Showing papers on "Barrier layer published in 1970"

The morphology and mechanism of formation of porous anodic films on aluminium

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.

Transport Numbers and the Structure of Porous Anodic Films on Aluminum

Abstract: Experiments are described in which aluminum samples, covered with a porous oxide layer by anodization in oxalic acid, are subsequently re‐anodized in boric acid ("forming"). The experimental techniques employed combine standard voltage and current measurements with gravimetric and optical methods for film thickness determination and measurements of the rate of film dissolution. The results show that for a given anodizing electrolyte the porosity depends only on the anodizing voltage and that it decreases with increasing voltage. The growth of the porous films is determined solely by the formation of oxide at the oxide/metal interface. This can be used to define a transport number for the positive ions during anodization, which was found to be . During forming in boric acid of a sample already covered with a porous oxide layer some of the oxide is formed in the pores and some at the metal/oxide interface. For this process a transport number was obtained. The average pore diameter, cell diameter, and barrier layer thickness vary linearly with the anodizing voltage, the cell wall thickness being somewhat thinner than the barrier layer.

Solder bump metallization system using a titanium-nickel barrier layer

Abstract: Solder bumps, for use in connecting electrically-conductive contacts on a semiconductor die to electrical leads on an underlying substrate, each include a barrier layer of metal adhering to a die contact, a wettable layer of metal placed over the barrier layer of metal, and solder adhering to the wettable layer of metal. In addition, an intermetallic layer is formed between the barrier metal and the wettable metal to increase the strength and diffusion resistance of each bump.

Flexible packaging film

Abstract: A multiple-layer flexible packaging film including layers of nylon, biaxially oriented polypropylene and a heat sealable polyolefin in which the polypropylene and the heat sealable polyolefin form exterior layers and the nylon is an interior layer positioned therebetween. A saran barrier layer is also included as an interior layer.

Implantable electric device

Abstract: An implantable electric device which has at least one electric cell, a casing of epoxy resin encapsulating the electric cell, and a thin barrier layer of metal covering the casing, which layer is permeable to gas and relatively impermeable to liquid.

Barrier layers for electrophotographic elements containing a blend of cellulose nitrate with a tetrapolymer having vinylidene chloride as the major constituent

Abstract: An electrophotographic element comprised of a support, an electrically conductive layer and an insulating photoconductive layer is provided with a barrier layer composed of a blend of cellulose nitrate with a tetrapolymer of methyl acrylate, acrylonitrile, acrylic acid and vinylidene chloride interposed between the electrically conductive layer and the insulating photoconductive layer. Barrier layers of this composition provide good adhesion to the contiguous layers, so as to permit flexing of the element without damage, as well as excellent electrophotographic properties.

Method of forming beam leads on semiconductor devices and integrated circuits

Abstract: Disclosed is an improved method for forming corrosion resistant beam lead connectors on semiconductor devices such as integrated circuits. A barrier layer of a titanium and tungsten alloy is deposited over the surface of the integrated circuit. A layer of gold is then deposited over the barrier layer. The layer of gold is patterned to define interconnection paths between the various devices of the integrated circuit and beam lead connection geometries, using photoresist and a gold etchant. The titaniumtungsten barrier layer is left intact during this step. The photoresist pattern is removed and a second pattern is applied to cover all areas of the integrated circuit except those areas where beam leads are desired. An additional layer of gold is plated to the appropriate thickness to form the beam leads, the photoresist pattern effecting a plating stop-off and the titanium-tungsten layer providing electrical continuity across the slice. Electrical separation between beam lead connectors and device interconnection paths is effected by etching the titaniumtungsten alloy with an etchant that attacks only the alloy, leaving the gold geometries intact.

Modifying barrier layer devices

Abstract: A METHOD IS DESCRIBED FOR PRODUCING SURFACE BARRIER DIODES WITH PREDETERMINED BARRIER HEIGHTS. AT LEAST TWO METALS ARE MIXED IN A PREDETERMINED PROPORTION AND DEPOSITED ON A SILICON SUBSTRATE. SUFFICIENT HEAT IS APPLIED TO CAUSE THE METALS TO REACT WITH THE SUBSTRATE, FORMING A MIXED METAL SILICIDE REGION. BY VARYING THE PROPORTIONS OF THE METALS A DESIRED BARRIER HEIGHT CAN BE ACHEIVED.

A laminate of a barrier layer enclosed in rigid high density polyolefin layers

Abstract: This invention provides economical multi-layer sheets that combine high barrier layers with thick layers of rigid high density polyolefins.

Method for fabricating multilayer magnetic devices

Abstract: METHOD FOR FABRICATING MULTILAYER MAGNETOSTATICALLYCOUPLED THIN-FILM MAGNETIC MEMORY DEVICES. A PLURALITY OF LAYERS ARE DEPOSITED IN SUCCESSION ON A GLASS OR QUARTZ SUBSTRATE. THE LAYERS INCLUDE A FIRST PERMALLOY MAGNETIC FILM, A CHROMIUM BARRIER LAYER, A CHROMIUM-COPPER ALLOY SECOND PERMALLOY MAGNETIC FILM, A SILICON MONOXIDE PROTECTIVE LAYERS, A CHROMIUM MASKING LAYER, AND A PHOTOSENSITIVE RESISTANT MATERIAL MASKING LAYER. OPENINGS DELINEATING THE BOUNDARIES OF THE DESIRED MAGNETIC MEMORY DEVICES ARE THEN FORMED IN THE MASKING LAYER OF PHOTOSENSITIVE RESISTANT MATERIAL. SELECTIVE ETCHING MATERIALS ARE THEN USED, IN FOUR SUCCESSIVE ETCHING OPERATIONS, TO INITIALLY FORM AN OPENING IN THE CHROMIUM MASKING LAYER (FIRST ETCHING OPERATION), FOLLOWED BY OPENINGS IN THE SILICON MONOXIDE PROTECTIVE LAYER, THE SECOND PERMALLOY MAGNETIC FILM, THE SILICON MONOXIDE SMOOTHING LAYER, AND THE CHROMIUM-COPPER ALLOY CONDUCTING LAYER (SECOND ETCHING OPERATION), AN OPENING IN THE CHROMIUM BARRIER LAYER (THIRD ETCHING OPERATION), AND AN OPENING IN THE FIRST PERMALLOY MAGNETIC FILM (FOURTH ETCHING OPERATION).

Nitride passivation of mesa transistors by phosphovapox lifting

Abstract: A method of forming a barrier layer impermeable to mobile ions over both the curved and upper plane portions of the principal surface of a mesa-structured semiconductor device. The barrier layer is caused to crack when placed over a special liftant but not when placed over the remainder of the device surface. An etching solution via the cracks then removes the liftant and desired portions of the barrier layer so that electrical contact can be made subsequently to active regions of the device.

Tungsten barrier electrical connection

Abstract: A tungsten or molybdenum electrical connector is attached to a surface of a semiconductor element adjacent an N-type region by a bonding layer comprised of aluminum. A tungsten or molybdenum refractory metal barrier layer is interposed between the bonding layer and the semiconductor surface, and thin refractory metal silicide layers are interposed between the bonding layer and the electrical connector and barrier layer. The bonding layer may be formed of an alloy of silicon and aluminum. An aluminum preform may be initially stacked between the refractory metal surfaces to form the bonding layer. The refractory metal silicide may be formed before bonding or may be formed by reaction of silicon with the refractory metal surfaces during bonding. The resulting electrical connection formed exhibits reduced internal resistance.

Electrophotographic element containing a barrier layer comprising block copolycarbonates

Abstract: ELECTROPHOTOGRAPHIC ELEMENTS COMPRISED OF A SUPPORT, AN ELECTRICALLY CONDUCTING LAYER, A NOVEL BARRIER LAYER AND A PHOTOCONDUCTIVE INSULATING LAYER. THE NOVEL BARRIER LAYERS ARE FORMED OF BLOCK COPOLYCARBONATES HAVE ONE RECURRING UNIT CONTAINING AN ALKYLIDENE DIARYLENE MOIETY AND ANOTHER RECURRING UNIT CONTAINING AN OXYTETRAMETHYLENE MOIETY THESE BARRIER LAYERS HAVE IMPROVED ADHESION WITH CONTIGUOUS LAYERS.

Physical development of a thin reversibly activatable photoconductor element having a resinous barrier layer

Abstract: THIS INVENTION RELATES TO A PHOTOGRAPHIC IMAGING MEDIUM COMPRISING A SUBSTRATE, REVERSIBLY ACTIVATABLE PHOTOCONDUCTOR LAYER PREFERABLY HAVING A THICKNESS OF LESS THAN ABOUT 2 MICRONS, AND A WATER OR ALCOHOL SOLUBLE, TRANSPARENT BARRIER LAYER HAVING A LOW PERMEABILITY TO OXYGEN OVER SAID RADIATION ACTIVATABLE PHOTO-CONDUCTOR LAYER. THE PHOTOGRAPHIC IMAGING MEDIUM IS CHARACTERIZED BY THE BARRIER LAYER WHICH SUBSTANTIALLY PROLONGS DECAY TIME OF A LATENT IMAGE STORED IN THE PHOTOCONDUCTOR WHICH LATENT IMAGE HAS BEEN FORMED BY EXPOSURE TO A SOURCE OF ACTIVATING RADIATION. PROLONGED DECAY TIME IS BELIEVED TO BE DUE TO THE BARRIER LAYER PREVENTING MASS TRANSPORT OF OXYGEN FROM THE ATMOSPHERE TO THE PHOTOCONDUCTOR.

Video tracking, lateral photoeffect seeking electro-optic detector

Abstract: Detector means for use in imaging tubes such as a vidicon imaging tubes, said detector means being constructed as a layered element including a layer of semi-conductor material having a transparent or semi-transparent conducting barrier forming layer in intimate contact with one of the surfaces thereof, a plurality of spaced ohmic contacts on the opposite surface of the semiconductor layer from the barrier layer, respective output connections to said spaced contacts in which signal responses are produced when incident light impinges on the barrier forming layer, a peripheral connection extending around the conducting layer and in contact with the conducting and semi-conductor layers, and a load circuit connected to said peripheral connection in which video output signals generated in the peripheral connection are produced. The subject detector means are particularly suitable for use with image forming optical systems or devices and with other means which scan the surface of the semi-conductor layer opposite from the surface on which incident light impinges to produce a video output for some purpose.

Readily removable opaque protective layers and articles containing them

Abstract: READILY REMOVABLE OPAQUE COATINGS OVER ONE OR BOTH SIDES OF A PHOTOGRAPHIC OR RADIOGRAPHIC FILM, WHICH COATINGS CAN BE REMOVED IN A SINGLE PIECE, CAN BE MANUFACTURED BY APPLYING OVER THE FILM A MULTILAYER COATING COMPOSITION COMPRISING (A) A FIRST "BARRIER" LAYER CONTAINING ONE OR MORE WATER SOLUBLE POLYMERS THAT ARE COMPATIBLE WITH GELATIN AND THAT ADHERE TENACIOUSLY TO THE "OPAQUE" LAYER (B) AND (B) AN "OPAQUE" LAYER (OVER THE "BARRIER LAYER") COMPOSED OF A BLEND OF FINELY DIVIDED CARBON AND AT LEAST ONE WATER-INSOLUBLE POLYMER. THE "OPAQUE" LAYER MUST BE FAIRLY PERMEABLE TO WATER, SO THAT WHEN IT IS DESIRED TO REMOVE THE "OPAQUE" COATING, THE FILM CAN SIMPLY BE IMMERSED IN WATER. WITHIN A VERY SHORT TIME THE "OPAQUE" LAYER FALLS AWAY FROM THE FILM IN A SINGLE PIECE, RATHER THAN IN SMALL TROUBLESOME FLAKES.

Nonwoven material and method of making the same

Abstract: A NONWOVEN MATERIAL COMPRISING A LAMINATE HAVING A LAYER OF ADHESIVE AND A MULTIPLICITY OF ELEMENTS LOOPED OUTWARDLY FROM THE LAYER, A BARRIER LAYER SECURED TO THE ADHESIVE LAYER AND MEANS ASSOCIATED WITH THE BARRIER LAYER FOR SECURING THE MATERIAL TO A SURFACE; AND A METHOD OF MAKING BY FIRST EMBEDDING A WEB OF ELEMENTS IN AN OPEN PATTERN OF ADHESIVE BONDING THE ELEMENTS IN THE ADHESIVE, CONSOLIDATING THE ADHESIVE, INTO A CONTINUOUS BACKING LAYER WHILE LOOPING THE ELEMENTS OUTWARDLY FROM THE ADHESIVE BACKING, LAMINATING A BARRIER LAYER TO THE ADHESIVE BACKING AND APPLYING A MEANS ASSOCIATED WITH THE BARRIER LAYER FOR SECURING THE FABRIC TO A SURFACE. IN CERTAIN INSTANCES A SECOND PATTERN OF ADHESIVE MAY BE APPLIED TO THE FIRST PATTERN OF THE ADHESIVE PRIOR TO THE CONSOLIDATION STEP.

Luminescent screen and process of manfacture

Abstract: 1,201,834. Luminescent screens. SYLVANIA ELECTRIC PRODUCTS Inc. 26 April, 1968 [28 April, 1867], No. 19900/68. Heading C4S. [Also in Division H1] A luminescent screen of the type comprising a first phosphor 15 1 excitable by a high-velocity electron beam and separated by a barrier layer 25 1 from a second phosphor 27 excitable by a low velocity electron beam, is characterized in 'that the barrier layer 25 is a conductive oxide, of one or more of copper, silver, zinc, cadmium gallium, indium, germanium and tin. In one method of making the screen the phosphor layer 15 1 is coated with a heat decomposable material, such as a lacquer solution, to provide a smooth surface on which a nucleating material such as silver, tin, aluminium, or chromium is evapor- 'ated. The barrier material, e.g. cadmium, is evaporated on to the nucleate and the screen is heated to 400‹ C. for forty-five minutes to remove the lacquer material and to convert the cadmium layer to cadmium oxide having a thickness of about 800 S.U. This layer is conductive and is connected to a graphite wall coating 37. Finally the second phosphor layer 27 is deposited on the barrier layer. The first phosphor may be Zn 2 SiO 4 : Mn and the second YVO 4 : Eu.