EP1410410A1 - Electroceramic component, multi-layer capacitor and method for production of the multi-layer capacitor - Google Patents

Electroceramic component, multi-layer capacitor and method for production of the multi-layer capacitor

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Publication number
EP1410410A1
EP1410410A1 EP02729916A EP02729916A EP1410410A1 EP 1410410 A1 EP1410410 A1 EP 1410410A1 EP 02729916 A EP02729916 A EP 02729916A EP 02729916 A EP02729916 A EP 02729916A EP 1410410 A1 EP1410410 A1 EP 1410410A1
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EP
European Patent Office
Prior art keywords
ceramic
layers
layer
base body
capacitor according
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP02729916A
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German (de)
French (fr)
Inventor
Lutz Kirsten
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
TDK Electronics AG
Original Assignee
Epcos AG
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Filing date
Publication date
Application filed by Epcos AG filed Critical Epcos AG
Publication of EP1410410A1 publication Critical patent/EP1410410A1/en
Withdrawn legal-status Critical Current

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
    • H01G4/00—Fixed capacitors; Processes of their manufacture
    • H01G4/002—Details
    • H01G4/018—Dielectrics
    • H01G4/06—Solid dielectrics
    • H01G4/08—Inorganic dielectrics
    • H01G4/12—Ceramic dielectrics
    • H01G4/1209—Ceramic dielectrics characterised by the ceramic dielectric material
    • H01G4/1254—Ceramic dielectrics characterised by the ceramic dielectric material based on niobium or tungsteen, tantalum oxides or niobates, tantalates
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B18/00—Layered products essentially comprising ceramics, e.g. refractory products
    • C—CHEMISTRY; METALLURGY
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    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
    • C04B35/495—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on vanadium, niobium, tantalum, molybdenum or tungsten oxides or solid solutions thereof with other oxides, e.g. vanadates, niobates, tantalates, molybdates or tungstates
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    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/626—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B
    • C04B35/62605—Treating the starting powders individually or as mixtures
    • C04B35/6261—Milling
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    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/626—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B
    • C04B35/62605—Treating the starting powders individually or as mixtures
    • C04B35/62625—Wet mixtures
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    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/626—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B
    • C04B35/62605—Treating the starting powders individually or as mixtures
    • C04B35/62645—Thermal treatment of powders or mixtures thereof other than sintering
    • C04B35/6265—Thermal treatment of powders or mixtures thereof other than sintering involving reduction or oxidation
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    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/626—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B
    • C04B35/63—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B using additives specially adapted for forming the products, e.g.. binder binders
    • C04B35/6303—Inorganic additives
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2311/00—Metals, their alloys or their compounds
    • B32B2311/02—Noble metals
    • B32B2311/08—Silver
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    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/30—Constituents and secondary phases not being of a fibrous nature
    • C04B2235/32—Metal oxides, mixed metal oxides, or oxide-forming salts thereof, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
    • C04B2235/3231—Refractory metal oxides, their mixed metal oxides, or oxide-forming salts thereof
    • C04B2235/3251—Niobium oxides, niobates, tantalum oxides, tantalates, or oxide-forming salts thereof
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    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/30—Constituents and secondary phases not being of a fibrous nature
    • C04B2235/32—Metal oxides, mixed metal oxides, or oxide-forming salts thereof, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
    • C04B2235/3289—Noble metal oxides
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    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/30—Constituents and secondary phases not being of a fibrous nature
    • C04B2235/32—Metal oxides, mixed metal oxides, or oxide-forming salts thereof, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
    • C04B2235/3289—Noble metal oxides
    • C04B2235/3291—Silver oxides
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
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    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/30—Constituents and secondary phases not being of a fibrous nature
    • C04B2235/34—Non-metal oxides, non-metal mixed oxides, or salts thereof that form the non-metal oxides upon heating, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
    • C04B2235/3409—Boron oxide, borates, boric acids, or oxide forming salts thereof, e.g. borax
    • C—CHEMISTRY; METALLURGY
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    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/50—Constituents or additives of the starting mixture chosen for their shape or used because of their shape or their physical appearance
    • C04B2235/54—Particle size related information
    • C04B2235/5418—Particle size related information expressed by the size of the particles or aggregates thereof
    • C04B2235/5436—Particle size related information expressed by the size of the particles or aggregates thereof micrometer sized, i.e. from 1 to 100 micron
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    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/65—Aspects relating to heat treatments of ceramic bodies such as green ceramics or pre-sintered ceramics, e.g. burning, sintering or melting processes
    • C04B2235/658—Atmosphere during thermal treatment
    • C04B2235/6583—Oxygen containing atmosphere, e.g. with changing oxygen pressures
    • C04B2235/6585—Oxygen containing atmosphere, e.g. with changing oxygen pressures at an oxygen percentage above that of air
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    • C04B2237/00—Aspects relating to ceramic laminates or to joining of ceramic articles with other articles by heating
    • C04B2237/30—Composition of layers of ceramic laminates or of ceramic or metallic articles to be joined by heating, e.g. Si substrates
    • C04B2237/40—Metallic
    • C—CHEMISTRY; METALLURGY
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    • C04B2237/00—Aspects relating to ceramic laminates or to joining of ceramic articles with other articles by heating
    • C04B2237/30—Composition of layers of ceramic laminates or of ceramic or metallic articles to be joined by heating, e.g. Si substrates
    • C04B2237/40—Metallic
    • C04B2237/408—Noble metals, e.g. palladium, platina or silver
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
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    • C04B2237/00—Aspects relating to ceramic laminates or to joining of ceramic articles with other articles by heating
    • C04B2237/50—Processing aspects relating to ceramic laminates or to the joining of ceramic articles with other articles by heating
    • C04B2237/70—Forming laminates or joined articles comprising layers of a specific, unusual thickness
    • C04B2237/704—Forming laminates or joined articles comprising layers of a specific, unusual thickness of one or more of the ceramic layers or articles

Definitions

  • the invention relates to a multilayer capacitor with a base body which is formed by a stack of layers lying one above the other with at least one ceramic dielectric layer and an electrode layer and in which the surface of the base body has two contact layers.
  • the known multilayer capacitors have the disadvantage that the ceramic used in the capacitor has a relatively low dielectric constant. As a result, capacitors with high capacities are produced Capacities of relatively large sizes are required. This is undesirable in the course of the progressive miniaturization of the electrical components, particularly in the mobile radio sector.
  • the aim of the present invention is therefore to provide a multilayer capacitor which allows high capacities to be achieved with small sizes at the same time.
  • the invention specifies a multilayer capacitor which has a base body.
  • the basic body is formed by a stack of superimposed layers. At least one of these layers is a ceramic dielectric layer. At least another of these layers is an electrically conductive electrode layer.
  • the surface of the base body has two contact layers. One of the dielectric layers has a dielectric constant e that is greater than 440.
  • e is the vacuum dielectric constant
  • A is the area of the opposing capacitor plates and d is the distance between the capacitor plates.
  • e is the dielectric constant of the dielectric arranged between the capacitor plates. Due to the high dielectric constant e> 440, a higher capacitance C of the component can be achieved with a constant plate capacitor area A or with constant spacing d of the capacitor plates. Conversely, the same capacitance C can be achieved with the aid of a component which has smaller geometric dimensions, which is determined by the area A of the capacitor plates or by the distance d of the capacitor plates from one another.
  • a dielectric layer contains a perovskite ceramic of the composition Ag (Nb ⁇ _ x Ta x ) O3. Furthermore, an electrode layer contains a metallic noble metal. This precious metal can be silver, for example.
  • the dielectric layers and the electrode layers of the layer stack forming the base body are sintered together.
  • Perovskite ceramics of the stated composition have been described according to the prior art, where only disk-shaped ceramic samples have been described and measured, in connection with smaller dielectric constants.
  • the construction of a multilayer capacitor and the joint sintering of the perovskite ceramic in conjunction with noble metal-containing electrode layers means that the perovskite ceramic has a significantly increased dielectric constant.
  • directly adjacent electrode layers are electrically conductively contacted. This results in a structure of two intermeshing combs with respect to the electrode layers, whereby individual capacitors formed by two adjacent electrode layers and the dielectric layer in between are connected in parallel with one another, whereby the capacitance of the multilayer capacitor can be increased.
  • a dielectric layer contains boric acid as a sintering aid in order to improve the sintering properties.
  • the invention specifies a method for producing the multilayer capacitor according to the invention, which has the following steps:
  • Process steps c) and f) are carried out in an atmosphere which has an increased oxygen content compared to normal ambient air.
  • Carrying out the process steps in an atmosphere with an increased oxygen content A has the advantage that the stability of the ceramic produced therewith is increased. It is important here that all process steps which take place after the addition of the silver and which take place at temperatures which are higher than room temperature are carried out in an atmosphere with an increased oxygen content.
  • Increased oxygen content means an increased oxygen content compared to air which has an oxygen content of approximately 21% by volume. The oxygen content must therefore be greater than 21%.
  • the mixture of the oxides Nb2Ü5 and Ta2Ü5 or their thermal treatment has the advantage that a mutual diffusion between the different oxides can take place.
  • the ceramic material in the dielectric layer is a single-phase perovskite ceramic as the main component. This has the advantage that the dielectric layers can be produced relatively easily, since, for example, different phases of one or more ceramic materials do not have to be produced.
  • FIG. 1 shows an example of a multilayer capacitor according to the invention in a schematic perspective illustration.
  • FIG. 2 shows the dependency of the relative change in the capacitance of various multilayer capacitors according to the invention as a function of the temperature.
  • FIG. 1 shows a multilayer capacitor which contains a stack 1 of layers 2, 3 lying one above the other. Dielectric layers 2 are alternately stacked together with electrode layers 3. Contact layers 4, 5 are applied to opposite outer sides of the layer stack 1.
  • the dielectric layers 2 are produced on the basis of a perovskite ceramic with the composition Ag (Nbg s ⁇ Tag 42) 03.
  • the exemplary ceramic thus has an x of
  • the dielectric layers have a thickness of approximately 14 ⁇ m in the sintered state.
  • the electrode layers are applied in the form of a screen printing paste to the dielectric layers which are still in the form of a green sheet at the start of production.
  • the electrode layers alternately have free edges 6 at their end of the base body 1 adjacent to the contact layer 4 or adjacent to the contact layer 5, on which the relevant electrode layer is not guided all the way to the edge of the layer stack. As a result, each electrode layer 3 is only contacted with one contact layer 4, 5. This creates for the electrode layer ten 3 the structure of interlocking combs, whereby the capacitance of the capacitor can be increased.
  • the contact layers 4, 5 have each been applied in the form of silver baking pastes to an end face of the base body 1 of the multilayer capacitor.
  • ⁇ C / C_ stands for the maximum relative change in the capacitance of the capacitor in the temperature interval between -25 ° C and + 25 ° C and ⁇ C / C + for the maximum relative change in the capacitance in the temperature interval between + 25 ° C and + 85 ° C, each given in percent and based on the capacitance of the capacitor at a temperature of 25 ° C.
  • Table 2 Electrical properties of various multilayer capacitors according to the invention, measured at a frequency of 1 kHz
  • FIG. 2 shows the relative change ⁇ C / C in the capacitance in relation to the capacitance of the capacitor at the temperature of 25 ° C. in the temperature range between -25 ° C. and + 85 ° C. for samples 1, 2 and 3.
  • Curve K1 relates to sample 1, curve K2 to sample 2 and curve K3 to sample 3.
  • the temperature dependence of the capacitance weakens with an increasing number of internal electrodes (see also table).
  • the changes in capacitance measured in the capacitors produced according to the exemplary embodiment do not meet the requirements of the C0G characteristic, according to which the capacitance may change by a maximum of 0.6% in the temperature interval from -55 ° C. to + 125 ° C.
  • the capacitors according to the invention have temperature coefficients for capacitance (TKC) which are in the order of magnitude of the COG characteristic.
  • the ceramic material is sintered together with a metallic noble metal in order to increase the dielectric constant of the ceramic material.
  • the precious metal can be silver, for example. From this, advantageous electro-ceramic components can also be provided without internal electrodes but only with contact layers arranged on the base body.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Ceramic Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Inorganic Chemistry (AREA)
  • Structural Engineering (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Power Engineering (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Ceramic Capacitors (AREA)
  • Fixed Capacitors And Capacitor Manufacturing Machines (AREA)

Abstract

The invention relates to a multi-layer capacitor with a base body (1), formed from a stack of superimposed layers (2, 3), with at least one dielectric layer (2) and an electrode layer (3), whereby the surface of the base body (1) comprises two contact layers (4, 5) and one dielectric layer (2) has a dielectric constant ∈ greater than 440. Said capacitor has the advantage of comprising a high dielectric constant and can thus be constructed in small sizes with high capacitance. The invention further relates to a method for the production of said multi-layer condenser and an electroceramic component.

Description

Beschreibungdescription
Elektrokeramiscb.es Bauelement, Vielschichtkondensator und Verfahren zur Herstellung des VielschichtkondensatorsElektrokeramiscb.es component, multilayer capacitor and method for producing the multilayer capacitor
Die Erfindung betrifft einen Vielschichtkondensator mit einem Grundkörper, der von einem Stapel aus übereinanderliegenden Schichten mit wenigstens einer keramischen Dielektrikumschicht und einer Elektrodenschicht gebildet ist und bei dem die Oberfläche des Grundkörpers zwei Kontaktschichten aufweist .The invention relates to a multilayer capacitor with a base body which is formed by a stack of layers lying one above the other with at least one ceramic dielectric layer and an electrode layer and in which the surface of the base body has two contact layers.
Aus der Druckschrift . Valant, D. Suvorov, "Microwave Cera- mics with Permittivity over 400", The 9th International Mee- ting on Ferroelectricity, Seoul, South Korea, 1997, Abstract Book, P-05-TH-067 sind Vielschichtkondensatoren bekannt, deren Dielektrikumschichten eine Keramik aufweisen, denen eine Niob-basierte perovskitartige "Solid-Solution" mit der allgemeinen Formel A (B]__xNbx) O3 zugrunde liegt. Es wurde gefunden, daß solche Keramiken sich durch eine hohe Dielektrizitätskonstante e «= 400 auszeichnen. Darüber hinaus weisen diese Keramikmaterialien bei niedrigen Frequenzen zwischen 100 kHz und 1 MHz geeignete dielektrische Eigenschaften auf, so daß sie für den Einsatz in Vielschichtkondensatoren geeignet sind.From the publication. Valant, D. Suvorov, "Microwave Ceramics with Permittivity over 400", The 9th International Meeting on Ferroelectricity, Seoul, South Korea, 1997, Abstract Book, P-05-TH-067, multilayer capacitors are known, the dielectric layers of which are one Have ceramics based on a niobium-based perovskite-like "solid solution" with the general formula A (B ] __ x Nb x ) O3. It has been found that such ceramics are distinguished by a high dielectric constant e <= 400. In addition, these ceramic materials have suitable dielectric properties at low frequencies between 100 kHz and 1 MHz, so that they are suitable for use in multilayer capacitors.
Aus der Druckschrift A. Kania, Ag (Nbι_xTax) O3 Solid Solutions - Dielectric Properties and Phase Transitions, Phase Transitions, 1983, Volume 3, p . 131 bis 140, ist ein Keramikmaterial bekannt, das auf der Basis von Silber, Niob und Tantal, im folgenden ANT genannt, hergestellt ist und das in Form einer "Solid Solution" der beiden Materialien AgNbC>3 und AgTaO vorliegt. Die in dieser Druckschrift beschriebene Keramik weist die Zusammensetzung Ag (Nb]__xTax) O3 / im folgenden ANTx genannt, auf, wobei x zwischen 0 und 0,7 variieren kann. Je nach Zusammensetzung weist die Keramik bei einer Temperatur von etwa 300 K ein e zwischen 80 und 400 auf. Aus der Druckschrift Matjaz Valant, Danilo Suvorov, New High- Permittivity Ag (Nb]__xTax) O3 Microwave Ceramics : Part 2, Dielectric Characteristics, J. Am. Ceram. Soc . 82 [1], pp. 88 - 93 (1999) ist es bekannt, daß scheibenförmige Kera- mikkörper aus ANTx mit einem x-Parameter zwischen 0,46 und 0,54 eine starke relative Änderung der Dielektrizitätskonstanten e im Temperaturintervall zwischen -20 °C und 120 °C aufweisen. Dabei wurde insbesondere gezeigt, daß der Verlauf der relativen Änderung von e mit der Temperatur einer Kurve folgt, die zwischen 20 °C und 70 °C ein Maximum aufweist und Werte zwischen -0,07 und 0,01 annimmt. Die Dielektrizitätskonstante e beträgt dabei zwischen 360 und 415, abhängig vom Tantalgehalt der Keramik.From the publication A. Kania, Ag (Nbι_ x Ta x ) O3 Solid Solutions - Dielectric Properties and Phase Transitions, Phase Transitions, 1983, Volume 3, p. 131 to 140, a ceramic material is known which is produced on the basis of silver, niobium and tantalum, hereinafter called ANT, and which is in the form of a "solid solution" of the two materials AgNbC> 3 and AgTaO. The ceramic described in this publication has the composition Ag (Nb] __ x Ta x ) O3 / hereinafter referred to as ANTx, where x can vary between 0 and 0.7. Depending on the composition, the ceramic exhibits an e between 80 and 400 at a temperature of around 300 K. From the publication Matjaz Valant, Danilo Suvorov, New High-Permittivity Ag (Nb] __ x Ta x ) O3 Microwave Ceramics: Part 2, Dielectric Characteristics, J. Am. Ceram. Soc. 82 [1], pp. 88-93 (1999) it is known that disk-shaped ceramic bodies made of ANTx with an x parameter between 0.46 and 0.54 have a strong relative change in the dielectric constant e in the temperature interval between -20 ° C. and 120 ° C. It was shown in particular that the course of the relative change in e with temperature follows a curve that has a maximum between 20 ° C. and 70 ° C. and takes values between -0.07 and 0.01. The dielectric constant e is between 360 and 415, depending on the tantalum content of the ceramic.
Aus der Druckschrift DE 196 53 792 AI sind Vielschichtkondensatoren bekannt, bei denen die Dielektrikumschichten aus verschiedenen Keramikmaterialien bestehen, wodurch verschiedene Temperaturkoeffizienten miteinander ausgeglichen werden können. Diese Kondensatoren haben den Nachteil, daß zu ihrer Herstellung die Erzeugung verschiedener keramischer Materialien und ein dementsprechend hoher Aufwand notwendig ist. Die verwendeten Keramiken basieren dabei zum einen auf Strontium- titanat beziehungsweise auf Strontiumtitanat mit Legierungen (TKC negativ) . Andererseits werden als Dielektrika mit posi- tiven Temperaturkoeffizienten Materialien auf der Basis von Tantaloxidmangantitanat verwendet .From the publication DE 196 53 792 AI multilayer capacitors are known in which the dielectric layers consist of different ceramic materials, whereby different temperature coefficients can be compensated for. These capacitors have the disadvantage that the production of various ceramic materials and a correspondingly high outlay are necessary for their manufacture. The ceramics used are based on strontium titanate and strontium titanate with alloys (TKC negative). On the other hand, materials based on tantalum oxide mangantitanate are used as dielectrics with positive temperature coefficients.
Ferner ist aus der Druckschrift WO 98/03446 bekannt, daß durch Dotierung von ANT mit Lithium, Wolfram, Mangan oder Wismut der Temperaturkoeffizient der Dielektrizitätskonstanten TKe bei einzelnen Temperaturen auf sehr kleine Werte bis zu +/-70 ppm/K reduziert werden kann.It is also known from the publication WO 98/03446 that by doping ANT with lithium, tungsten, manganese or bismuth the temperature coefficient of the dielectric constant TKe can be reduced to very small values of up to +/- 70 ppm / K at individual temperatures.
Die bekannten Vielschichtkondensatoren haben den Nachteil, daß die zur Anwendung kommende Keramik in dem Kondensator eine relativ kleine Dielektrizitätskonstante aufweist. Dies hat zur Folge, daß zur Herstellung von Kondensatoren mit hohen Kapazitäten relativ große Baugrößen erforderlich sind. Dies ist im Zuge der fortschreitenden Miniaturisierung der elektrischen Bauelemente, insbesondere auf dem Mobilfunksektor, unerwünscht .The known multilayer capacitors have the disadvantage that the ceramic used in the capacitor has a relatively low dielectric constant. As a result, capacitors with high capacities are produced Capacities of relatively large sizes are required. This is undesirable in the course of the progressive miniaturization of the electrical components, particularly in the mobile radio sector.
Ziel der vorliegenden Erfindung ist es daher, einen Vielschichtkondensator anzugeben, der es erlaubt, hohe Kapazitäten bei gleichzeitig kleinen Baugrößen zu realisieren.The aim of the present invention is therefore to provide a multilayer capacitor which allows high capacities to be achieved with small sizes at the same time.
Dieses Ziel wird erfindungsgemäß durch einen Vielschichtkondensator nach Patentanspruch 1 erreicht. Vorteilhafte Ausgestaltungen der Erfindung und ein Verfahren zur Herstellung des Vielschichtkondensators sind den weiteren Patentansprüchen zu entnehmen .This goal is achieved according to the invention by a multilayer capacitor according to claim 1. Advantageous refinements of the invention and a method for producing the multilayer capacitor can be found in the further patent claims.
Die Erfindung gibt einen Vielschichtkondensator an, der einen Grundkörper aufweist. Der Grundkorper ist von einem Stapel aus übereinanderllegenden Schichten gebildet. Wenigstens eine dieser Schichten ist eine keramische Dielektrikumschicht. We- nigstens eine weitere dieser Schichten ist eine elektrisch leitfähige Elektrodenschicht. Die Oberfläche des Grundkörpers weist zwei Kontaktschichten auf. Eine der Dielektrikumschichten weist eine Dielektrizitätskonstante e auf, die größer als 440 ist.The invention specifies a multilayer capacitor which has a base body. The basic body is formed by a stack of superimposed layers. At least one of these layers is a ceramic dielectric layer. At least another of these layers is an electrically conductive electrode layer. The surface of the base body has two contact layers. One of the dielectric layers has a dielectric constant e that is greater than 440.
Für die Kapazität eines Plattenkondensators gilt :The following applies to the capacitance of a plate capacitor:
C = 6 ■ 60 • - dC = 6 ■ 6 0 • - d
wobei e die Vakuum-Dielektrizitätskonstante, A die Fläche der einander gegenüberliegenden Kondensatorplatten und d der Abstand der Kondensatorplatten voneinander ist. e ist die Dielektrizitätskonstante des zwischen den Kondensatorplatten angeordneten Dielektrikums . Aufgrund der hohen Dielektrizitätskonstante e > 440 kann bei gleichbleibender Plattenkondensatorflache A beziehungsweise bei gleichbleibendem Abstand d der Kondensatorplatten eine höhere Kapazität C des Bauelements erreicht werden. Umgekehrt kann dieselbe Kapazität C mit Hilfe eines Bauelements erreicht werden, das kleinere geometrische Dimensionen aufweist, die durch die Fläche A der Kondensatorplatten beziehungsweise durch den Abstand d der Kondensatorplatten voneinander bestimmt ist.where e is the vacuum dielectric constant, A is the area of the opposing capacitor plates and d is the distance between the capacitor plates. e is the dielectric constant of the dielectric arranged between the capacitor plates. Due to the high dielectric constant e> 440, a higher capacitance C of the component can be achieved with a constant plate capacitor area A or with constant spacing d of the capacitor plates. Conversely, the same capacitance C can be achieved with the aid of a component which has smaller geometric dimensions, which is determined by the area A of the capacitor plates or by the distance d of the capacitor plates from one another.
In einer vorteilhaften Ausführungsform der Erfindung enthält eine Dielektrikumschicht eine Perovskitkeramik der Zusammensetzung Ag (Nbι_xTax) O3. Ferner enthält eine Elektrodenschicht ein metallisches Edelmetall. Dieses Edelmetall kann bei- spielsweise Silber sein. Zudem sind die Dielektrikumschichten und die Elektrodenschichten des den Grundkörper bildenden Schichtstapels gemeinsam gesintert.In an advantageous embodiment of the invention, a dielectric layer contains a perovskite ceramic of the composition Ag (Nbι_ x Ta x ) O3. Furthermore, an electrode layer contains a metallic noble metal. This precious metal can be silver, for example. In addition, the dielectric layers and the electrode layers of the layer stack forming the base body are sintered together.
Perovskitkeramiken der genannten Zusammensetzung sind nach dem Stand der Technik, wo ausschließlich scheibenförmige Keramikproben beschrieben und vermessen worden sind, in Zusammenhang mit kleineren Dielektrizitätskonstanten beschrieben worden. Überraschenderweise wird durch den Aufbau eines Viel- schichtkondensators und durch die Gemeinsamsinterung der ge- nannten Perovskitkeramik in Verbindung mit edelmetallhaltigen Elektrodenschichten erreicht, daß die Perovskitkeramik eine deutlich erhöhte Dielektrizitätskonstante aufweist.Perovskite ceramics of the stated composition have been described according to the prior art, where only disk-shaped ceramic samples have been described and measured, in connection with smaller dielectric constants. Surprisingly, the construction of a multilayer capacitor and the joint sintering of the perovskite ceramic in conjunction with noble metal-containing electrode layers means that the perovskite ceramic has a significantly increased dielectric constant.
Desweiteren ist es vorteilhaft, wenn für den Parameter x in der oben angegebenen Zusammensetzung gilt:Furthermore, it is advantageous if the following applies to parameter x in the composition given above:
0,5 ≤ l - x ≤ 0,7.0.5 ≤ l - x ≤ 0.7.
Dadurch wird der Vorteil erreicht, daß die Änderung der Kapa- zität des Kondensators mit der Temperatur relativ gering ist. Desweiteren ist es für die Erfindung vorteilhaft, wenn die Zahl der Elektrodenschichten größer als zehn ist. Es hat sich bei der Herstellung verschiedener Vielschichtkondensatoren gezeigt, daß mit zunehmender Anzahl von Innenelektroden die Dielektrizitätskonstante des Kondensators weiter ansteigt.This has the advantage that the change in the capacitance of the capacitor with the temperature is relatively small. Furthermore, it is advantageous for the invention if the number of electrode layers is greater than ten. It has been shown in the manufacture of various multilayer capacitors that the dielectric constant of the capacitor increases further with an increasing number of internal electrodes.
In einer weiteren Ausführungsform der Erfindung sind direkt benachbarte Elektrodenschichten mit jeweils einer verschiedenen KontaktSchicht elektrisch leitend kontaktiert. Dadurch entsteht bezüglich der Elektrodenschichten eine Struktur von zwei nach dem Reißverschluß-Prinzip ineinandergreifenden Kämmen, wodurch durch zwei benachbarte Elektrodenschichten und der dazwischenliegenden Dielektrikumschicht gebildete Einzel- kondensatoren miteinander parallel geschaltet sind, wodurch die Kapazität des Vielschichtkondensators erhöht werden kann.In a further embodiment of the invention, directly adjacent electrode layers, each with a different contact layer, are electrically conductively contacted. This results in a structure of two intermeshing combs with respect to the electrode layers, whereby individual capacitors formed by two adjacent electrode layers and the dielectric layer in between are connected in parallel with one another, whereby the capacitance of the multilayer capacitor can be increased.
Desweiteren ist es vorteilhaft, wenn zur Verbesserung der Sintereigenschaften eine Dielektrikumschicht als Sinterhilfsmittel Borsäure enthält .Furthermore, it is advantageous if a dielectric layer contains boric acid as a sintering aid in order to improve the sintering properties.
Desweiteren gibt die Erfindung ein Verfahren zur Herstellung des erfindungsgemäßen Vielschichtkondensators an, das folgende Schritte aufweist:Furthermore, the invention specifies a method for producing the multilayer capacitor according to the invention, which has the following steps:
a) Herstellen einer ersten Mischung aus Nb2Ü5 und Ta2θ5 unda) Preparation of a first mixture of Nb2Ü5 and Ta2θ5 and
Kalzinieren der ersten Mischung zur Bildung eines PrecursorsCalcining the first mixture to form a precursor
b) Vermischen von Ag2θ und H3BO3 mit dem Precursor zur Bildung einer zweiten Mischungb) Mixing Ag2θ and H3BO3 with the precursor to form a second mixture
c) Kalzination der zweiten Mischungc) calcination of the second mixture
d) Herstellen von keramischen Folien aus der zweiten Mischungd) producing ceramic films from the second mixture
e) Übereinanderstapeln von keramischen Folien und Elektrodenschichten f) Sintern des Folienstapelse) stacking of ceramic foils and electrode layers f) sintering the film stack
g) Aufbringen von Kontaktschichteng) Application of contact layers
Dabei werden die Verfahrensschritte c) und f) in einer Atmosphäre durchgeführt, die einen gegenüber normaler Umgebungsluft erhöhten Sauerstoffgehalt ausweist. Insbesondere ist es vorteilhaft, die genannten Verfahrensschritte in reiner Sauerstoffatmosphäre durchzuführen. Die Durchführung der Verfah- rensschritte in einer Atmosphäre mit erhöhtem Sauerstoffgehalt A hat den Vorteil, daß die Stabilität der damit hergestellten Keramik erhöht wird. Es kommt hierbei darauf an, daß sämtliche Verfahrensschritte, die nach der Zugabe des Silbers erfolgen und die bei gegenüber Raumtemperatur erhöhten Tempe- raturen ablaufen, in einer Atmosphäre mit erhöhtem Sauerstoffgehalt durchgeführt werden. Erhöhter Sauerstoffgehalt bedeutet einen gegenüber Luft, die einen Sauerstoffgehalt von zirka 21 Volumen-% aufweist, erhöhten Sauerstoffgehalt . Der Sauerstoffgehalt muß also größer als 21 % sein.Process steps c) and f) are carried out in an atmosphere which has an increased oxygen content compared to normal ambient air. In particular, it is advantageous to carry out the process steps mentioned in a pure oxygen atmosphere. Carrying out the process steps in an atmosphere with an increased oxygen content A has the advantage that the stability of the ceramic produced therewith is increased. It is important here that all process steps which take place after the addition of the silver and which take place at temperatures which are higher than room temperature are carried out in an atmosphere with an increased oxygen content. Increased oxygen content means an increased oxygen content compared to air which has an oxygen content of approximately 21% by volume. The oxygen content must therefore be greater than 21%.
Die Mischung der Oxide Nb2Ü5 und Ta2Ü5 beziehungsweise deren thermische Behandlung hat den Vorteil, daß eine wechselseitige Diffusion zwischen den verschiedenen Oxiden stattfinden kann.The mixture of the oxides Nb2Ü5 and Ta2Ü5 or their thermal treatment has the advantage that a mutual diffusion between the different oxides can take place.
Vorteilhaft ist es zudem, wenn das Keramikmaterial in der Dielektrikumschicht als Hauptkomponente eine einphasige Perovskitkeramik ist. Dies hat den Vorteil, daß die Dielektrikumschichten relativ einfach hergestellt werden können, da beispielsweise nicht verschiedene Phasen eines oder mehrerer Keramikmaterialien hergestellt werden müssen.It is also advantageous if the ceramic material in the dielectric layer is a single-phase perovskite ceramic as the main component. This has the advantage that the dielectric layers can be produced relatively easily, since, for example, different phases of one or more ceramic materials do not have to be produced.
Ein beispielhaftes Verfahren zur Herstellung eines erfindungsgemäßen Vielschichtkondensators ist der folgenden Tabel- le zu entnehmen: Tabelle 1An example of a method for producing a multilayer capacitor according to the invention can be found in the following table: Table 1
Ablauf der Keramikherstellung für die ANTx-Keramik beziehungsweise Herstellung eines erfindungsgemäßen Vielschicht- kondensatorsSequence of ceramic production for the ANTx ceramic or production of a multilayer capacitor according to the invention
Im folgenden wird die Erfindung anhand von Ausführungsbei- spielen und den dazugehörigen Figuren näher erläutert . Figur 1 zeigt beispielhaft einen erfindungsgemäßen Vielschichtkondensator in einer schematischen perspektivischen Darstellung .The invention is explained in more detail below with the aid of exemplary embodiments and the associated figures. FIG. 1 shows an example of a multilayer capacitor according to the invention in a schematic perspective illustration.
Figur 2 zeigt die Abhängigkeit der relativen Änderung der Kapazität verschiedener erfindungsgemäßer Vielschichtkondensatoren in Abhängigkeit von der Temperatur.FIG. 2 shows the dependency of the relative change in the capacitance of various multilayer capacitors according to the invention as a function of the temperature.
Figur 1 zeigt einen Vielschichtkondensator, der einen Stapel 1 von übereinanderliegenden Schichten 2, 3 enthält. Dabei sind Dielektrikumschichten 2 abwechselnd mit Elektrodenschichten 3 miteinander verstapelt. An gegenüberliegenden Außenseiten des Schichtstapels 1 sind Kontaktschichten 4, 5 aufgebracht. Figur 1 zeigt eine spezielle Bauform eines Viel- Schichtkondensators mit den Abmessungen: Länge = 1,25 mm, Breite = 2 mm und Höhe = 0,8 mm.FIG. 1 shows a multilayer capacitor which contains a stack 1 of layers 2, 3 lying one above the other. Dielectric layers 2 are alternately stacked together with electrode layers 3. Contact layers 4, 5 are applied to opposite outer sides of the layer stack 1. Figure 1 shows a special design of a multi-layer capacitor with the dimensions: length = 1.25 mm, width = 2 mm and height = 0.8 mm.
Die Dielektrikumschichten 2 sind auf der Basis einer Perovskitkeramik der Zusammensetzung Ag(Nbg sβTag 42)03 her- gestellt. Die beispielhafte Keramik weist somit ein x vonThe dielectric layers 2 are produced on the basis of a perovskite ceramic with the composition Ag (Nbg sβTag 42) 03. The exemplary ceramic thus has an x of
0,42 auf. Dieser Keramik ist additiv noch 1 Gew.-% H3BO3 zugefügt worden. Die Dielektrikumschichten weisen dabei eine Dicke von etwa 14 μm im gesinterten Zustand auf. Die Elektrodenschichten bestehen aus einer Paste, die eine Mischung aus Silber und Palladium im Gewichtsverhältnis von Ag/Pd = 70/30 enthält. Es kann auch ein anderes Gewichtsverhältnis gewählt werden. Wichtig ist lediglich, daß der Silbergehalt größer als 60 % ist. Die Elektrodenschichten werden in Form einer Siebdruckpaste auf die zu Beginn der Herstellung noch in Form einer Grünfolie vorliegenden Dielektrikumschichten aufgebracht. Die Elektrodenschichten weisen abwechselnd an ihrem der Kontaktschicht 4 angrenzenden beziehungsweise an der Kontaktschicht 5 angrenzenden Ende des Grundkörpers 1 Freiränder 6 auf, an denen die betreffende Elektrodenschicht nicht bis ganz zum Rand des Schichtstapels geführt ist. Dadurch ist jede Elektrodenschicht 3 nur mit jeweils einer KontaktSchicht 4, 5 kontaktiert. Dadurch entsteht für die Elektrodenschich- ten 3 die Struktur von ineinandergreifenden Kämmen, wodurch die Kapazität des Kondensators erhöht werden kann.0.42. 1% by weight of H3BO3 was added to this ceramic. The dielectric layers have a thickness of approximately 14 μm in the sintered state. The electrode layers consist of a paste that contains a mixture of silver and palladium in a weight ratio of Ag / Pd = 70/30. Another weight ratio can also be selected. It is only important that the silver content is greater than 60%. The electrode layers are applied in the form of a screen printing paste to the dielectric layers which are still in the form of a green sheet at the start of production. The electrode layers alternately have free edges 6 at their end of the base body 1 adjacent to the contact layer 4 or adjacent to the contact layer 5, on which the relevant electrode layer is not guided all the way to the edge of the layer stack. As a result, each electrode layer 3 is only contacted with one contact layer 4, 5. This creates for the electrode layer ten 3 the structure of interlocking combs, whereby the capacitance of the capacitor can be increased.
Die Kontaktschichten 4, 5 sind in Form von Silbereinbrennpa- sten jeweils auf eine Stirnseite des Grundkörpers 1 des Vielschichtkondensators aufgebracht worden.The contact layers 4, 5 have each been applied in the form of silver baking pastes to an end face of the base body 1 of the multilayer capacitor.
Es wurden basierend auf der zur Figur 1 beschriebenen Perovskitkeramik elektrische VielSchichtbauelemente mit einer unterschiedlichen Anzahl von Elektrodenschichten hergestellt. Die Anzahl der Elektrodenschichten ist gleich der Anzahl der Innenelektroden. Die folgende Tabelle 1 zeigt im Überblick die elektrischen Eigenschaften der hergestellten Vielschichtkondensatoren im Vergleich. Dabei steht in der ersten Spalte die Nummer der entsprechenden Probe. Desweiteren steht N für die Anzahl der Innenelektroden, C für die Kapazität des Kondensators in der Einheit Nanofarad, e für die Dielektrizitätskonstante, tangδ für den Verlustfaktor, R-j_s für den Isolationswiderstand in der Einheit 106 MΩ. ΔC/C_ steht für die maximale relative Änderung der Kapazität des Kondensators im Temperaturintervall zwischen -25°C und +25°C sowie ΔC/C+ für die maximale relative Änderung der Kapazität im Temperaturintervall zwischen +25°C und +85°C, jeweils angegeben in Prozent und bezogen auf die Kapazität des Kondensators bei der Temperatur 25°C.Based on the perovskite ceramic described for FIG. 1, electrical multilayer components with a different number of electrode layers were produced. The number of electrode layers is equal to the number of internal electrodes. The following Table 1 shows an overview of the electrical properties of the multilayer capacitors produced in comparison. The number of the corresponding sample is in the first column. Furthermore, N stands for the number of internal electrodes, C for the capacitance of the capacitor in the nanofarad unit, e for the dielectric constant, tangδ for the loss factor, R-j_ s for the insulation resistance in the unit 10 6 MΩ. ΔC / C_ stands for the maximum relative change in the capacitance of the capacitor in the temperature interval between -25 ° C and + 25 ° C and ΔC / C + for the maximum relative change in the capacitance in the temperature interval between + 25 ° C and + 85 ° C, each given in percent and based on the capacitance of the capacitor at a temperature of 25 ° C.
Tabelle 2 : Elektrische Eigenschaften verschiedener erfindungsgemäßer Vielschichtkondensatoren, gemessen bei einer Frequenz von 1 kHzTable 2: Electrical properties of various multilayer capacitors according to the invention, measured at a frequency of 1 kHz
In Figur 2 ist die relative Änderung ΔC/C der Kapazität bezogen auf die Kapazität des Kondensators bei der Temperatur von 25°C im Temperaturbereich zwischen -25°C und +85°C für die Proben 1, 2 und 3 dargestellt. Dabei bezieht sich die Kurve Kl auf die Probe 1, die Kurve K2 auf die Probe 2 und die Kurve K3 auf die Probe 3. FIG. 2 shows the relative change ΔC / C in the capacitance in relation to the capacitance of the capacitor at the temperature of 25 ° C. in the temperature range between -25 ° C. and + 85 ° C. for samples 1, 2 and 3. Curve K1 relates to sample 1, curve K2 to sample 2 and curve K3 to sample 3.
Es wird beobachtet, daß die Temperaturabhängigkeit der Kapazität mit zunehmender Anzahl von Innenelektroden schwächer wird (vgl. auch Tabelle) . Die bei den gemäß dem Ausführungsbeispiel hergestellten Kondensatoren gemessenen Änderungen der Kapazität erfüllen zwar nicht die Vorgaben der C0G- Charakteristik, wonach sich die Kapazität im Temperaturintervall von -55°C bis +125°C um maximal 0,6 % ändern darf, je- doch haben die erfindungsgemäßen Kondensatoren Temperaturkoeffizienten für die Kapazität (TKC) , die in der Größenordnung der COG-Charaktteristik liegen.It is observed that the temperature dependence of the capacitance weakens with an increasing number of internal electrodes (see also table). The changes in capacitance measured in the capacitors produced according to the exemplary embodiment do not meet the requirements of the C0G characteristic, according to which the capacitance may change by a maximum of 0.6% in the temperature interval from -55 ° C. to + 125 ° C. the capacitors according to the invention have temperature coefficients for capacitance (TKC) which are in the order of magnitude of the COG characteristic.
Die Untersuchungen zeigen, daß durch die Gemeinsamsinterung der Silber, Niob und Tantal enthaltenden Perovskitkeramik mit silberhaltigen Innenelektroden eine wesentliche Verbesserung der Dielektrizitätskonstante erreicht werden kann. Es hat sich ferner gezeigt, daß eine weitere Verbesserung erreicht werden kann, indem eine möglichst große Kontaktfläche zwi- sehen Keramikschichten und Innenelektroden vorgesehen wird. Eine solche erhöhte Kontaktfläche kann beispielsweise durch eine erhöhte Anzahl von Innenelektroden erreicht werden. Es ist aber genauso gut denkbar, bei gleichbleibender Zahl von Innenelektroden die Grundfläche des Grundkδrpers gemäß Figur 1 zu vergrößern.The investigations show that by sintering the perovskite ceramic containing silver, niobium and tantalum with silver-containing internal electrodes, a significant improvement in the dielectric constant can be achieved. It has also been shown that a further improvement can be achieved by providing the largest possible contact area between ceramic layers and internal electrodes. Such an increased contact area can be achieved, for example, by an increased number of internal electrodes. However, it is equally conceivable to enlarge the base area of the base body according to FIG. 1 while the number of internal electrodes remains the same.
Es kommt also lediglich darauf an, daß das Keramikmaterial zusammen mit einem metallischen Edelmetall gesintert wird, um die Dielektrizitätskonstante des Keramikmaterials zu erhöhen. Das Edelmetall kann beispielsweise Silber sein. Daraus können vorteilhafte elektrokeramische Bauelemente auch ohne Innenelektroden sondern lediglich mit auf dem Grundkörper angeordneten Kontaktschichten bereitgestellt werden. It is only important that the ceramic material is sintered together with a metallic noble metal in order to increase the dielectric constant of the ceramic material. The precious metal can be silver, for example. From this, advantageous electro-ceramic components can also be provided without internal electrodes but only with contact layers arranged on the base body.

Claims

Patentansprüche claims
1. Elektrokeramisches Bauelement (1),1. electro-ceramic component (1),
- mit einem Grundkörper (1) , auf dessen Oberfläche zwei Kontaktschichten (4, 5) angeordnet sind,- With a base body (1), on the surface of which two contact layers (4, 5) are arranged,
- bei dem der Grundkörper (1) eine einphasige Perovskitkeramik der Zusammensetzung Ag (Nbl-xTax) O3 enthält, die zusammen mit einem in dem Grundkörper angeordneten metallischen Edelmetall gesintert ist .- In which the base body (1) contains a single-phase perovskite ceramic of the composition Ag (Nbl- x Ta x ) O3, which is sintered together with a metallic noble metal arranged in the base body.
2. Vielschichtkondensator mit einem Grundkörper (1), der von einem Stapel aus übereinanderliegenden Schichten (2, 3) mit wenigstens einer keramischen Dielektrikumschicht (2) und einer Elektrodenschicht (3) gebildet ist, - bei dem die Oberfläche des Grundkδrpers (1) zwei Kontakt- schichten (4, 5) aufweist2. multilayer capacitor with a base body (1), which is formed by a stack of superimposed layers (2, 3) with at least one ceramic dielectric layer (2) and an electrode layer (3), - in which the surface of the base body (1) two Has contact layers (4, 5)
- und bei dem eine Dielektrikumschicht (2) eine Dielektrizitätskonstante e aufweist, die größer als 440 ist.- And in which a dielectric layer (2) has a dielectric constant e which is greater than 440.
3. Vielschichtkondensator nach Anspruch 2, bei dem Dielektrikumschichten (2) und Elektrodenschichten (3) gemeinsam gesintert sind,3. multilayer capacitor according to claim 2, in which dielectric layers (2) and electrode layers (3) are sintered together,
- bei dem eine Dielektrikumschicht (2) eine Perovskitkeramik der Zusammensetzung Ag (Nbl-xTax) O3 enthält, - und bei dem eine Elektrodenschicht (3) ein metallisches Edelmetall enthält.- in which a dielectric layer (2) contains a perovskite ceramic of the composition Ag (Nbl- x Ta x ) O3, - and in which an electrode layer (3) contains a metallic noble metal.
4. Vielschichtkondensator nach Anspruch 3, bei dem für die Perovskitkeramik gilt: 0,5 ≤ 1-x < 0,7.4. Multi-layer capacitor according to claim 3, in which the following applies to the perovskite ceramic: 0.5 ≤ 1-x <0.7.
5. Vielschichtkondensator nach einem der Ansprüche 2 bis 4, bei dem die Zahl der Elektrodenschichten (3) größer als zehn ist .5. multilayer capacitor according to one of claims 2 to 4, wherein the number of electrode layers (3) is greater than ten.
6. Vielschichtkondensator nach einem der Ansprüche 2 bis 5, bei dem jede Elektrodenschicht mit genau einer der Kontakt- schichten (4, 5) kontaktiert ist und bei dem benachbarte Elektrodenschichten mit verschiedene Kontaktschichten (4, 5) kontaktiert sind.6. multilayer capacitor according to one of claims 2 to 5, in which each electrode layer is contacted with exactly one of the contact layers (4, 5) and in the adjacent Electrode layers are contacted with different contact layers (4, 5).
7. Vielschichtkondensator nach einem der Ansprüche 3 bis 6, bei dem die Perovskitkeramik als Sinterhilfsmittel 0,1 - 10 Gew.-% Borsäure enthält.7. Multi-layer capacitor according to one of claims 3 to 6, in which the perovskite ceramic contains 0.1-10 wt.% Boric acid as sintering aid.
8. Verfahren zur Herstellung eines Vielschichtkondensators nach einem der Ansprüche 2 bis 7 mit folgenden Schritten:8. A method for producing a multilayer capacitor according to one of claims 2 to 7 with the following steps:
a) Herstellen einer ersten Mischung von Nb2Ü5 und Ta2Ü5 und Kalzinieren der ersten Mischung zur Bildung eines Precursors b) Vermischen von Ag2θ und H3BO3 mit dem Precursor zur Bildung einer zweiten Mischung c) Kalzination der zweiten Mischung d) Herstellen von keramischen Folien aus der zweiten Mischung e) Übereinanderstapeln von keramischen Folien und Elektrodenschichten (3) f) Sintern des Folienstapels g) Aufbringen von Kontaktschichten (4, 5)a) producing a first mixture of Nb2Ü5 and Ta2Ü5 and calcining the first mixture to form a precursor b) mixing Ag2θ and H3BO3 with the precursor to form a second mixture c) calcining the second mixture d) producing ceramic films from the second mixture e) stacking of ceramic foils and electrode layers (3) f) sintering the foil stack g) applying contact layers (4, 5)
wobei die Schritte c) und f) in einer Atmosphäre durchgeführt werden, die einen gegenüber der Umgebungsluft erhöhten Sauerstoffgehalt aufweist.wherein steps c) and f) are carried out in an atmosphere which has an increased oxygen content compared to the ambient air.
9. Elektrokeramisches Bauelement nach Anspruch 1, bei dem das Edelmetall Silber ist .9. The electro-ceramic component according to claim 1, wherein the noble metal is silver.
10. Vielschichtkondensator nach einem der Ansprüche 2 bis 7, bei dem das Edelmetall Silber ist. 10. multilayer capacitor according to one of claims 2 to 7, wherein the noble metal is silver.
EP02729916A 2001-07-26 2002-05-27 Electroceramic component, multi-layer capacitor and method for production of the multi-layer capacitor Withdrawn EP1410410A1 (en)

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JP2006265629A (en) * 2005-03-24 2006-10-05 Yamaha Marine Co Ltd Electrode for electrolytic protection device
JP2006265628A (en) * 2005-03-24 2006-10-05 Yamaha Marine Co Ltd External power source type electrolytic protection device for engine for vessel
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CN111524705A (en) * 2020-04-29 2020-08-11 深圳市峰泳科技有限公司 Planar capacitor with stacked structure and manufacturing method thereof

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JPS60124306A (en) * 1983-12-06 1985-07-03 京セラ株式会社 Dielectric porcelain composition
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