Showing papers on "Tantalum capacitor published in 1990"

Solid electrolytic capacitor

Abstract: PURPOSE:To obtain the title capacitor having very small change in the value after leaving it at high temperature against the initial value of leakage current characteristics and also having excellent heat resisting property by a method wherein a coating material, consisting of vinyl resin material containing particulates of an inorganic substance or an inorganic compound, is firmly formed on the circumference of a capacitor element consisting of a valve-acting metal sintered body. CONSTITUTION:A coating material consist of vinyl resin containing particulates of inorganic substance or inorganic compound. Flakelike or spherical material is preferable as the particulates of inorganic substance or inorganic compound, and its average grain diameter is 30mum or smaller. As the inorganic substance, the metalloid such as carbon, boron, silicon and the like are used, and as the inorganic compound, the oxide such as silica and the like, the nitride such as silicon nitride and the like, the carbide such as silicon carbide and the like, the boride such as zirconium boride and the like are used. Then, the vinyl fundamental resin such as vinyl chloride resin, polyvinyl acetate resin and the like are used as resin. Pertaining to the compounding ratio of the particulates and the resin, the quantity of the particulates is set at 10 to 99%. The coating material, formed by compounding the above- mentioned material, is adhered entirely to a tantalum capacitor element as the prime coating resin, it is hardened by heating, and an outer covering is provided using epoxy resin.

Method of making electrically insulating metallic oxides electrically conductive

Abstract: A method of making an electrical contact to a metal on which an electrically insulating native oxide is formed includes applying atoms or ions to the native oxide, heating the metal and oxide to a temperature and for a time effective to make the oxide, where the atoms and/or ions have been applied, electrically conducting and in electrical communication with the metal. The invention may be employed to establish electrical contacts with native oxides on aluminum, molybdenum, niobium, tantalum, titanium, tungsten, and zirconium. The atoms and ions include aluminum, antimony, arsenic, boron, gallium, indium, phosphorus, and silicon. An aqueous solution of boric acid and trisodium phosphate may be applied to establish electrically conductive regions in an oxide on niobium, tantalum, titanium, and stainless steel after heat treatment. Brushing with palladium wires mechanically applies palladium atoms to tantalum oxide to establish electrical contact to the tantalum after heat treatment. The invention is useful in forming containers for electrolytic tantalum capacitors and making direct metal-to-metal electrical connections for capacitors and contacts for switches and relays.

Ceramic multilayer chip capacitor and method for making

Abstract: In a ceramic multilayer chip capacitor comprising alternately stacked internal electrodes of Ni or Ni alloy and dielectric layers, an oxide layer having a different composition from the dielectric layer is formed on the periphery of each internal electrode. The dielectric layer consists essentially of grains and a grain boundary phase, the percent area of the grain boundary phase being up to 2% of the area of a cross section of the dielectric layer. The capacitor is prepared by alternately stacking Ni or Ni alloy and a dielectric material in layer form, firing and then heat treating the stack under predetermined oxygen partial pressures. The dielectric material is a barium titanate base oxide material. The capacitor has a long effective life.

High-performance tantalum oxide capacitors fabricated by a novel reoxidation scheme

Abstract: High-performance tantalum oxide capacitors with excellent reliability that were developed by a two-step oxidation scheme are discussed. An anodic reoxidation process is applied to the reactively sputter-deposited tantalum oxide films to make the densified oxide structure. The electrical and physical properties as well as the reliability of these two-step oxidized sputtered/anodized tantalum oxide films are shown to be much superior to those of conventional tantalum oxide films prepared by either anodization or sputtering alone. Capacitors made of the sputtered/anodized tantalum oxide film have greatly improved electrical properties and better reliability than anodized or sputtered tantalum oxide capacitors and are very useful for applications to high-capacity storage capacitors in future high-density VLSI memories. >

Thin decoupling capacitor for mounting under integrated circuit package

Abstract: A rugged, highly reliable, leadless decoupling capacitor is provided which may be positioned between a circuit board and an integrated circuit package including, for example, a leaded surface mounted IC package or Pin Grid Array package. This decoupling capacitor is comprised of a rugged ceramic or like substrate having printed or otherwise applied thereon a very thin high capacitance layer made by thick or thin film processes which is sandwiched between two thin electrode layers. Conductive castellations extend from the electrode layers along the surface of the ceramic substrate for connection to the circuit board. Preferably, an electrically insulative protective layer encapsulates the capacitor. The dielectric layer preferably comprises a high dielectric glass/ceramic dielectric paste or dielectric sol-gel layer. The overall thickness of the decoupling capacitor may be less than 0.020 inch.

Semiconductor capacitor with a metal nitride film and metal oxide dielectric

Abstract: A semiconductor device having a capacitor part which is composed of the first electrode including a first titanium nitride film, a dielectric layer and a second electrode including a second titanium nitride film, the titanium nitride film being sandwiched between the dielectric layer and the first and second electrodes, whereby it is possible to obtain a capacitor having a high capacitance value and which can inhibit the reaction between the dielectric layer and the electrode and which does not result in an increase in a leakage current of the dielectric layer and a deterioration of isolation voltage.

Capacitor method for improved oxide dielectric

Abstract: Capacitor structure capable of achieving increased energy storage density is disclosed together with a fabrication sequence for the capacitor and its anodic oxide dielectric material. Soft porous aluminum oxide which has been formed in a first anodization step and has been densified or transformed to hard barrier oxide in a second anodization step is preferred for the capacitor dielectric material. The first anodization may be performed in a sulfuric acid electrolyte while the second anodization may be performed in a boric acid electrolyte. The boric acid may be diluted with ethylene glycol. The disclosed capacitor is fabricated on a silicon wafer substrate.

A new high temperature multilayer capacitor with acrylate dielectrics

Abstract: A capacitor technology that makes use of vacuum-deposited electron-beam cross-linked acrylate materials has been developed. Polymer multilayer monolithic capacitors are produced by a continuous high-speed vacuum process. The polymer dielectric is formed by flash-evaporating an acrylate monomer material onto a rotating drum and then cross-linking it by electron-beam irradiation. The resulting polymer is thermally stable at temperatures in excess of 300 degrees C. The dielectric films are pinhole-free, with stable electrical properties. The capacitor electrodes are vapor-deposited aluminium and are thin enough to allow the capacitor to self-heal. The number of layers typically varies between 1000 and 5000 and the dielectric thickness between 0.3 and 1.0 mu m. The low dielectric thickness results in capacitor chips with high volumetric efficiency that can be surface mounted by conventional soldering techniques. An overview of the vacuum process, chip cutting, termination, packaging, electrical characteristics, and general test methodology is given here. >

Integrated circuit chip formed with a capacitor having a low voltage coefficient, and method of making such capacitor

Abstract: An integrated-circuit (IC) chip formed with a capacitor comprising a lower layer of polysilicon clad (14) with a thin film of TiSi2 (16) serving as the lower plate of the capacitor, a layer of dielectric (18), a thin film of titanium nitride (TiN) (20) on the upper surface of the dielectric to serve as the upper plate of the capacitor, a second layer of polysilicon (22) (doped with phosphorous) over the TiN film, and metallization to make contact with the top plate of the capacitor (28).

Surface mount non-polar tantalum capacitor

Abstract: A service mountable non-polar capacitor assembly is disclosed. The assembly includes a pair of polar tantalum capacitors disposed in axial alignment the anode rods of the capacitors being mechanically and electrically connected as by welding. An insulating sleeve encompasses the body portions of the capacitors leaving projecting portions extending beyond the ends of the sleeve. The void space within the sleeve between the opposed ends of the capacitors may be filled by a polymeric insulating and rigidifying material.

Decoupled electrolytic capacitor

Abstract: A filter capacitor network includes an inductor connected in series with an aluminum electrolytic capacitor with the inductor and aluminum electrolytic capacitor bypassed with a capacitor having relatively better high frequency performance characteristics than the aluminum electrolytic capacitor. The inductor decouples the aluminum capacitor from the network at middle and upper frequencies so that the bypass capacitor dominates the characteristics of the network in that range. A signal coupling/DC blocking capacitor network of the same configuration is also disclosed. An amplifier design includes the filter network in the power supply. The filter network is also disclosed in an audio signal path for use in signal coupling/DC blocking.

Equivalent series resistance-the fourth parameter for tantalum capacitors

Abstract: The author outlines the reasons behind the interest in ESR (equivalent series resistance) of surface mount devices and details the processing steps which affect the ESR of a tantalum capacitor. It is noted that the operating frequencies of products which use tantalum surface mount capacitors are continually increasing. These higher frequencies have resulted in ESR becoming a specified parameter in numerous user drawings, industry standards, and military specifications for tantalum chips. >

Sintered type barium titanate capacitor

Abstract: PURPOSE: To enable a process to be simplified and a yield to be improved by using colloidal carbon as an opposing electrode of a capacitor. CONSTITUTION: A barium titanate dielectric layer 2 is formed on an anode body 1 where a titanium wire 8 is led out, a colloidal carbon layer 3 and a silver paste layer 4 are provided on it as an opposing electrode for obtaining a capacitor element, and an anode element 9 and a cathode terminal 7 are connected to the titanium wire 8 and the capacitor element, respectively, thus enabling a process to be simplified as compared with the manganese dioxide method and yield to be improved. COPYRIGHT: (C)1991,JPO&Japio

Electrical properties of co-fired high and low dielectric constant multilayer package materials

Abstract: The problems encountered in mixing high-dielectric-constant (high-K) lead-oxide-based capacitor layers in the same body as low-dielectric-permittivity (low-K) signal distribution layers were studied. Compatibility between the high-K capacitor material and low-fire (850-950 degrees C) glass-Al/sub 2/O/sub 3/ substrates was investigated. Most high-K ceramic materials sinter at temperatures above 1000 degrees C; firing at 900 degrees C or lower can result in a porous structure with poor electrical properties. >

An exploration of leakage current

Abstract: A simple programmable sequence of measurements which allows classification of leakage currents of capacitors based on their time, temperature, and voltage characteristics has been devised. The method adopts the concept that the measured current is the sum of independent flow mechanisms, one of which is present to a consistent extent in all the capacitors. By removal of this part from the total, the true behavior pattern of the excess current can be determined. This method was applied to solid tantalum capacitors. Examination of capacitors in this manner produces a wide range of behavior patterns. In some instances, the voltage dependence is essentially ohmic, while in others there is a very steep slope to the current/voltage plots. These plots can also display sudden breaks due to self-healing or catastrophic localized breakdown. From the temperature characteristics, activation energies for the current flow can be estimated, and these are generally in the region of 0.1 to 0.4 eV. However, detailed comparison of these activation energies often suggests that the simple Arrhenius equation may not adequately represent the behavior. In addition to the measurement of leakage current, further evidence of flaws can be gleaned from the discharge currents. Direct contact between the manganese dioxide and the tantalum due, for instance, to rupture of the dielectric under high mechanical stress can produce a battery effect leading to low currents which are detectable in the discharge mode. >

Novel Methods for Preparing Thin, High Permittivity Polymer Dielectrics for Capacitor Applications U.S. Army Electronics Technology and Devices Laboratory,

Abstract: In order to create new materials which can be used as solid dielectric in high energy density capacitors, a number of insulating polymer films possessing very high dielectric constants and high breakdown strengths have been synthesized and/or modified by a variety of electrochemical and chemical techniques. The physical and dielectric properties of each type of film is evaluated and compared.

Tantalum electrolytic capacitor and its manufacture

Abstract: PURPOSE:To obtain a ripple-resistant tantalum electrolytic capacitor by a method wherein a film in which a porous chemical-formation film has been restored by using a barrier chemical-formation film is formed as a dielectric. CONSTITUTION:A tantalum capacitor element 11 is immersed in a chemical- formation liquid containing ions of nitric acid. A prescribed direct-current voltage according to a rated working voltage is applied while the capacitor element 11 is used as a positive pole and the chemical-formation liquid is used as a negative pole. Consequently anodic oxidation occurs and a porous chemical- formation film 12 is formed. After that, this assembly is immersed in a chemical- formation liquid containing ions of phosphoric acid. A definite electric current is applied while the capacitor element 11 is used as the positive pole and the chemical-formation liquid as the negative pole. So as to restore a hollow part 13 of the porous chemical-formation film 12 by using a barrier chemical- formation film 14. Thereby, it is possible to enhance a ripple-resistant property of a product.

Solid tantalum capacitor

Abstract: PURPOSE:To reduce an initial tandelta value and its irregularity and to reduce a change in a tandelta value at a humidity-resistant test by a method wherein a cathode extraction part is constituted in such a way that a second carbon layer which is composed of a thermoplastic resin and of a powder having a specific particle size and a nickel oxide cathode layer are formed sequentially on a first carbon layer. CONSTITUTION:A tantalum anodic-oxidation film layer 13 is formed on the surface of a tantalum porous electrode body 12 provided with a tantalum anode extraction wire 11; a solid electrolyte layer 14 composed of a manganese dioxide layer and a first carbon layer 15 are formed sequentially; a coating film as a second carbon layer 16 which is composed of a carbon powder having an average particle size of 1 to 30mum and an acrylic resin is formed on them; in addition, a coating film as a cathode layer 17 which is composed of a nickel oxide powder having an average particle size of 10 to 60mum and an acrylic resin is formed on it. Thereby, a capacitor element is obtained. Then, an external cathode terminal 19 is arranged and installed at the cathode layer 17 via a silver adhesive 18; the anode extraction wire 11 is welded to an external anode terminal 20; after that, an outer-package resin 21 is executed. When the particle size of carbon is outside said range, a tandelta value becomes large. When the particle size of nickel oxide is at 10mum or lower, the tandelta value becomes large. When the size is at 60mum or higher, the surface state of the coating film becomes worse.

Capacitor, capacitor network, and r-c network

Abstract: PURPOSE: To provide a small sized, large-capacitance, stable capacitor with substantially zero temperature coefficient by combining dielectric films with different temperature coefficients. CONSTITUTION: A capacitor includes an insulating substrate 1, on which are provided a first electrode 2, a first dielectric 3 with a positive or negative temperature coefficient, a second electrode 4, a second dielectric 5 with a negative or positive temperature coefficient, and a third dielectric 6. The first electrode 2 is formed by etching a thin palladium film, which can be formed by vacuum deposition. The first dielectric 3 is formed by etching barium titanate that is deposited by sputtering and has a positive temperature coefficient. On the dielectric 3, an electrode 4 is formed and then covered with a strontium titanate film by sputtering with a metal mask. The strontium titanate has a negative dielectric temperature coefficient, and it serves as the second dielectric 5. Finally, the third electrode 3 is formed. COPYRIGHT: (C)1991,JPO&Japio

Low resistivity low ESR capacitor electrolyte

Abstract: A phthalate electrolyte containing benzil provides aluminum electrolytic capacitors having low equivalent series resistance and low rates of change in equivalent series resistance with time on voltage.

Solid electrolytic capacitor, namely tantalum capacitor, with incorporated controllable fuse

Abstract: A solid electrolytic capacitor includes, embedded in an electrically insulating resin block, a capacitor body equipped with two electrodes connected up respectively, by two connection tabs (5, 6A/B) for the output terminals (+, -) and test fuse; one of the connection tabs (6) is formed of a first segment (6A) fixed to one of the electrodes (4) of the capacitor body (2) and emerging outside the body to form the test fuse terminal and of a second segment (6B), electrically insulated from the first segment (6A) and from the capacitor body (2), and emerging outside the block (9) to form a normal application terminal; a fuse element (10) establishes on its own an electrical link between the segments (6A, 6B) whilst being surrounded by a thermally insulating resin support mass (14) stretching from one to the other of the two segments and itself embedded in the resin constituting the block (9).

Novel methods for preparing thin, high permittivity polymer dielectrics for capacitor applications

Abstract: In order to create new materials which can be used as solid dielectric in high energy density capacitors, a number of insulating polymer films possessing very high dielectric constants and high breakdown strengths have been synthesized and/or modified by a variety of electrochemical and chemical techniques. The research goal was to increase effective bulk dielectric constants (and therefore capacitance) of thin, easily formed, flexible polymer films that could be used as solid dielectrics in wound capacitor designs. The physical and dielectric properties of each type of film are evaluated and compared. >

Recovery of tantalum metal from Ta capacitor scraps with hydrogen plasma melting and refining

Abstract: The scrap of used tantalum capacitor is now an important secondary resource of tantalum and the composition of those scraps is simply identical to Ta-Ta205-Mn02 ternary mixture (Ta is above 90%, Mn and oxygen content are a few percent, respectively). In this work, recovery of tantalum metal from tantalum capacitor scraps has been examined by plasma melting process and hydrogen plasma melting was available to obtain ductile pure tantalum (0 < 100, Mn < 20 mass ppm, Hv =90-100) with effective deoxidation and demanganese directly from those scraps.Manganese was removed rapidly with vaporization of manganese from melt by Ar, H2 -Ar plasma melting and reduced to under 20 mass ppm. Also deoxidation proceeded by H2 -Ar plasma melting and oxygen content reduced to under 100 mass ppm. But oxygen was scarcely removed by Ar plasma. Since the deoxidation rate increased in proportional to the square root of hydrogen content of plasma gas, deoxidation is considered to be caused by dissociated and activated hydrogen atoms in hydrogen plasma. And the addition of carbon within equivalent of oxygen content in the scraps enhanced the deoxidation procedure.Furthermore the other minor impurities such as nitrogen, iron, nickel in tantalum capacitor scraps were eliminated as much as possible by hydrogen plasma melting.

Manufacture of anode body of tantalum capacitor

Abstract: PURPOSE:To enable the formation of uniform dielectric films by resintering at the second sintering temperature of 1,400-1,800 degC after welding a tantalum wire to a sintered body sintered at the first sintering temperature of 1,200-1,500 degC CONSTITUTION:Only tantalum powder is pressure-formed and sintered in a vacuum or inactive gas at the first sintering temperature of 1,200-1,500 degC to obtain a sintered body 1 Next, a tantalum wire 3 is butt-welded to the surface of this sintered body 1 and made in one body Then, it is sintered in a vacuum at the second sintering temperature of 1,400-1,800 degC to make an anode body 5 For example, tantalum powder is pressure-formed into a columnlike shape of 3mm in diameter and 35mm in length, and this is sintered in a vacuum to make a sintered body 1 A piece of tantalum wire of 03mm in diameter is joined to the surface 2 of this sintered body 1 by butt-welding 4 as the anode extension line 3 Then, an anode body 5 is made by resintering it in a vacuum at a sintering temperature higher than the initial one And, this enables uniform film formation without oxidizing the welded part of the sintered body with the wire partially

Segmented cathode for tantalum capacitor

Abstract: A capacitor having non-contiguous cathode elements (30) prepared by diffusion bonding size-reduced cathode elements (30) to a case (20).

Solid tantalum electrolytic capacitor

Abstract: PURPOSE:To obtain excellent humidity-resisting characteristics by a method wherein the total Na ions contained in the material of a solid electrolytic layer, a carbon layer, a silver coated layer, a conductive binding means and a resin sheathing body is limited to the specifically prescribed quantity or less. CONSTITUTION:On the tantalum powder anode sintered body 1 having an anode lead 1a and a synthetic film 2 formed on the surface, a solid electrolytic layer 3, a carbon layer 4 as a cathode conductor and a silver-coated layer 5 are formed successively. After a cathode lead wire 7 has been attached to the above- mentioned silver-coated layer 5 through the intermediary of the conductive bonding means such as solder or bonding silver 6 and the like, a resin sheathing body 11 is formed on the circumference of the lead wire 7. In the above- mentioned solid electrolytic capacitor, the total quantity of Na ions contained in the material, constituting a carbon layer 4, a silver-coated layer 5, a conductive bonding means 6 and a resin sheathing body 11, should be 10ppm or less. As a result, the title capacitor having excelling humidity-resisting property such as the assurance of PCT 100 hours or longer and the humidity resistance of 60 deg.C at 90 to 95% for 1000 hours, for example, can be obtained.