Showing papers on "Tantalum capacitor published in 1989"

Tantalum capacitor and method of making same

Abstract: A method of manufacturing a tantalum capacitor includes compacting tantalum powder about a tantalum anode rod in such manner than the tantalum powder in a region in registry with the tantalum rod is compacted to a density of from about 8 to 10 grams per cc or more, whereas the density of the remaining portions of the tantalum powder mass are compacted to a density of from about 4 to 7 grams per cc. The disclosure further relates to a improved capacitor formed in accordance with the method, as well as to an improved capacitor preform, the capacitor and preform being characterized in that a higher reliability mechanical and electrical connection is effected between the anode rod and the tantalum materials surrounding the rod.

Stacked multi-polysilicon layer capacitor

Abstract: A multilayer polysilicon structure is formed, where the various polysilicon layers and a conductive diffused region form plates of stacked capacitors, and electrodes contact each of the capacitor plates. The resulting capacitor structure inherently forms a series connected capacitor structure where each capacitor shares a plate with an adjacent capacitor. The structure is well suited for use in a voltage multiplier where each capacitor is charged to the supply voltage with the total voltage across the series connected capacitors being a multiple of the supply voltage. The dielectric layer between each of the polysilicon layers and between the first polysilicon layer and the diffused region may be nitride, oxide, or a combination of both.

Capacitor grade tantalum powder

Abstract: Tantalum powders of capacitor grade are provided, containing interacting silicon and phosphorous dopants and are used to make anodes for ectrolytic capacitors.

Capacitor and method for producing the same

Abstract: A capacitor including a dielectric film of a metal oxide, in which two electrodes contact with the surfaces of the dielectric film, and at least one of the electrodes is a conductive metal compound to which oxygen is added. A method for producing the capacitor is also disclosed.

Stacked insulating film including yttrium oxide

Abstract: A capacitor, and a method for making the same, are disclosed, wherein one plate of the capacitor comprises silicon. The dielectric material of the capacitor includes a silicon nitride layer disposed adjacent the silicon plate, and a layer of yttrium oxide disposed thereover. The second plate of the capacitor is formed over the yttrium oxide layer. The silicon nitride provides a barrier to the diffusion of silicon into the yttrium oxide film if the structure is heated, providing for a high dielectric constant capacitor dielectric which has improved leakage characteristics.

Semiconductor memory device having a stacked type capacitor and manufacturing method therefor

Abstract: A capacitor of a semiconductor memory device includes a planar type capacitor portion formed on a surface of an impurity region and a stacked type capacitor portion extending above the gate electrode. The stacked capacitor portion has a three-layer structure of polycrystalline silicon in which upper, lower and side surfaces of a lower electrode are surrounded by a dielectric layer and the upper electrode. A portion of a dielectric layer in the stacked capacitor portion is coupled to another dielectric layer formed on the surface of one impurity region. The capacitor has a planar type capacitor provided in the planar area of occupation of the stacked capacitor portion, whereby the capacitance of the capacitor can be increased without increasing the planar area of occupation.

Capacitor in semiconductor device

Abstract: A capacitor including two electrode layers and a dielectric interposed between the electrode layers. The dielectric layer includes a silicon nitride film and a silicon oxide film formed on the surface of the silicon nitride film. The thickness of the silicon oxide film is not smaller than 25 Å and not larger than 35 Å. In this thickness range there is attained the maximum capacitor life. The capacitor is used in a semiconductor memory, improving the device reliability.

Field effect transistor having an integrated capacitor

Abstract: An integrated field effect transistor capacitor structure having a capacitor connected between source and drain electrodes is described. In one embodiment, the capacitor is formed over a drain contact by providing a dielectric over said contact and an airbridge upper plate between said dielectric to the adjacent source contact. Preferably, the capacitor dielectric is the same dielectric as the FET passivation.

Tantalum oxide thin-film capacitor suitable for being incorporated into an integrated circuit package

Abstract: The authors have developed a tantalum oxide thin-film capacitor that is compatible with die-bonding by gold-silicon solder and hermetic glass-sealed packaging. Its lower electrode is a metal plate, and the upper one is a metal thin film. A Ta/sub 2/O/sub 5/ thin-film capacitor that uses a rolled tape of iron-42% nickel alloy as the metal plate and aluminium as the metal thin film is described. This capacitor can withstand a temperature of 500 degrees C for more than ten minutes. Its thermal coefficient of capacitance is less than 400 p.p.m./ degrees C in the range from 25 degrees C to 150 degrees C. The dependence of capacitance on frequency is very small in the range from 1 MHz to 1 GHz. The dielectric loss tangent is less than 0.5% at 1 MHz. The authors compared with Ta/sub 2/O/sub 5/ thin-film capacitor's performance with that of a barium-titanate-based single-layer chip capacitor by measuring the gain of an amplifier composed of an amplifier IC chip and a capacitor in a leadless chip carrier package. Incorporating Ta/sub 2/O/sub 5/ thin-film capacitors into the IC package was confirmed to be a more effective decoupling technique, particularly above than 100 Mhz. >

Measurement of electrode surface effects in air capacitors using a precise Coulombmeter

Abstract: A method by which air capacitor electrodes are charged with a DC voltage and then quickly discharged is described. Immediately afterwards, a very sensitive Coulombmeter is switched on to measure the additional discharging of thin dielectric films on the electrodes. The method makes possible the measurement of effects having a time constant of several milliseconds to several thousand seconds, and also enables the frequency dependence of the capacitance to be determined, even for time constants below 1 ms. >

Tantalum capacitor with non-contiguous cathode elements and method for making

Abstract: A capacitor having non-contiguous cathode elements prepared by diffusion bonding size-reduced cathode elements to a case.

A ceramic capacitor for AC applications

Abstract: A description is given of a multilayer ceramic capacitor developed for AC voltage operation by using a dielectric characterized by very low loss, even at large signal amplitudes. The result is a new class of ceramic capacitors useful in many medium power AC application such as line isolation and bypass to ground, small motor controls, etc. The dF of these ceramic capacitors compares favorably with that of small aluminium electrolyte capacitors. Comparable films are much larger, and the ceramic devices can be rated for much higher ambient temperature operation. Novel approaches to large-signal capacitor measurement, under conditions closely approximating use conditions, are presented for a range of low frequencies up to at least 10 kHz. It is demonstrated that at high frequencies, high resonant frequency and low series resistance are good figures of merit for capacitors. >

Composite chip-type solid electrolytic capacitor

Abstract: PURPOSE:To obtain a composite chip-type ceramic capacitor at a low cost with good productivity, by covering a solid electrolytic capacitor with a sheathing resin with leads from its anode and cathode metallic terminals being exposed, disposing and fixing a chip-type ceramic capacitor within a groove provided on the bottom of the resin and connecting the leads to terminals of the capacitor. CONSTITUTION:An anode lead 2 of a tantalum capacitor element 1 is welded to an anode metallic plate terminal 3 at its welding section and a cathode metallic plate terminal 5 is bonded to a cathode layer by means of a conductive adhesive or solder 6. Sheathing resin 8 raving a groove 7 on the bottom thereof is formed such that the terminals 3, 5 are led out from the opposite side faces. A chip-type ceramic capacitor 9 is arranged in the groove 7 and the terminals 3, 5 are bent downwards so as to make approximately a right angle and to extend along the opposite side faces. The terminals 3, 5 are further bent inwards so as to wrap the capacitor and are connected to terminals 10 of the capacitor 9 by means of a conductive adhesive 11. In this manner, a composite chip-type capacitor can be produced at a low cost with good productivity.

Manufacture of solid tantalum electrolytic capacitor

Abstract: PURPOSE: To obtain a capacitor having excellent electric characteristics at a low cost by forming a conductive macromolecular film as a solid-state electrolyte on the surface of a tantalum sintered body on which a dielectric oxide film is formed. CONSTITUTION: A tantalum sintered body element on the surface of which a dielectric oxide film is formed is immersed into aqueous solution incorporating hydrogen peroxide and oxygen. Thereafter, the element is immersed into pyrrole monomer or into the solution of water-insoluble solvent containing pyrrole monomer. A polypyrrole film is formed by chemical oxidizing polymerization on the dielectric oxide film. Then, the element is immersed into electrolyte incorporating the pyrrole monomer and paratoluene sulfonate. Electrolytic polymerization is performed. Thus, a polypyrrole film formed by the electrolytic polymerization is formed on the polypyrrole film formed by the chemical oxidizing polymerization. In this way, the capacitor having the excellent electric characteristics is obtained. COPYRIGHT: (C)1991,JPO&Japio

Electrical component for surface-mounting, and method for its fabrication

Abstract: The electrical component is, in particular, a chip capacitor in the form of a foil capacitor having metallised foils or - preferably, - of a tantalum capacitor having a solid electrolyte, with a casing produced from fluidised-bed coating powder in a fluidised-bed coating process, and with frontal front-contact (butting-contact) layers. In order to preclude soldering problems owing to the camber (crown) of the casing obtained in conventional fluidised-bed coating processes, the coating is pressed flat on at least one side to produce a planar face which runs parallel to the component axis, the front-contact layers which project axially beyond the casing terminating at said planar face or slightly projecting beyond it. Said pressing flat can be effected, after the fluidised-bed coating process, between heated cheek plates, after the fluidised-bed coating powder has been gelled on by a heat treatment.

Leaching reaction of manganese dioxide from tantalum capacitor scrap - A study on the recycling of high quality rare metal secondary resource.

Abstract: A new process was proposed for the recycling of Ta capacitor scrap containing about 4-7% of MnO2as solid electrolyte. This paper describes the removal leaching of MnO2with various reductive agents, and moreover, disscuses the dissolution reactions of MnO2in FeSO4-H2SO4aqueous solution from both thermodynamic and kinetic aspects. The results are summarized as follows:1) In the leaching of block Ta anode scrap, H2O2and Na2SO3solution were the most effective leaching agents with more than 90% of Mn extraction at room temperature after 24 hours.2) When the sample was ground to-200 mesh, MnO2was almost completely removed in a short time by use of H2O2solution, cheap FeSO4solution also showed satisfactory result.3) In the dissolution reactions of MnO2with FeSO4-H2SO4solution, primary and secondary periods were observed. The reaction rate of primary was in proportion to [Fe2+] 0.65, and [H+] 0, while the reaction rate of secondary showed the dependency of [Fe2+] 0.45 and [H+] 0.25 The activation energies for primary and secondary were 4.6 kJ/mole and 5.1 kJ/mole respectively.4) The overall reaction of primary was seemed to be controlled by a mass transfer of Fe2+ions through the boundary layer between the solution and the surface of MnO2inside the capacitor, while dissolution of Fe (OH) 3 and other reaction products was the rate determining step in the secondary.5) Hermetic seal type Ta capacitor scraps were graded up by applying the Fe3+/Fe2+oxidative-reductive consistent leaching method.

Manufacture of anode substance for tantalum capacitor

Abstract: PURPOSE:To shorten a manufacturing process by a method wherein, after a sintered substance has been produced by a vacuum sintering operation, a tantalum wire is welded in a non-oxidizing atmosphere in order to obtain an electrical characteristic as a capacitor without executing a sintering operation again. CONSTITUTION:A tantalum powder is thoroughly mixed with a 4wt.% solution of camphor in an alcohol after which this mixture is filled into a metal mold, are pressed from the upper part and lower part in order to manufacture a molded substance. This substance is baked in a vacuum in order to manufacture a sintered substance 10. This sintered substance 10 is welded 13 to a tantalum wire 12 by spraying argon gas onto a part to be welded; an anode substance 15 is manufactured.

Study of the impregnation of porous anodes of tantalum capacitors with liquids

Abstract: The impregnation of anodes of Ta capacitors with liquids from models developed for the impregnation by capillarity of porous solids is described. The process is assessed by the impregnation time, which is defined as the time needed for the liquid to saturate the porous structure. This parameter depends on the variables of the system and it assesses the impregnation capacity of the anode in specific conditions. A theoretical study of the effect of the variables of the system on the impregnation time is carried out and an experimental method to measure it is described. As an example of its application, the length of anode variable is studied. A good correlation between the experimental results and those of theoretical model is found.

Chip tantalum solid electrolytic capacitor

Abstract: PURPOSE:To absorb mechanical stress, preventing a capacitor device from being damaged by a method wherein a neck of specific width is provided at a crank between the capacitor device and a cathode outer terminal. CONSTITUTION:A tantalum capacitor device 1 provided with a tantalum lead line 2 of a line diameter of 0.2 to 0.3mm is connected to metal plate terminals 3, 4 as thick as 0.1 to 0.15mm consisting of nickel, iron, iron-nickel alloy, stainless or copper alloy. When the device 1 is coated with resin, a neck having width of 0.15 to 0.6mm is provided at a crank 5 between the capacitor device 1 and the cathode outer terminal 4. It is because pressure for clamping is applied to a metal terminal to make it extend when the device is set in a high temperature mold, and this force is applied to the capacitor device 1 that the capacitor device 1 is applied with stress mechanically and physically during process of resin coating. Therefore, a point (neck) which is much weaker mechanically and physically than the capacitor device 1 is provided so that this point absorbs said force.

Non-polarized solid tantalum electrolytic capacitor

Abstract: PURPOSE:To form a non-polarized solid tantalum electrolytic capacitor as a single item by a method wherein a tantalum pentoxide, having high reverse withstand voltage, is formed on both surfaces of a tantalum pellet CONSTITUTION:When tantalum pentoxide 2 is formed on a tantalum pellet 1, the formation voltage of an oxide film is increased to about 6-8 times, for example, of the rated voltage, and the reverse withstand voltage of a tantalum element is increased to a high level Subsequently, an electrolytic member 3 is formed on both ends of the tantalum pellet 1, and an electrode lead-out terminal 9 is provided on both sides of said electrolytic member 3 As a result, the reverse withstand voltage of the same value as the rated voltage can be obtained, and the state of non-polarization can be formed A non-polarized solid tantalum electrolytic capacitor can be obtained easily in single item without inserting a fuse into the internal part for the purpose of preventing breakdown caused by the application of inverse voltage When this capacitor is used for an electronic circuit, it can be installed on a printed substrate irrespective of polarity, and the capacitor can be used effectively from the view point of quality

Implantation-enhanced oxidation of tantalum for capacitor structures

Abstract: The letter investigates the enhanced thermal oxidation of tantalum using oxygen-ion implantation. A comparison of the electrical and dielectric properties is made between the oxygen-implanted thermal oxides and of those fabricated without implantation. The ion-implanted tantalum-oxide films are shown to be superior to the unimplanted layers for the fabrication of oxide capacitors.

Metal strip for the production of solid electrolytic capacitors, process for its production and capacitors obtained

Abstract: The invention relates to solid-electrolyte electrolytic capacitors whose anode part consists of etched and oxidised metal sheets. The electrolyte (54) of these capacitors consists of a material deposited in lacquer form on the metal sheets (50). … Application to the production of solid-electrolyte and aluminium electrolytic capacitors. … …