Showing papers on "Tantalum capacitor published in 1980"

Tantalum thin film capacitor

Abstract: A tantalum film capacitor has an α-tantalum as a lower electrode, a chemical conversion layer of α-tantalum as a dielectric and an upper electrode, an improvement involving forming a highly nitrogen-doped tantalum film between the α-tantalum and a substrate, and also, another improvement involving forming a transitional thin tantalum layer between said highly nitrogen-doped tantalum film and said α-tantalum. The nitrogen concentration of the highly nitrogen-doped tantalum film is from 14 to 30 atomic %. The electrical properties, especially leakage current, are improved over those of the prior art. A disadvantage of the conventional α-tantalum thin film capacitor, that is the necessity of using an expensive partial glazed Al2 O3 substrate, is eliminated, and a non-glazed Al2 O3 substrate can be used in the present invention.

Alpha tantalum thin film circuit device

Abstract: Fabricating thin film RC networks (10) includes forming alpha tantalum capacitor base electrodes (14be) on a substrate (12), while simultaneously forming alpha tantalum anodization bus bars (14p and 14s) on the substrate. A portion of each base electrode (14be) then is anodized to form a capacitor dielectric (20) in a single anodizing step. A tantalum nitride resistor film (24) and electrically conductive films (26 and 28) then are deposited on the resultant assembly. Next, portions of the electrically conductive films are removed to define portions of capacitor counterelectrodes (22), to expose sections of the tantalum nitride resistor film (24) destined for use as resistors (24r). and to define conductor networks (30). Portions of the tantalum nitride resistor film (24) then are removed to define capacitor counterelectrode portions (24ce) and the resistors (24r), while simultaneously removing the anodization bus bars (14p and 14s). The resultant networks (10) then are thermally stabilized.

Ceramic power capacitor

Abstract: A multilayer, ceramic dielectric power capacitor made of plural layers of thin films of dielectric material having a thickness between 20 and 200 microns and a dielectric strength which is greater than that of thick layers, but which reduces the volume of the capacitor. Formed on each dielectric thin film is a conductive foil having a thickness between 2 and 10 microns. The thickness of the dielectric films is quite thin to reduce the volume of the capacitor, while that of the foils is thick, as compared to the prior art, to facilitate removal of heat. An anti-corona groove is provided to protect the connections at the capacitor terminals. The capacitor is useful in high frequency generator applications.

Monolithic hybrid integrated circuits

Abstract: A method of fabricating a thin film semiconductor hybrid circuit is disclosed. After processing of the integrated circuit in the semiconductor wafer up to the point of establishing ohmic contacts (14) to devices (13), a thin film RC circuit is fabricated on an insulating layer (11,12) overlying the wafer. This is accomplished by first forming the capacitor anodes (15') on the insulator by depositing and etching a layer such as alpha tantalum. Resistors (16) are then formed by depositing and etching a layer such as tantalum nitride. Portions of the capacitor anodes are then anodized using an appropriate mask (17) to form the capacitor dielectric. Capacitor counterelectrodes (20') and interconnect conductors (20'") are formed by depositing and etching successive layers of metal such as nickel-chromium and gold. After all thin film components are formed, the resistors and capacitors are stabilized by heating the circuit in an atmosphere comprising high pressure steam.

Electrical apparatus having an improved dielectric system

Abstract: An electrical apparatus, such as a capacitor, having an improved dielectric system. The capacitor includes alternate layers of metal foil and dielectric material which is impregnated with 1,1-bis(3,4-dimethylphenyl)ethane. The capacitor has improved corona characteristics and low dielectric losses. The liquid dielectric is biodegradable and environmentally acceptable.

Properties of Low Anodization Voltage Thin-Film Capacitors Based on alpha -Ta with Nitrogen Concentrations Between 14 and 30 Atomic Percent

Abstract: Tantalum oxide thin-film capacitors have been made with capacitance densities up to about a factor of three greater than those currently used for the fabrication of precision resistor-capacitor (RC) filters based on nitrogen-doped Ta films. This is accomplished by decreasing the dielectric thickness via reduction of the anodization voltage from 190 V to as low as 70 V. The dissipation factor, temperature coefficient of capacitance, and dc leakage current, after appropriate heat treatment, are only slightly higher than those of capacitors anodized at 190 V; however, the effects of nitrogen concentration in the alpha-Ta films become more significant. In addition, the expected long-term aging (20 years, 65°C) of capacitors anodized to either 90 V or 190 V is about equivalent.

Investigation of the Dissipation Process in Electrolytic Capacitors

Abstract: An experimental study of electrolytic capacitors was conducted, with emphasis on their thermal properties. The capacitors were subjected to charge–discharge cycles with various values of peak voltage. The observed power dissipated did not agree with that which would be expected if constant capacitance and constant effective series resistance (ESR) are assumed for the capacitors. In order to explain the discrepancy, the capacitance and ESR variations were measured with respect to voltage, temperature, and frequency. A predicted power dissipation was calculated for each capacitor; these dissipations compared favorably with those that were experimentally observed. In addition, voltage versus time profiles were measured for each unit and these were analyzed to determine the charge transport characteristics of the capacitors. The populations and mobilities of each type of charge carrier turned out to be quite similar from one capacitor sample to the next.

Method of welding tantalum lead wires to tantalum capacitor anodes

Abstract: This application relates to a method and apparatus for welding together small oxide coated components by driving a sharp edge or point of one part into a face of another part and then discharging electrical energy, for example, a capacitively stored electrical current through the joint. Precision micrometer control of the distance one part accelerates toward the other along with continuously adjustable spring tension are used to program the inelastic collision of the two parts. The electrical discharge circuit is controlled to provide a controlled arc after collision.

Capacitor with a metallised dielectric for high voltages.

Abstract: Wound metallised dielectric capacitors of cylindrical shape. This type of capacitor is the site of interior arcs due to defects in the dielectric, and which are useful for restoring the insulation of the capacitor by volatilisation, but which, in the case of high voltages, liberate excessive energy which can cause the destruction of the capacitor. The invention divides the conductive electrodes deposited on the dielectric into compartments (6) of limited area, with narrower regions forming either a fuse (7), or a current-limiting resistor, such as (4). The divisions are advantageously made by laser beam. Applications to the field of high-voltage circuits, typically greater than 100 volts.

Solid tantalum capacitor with clean riser

Abstract: The anode riser of a solid tantalum capacitor is cleaned by means of a laser beam which removes all coatings from the riser in the area of the weld between the riser and an external lead so as to leave no conducting path from the riser to the cathode.

Dielectric liquid composition used in an electrical capacitor

Abstract: An electrical capacitor having an improved dielectric system. The capacitor includes layers of metal foil and a dielectric sheet material which is impregnated with a liquid dielectric composition composed of a mixture of methyl diphenyl ethane and a lower alkyl diphenyl.

A tantalum thin film capacitor and process for producing the same

Abstract: In a tantalum thin film capacitor, comprising an a-tantalum as a lower electrode, a chemical conversion layer of a-tantalum as dielectrics and an upper electrode, an improvement which comprises forming a highly nitrogen-doped tantalum film between the a-tantalum and a substrate, and also, another improvement which comprises forming a transitional thin tantalum layer between said highly nitrogen-doped tantalum film and said a-tantalum. The nitrogen concentration of the highly nitrogen-doped tantalum film is from 14 to 30 atomic %. The electrical properties, especially leakage current, are improved over those of the prior art. A disadvantage of the conventional a-tantalum thin film capacitor, that is the necessity of using an expensive partial glazed Al 2 O 3 substrate, is eliminated, and a non-glazed Al 2 O 3 substrate can be used in the present invention.

Tantalum capacitors with internal current-limiting means

Abstract: An improved solid-electrolyte tantalum capacitor for decreasing the danger of tantalum capacitors fires. An opening is provided in the external protection of the capacitor to allow the evacuation of the solder providing the contact between the cathode lead and the cathode when molten.

Physical Interpretation of the Tantalum Chip Capacitor Life-Test Results

Abstract: Tantalum chip capacitors that survived accelerated life tests at 85°C and 2.5 times the rated voltage exhibited different dc electrical relationships prior to the accelerated life tests than did tantalum chip capacitors that failed the tests. This useful dc characterization may be interpreted in terms of the presence of an effcient blocking barrier between the MnO 2 cathode and the Ta 2 0 5 dielectric film in good capacitors and the absence of the barrier in defective capacitors.

Methods for mounting connection wires on a solid electrolyte capacitor

Abstract: A tantalum capacitor comprising a cylindrical body and an axial tantalum anode wire. This wire is first folded and then soldered to an anode connection wire roughly parallel to a cathode connection wire which is itself soldered to the body of this capacitor. The connection wires include preferably a double right-angled section so that the distance between the outward portions of this wire correspond to predetermined standards.

Mains rectifier has capacitor combined with diode - to form single integrated unit and with shared connections in housing

Abstract: The mains rectifier has at least one of its diodes connected to a capacitor with shared connections in a housing as a unit using known integrating techniques. Several such combined diode/capacitor units are combined with individual components (e.g. diodes) to form a bridge and located in a shared housing. The capacitor is a slid electrolyte tantalum capacitor (in chip form) and combined with the diode (Si crystal) and subsequently treated to produce a single integrated unit. Alternatively the capacitors in parallel with the diodes may be electrolytic and may form a combined capacitance with the charging capacitor in order to increase the bridge's efficiency.

A Method of Reducing Cost in the Production of High Stability Thin-Film RC Networks

Abstract: Several methods of producing RC thin-film hybrid integrated circuits have been described in the literature. A specific method presented in a paper by Duff et al. at the 1978 Electronic Component Conference utilized alpha tantalum to form the capacitors and tantalum nitride for the resistors to produce a high stability RC network. A significant modification of this process which allows for a reduction in cost while retaining the stable properties of alpha tantalum capacitors is described herein. Consideration in developing this method centered on quantifying the thermal effects on the capacitors and evaluating a modified counterelectrode metalization. The process developed, which is easily adaptable to large-scale manufacturing, is simplified by reducing both the number of metal depositions and photolithographic steps. The capacitor properties and long-term reliability are shown to be at least equivalent to those of capacitors made using other processes.

Design of an Internal Fuse for a High-Frequency Solid Tantalum Capacitor

Abstract: A miniature fuse module was designed and incorporated into a solid tantalum capacitor for high-frequency bypass applications. The fuse consists of a fine bimetallic wire which reacts exothermically upon reaching a critical initiation temperature. It is housed in an electrically and thermally insulative body to minimize fusing energy. The desirability of having fused devices is discussed. Design constraints, in particular those design considerations which minimize inductance and series resistance while optimizing fusing characteristics, are presented. Construction techniques to produce fuse assemblies and join them to capacitors are reviewed, and parametric measurements of fused and unfused devices are compared. Factors affecting the amount of energy required to actuate the fuse and the reliability of actuation are identified. Typically, fuse actuation occurs within 25 ms of short circuit capacitor failure and requires between 1.5 and 2.5 A to initiate with the total energy used being less than 150 mJ. A device can now be produced that withstands switching and transient surges without incident while protecting circuits and equipment from disruption and damage caused by short circut capacitor failures.

Solid electrolyte capacitor - comprising dielectric oxide layer coated with sintered valve metal anode, semiconducting oxide cathode covered with graphite and metal layer

Abstract: Solid electrolyte capacitor which consists of a dielectric oxide layer provided with a sintered valve metal anode and a semiconducting metal oxide as cathode, which is covered with a graphite layer and a metallic conductive layer serving as current lead, is described in which this layer is interspersed with a framework of insulating particles. The layer may also contain reactants. The capacitor is placed in a metal can and sealed in with a plastics filling, esp. epoxy resin. In the event of shorting out of the capacitor due to breakdown an insulating skin remains present on the anode preventing the breakout of fire locally, which may produce distortion in neighbouring components, which in turn may lead to further breakdown. The insulating framework has an elastic or plastic structure which protects the anode against stress during assembly and against the effects of thermal work.