Showing papers on "Tantalum capacitor published in 1997"

Electrolytic capacitor life testing and prediction

Abstract: The aluminum electrolytic capacitor is widely used in various power electronic circuits and systems such as 3-phase PWM inverters. Its functions include, bus voltage stabilisation, conduction of ripple current due to switching events, etc. In automotive applications, one of the big issues is the extreme and harsh temperatures they have to withstand, underhood, which during the summer months would reduce their life. Most of the capacitors have maximum temperature ratings of either 85 or 105/spl deg/C and a few are rated at 125/spl deg/C. According to literature found, one of the primary wear-out mechanisms in electrolytic capacitors is mainly due to the loss of electrolyte by vapor diffusion through the seals. Other reports suggest that the main wearout mechanism is deterioration of the electrolyte. Experiments conducted to date and the results from the same are compared against modeling results based on a model reported in literature.

A method for predicting the expected life of bus capacitors

Abstract: Predicting the expected life of motor drive bus capacitors is complicated by several factors: the equivalent series resistance of aluminum electrolytic capacitors is frequency and temperature sensitive; the ripple current is a composite waveform; and the capacitor expected life is very sensitive to operating temperature. This paper describes a method that addresses all these factors by developing separate models for capacitor equivalent series resistance, motor drive circuitry, heat transfer conditions and capacitor life.

Thin film capacitors and process for making them

Abstract: A thin film capacitor for use in semiconductor integrated circuit devices such as analog circuits, rf circuits, and dynamic random access memories (DRAMs), and a method for its fabrication, is disclosed. The capacitor has a dielectric thickness less than about 50 nm, a capacitance density of at least about 15 fF/μm2, and a breakdown field of at least about 1 MV/cm. The dielectric material is a metal oxide of either titanium, niobium, or tantalum. The metal oxide can also contain silicon or nitrogen. The dielectric material is formed over a first electrode by depositing the metal onto the substrate or onto a first electrode formed on the substrate. The metal is then anodically oxidized to form the dielectric material of the desired thickness. A top electrode is then formed over the dielectric layer. The top electrode is a metal that does not degrade the electrical characteristics (e.g. the leakage current or the breakdown voltage) of the dielectric layer.

Solid electrolyte capacitor and its manufacture

Abstract: Dense and uniform solid electrolyte layers made of conductive polymer are formed in a winding type capacitor to obtain a large capacitance solid electrolyte capacitor having excellent electrical characteristics. An anode foil (1) and a cathode foil (2) are wound with separators (3) therebetween to form a capacitor element (10) which is impregnated with mixture solution made of 3,4-ethylene dioxythyophene and an oxidizing agent. The mixture solution permeates into the inside of the capacitor element (10). By gentle polymerization reaction between 3,4-ethylene dioxythyophene and the oxidizing agent in the process of permeation. After the permeation, polyethylene dioxythyophene layers, i.e. solid electrolyte layers, are formed in the capacitor element (10). Further, a low impedance solid electrolyte capacitor in which the electrolyte layers are well formed can be provided. 3,4-Ethylene dioxythyophene is polymerized by the oxidizing agent in a solvent consisting of one or two among secondary alcohol, tertiary alcohol and delivertive of secondary alcohol. By this process, the polymerization reaction can be maintained in a satisfactory state, and accelerated. Thus, polyethylene dioxythyophene electrolyte layers having a high degree of polymerization and a high conductivity is provided.

Sputtered and anodized capacitors capable of withstanding exposure to high temperatures

Abstract: Novel structures for capacitors which are capable of withstanding heat treatments to at least 400° C. while providing low defect densities and low electrical series resistance in its electrodes are disclosed. In one embodiment of the present invention, a capacitor structure includes a bottom capacitor electrode formed of a first sub-layer of aluminum, a second sub-layer of tantalum nitride, and a third sub-layer of tantalum. The capacitor structure further includes a sputtered dielectric layer of tantalum pentoxide over the tantalum sub-layer of the bottom electrode. The resulting structure is anodized such that the underlying tantalum layer is fully anodized, and preferably such that a portion of the tantalum nitride layer is converted to a tantalum oxy-nitride. The tantalum nitride layer was discovered by the inventors to act as a good high temperature diffusion barrier for the aluminum, preventing the aluminum from migrating into the anodized tantalum pentoxide layer under high temperature processing conditions, where it would chemically reduce the tantalum atoms in the tantalum pentoxide layer and introduce conductive paths of tantalum in the dielectric (tantalum pentoxide) layer. The aluminum layer provides good electrical conductivity for the bottom electrode, and is anodized to fill any pinhole defects in the layers formed above it, thereby increasing manufacturing yields.

Electric double layer capacitor and an assembled cell type power source device

Abstract: An electric double layer capacitor used as a unit capacitor for forming an assembled cell type power source device by connecting a plurality of capacitor elements in series, wherein each of the capacitor elements is formed by impregnating an electrolyte in at least one pair of polarization electrode sheets between which a separator is inserted, wherein a protective circuit in which a Zener diode each having an operation resistance of 10-150 Ω at the average operation voltage of the electric double layer capacitor are connected in parallel to each of the electric double layer capacitors.

Method for manufacturing dielectric capacitor, dielectric memory device

Abstract: A dielectric capacitor is provided which has a reduced leakage current. The surface of a first electrode (38) of the capacitor is electropolished and a dielectric film (40) and a second electrode (37) are successively laminated on it. The convex parts pointed end (38a) existing on the surface of the first electrode is very finely polished uniformly by dissolving according to electropolishing, a spherical curved surface in which the radius of curvature has been enlarged is formed, and the surface of the first electrode is flattened. Therefore, concentration of electrolysis can be prevented during the operation at the interface of the first electrode and the dielectric film, and the leakage current can be reduced considerably.

Thin film tantalum oxide capacitors and resulting product

Abstract: In accordance with the invention, a thin film capacitor including a dielectric of nitrogen or silicon-doped tantalum oxide and at least one electrode including chromium. Preferably the capacitor is fabricated by anodically oxidizing TaN x or Ta 2 Si and forming a Cr counterelectrode. The method is fully compatible with MCM processing. It produces anodic Ta 2 O 5 capacitors having exceptionally low leakage currents ( 4 MV/cm) and high capacitance densities (70 nF/cm 2 ). The devices are stable at 350° C. with excellent capacitor properties and are particularly useful as thin film capacitors of large area (>1 mm 2 ).

Ceramic capacitor and semiconductor device in which the ceramic capacitor is mounted

Abstract: In a capacitor, one capacitor electrode is formed on first principal face of a ceramic dielectric substrate. An area of a first capacitor electrode is smaller than an area of the first principal face. A second capacitor electrode is formed on a second principal face of the ceramic dielectric substrate, and connected to a lead electrode which is formed at the periphery of the first principal face of the ceramic dielectric substrate so as to be separated from the one capacitor electrode by a gap and to surround the first capacitor electrode. The ceramic capacitor is mounted on a semiconductor element through an insulating layer. The capacitor electrodes and lead electrode of the ceramic capacitor are connected to terminals of the semiconductor element by a wire bonding.

Study of tantalum oxide thin film capacitors on metallized polymer sheets for advanced packaging applications

Abstract: Tantalum oxide thin film capacitors were fabricated on metallized polyimide sheet substrates and tested. It was found that the substrates' surface topography has a strong influence on the electrical properties and yields of the thin film capacitors. The leakage current density and breakdown field strength of the capacitors are qualitatively correlated to the amount and degree of surface irregularities on the substrates, which were analyzed using scanning electron microscopy (SEM), atomic force microscopy (AFM), and profilometry. It was demonstrated that Benzocyclobutene (BCB) can be used to planarize the surface irregularities and to improve the capacitor yield and performance. The importance of choosing the right substrate materials for thin film capacitor fabrication is also discussed.

Structure for thin film capacitors

Abstract: A capacitor is fabricated on a base surface by applying a first pattern of electrical conductors (a first capacitor plate) over the base surface with an outer surface of the first pattern of electrical conductors including molybdenum. A first hard portion of a capacitor dielectric layer including amorphous hydrogenated carbon is deposited over the first capacitor plate and the base surface, a soft portion of the capacitor dielectric layer is deposited over the first hard portion, and a second hard portion of the capacitor dielectric layer is deposited over the soft portion. The deposition of the soft portion occurs at a lower bias voltage than the deposition of the first and second hard portions. A second pattern of electrical conductors (a second capacitor plate) is applied over the capacitor dielectric layer which is then patterned. A polymer layer is applied over the first and second capacitor plates, and two vias are formed, a first via extending to the first capacitor plate and a second via extending to the second capacitor plate. An electrode-coupling pattern of electrical conductors is applied over the polymer layer, a first portion extending into the first via and a second portion extending into the second via. Deposition of the capacitor dielectric layer can include using a methylethylketone precursor. Additional capacitor dielectric layers and plates having staggered via landing pads can be layered to increase the capacitance.

Multilayer capacitor including a dielectric breakdown prevention layer

Abstract: A multilayer capacitor capable of having reducing electrical field intensity at external electrode edges while preventing occurrence of surface dielectric breakdown. This multilayer capacitor has a capacitor main body which includes a capacitance formation section having alternately laminated pluralities of internal electrodes and dielectric layers, and outer dielectric layer sections laminated on the upper and lower surfaces of the capacitance formation section. The capacitor also has external electrodes formed on respective opposite external side surfaces of the capacitor main body and each connected to certain ones of the internal electrodes. The outer layer sections each have respective dielectric breakdown prevention layers therein, each of which exhibits a carefully designed relative dielectric constant e which is less than that of the dielectric layers in the capacitance formation section, and not more than 300, and has a thickness d μm! satisfying the relation: d>(0.2×e)+20.

Semiconductor device having high ferroelectric thin-film capacitor and manufacture thereof

Abstract: PROBLEM TO BE SOLVED: To increase the capacity of a capacitor, to lessen leakage current in the capacitor and moreover, to prevent the electrical performances of semiconductor active elements from being deteriorated by a method wherein a layer having a hydrogen diffusion stopping action is arranged between the capacitor and the elements at a region arranged with the capacitor. SOLUTION: A memory cell transistor 102 and a peripheral transistor 103 are respectively formed on a silicon substrate 101 as a semiconductor active element. There is an inter-layer insulating layer 104 for insulating electrically both a capacitor layer and a transistor layer from each other between the capacitor and transistor layers, and the capacitor and transistor layers are electrically connected with each other through plugs. Moreover, a hydrogen diffusion stopping layer 107, which is lower in the range of hydrogen diffusion than that of hydrogen diffusion in the layer 104 and consists of an insulator, is arranged between the layer 104 and the capacitor layer. The deterioration of a capacitor due to hydrogen which has diffused from the lateral direction of the capacitor is inhibited by the actions of a second plug 106 arranged under the lower part of the capacitor and the layer 107. COPYRIGHT: (C)1999,JPO

Semiconductor device with tantalum and ruthenium

Abstract: Disclosed is a semiconductor device, comprising a semiconductor substrate, a cell transistor formed in the semiconductor substrate, an interlayer dielectric film in which is formed a contact hole communicating with a part of the cell transistor, a contact plug buried in the contact hole formed in the interlayer dielectric film, a capacitor lower electrode formed of a ruthenium/tantalum laminate film consisting of a tantalum film and a ruthenium film formed on the tantalum film, the lower electrode being formed on interlayer dielectric film and connected to the contact plug, a capacitor dielectric film formed on the ruthenium film included in the capacitor lower electrode and consisting of a metal oxide, and a capacitor upper electrode formed on the capacitor dielectric film, the ruthenium film exhibiting (00n) dominant orientation, where n denotes a positive integer.

Dielectric thin film capacitor element

Abstract: The present invention provides a dielectric thin film capacitor element in which leak current may be suppressed from increasing over time while energizing at high temperature and which has excellent insulating quality and reliability and a manufacturing method thereof. The dielectric thin film capacitor element is constructed by forming a lower electrode, a dielectric thin film and an upper electrode one after another on a substrate, wherein the dielectric thin film capacitor element is characterized in that the dielectric thin film is made of an oxide material composed of at least titanium and strontium and containing erbium.

DC bus capacitor arrangement

Abstract: A capacitor arrangement across a direct current bus provides a high ripple current capability and high capacitance at a low cost. The circuit is used in electronic power conversion devices such as electric motor drives and inverters. A combination of film capacitors and electrolytic capacitors are used in the circuit and are placed across the dc bus. The film capacitors carry substantially all of the ripple current, while the electrolytic capacitors provide the majority of the capacitance. A resistor and a diode are used to isolate the electrolytic capacitors from the ripple current. This results in a low cost compact bus capacitor configuration.

Method of fabricating a semiconductor integrated circuit having a capacitor with lower electrode comprising titanium nitride

Abstract: In order to fabricate a semiconductor device having a stacked capacitor cell, a silicon substrate is first prepared. A lower capacitor electrode having a porous surface is then formed on the silicon substrate. Following this, the lower capacitor electrode is selectively covered with a titanium nitride film. Further, a dielectric film of a material, exhibiting high permittivity or feroelectricity, is deposited on said titanium nitride film, and an upper capacitor electrode is deposited on the dielectric film.

Multilayered solid electrolytic capacitor

Abstract: PROBLEM TO BE SOLVED: To provide a solid electrolytic capacitor, in which anodes of multiple solid electrolytic capacitor plates are directly connected to an anode lead frame without jointing different metallic plates to the anodes SOLUTION: A solid electrolytic capacitor plate is made by forming a conductive polymeric membrane layer as electrolyte on the surface of an aluminum plate which has been subjected to conversion treatment Multiple solid electrolytic capacitor plates are laminated An anode lead frame 1 is connected to their anodes, and a cathode lead frame 2 is connected to their cathodes to form a multilayered solid electrolytic capacitor In this case, a notch is formed on the aluminum plate on the anode of the solid electrolytic capacitor plate Also, the anode lead frame 1 is made of a metallic plate, and steps 1f and 1g are formed by bending a part of its extremity Multiple anode jointing surfaces 1h, 1i, 1j and 1k divided by the steps 1f and 1g are provided The anodes of the solid electrolytic capacitor plates are respectively jointed to the multiple anode jointing surfaces 1h, 1i, 1j and 1k to laminate the multiple solid electrolytic capacitor plates COPYRIGHT: (C)1999,JPO

Dry-etching-free process for high dielectric and ferroelectric memory cell capacitor

Abstract: Aims to provide a dielectric capacitor and a dielectric memory device wherein residue is minimal, electric current leakage is minimal, the shape is superior, is suited for enhancing the integration, and has favorable insulation property and an economical and efficient manufacturing method Dielectric capacitors CAP(1)-CAP(4)) which have bottom electrode 29, dielectric films 20 and 34 formed by contacting this bottom electrode, top electrode 23 formed by contacting this dielectric film, and insulation films 21 and 33 provided by contacting the periphery of bottom electrode 29, and wherein elimination part 17 is formed beforehand in said insulation film, bottom electrode 29 adhered at least within said elimination part is formed into smooth concave surface 29a or convex surface 29b according to etch back or chemical-mechanical polishing process, and dielectric film 20 is formed on this surface, dielectric memory devices M-CEL(1)-M-CEL(4) which have these dielectric capacitors, and a manufacturing method for these capacitors or memory cells

Aluminum electrode foil for electrolytic capacitor and electrolytic capacitor using the foil

Abstract: An aluminum electrode foil (1) for an electrolytic capacitor has a sponge-like etching layer (2) formed on at least one of the surfaces thereof, and the sponge-like etching layer is reduced in a direction of thickness. The aluminum density of the reduced sponge-like etching layer 'd2' is set from 0.8 to 2.2 g/cm 3 .

Method and device for manufacturing organic solid electrolytic capacitor

Abstract: PROBLEM TO BE SOLVED: To make a first aging treatment performable on the capacitor elements of an organic solid electrolytic capacitor, without deteriorating the productive efficiency even when a short-circuited capacitor element exists. SOLUTION: In a method for manufacturing organic solid electrolytic capacitor, the shells of capacitor elements 1 for an organic solid electrolytic capacitor, in which anode leads 10 are protruded from anode bodies and conductive layers 11 are arranged on cathode layers, are formed by performing the first aging treatment on the element 1 and the organic solid electrolytic capacitor is manufactured by performed the second aging treatment. The process for performing the first aging treatment in the manufacturing method includes a step of respectively arranging the elements 1 on a plurality of carbon sheet pieces 3 which are arranged in such a way that the pieces 3 are not electrically connected to each other so that the conductive layers 11 of the elements 1 may come into contact with the pieces 3, a set of connecting the anode lead 10 of each element 1 to the positive pole of a power source 6, a step of connecting each piece 3 to the negative pole of the power source 6 through a current limiter 5, and a step of impressing a voltage upon the elements 1 from the power source 6. COPYRIGHT: (C)1999,JPO

Aluminium electrolytic capacitors - a brief history

Abstract: The author discusses the theory of aluminium electrolytic capacitors and their manufacturing process. The raw materials-aluminium, electrolyte, spacers and other materials-are described. The electrical characteristics and their variation are outlined, as is expected capacitor life. (6 pages)

Method for manufacturing a solid electrolytic capacitor

Abstract: Cathode and anode sides of a plurality of solid electrolytic capacitors are connected by simultaneous electric welding. The welding step is effected to connect an anode lead of a lead frame to the anode electrode of a capacitor body and simultaneously connect a cathode lead of the lead frame to the cathode conductor layer of an adjacent capacitor body. The welding electrode for the cathode lead exerts moderate force to the capacitor bodies using a spring function of the capacitor lead. The simultaneous welding for the adjacent capacitor bodies and the moderate force prevent electrical and mechanical damages of the insulator layer of the solid electrolytic capacitors during the welding.

Discharge characteristics of high energy storage double layer capacitors

Abstract: The double-layer capacitor is a recent innovation that combines high surface area electrode materials with the high capacitance per unit area of the chemical double layer. Commercially available devices with a capacitance of 1500 F are now available (Matsushita, 1992). This improvement in rated capacitance has presented opportunities for the use of double layer capacitors in high power and/or high energy storage applications (Burke, 1995 and Hall, 1995). This paper examines the discharge performance characteristics of several capacitors, including both aqueous and organic electrolyte devices. A useful simplified model is assumed for the double layer capacitor, consisting of an equivalent series resistance (ESR) and a capacitor in series. Values for these two parameters are determined in this investigation under various discharge conditions, along with peak current during short circuit conditions.

Method and structure for integration of passive components on flexible film layers

Abstract: A method for fabricating a flexible interconnect film includes applying a resistor layer (16,18) over one or both surfaces of a dielectric film (10); applying a metallization layer (22) over the resistor layer with the resistor layer including a material facilitating adhesion of the dielectric film and the metallization layer; applying a capacitor dielectric layer (24a) over the metallization layer; and applying a capacitor electrode layer (26a) over the capacitor dielectric layer. The capacitor electrode layer is patterned to form a first capacitor electrode; the capacitor dielectric layer is patterned; the metallization layer is patterned to form a resistor (28); and the metallization layer and the resistor layer are patterned to form an inductor (33) and a second capacitor electrode. In one embodiment, the dielectric film includes a polyimide, the resistor layer includes tantalum nitride, and the capacitor dielectric layer includes amorphous hydrogenated carbon or tantalum oxide. If the resistor and metallization layers are applied over both surfaces of the dielectric film, passive components can be fabricated on both surfaces of the dielectric film. The dielectric film can have vias therein with the resistor and metallization layers extending through the vias. A circuit chip can be attached and coupled to the passive components by metallization patterned through vias in an additional dielectric layer.

Revolutionary approach in tantalum capacitor design which has made microminiature 0603 case size possible and improved electrical performance

Abstract: Present manufacturing technology is unable to manufacture a useful tantalum capacitor below the size of 0805. This paper reviews a breakthrough in manufacturing methodology which for the first time allows a 0603 (1.52/spl times/0.76 mm) capacitor to be manufactured with high volumetric efficiency and low equivalent series resistance (ESR). 4.7 /spl mu/F capacitors in the 0603 case size are now in production.

A 170 Volt Tantalum Hybrid™ Capacitor - Engineering Considerations

Abstract: The electrical performance of Hybrid capacitors (US Patent 5,369,547) using high capacitance density electrochemical capacitor cathodes, electrolytic capacitor anodes and dielectric, and compatible electrolytes is strongly influenced by the nature of the electrolyte employed and the physical characteristics of the electrodes. Management of overall capacitor performance usually involves optimizing one set of material properties against another. This work describes our efforts in producing a tantalum Hybrid capacitor with a 170 V working voltage.

Charge/discharge characteristics of prototype aluminum electrolytic capacitors

Abstract: Aluminum anode foils were subjected to constant current charge/discharge cycling in an electrolytic cell. From the voltage-time data, the charge and discharge energies and energy loss were calculated. The loss has a minimum value equal to the dissipation factor of the oxide dielectric and increases with the charge field. It depends on the oxide structure and details of the oxide formation process. A surprising observation is a significant dependence on the substrate morphology (etch structure). It is proposed that the high energy loss observed during this operating mode, and also during pulse discharge, is the result of frictional loss in the oxide film resulting from expansion of the oxide at high field and contraction at low field.

High voltage multilayer polymer capacitors fill technology gap

Abstract: Within the family of electrostatic polymer film capacitors, specially stacked or "multilayer polymer" types offer the highest power density and dv/dt pulse ratings. The original stacked film capacitors were developed for lower voltage applications and RFI suppression where good high frequency characteristics were required for noise attenuation. The trend over the last ten years has been to higher voltage systems to fill a technology gap wherein ceramic and tantalum capacitors are either not stable or reliable under application stresses. The demand for surface mount devices has fostered the multilayer polymer over conventional, wound film styles which are too heat sensitive or physically large for board mounting applications. Today chip and lead framed chip type multilayer polymer capacitors based upon an innovative technology are available from 25 to 500+ volts. Power train designers must calculate the parasitic losses of filter components to determine their real world ESR and ESL contribution. It is important to understand the stability of the filter components over the application parameters and use components that can be reliable under stresses such as the prescribed base plate temperature and peak voltage. ITW Paktron has introduced a series of multilayer polymer capacitors intended for high frequency current handling at relatively high voltage. Because of the polymer dielectric system used, the devices are stable under various combinations of voltages and power levels and have proven reliable in power train filtering and bypass applications.