International Business Machines Corporation

Holger Hinkel

Georg Kraus

Gerhard Kaus

Gerhard Elsner

Upali Bandara

Ulrich Kuenzel

Gerhard E Schmid

Werner Steiner

Jurgen Kempf

Volker Heinrich

Ulrich Kunzel

Erhard Max

Johann Greschner

Thomas Bayer

Marian Briska

Gerhard Trippel

Werner Zapka

Albert Frosch

Artur Lang

Friedrich Ertingshausen

Rolf Schafer

Jochen Schneider

Reinhold Muehl

Manfred Schrader

Hans-Georg Nauth

Kurt Kleischmann

Michael Glatzel

Annelie Monnich

Erwin Prinz

A method of automatically forming identically positioned alignment marks on the front side and the back side of a silicon wafer especially prepared for use in silicon micromechanical technology. The front side and the back side of the silicon wafer are coated with an insulating layer. High-energy heavy ions are directed onto the front side insulating layer. The heavy ions penetrate the front side insulating layer, the wafer, and the back side insulating layer, thus forming single disturbed crystal lattice nuclear tracks in both insulating layers, with the wafer remaining undisturbed. The nuclear tracks in both insulating layers are etched so that corresponding identically positioned pores are opened. These pores are used as alignment marks for individual further method steps.

Method of forming identically positioned alignment marks on opposite

Method for measuring the properties of a slider/disk interface in a magnetic disk storage apparatus by measuring a triboelectric current flowing between disk and slider. Rotational speed is adjusted between 100 and 500 rpm so as to obtain a frictional contact between disk and slider. The shape of the tribo current curve obtained during the measuring time interval is analyzed. An early maximum of the tribo current amplitude and a subsequent continual decay indicates a good slider/disk interface and a long lifetime.

System for testing magnetic head/disk interfaces

The magnetic disk contains on a disk substrate a magnetic layer comprising a binder, magnetic particles and abrasion-resistant particles, the abrasion-resistant particles being enveloped with a layer intensifying the bond between binder and abrasion-resistant particles. The enveloping layer either has a large specific surface and consists e.g. of SiO.sub.2 /Al.sub.2 O.sub.3 produced by processing the particles with an alkali metal silicate solution and an aluminum sulphate solution, or it is chemically bonded to the binder by enveloping the particles with poly(tetrafluroethylene) and coupling the latter, via an amino bridge to the binder, e.g. an epoxide resin.

Magnetic disk and method of making same

The frictional coefficient and triboelectric current that exist between the magnetic-head carrying slider and the surface of a magnetic disk when both are in sliding contact are reduced by an appropriate pre-conditioning. The pre-conditioning comprises running the head-disk assembly for at least several minutes at a low velocity of, e.g. 200 to 400 rpm, in a dry gas atmosphere. By this pre-conditioning the lifetime of lubricated head-disk assemblies is increased.

Method for lowering the frictional coefficient of the magnetic head-disk

A magnetic recording disk comprises a magnetic layer consisting of a binder and magnetic particles, a silicon substrate and abrasion-resistant material formed on the silicon substrate. The abrasion-resistant material is in the form of elevations which protrude from the silicon substrate and whose surface is coplanar with the surface of the magnetic layer. The abrasion-resistant elevations are formed on the substrate in a predetermined uniform distribution either after the surface of the substrate has been blanket doped and/or covered with a layer comprising aluminum as a main component, by tempering and optionally oxidizing; or after the surface of the substrate has been selectively doped, by etching off the undoped regions of the surface of the substrate.

Abrasion-resistant magnetic recording disk

For making rails in workpieces for magnetic head sliders for sensors of magnetizable media, anodic oxidation of highly pure aluminum substrates is applied. For that purpose, the respective surface of the substrates is covered with a mask cover which leaves uncovered the zones in the substrate surface area which are intended for the forming of rails. By means of anodic oxidation of the aluminum in the exposed regions, rail layer regions of oxide are formed which after the removal of the mask cover can themselves be used as an etching mask in order to provide a recessed region between two respective rails by means of chemical wet etching.

Method of making magnetic head sliders

The invention relates to a composite magnetic disk for magnetic recording, which consists of an annular core of polymeric material to which is bonded at least one disk of reaction-bonded silicon carbide with a magnetic recording layer on its outer surface. After its processing, the SiSiC disk surface shows optimum planarity and smoothness so that it can be used as a magnetic disk substrate. Furthermore, the material has a low density and an extremely high specific modulus of elasticity so that numbers of revolution higher than obtainable with formerly known AlMg5 disk substrates can be reached.

Composite magnetic disk with Si and SiC substrate

The magnetic disc comprises a magnetizable layer (1) to which an adhesion promoting layer (4) and thereto a lubricant film (5) are applied. Onto the substrate of the magnetic head (2) an adhesion reducing layer (9) is deposited. The apparatus can also show only one adhesion-influencing layer. The layers (4) and (9) are formed by the reaction of a sililating agent with reactive groups on the surface of the magnetizable layer (1), or of the substrate of the magnetic head (2), respectively. The sililating agents used differ in their terminal groups of which one category produce van der Waals bonds to the lubricant molecules, and the other is chemically indifferent relative to the lubricant molecules. The two layers (4) and (9) are made e.g. by the spin-coating of a solution of the sililating agent, and subsequent drying. The apparatus ensures a homogeneous coating of the magnetizable layer (1) with lubricant, and it prevents the pick-up of lubricant by the substrate of the magnetic head (2).

Apparatus comprising a lubricant-coated magnetic disc and a magnetic

A magnetic head slider consisting of a mixed ceramic made of aluminum oxide/titanium carbide has on its sliding side adjacent a magnetic record carrier a thin layer from which the titanium carbide component has been removed. The titanium carbide component preferably is removed by preferential reactive ion etching in a CF.sub.4 plasma. The magnetic head slider with its sliding surface thus modified exhibits greatly improved sliding properties compared with sliders of the same material having a non-modified sliding surface.

Magnetic head slider of ceramic material

A plasma reactor comprises a reaction chamber having two plate-shaped electrodes arranged parallel to and above each other, whereby the substrates are supported on the lower electrode and this electrode is additionally provided with a center opening (5) through which gas is fed into the electrode space or which is evacuated from it, and where (a) the upper electrode is connected to a high frequency AC or RF voltage and (b) which has no electrode material in the regions opposite the substrates and (c) where their position and shape are determined by the substrates on the lower electrode, causing the electric field in the electrode space to be selectively weakened at at least above the substrates.

Plasma reactor for etching and coating substrates

The substrate 1 for magnetic disks takes the form of a laminate made up of a plurality of individual thin, fiber-reinforced, anisotropic and unidirectional lamellae. These lamellae are arranged staggered on top of each other at few angular spacings, i.e., at great angles of up to 60.degree., and are finally pressed together. The outer layers and lamellae, respectively, may be reinforced by stronger fibers or other material, such as carbon fibers outside and glass fibers inside, to influence the flexural modulus and the shearing modulus independently of each other. This makes for a substrate which consists of anisotropic material, whose characteristics are essentially isotropic, which is lighter than previously used substrates, and which has a higher critical number of revolutions.

Magnetic disk substrate of fiber-reinforced plastic

A substrate for a magnetic recording disk employs an annular core of synthetic material having thin metal foils bonded to opposite faces, the metal foils serving to receive a magnetic recording material to form a magnetic recording structure. The inner surfaces of foils which are bonded to the core faces have applied thereto a thin, soft, deformable layer such as copper to prevent irregularities in the core faces from affecting the outer surfaces of the metal foils.

Magnetic disk substrate with a core of synthetic material

Disclosed is a simplified method of producing semiconductor device structures in an integrated technology using at least one ion implantation step. Implantation of the doping ions into a silicon wafer, for example, for producing a subcollector or an emitter, is not effected, as previously, in an ultra-high vacuum atmosphere through a thin protective layer of silicon dioxide which is applied by a separate thermal oxidation step prior to implantation, but the doping ions are directly implanted into the bare silicon wafer. The latter implantation is effected in an atmosphere of increased partial pressure of oxygen. Enhanced diffusion of the oxygen adsorbed at the surface occurs into the vacancies which are generated by the implanted doping ions close the surface of the silicon wafer. In this manner a silicon dioxide protective layer is formed already in the initial stage of ion implantation. As a result one process step can be saved, namely, the production of the protective layer by thermal oxidation prior to ion implantation.

Method of making semiconductor device structures by means of ion

A direct heated rod-shaped cathode for an ion source is provided with a region of reduced cross-section adjacent its negative end to maximize the path length of electron movement within the discharge chamber and to provide effective control of the cathode resistance in a region that is relatively free of sputtering erosion during use.

Ion source having improved cathode

A method and apparatus for making a rastered photoconductive layer for electrophotography in order to achieve an improved representation of black areas. The raster is produced by means of ion implantation of substances altering the dark discharge speed.

Growing community of inventors

Boeblingen, Germany

Holger Hinkel