Showing papers on "Tantalum capacitor published in 2005"

Lifetime of Electrolytic Capacitors in Regenerative Induction Motor Drives

Abstract: Electrolytic capacitors are normally used as the energy storage element in the DC link of voltage-source converters because of their high density. Unfortunately, they are bulky and their lifetime is significantly reduced by their operating temperatures. Thus, reducing, or even better eliminating, the amount of electrolytic capacitors is an important goal since the capacitor could be a single point of failure. This paper analyses the lifetime of electrolytic capacitors used in the DC link of an induction motor (IM) drive whose front end consists of a controlled rectifier. The latter controls the DC-link voltage and input power factor. Both, the inverter and rectifier operate under space vector modulation (SVM). The peak ripple voltage, ripple current, core temperature and lifetime of electrolytic capacitors ranging from 200 muF to 12000 muF are calculated for different values of the source inductance and the ambient temperature when the IM is operating at rated load. In addition, the IM ripple torque and speed response time are also calculated and an 8.2 muF ceramic capacitor case is included for completeness. The evaluation is based on Matlabtrade/Simulink simulation results of the IM drive that are used to calculate harmonic components of the different current waveforms. The results show that the lifetime of electrolytic capacitors is significantly reduced for decreasing capacitance values. The main reason is that the effective series resistance (ESR), and hence heat losses, increases for decreasing capacitance values leading to increased core temperatures that are detrimental to the capacitor lifetime

Hafnium-doped tantalum oxide high-k dielectrics with sub-2 nm equivalent oxide thickness

Abstract: Hafnium-doped tantalum oxide high dielectric constant films, i.e., with an equivalent oxide thickness as low as 1.3 nm, have been prepared and studied. The doped film has a bulk layer dielectric constant greater than 28 and an interface layer (formed with silicon substrate) dielectric constant greater than 8. The doping process changed the bulk and the interface layer structures as well as energy band gaps. The postdeposition annealing atmosphere showed major impacts on material and electrical properties. The new high-k material is a viable gate dielectric film for future metal-oxide-semiconductor transistors.

Flat back case for an electrolytic capacitor

Abstract: An enclosure for an electrical energy storage device such as a wet tantalum electrolytic capacitor or an electrochemical cell such as a lithium/silver vanadium oxide cell is described. The enclosure comprises two metallic casing components or portions. The first is a drawn member having a planar face wall supporting a surrounding sidewall and is shaped to nest the anode, cathode and intermediate separator components. The surrounding sidewall has an annular flange at its outer periphery. A mating cover is a stamped planar piece of similar material whose periphery fits inside the annular flange or rim as a complementary piece.

Flat panel display with high capacitance and method of manufacturing the same

Abstract: A flat panel display device having a high capacitance and a high aperture ratio. A thin film transistor and a capacitor are formed on an insulating substrate. The thin film transistor includes a semiconductor layer, a gate electrode and source and drain electrodes. The capacitor has first and second capacitor electrodes and a dielectric layer. An insulating layer is formed over the transistor to insulate the gate electrode from the source and drain electrodes, and a portion of the insulating layer is formed as the dielectric layer between the first and second capacitor electrodes. A non-planar shape of the first capacitor electrode and a conforming shape of the dielectric layer and a second capacitor electrode increase a capacitance of the capacitor. The portion of the insulating layer serving as the capacitor dielectric is formed to be thinner than the portion of the insulating layer formed over the gate electrode.

Porous Anode Body For Solid Electrolytic Capacitor, Production Method Thereof and Solid Electrolytic Capacitor

Abstract: The invention provides a method of manufacturing a porous anode for a solid electrolytic capacitor, comprising a step of subjecting a molded body containing powder of at least one material selected from oxygen-containing niobium material and oxygen-containing tantalum material and a pore-forming agent which is solid at reduction temperature to reduction reaction using reducing agent and another step of removing the pore-forming agent from the reduction reaction product and a solid electrolytic capacitor using an anode obtained thereby. As niobium material and tantalum material, at least one material selected from niobium, niobium alloy, niobium compound, tantalum, tantalum alloy and tantalum compound is used respectively. In the invention, the peak position, the number and quantity of pores can be optimized according to the cathode agent used, whereby a solid electrolytic capacitor having an improved property for impregnation with cathode agent, high capacitance, low ESR, good tan δ characteristics and long-term reliability, is obtained.

Film capacitors with improved dielectric properties

Abstract: A film capacitor (10) including a first electrode (12) is provided. The film capacitor (10) also includes a first dielectric layer (14) having a first dielectric constant disposed upon a first electrode (12) and a second dielectric layer (16) having a second dielectric constant disposed upon the first dielectric layer (14), wherein the second dielectric constant is at least fifty percent greater than the first dielectric constant. It further includes a second electrode disposed upon the second dielectric layer (16).

Capacitors with high energy storage density and low esr

Abstract: Electrostatic capacitors with high capacitance density and high-energy storage are implemented over conventional electrolytic capacitor anode substrates using highly conformal contact layers deposited by atomic layer deposition. Capacitor films that are suitable for energy storage, electrical and electronics circuits, and for integration onto PC boards endure long lifetime and high-temperature operation range.

Structure of an interleaving striped capacitor substrate

Abstract: An interleaving striped capacitor substrate structure for pressing-type print circuit boards is disclosed. To meet the high-frequency, high-speed, and high-density requirements in modern electronic systems, the interleaving striped capacitor substrate structure uses several dielectric materials of different dielectric coefficients to make a dielectric layer. One dielectric layer can be stacked on another to form a multi-layered capacitor substrate so that a single capacitor substrate can provide the highest capacitance required for the decoupling capacitor to suppress high-frequency noise signals, and the lower dielectric coefficient substrate required for high-speed signal transmission. This simultaneously achieves the effects of reducing high-frequency transmission time and suppressing high-frequency noise.

Multilayer ceramic capacitor and its production method

Abstract: The invention aims to provide a multilayer ceramic capacitor with high dielectric constant, a high capacitance, and an excellent reliability by eliminating oxygen vacancy in dielectric layers and suppressing oxidation of Ni inner electrodes. The multilayer ceramic capacitor comprises a multilayered dielectric body composed by alternately piling up dielectric layers containing mainly barium titanate and inner electrode layers containing mainly Ni and a first hetero-phase containing Mg—Si—O as constituent elements exists in the capacitor.

Electrolytic capacitor failure prediction of LC filter for switching-mode power converters

Abstract: The objective of this paper is to propose a new method to detect the rise of equivalent series resistor (ESR) in order to realize the on-line failure prediction of the electrolytic capacitor for LC filter of switching-mode power converter. Characteristics of electrolytic capacitors are introduced in this paper. Different experimental measurements are conducted and shown to illustrate the properties of electrolytic capacitors. The proposed on-line failure prediction method has the merits of low cost and circuit simplicity. Hardware experimental results are shown to verify the performance of the proposed method.

Metal-insulator-metal capacitor structure having low voltage dependence

Abstract: A semiconductor capacitor device. A dielectric layer is on a substrate. A stack capacitor structure is disposed in the dielectric layer and comprises first and overlying second MIM capacitors electrically connected in parallel. The first and second MIM capacitors have individual upper and lower electrode plates and different compositions of capacitor dielectric layers.

Capacitor, circuit board with built-in capacitor and method of manufacturing the same

Abstract: In a capacitor 10, a first electrode 21, a dielectric layer 23, a solid electrolytic layer 50 and a second electrode 31 are provided. In a manufacturing process, the dielectric layer 23 and a first solid electrolytic layer 24 formed by a chemical polymerization film are provided on the first electrode 21 side, while a second solid electrolytic layer 32 formed by an electrolytic polymerization film is provided on the second electrode 31 side. Then, the solid electrolytic layers are bonded to each other.

Method of electrolytic deposition of an intrinsically conductive polymer upon a non-conductive substrate

Abstract: A capacitor and method for manufacturing the capacitor. The capacitor comprises an anode; a dielectric oxide layer coated on the anode and a plurality of conductive islands coated on the dielectric oxide layer. An organic conductive cathode is coated on the dielectric layer and conductive islands.

Analog capacitor and method of manufacturing the same

Abstract: An analog capacitor capable of reducing the influence of an applied voltage on a capacitance and a method of manufacturing the analog capacitor are provided. The analog capacitor includes a lower electrode which is formed on a substrate, a multi-layered dielectric layer which includes at least one oxide layer and at least one oxynitride layer which are formed of a material selected from the group consisting of Hf, Al, Zr, La, Ba, Sr, Ti, Pb, Bi and a combination thereof and is formed on the lower electrode, and an upper electrode which is formed on the multi-layered dielectric layer.

Wet electrolytic capacitor

Abstract: The electrolytic capacitor and the electric double-layer capacitor both have difficulties to satisfy recent demands that the capacitor should have lower resistance, larger capacitance and moreover smaller size and thinner film thickness, altogether. The present invention provides a wet electrolytic capacitor which comprises a porous anode substance wherein at least a surface of a porous material made of a powder of a valve metal is an oxide film of the valve metal, a cathode formed of either an active carbon layer or a porous material made of a powder of a valve metal and an acid electrolytic solution contained between the porous anode substance and the cathode electrode.

Method of fabricating analog capacitor using post-treatment technique

Abstract: There is provided a method of fabricating an analog capacitor using a post-treatment technique. The method includes forming a lower insulating layer on a semiconductor substrate. A bottom electrode is formed on the lower insulating layer, and a capacitor dielectric layer is formed on the bottom electrode. Then, the capacitor dielectric layer is post-treated in a deoxidizing medium. Then, the post-treated capacitor dielectric layer is post-treated in an oxidizing medium. A top electrode is formed on the post-treated capacitor dielectric layer. The analog capacitor fabricated through the post-treatment as above has a low VCC.

Capacitor element and carbon paste

Abstract: The present invention provides a capacitor wherein increase in the ESR value after a high temperature loading test is mitigated. A capacitor element, comprising an electric conductor having formed on the surface thereof a dielectric layer as one electrode, and a semiconductor layer, carbon layer and electrode layer formed sequentially on the dielectric layer, which capacitor element is characterized in that the carbon layer contains a dopant; a carbon paste as a material of the capacitor element; a capacitor using the capacitor element; and an electronic circuit and an electronic device using the capacitor.

Dielectric ceramics, multilayer ceramic capacitor and method for manufacturing the same

Abstract: Crystal grains mainly composed of barium titanate have a mean grain size of not more than 0.2 μm. The volume per unit cell V that is represented by a product of lattice constant (a, b, c) figured out from the X-ray diffraction pattern of the crystal grains is not more than 0.0643 nm 3 . Thereby, a dielectric ceramics having high relative dielectric constant can be obtained. A multilayer ceramic capacitor comprises a capacitor body and an external electrode that is formed at both ends of the capacitor body. The capacitor body comprises dielectric layers composed of the dielectric ceramics, and internal electrode layers. The dielectric layers and the internal electrode layers are alternately laminated.

Ripple Current Reduction of DC Link Electrolytic Capacitors by Switching Pattern Optimisation

Abstract: The use of electrolytic capacitors in automotive applications is critical. High ambient temperatures lower lifetime and reliability, while further disadvantages arise from costs and installation space. The presented work shows a method to reduce the capacitor ripple current, which accordingly leads to a reduced demand on DC link electrolytic capacitors. The proposed method is based on applying an optimised switching pattern to the power transistors. Thereby, the ripple current can be reduced to approximately one third compared to conventional PWM signals. The optimisation is also described graphically, and measurements verify the practicability

Integrated circuit (ic) with high-q on-chip discrete capacitors

Abstract: A semiconductor structure that may be a discrete capacitor, a Silicon On Insulator (SOI) Integrated Circuit (IC) including circuits with discrete such capacitors and/or decoupled by such discrete capacitors and an on-chip decoupling capacitor (decap). One capacitor plate may be a well (N-well or P-well) in a silicon bulk layer or a thickened portion of a surface silicon layer. The other capacitor plate may be doped polysilicon and separated from the first capacitor plate by capacitor dielectric, e.g., CVD or thermal oxide. Contacts to each of the capacitor plates directly connect and extend from the respective plates, such that direct contact is available from both plates.

High temperature-resistant niobium wire

Abstract: High temperature-resistant niobium wire enriched with phosphorous is suitable as a connecting wire for niobium, niobium oxide, or tantalum capacitors.

An experimental technique for estimating the aluminum electrolytic capacitor equivalent circuit, at high frequencies

Abstract: This paper presents an experimental technique that allows the determination of the equivalent circuit of an aluminium electrolytic capacitor. The impedance of these electrolytic capacitors changes with frequency, becoming approximately equal to a resistance near their resonance frequency. This resistance, the equivalent series resistance (ESR), becomes one of the most critical problems of static converters, which operate near the resonant frequency of the capacitor. The ESR leads to a significant increase in the alternating (AC) component of the output voltage, requiring a constant action of the control system. To validate this technique some experimental and simulated results are presented

Multi-layered solid electrolytic capacitor and method of manufacturing same

Abstract: A multi-layered solid electrolytic capacitor and a method of manufacturing the capacitor that improve the product yield drastically by preventing increases in leakage current and defects due to short circuits without increasing manufacturing cost or capacitor size. A multi-layered solid electrolytic capacitor includes: a plurality of capacitor elements, each including an aluminum foil having an anode portion and a cathode portion having a dielectric oxide film and a cathode layer formed in succession on a surface of the aluminum foil, wherein the plurality of capacitor elements are stacked on top of one another, the anode portions of adjacent capacitor elements are welded each other, and the anode portion of one of the outermost capacitor elements is weld-secured to an anode terminal, the multi-layered solid electrolytic capacitor having a first stress alleviating groove and a second stress alleviating groove formed in at least one of weld surfaces of the anode portion.

High capacitance tantalum flakes and methods of producing the same

Abstract: Methods of maximizing a tantalum capacitor's capacitance are disclosed, as well as tantalum flake powder and anodes. A two step milling process can be used to mill tantalum particles into tantalum flake powder having flakes of the desired thickness. This flake powder can then be pressed and sintered thereby forming an anode. Other flake capacitance methods and products are also described.

Methods of forming metal-insulator-metal (MIM) capacitors with separate seed and main dielectric layers and MIM capacitors so formed

Abstract: A metal-oxy-nitride seed dielectric layer can be formed on a metal-nitride lower electrode of a meta-insulator-metal (MIM) type capacitor. The metal-oxy-nitride seed dielectric layer can act as a barrier layer to reduce a reaction with the metal-nitride lower electrode during, for example, backend processing used to form upper levels of metallization/structures in an integrated circuit including the MIM type capacitor. Nitrogen included in the metal-oxy-nitride seed dielectric layer can reduce the type of reaction, which may occur in conventional type MIM capacitors. A metal-oxide main dielectric layer can be formed on the metal-oxy-nitride seed dielectric layer and can remain separate from the metal-oxy-nitride seed dielectric layer in the MIM type capacitor. The metal-oxide main dielectric layer can be stabilized (using, for example, a thermal or plasma treatment) to remove defects (such as carbon) therefrom and to adjust the stoichiometry of the metal-oxide main dielectric layer.

Preparation and Characterization of Barium Titanate Electrolytic Capacitors from Porous Titanium Anodes

Abstract: BaTiO 3 is widely used as the dielectric in ceramic chip capacitors and multilayer capacitors, because of its high dielectric constant and ferroelectric properties. Multilayer capacitors provide fairly high capacitance per unit volume (volumetric efficiency); however, processing difficulties in the preparation of ultrathin layers limit further enhancement. Tantalum solid electrolytic capacitors, on the other hand, provide very high volumetric efficiencies, because of the large surface area of the sintered, porous tantalum anode on which the dielectric Ta 2 O 5 is electrochemically deposited. Recent developments in electrochemical methods to deposit BaTiO 3 on titanium substrates provide an opportunity to fabricate barium titanate electrolytic capacitors using sintered, porous titanium anodes. The high dielectric constant of BaTiO 3 and the high surface area of the sintered, porous anode provide a good combination to achieve larger volumetric efficiencies. Current work involves the fabrication and characterization of barium titanate electrolytic capacitors. Effects of electrochemical processing parameters on the formation of BaTiO 3 on the surface of sintered titanium anodes are described. Influence of the purity of titanium powder, the porosity of the sintered anode, and the post-deposition heat treatment on the dielectric properties of the fabricated capacitors is discussed. Complete penetration of the electrolyte solution and a thin uniform coating of TaTiO 3 over the entire titanium surface was achieved using high-porosity (35%-40% of theoretical density) sintered titanium anodes. Samples treated for 8 h in 0.5M Ba(OH) 2 .8H 2 O electrolyte solutions at 100°C with an applied cell voltage of 12 V show the formation of a dense, uniform BaTiO 3 coating on the surface of the titanium anode. High-purity, chloride-free titanium powder provides smaller dissipation factors at low frequencies. Heat treatment at 400°C significantly increases the capacitance at all frequencies, whereas the heat treatment lowers the dissipation factors at low frequencies. Calculated volumetric efficiencies are comparable to those typically obtained for tantalum solid electrolytic capacitors but are not as high as expected for barium titanate electrolytic capacitors. Penetration of the colloidal-carbon (external) electrode was limited to a depth of -300 μm, which might have caused the lower volumetric efficiencies.

Solid electrolytic capacitor with first and second anode wires

Abstract: A solid electrolytic capacitor (A1) includes a first and a second anode terminals (11 a, 11 b) projecting in different directions from each other. Preferably, a metal cover (22) for electrically connecting the anode terminals (11 a, 11 b) to each other is provided. With such an arrangement, the ESR and the ESL can be reduced, and the high frequency characteristics can be enhanced.

Plasma treatment of anodic oxides for electrolytic capacitors

Abstract: An oxygen plasma process for treating a dielectric oxide layer, particularly an anodic oxide, subsequent to its incorporation into an electrolytic capacitor is described. The present treatment reduces DC leakage and improves shelf life stability of the resulting capacitor in comparison to anodic oxides treated in a conventional manner. This is important for critical applications such as implantable cardioverter defibrillators where capacitor charging time and charge/discharge energy efficiency are critical.

Capacitors, methods of forming capacitors, and methods of forming capacitor dielectric layers

Abstract: A method of forming a capacitor includes forming first and second capacitor electrodes over a substrate. A capacitor dielectric region is formed intermediate the first and second capacitor electrodes, and includes forming a silicon nitride comprising layer over the first capacitor electrode. A silicon oxide comprising layer is formed over the silicon nitride comprising layer. The silicon oxide comprising layer is exposed to an activated nitrogen species generated from a nitrogen-containing plasma effective to introduce nitrogen into at least an outermost portion of the silicon oxide comprising layer. Silicon nitride is formed therefrom effective to increase a dielectric constant of the dielectric region from what it was prior to said exposing. Capacitors and methods of forming capacitor dielectric layers are also disclosed.

Powder metallurgical processing and metal purity: A case for capacitor grade sintered tantalum

Abstract: The paper reviews the role of sintered tantalum as volumetric efficient electrical capacitor Powder characteristics and sintering aspects are discussed The role of impurities in influencing the electrical properties has been described Today’s driving force behind the Ta market is the use of surface mounted versions known as chip types, for applications requiring a wide range of operational temperature, such as automotive electronics