typical CVD rates for epitaxy suggests that detrimental effects such as substrate evaporation or impurity deposition were overcome by the higher deposition rate.

Evaporation characteristics of materials from an electron beam gun II

Abstract: Measurements have been made of the evaporation characteristics of aluminum, alumina, aluminum nitride, barium titanate, boron carbide, boron nitride, carbon, copper, chromium, gold, iron, inconel, lead, magnesium, magnesium fluoride, molybdenum, nickel, niobium, permalloy, sapphire, silicon, silicon monoxide, silicon dioxide, silver, tantalum, tin, tin oxide, titanium, titanium monoxide, titanium dioxide, tungsten, and zinc. Using a 6-kW, 180 ° bent-beam gun, the deposition rate, required beam power, charge material form, and suitability for evaporation were determined for each material. The evaporation rate is reported in angstroms/minute. Methods of transferring these data to other guns are developed. The beam power limit is discussed and methods of increasing the evaporation rate of power limited materials are explored. Extension of these results to other materials is discussed and examples are given.

High Electron Mobility InSb Films Prepared by Source-Temperature-Programed Evaporation Method

Abstract: InSb thin films are prepared by a source-temperature-programed evaporation method to reduce imperfections of crystal structure, and their crystalline and electrical properties are studied. An optimum source temperature program is investigated to obtain an appropriate source material composition. Films thus prepared has an electron mobility of 61,000 cm2/Vsec at room temperature and a donor concentration of 3.5×1015/cm3. An X-ray analysis of the film showes a high degree of stoichiometry.

Al2O3 Films Prepared by Electron-Beam Evaporation of Hot-Pressed Al2O3 in Oxygen Ambient

Abstract: This paper describes the deposition as well as the electrical and physical evaluation of Al2O3 films on silicon substrates prepared by reactively evaporating Al2O3 in an oxygen ambient. The Al2O3 was evaporated using an electron-beam gun. Several ambient parameters were varied in order to obtain their effects on film properties. Variations in the substrates preheating, in temperature of the substrates during evaporation, and rates of evaporation were made. Measurement of MOS capacitance vs voltage provided data concerning the interface properties between oxide and silicon as well as conduction of the Al2O3 with applied bias conditions. These measurements indicated that mobile charge manifested by offset voltage in the C-V plots could be reduced below 7×1011 e/cm2 either by post heat treatments or deposition on heated substrates. The dielectric constant of these films at 100 kHz ranged between 7.6 and 7.8. Ellipsometry measurements show that the index of refraction varies from 1.72 to 1.55 as the depositio...

Optical Properties of Evaporated Rhodium Films Deposited at Various Substrate Temperatures in the Vacuum Ultraviolet from 150 to 2000 Å

Abstract: Evaporated Rh films preparation at various substrate temperatures in vacuum UV, determining reflectance and optical constants

Apparatus for metal vaporization comprising a heater and a refractory vessel

Abstract: An improved evaporation source for vacuum deposition of metals comprises a refractory vessel heated and supported by a separate heater. The vessel has a cavity to contain the metal to be evaporated and has a uniform wall thickness beneath the cavity. The heater comprises an electrically conductive refractory material shaped so as to support the vessel only at the ends thereof but to be in efficient heat transfer relationship therewith.

Resistance of Thin Metal Films Grown under a Longitudinal Electric Field

Abstract: Thin‐film samples of platinum, silver, and gold were prepared in pairs on glass substrates by evaporation in a vacuum of 10−6−10−7 Torr, one sample of the pair under an electric field (usually 40 V/cm, either dc or 500‐Hz square wave) applied along the substrate surface and the other sample under no field. Sample resistances were measured in the vacuum at temperatures ranging from roughly 0 °C to 4 °K. The resistances of the samples deposited under a field were almost invariably lower, sometimes by orders of magnitude, than those of the corresponding samples grown under no field. Electron micrographs show that the former samples had elongated and interconnected grains while the latter samples had roundish and more islolated grains. The data are discussed in terms of a simple model based on the notion that the film particles polarize, stretch, and even coalesce under the applied electric field before they solidify.

Method of making a thin film having a high coercive field

Abstract: An isotropic thin film having a high coercive field for use as a magnetic memory, and comprising a non-ferromagnetic substrate, at least one chromium layer having a thickness smaller than 10,000 A overlying said substrate and at least one cobalt layer having a thickness smaller than 1,000 A overlying the chromium layer. In a process for the fabrication of the thin film, the chromium layer or layers and the cobalt layer or layers are deposited on the non-ferromagnetic substrate by evaporation under a vacuum.

Properties of Evaporated SiO(2), SiO(x)N(y), and TiO(2), Films.

Abstract: Films of SiO2, SiOxNy, and TiO2, were prepared by reactive evaporation in ionized gases. Refractive index, absorptance, ir transmittance, stability, structure, and stress of these films were investigated. The SiO2 films had the same refractive index as bulk quartz glass and an absorption coefficient of less than 40 cm−1 at 190 nm. The internal stress in the SiO2 films was considerably lower than that for silicon oxide films prepared by conventional reactive evaporation. SiOxNy films formed extremely smooth surfaces when heated in air after evaporation. On unheated substrates TiO2 films with refractive indices up to 2.3 and an absorption coefficient of less than 40 cm−1 at 633 nm were obtained. All films were x-ray amorphous and proved to be mechanically stable and water resistant.

Apparatus for continuous vacuum deposition

Abstract: A vapor deposition apparatus is provided wherein a workpiece strip is passed over a rotatable masking wheel within a vacuum environment. The evaporation source and material to be evaporated and deposited upon the strip is located within the perimeter of the masking wheel. It is deposited upon the strip as it passes along the masking wheel. The masking wheel consists of two or more parallel, and independently mounted rings which are axially aligned and axially adjustable for altering the gap between the rings, and hence the width(s) of the material deposited on the workpiece strip.

Method for controlling the composition of a deposited film

Abstract: DEPOSITION OF A FILM OF A COMPOUND ON A SUBSTRATE BY ELECTRON BEAM EVAPORATION OF THE COMPOUNDS IS CONTROLLED BY REESTABLISHING SUBSTRATE ELECTRICAL POTENTIAL. AN ELECTRICAL POTENTIAL IS APPLIED TO THE SUBSTRATE AND IS PROPERLY ADJUSTED TO ATTRACT OR REPEL A PREDETERMINED PORTION OF THE NEGATIVELY CHARGED IONS FORMED DURING EVAPORATION OF THE COMPOUND.

Vacuum deposition of tin-selenium films

Abstract: Films of tin and the volatile element selenium, composed in an arbitrary ratio, are produced with high reproducibility by the vacuum deposition technique which has been newly developed. This method comprises a two stepped-evaporation from the mother alloy containing selenium dissolved in tin. The mechanism of this method is investigated experimentally and theoretically, and the process of the first and second step of evaporation is discussed.

Boron nitride base evaporation vessel having a surface coating of titanium-silicon thereon

Abstract: A boron nitride containing evaporation vessel which is readily wetted by molten metals and accordingly ideally suited for use in a vacuum metallizing system is provided by coating at least a portion of the evaporation surface of the vessel with a titanium-silicon base alloy.

DC Characteristics of Electroluminescent Evaporated ZnS: Mn, Cu, Cl Films

Abstract: Electroluminescent cells are prepared by evaporation of ZnS:Mn, Cu, Cl onto tin oxide-coated glass substrates, subsequent heat treatment at greater than 600°C, evaporation of an Al electrode, and finally complete forming by application of positive voltage to the Al electrode. There is an indication that after deposition the Cu concentration is higher adjacent to the substrate, and that Cu is redistributed by the heat treatment. Forming occurred also, if an oxide film is deposited before the Al. It is likely that Cu ions drift during forming causing shorting paths of Cu to be opened near the Al electrode. The presence of a high resistance layer between the Cu and Al is required to initiate the migration of Cu. An exp √V dependence of current on voltage is found, suggesting Schottky emission of electrons from Cu to ZnS. The ratio of brightness to current exhibits an exp √1/V dependence on voltage.

Applications of scanning electron microscopy to thin film studies on semiconductor devices

Abstract: Some of the various uses of the scanning electron microscope (SEM) as applied to thin film studies on semiconductor devices are illustrated. Examples presented include the use of the SEM to measure thickness variations in an aluminum film, to determine evaporation coverage of aluminum films over oxide steps, to locate θ phase (CuAl 2 ) particles in an Al-2% Cu thin film, to determine crystallographic orientation using Coates-Kikuchi patterns, to find an open circuit in a nichrome resistor, to follow the fuse blowout of an aluminum stripe, and to determine the chemical composition of thin films. In these examples, the secondary backscatter electron beam induced current (EBIC), voltage contrast, and X-ray modes are demonstrated as well as the rapid scan technique.

Improvements in or relating to processes of vacuum-vapor depositing a binary metal coating on a substrate

Abstract: 1,235,412 Vapour depositing alloy coatings JONES & LAUGHLIN STEEL CORP Jan10, 1969, No1590/69 Heading C7F A moving strip of eg steel, is coated by evaporation with metals in crucibles 2, 3, which are so arranged to give a coating of metal A, eg Zn, an alloy of metals A, B and metal B, eg Mg The strip may be precoated with Zn The strip is heated to 520‹F immediately prior to or after coating

Glow discharge technique for the preparation of electrophotographic plates

Abstract: A method of preparing an electrophotographic plate having a metallic oxide coating interface is disclosed. The preparation of the plate involves subjecting a metallic substrate to a glow discharge process by utilizing it as the anode electrode in the electrical discharge process. The glow discharge effects oxidation of the surface as well as heating the substrate to a temperature at which vacuum evaporation of the photoconductive layer takes place. The process has particular utility because the glow discharge - oxidation process effectively cleans the metallic substrate thereby preparing it for the subsequent evaporation of a pure photoconductive material such as selenium.

Epitaxial Growth of Silicon Films on Sapphire and Spinel by Vacuum Evaporation

Abstract: Single-crystal silicon films are formed on (01, 2) and (11, 0) sapphire and also on (111), (001) and (113) spinel surfaces by evaporation in a vacuum of 2×10-6 Torr. The growth process of these single-crystal films is studied by reflection electron diffraction. The initial deposits on sapphire contain a few orientations, and further deposition leads to the eventual predominance of one orientation. The initial deposits on spinel consist of only one orientation parallel to the substrate orientation, and no orientation change occurs during film growth. A feature in the growth of silicon on these substrates is found to be the growth of the (110) fibrous structure at lower substrate temperatures.

Deposition and Detection of Ag and Au Films Below 0.01 Monolayer

Abstract: The controlled deposition of extremely small amounts of Ag and Au is described. A shutter arrangement was developed which permits the deposition of metals from 10−3 monolayer upwards, in conjunction with a rate-controlled evaporation source. Either continuous or stepwise variation of film thickness was attained. Deposits below about 1 monolayer consisted of particles which were invisible ill the electron microscope. Their presence was detected by subsequent amplification of their size such that a visible deposit was formed. This was accomplished either by physical development, as known in photographic chemistry, or by vacuum deposition of zinc which was nucleated by these particles. The detection sensitivity of the methods is compared.

Studies of the Tungsten-Oxygen Surface Reaction by Means of Reflexion High Energy Electron Diffraction

Abstract: The reactions between both (100) and (110) surfaces of tungsten and oxygen have been studied in an ultra-high vacuum environment by means of reflexion mode high energy electron diffraction. Particular attention has been paid to changes in interfacial geometry owing to faceting which occurs on the (100) surface, and oxide nucleation which occurs on both faces. The faceting of the (100) face is shown to be more complicated than had previously been supposed, the faceted surface being composed of {211} planes which are themselves faceted into {110} planes. The activation energy for the degradation of facets in a vacuum has been measured as 6.5 $\pm $ 1.5 eV, greatly in excess of values reported for the formation of facets. It is suggested that faceting arises from the evaporation of oxide molecules. At temperatures below 1025 K tungsten trioxide nuclei form on both the (100) and (110) surfaces when exposed to oxygen. The exposures needed to form nuclei are much greater for the (110) surfaces than for the (100). Nuclei also form on (100) surfaces which have been previously faceted by heating in oxygen at temperatures above 1025 K. In this case the exposures needed to produce nuclei are characteristic of the (110) surface. The epitaxial relationships between the oxide and the metal have been determined. A simple relation has been found to hold. It is postulated that the metal plane at the oxide interface is not necessarily that which was originally exposed to the gas phase.

Process for treating a coating of aluminium deposited on a metal support,more particularly,sheet metal

Abstract: A PROCESS FOR TREATING AN ALUMINIUM COATING DEPOSITED ON SHEET-METAL SUCH AS A STEEL PLATE, SHEET OR STRIP, COMPRISING APPLYING THE ALUMINIUM COATING BY EVAPORATION UNDER VACUUM, WITH A THICKNESS LESS THAN 20 MICRONS, ONTO SHEET-METAL WHICH ADVANCES CONTINUOUSLY, SUBJECTING SYSTEMATICALLY THE ALUMINIUM COATING TO SUPERFICIAL HOT OXIDATION BY PASSING THE COATED SHEET-METAL DIRECTLY TO ATMOSPHERE WHILE ITS TEMPERATURE IS STILL 100*C. SO AS TO FORM A FILM OF ALUMINIUM OXIDE, SUBJECTING THE THUS FORMED FILM OF ALUMINIUM OXIDE TO THE ACTION OF A HOT FLUID BASED ON WATER WHILE THE SHEET-METAL IS STILL ADVANCING CONTINUOUSLY IN ORDER TO TRANSFORM THE ALUMINIUM OXIDE TO HYDRATED ALUMINIUM OXIDE.