Showing papers on "Tantalum capacitor published in 1982"

Laser annealed dielectric for dual dielectric capacitor

Abstract: A thin film capacitor having a high dielectric constant and low leakage current includes a dual dielectric structure. The dual dielectric comprises a leakage current blocking first dielectric layer and a high dielectric constant second dielectric layer. The high dielectric constant second dielectric layer is formed by laser annealing a ferroelectric forming titanate or zirconate into a ferroelectric. A leakage current blocking first dielectric layer may also serve as an antireflective coating for the titanate or zirconate layer so that better coupling of the laser energy to the titanate or zirconate layer is obtained.

Lumped passive components and method of manufacture

Abstract: Lumped passive components including a capacitor having a silicon nitride dielectric, a tantalum film resistor, and a capacitor having a tantalum oxide dielectric are formed on a semi-insulating substrate by first providing an insulating layer, here of silicon nitride, over the substrate and metal contacts having previously been formed on such substrate. The metal contacts provide a first plate for each one of such capacitors. A tantalum layer is reactively sputtered on the insulating layer, and a protective masking layer is next provided on such tantalum layer. An area where the anodized tantalum capacitor is to be formed is then opened in the protective masking layer over a selected one of the metal contacts. A portion of the tantalum is anodized in such area to form an area of a tantalum oxide (Ta 2 O 5 ). The area where the tantalum oxide is formed is confined generally to the area in the tantalum layer over the contact. The masking layer is removed and a second masking layer is patterned to provide an etching mask used to etch the tantalum layer to define each one of such capacitors, and to provide a strip of tantalum, defining a region for said tantalum resistor. Top metal contacts are then provided aligned with the first set of such contacts, and thus providing a second metal plate of the anodized tantalum capacitor and a second metal plate of the silicon nitride capacitor. Further, a set of metal contacts is provided to each end of the tantalum strip to provide the tantalum resistor.

Tantalum oxide capacitors for GaAs monolithic integrated circuits

Abstract: The performance of a high-yield tantalum oxide capacitor for use in GaAs monolithic microwave integrated circuits is described. The integral metal-insulator-metal sandwich structure is reactively sputter-deposited at low temperatures, compatible with a photoresist lift-off process, on semi-insulating GaAs substrate. Dielectric constants of 20-25 were achieved in the capacitors fabricated. An initial application of this process as an interstage coupling capacitor for a two-stage preamplifier is given.

Base metal conductor cathode coating for tantalum capacitors

Abstract: Cathodic coating for tantalum capacitors containing (a) a mixture of finely divided copper and tin or tin alloy particles dispersed in a solution of (b) organic acid flux, and (c) organic amine in (d) inert organic medium.

Polyglycol dielectric capacitor fluid

Abstract: Polypropylene glycol dielectric fluids are used to impregnate electrical capacitors and particularly metallized capacitors for improved performance.

CMOS Bridge for capacitive pressure transducers

Abstract: A fixed reference capacitance (10) and a variable, pressure sensitive capacitance (12) are defined by a common conductive layer (14), and a common dielectric layer (16). A peripheral conductive layer 20 completes the reference capacitor and a central conductive layer (22) completes the variable capacitor. A peripheral supporting layer or structure (18) prevents the thickness or the dielectric constant of the dielectric layer peripheral portion but not the central portion from varying in response to pressure changes. In this manner, the reference and variable capacitors may be placed closely adjacent without pressure isolating the reference capacitor. An oscillator (30) provides an AC, such as square wave, driving signal to first and second temporary storage capacitors (52, 54). A bridge (70) of CMOS transistors selectively connects the first and second storage capacitors with the reference and variable capacitors. A gating control circuit (90) selectively gates the CMOS transistors of the bridge conductive and nonconductive such that during a positive square wave half cycle, the first storage capacitor is connected with the reference capacitor and the second storage capacitor is connected with the variable capacitor and during a negative half cycle the first storage capacitor is connected with the variable capacitor and the second storage capacitor is connected with the reference capacitor.

Method of forming tantalum capacitor anodes and making the capacitors

Abstract: A solid tantalum electrolytic capacitor is formed by a method comprising anodizing a tantalum sintered body for substantial dielectric film growth in a substantially aqueous electrolyte; anodically treating said anodized tantalum body in at least one fused salt selected from the group of nitrates of alkali metals, nitrates of alkaline earth metals and nitrites of alkali metals with an applied voltage which is as high as possible but within a range wherein capacitance-decrease of the anode formed in the aqueous electrolyte is not caused; and anodically treating said fused salt-treated tantalum body in a substantially aqueous electrolyte with an applied voltage which is as high as possible but within a range wherein re-anodization will not occur, the temperature of said fused salt being in the range of 250° C. to 350° C.

Electroplating method for producing porous tantalum capacitor electrode

Abstract: A tantalum wire is coated along part of its length with a high-surface-area electro deposit of tantalum from a molten K-salt. This process is relatively very simple and produces an openly porous tantalum sponge having exceptionally high purity for use as an anode in a tantalum capacitor.

Method for 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.

Tantalum capacitor lead connections - has nickel lead wave solders onto preheated silver coated cathode in continuous process

Abstract: The successive operations are as follows; one conducting lead is spot welded to the other existing component lead (16). The cathode lead is nickel and the anode lead is tantalum and the nickel lead is bent round and supported on a flexible adhesive band which is driven (4) in a production chain. Next, the cathode and connecting wire (36) are preheated by infrared to between 80 and 90 deg.C. The body is then wave fluxed with a resin flux and wave soldered to the lead (36) with lead tin soldered at below 200 deg.C. The thickness of the solder (6) is continuously adjacent and the joint cleaned to remove traces of flux with trichloroethylene. The body of the capacitor (1a) is the cathode and is formed from manganese dioxide coated with graphite and that coated with silver. The dielectric is tantalum pentoxide.

Arrangement having tantalum capacitors which are mounted flat on a printed-circuit board

Abstract: In order to mount a tantalum capacitor (1) having a solid electrolyte in a space-saving manner and such that it is resistant to acceleration on a base (7) having conductor tracks (8, 9), a lead wire (4) is welded via a crossover to the anode connecting wire (3), which lead wire is firmly connected to a conductor track (8), and the cathode connecting layer (2) is additionally connected to the corresponding conductor track (9) via flexible gold wires (10). The latter may also be wound around the anode connecting layer in the form of screw turns.

Solid electrolyte capacitor mfr. esp. tantalum capacitors - where anode is formed by stack of thin sintered tantalum discs

Abstract: Several modular anode discs are made by sintering a metal powder. The discs are made into a stack to obtain an anode; and an electric connection, esp. a wire, is attached to the stack, which is then subjected to a second sintering operation. The connector wire may be located on the periphery of the stack, or in coaxial holes in the discs. The connector wire is pref. welded to the top and bottom discs in the stack or to all of the discs; and a powder may be located between the wiRe and the discs. The discs, wire and powder pref. all consist of tantalum. Capacitors with optimum properties are obtd. at relatively low cost.

Tantalum capacitor and suspension for applying silver layers in this capacitor

Abstract: A suspension for applying silver layers in tantalum capacitors is proposed, which is readily wettable by solder, in particular molten soldering tin, and is not worn down by the formation of alloys. The suspension contains fine silver particles and polystyrene as a binder in an organic solvent. A tantalum capacitor is also proposed, whose tantalum anode is coated with an oxide layer, a semiconductor layer, a carbon layer, a silver layer and a solder layer, the silver layer containing polystyrene as binder.