US3569802A - Dielectric capacitors with inner barrier layers and low temperature dependence - Google Patents

Dielectric capacitors with inner barrier layers and low temperature dependence Download PDF

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US3569802A
US3569802A US762220A US3569802DA US3569802A US 3569802 A US3569802 A US 3569802A US 762220 A US762220 A US 762220A US 3569802D A US3569802D A US 3569802DA US 3569802 A US3569802 A US 3569802A
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dielectric capacitor
percent
crystallites
doping substance
dielectric
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Horst Brauer
Renate Kuschke
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Siemens AG
Siemens Corp
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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
    • H01G4/1272—Semiconductive ceramic capacitors
    • H01G4/1281—Semiconductive ceramic capacitors with grain boundary layer
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • 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
    • C04B35/46—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 titanium oxides or titanates
    • C04B35/462—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 titanium oxides or titanates based on titanates
    • C04B35/465—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 titanium oxides or titanates based on titanates based on alkaline earth metal titanates
    • C04B35/468—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 titanium oxides or titanates based on titanates based on alkaline earth metal titanates based on barium titanates
    • C04B35/4682—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 titanium oxides or titanates based on titanates based on alkaline earth metal titanates based on barium titanates based on BaTiO3 perovskite phase
    • C04B35/4684—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 titanium oxides or titanates based on titanates based on alkaline earth metal titanates based on barium titanates based on BaTiO3 perovskite phase containing lead compounds
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B3/00—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties
    • H01B3/02—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of inorganic substances
    • H01B3/025—Other inorganic material

Definitions

  • Kallam Att0rny-Hill, Sherman, Meroni, Gross & Simpson ABSTRACT Dielectric capacitor structures (and method of making the same) comprising a plurality of bound together crystallites having a barium-titanate perovskite lattice structure of the general formula:
  • (B81 -My)OZ(TI1 yML )Og which includes at least two different doping substances, one of which predominantly effects N-conductivity in the interior of the crystallites and the other which predominantly effects P- conductivity on the surface of the crystallites.
  • M" is selected from the group consisting of Ca, Sr, Pb, Mg and mixtures thereof; M is selected from the group consisting of Zr, Sn and mixtures thereof; at and y are numerals ranging up to one; z is a number ranging from 1.005 to 1.05 the first doping substance is selected from the group consisting of Bi, Ce, La, Nb, Nd, Pr, Sb, Sm and Ta; and the second doping substance is selected from the group consisting ofCu, Fe and Mn.
  • the invention relates to dielectric capacitor bodies having inner barrier layers, more particularly-the invention relates to dielectric capacitor materials and bodies composed thereof having inner barrier layers and a low temperature dependence.
  • barrier-layer capacitors have a chemically reduced ceramic body generally composed of barium-titanate materials having dielectric layers therein formed through a reoxidation at the capacitor body surface.
  • a disadvantage of these conventional barrier-layer capacitors" is that one can easily detect the thickness of the dielectrically effective layer at the surface of such bodies. This materially limits the application of such barrier-layer capacitors.
  • Another disadvantage of the heretofore available barrier-layer capacitors (formed through reduction and surface reoxidation of a ceramic body manufactured in a conventional manner), is that they exhibit extremely small dielectric strength. Further, where an operating voltage of more than v. is contemplated, such known barrier-layer capacitorscannot, generally, be utilized.
  • Dielectric capacitor structures having inner barrier layers must have the interior of the crystallites as conductive as possible.
  • certain maximum quantities in accordance with recognized teachings in the art, i.e. 0 Saburi, Journal of the Physical Soc. of Japan," vol. 14, No. 9, Sept. 1959, pp. 1159- l 174, particularly page 1173, and W. l'leywang, Journal of the American Ceramic Soc., vol. 47, No. 10, Oct. 1964, pp. 484-490 of such doping substances are necessary to achieve a maximum conductivity in barium-titanate materials.
  • Sb antimony
  • La lanthanum
  • Nb niobium
  • Bi bismuth
  • Nd neodymium
  • Ce cerium
  • Sm samarium
  • Ta tantalum
  • other rare earths or similar materials such as niobium (Nb), bismuth (Bi), neodymium (Nd), cerium (Ce), samarium (Sm), tantalum (Ta) and other rare earths or similar materials.
  • An important feature of the invention is to provide a dielectric capacitor body consisting of a plurality of crystallites (polycrystalline bound together in a disc-shaped, tube-shaped or foiled-shaped ceramic body composed of barium-titanate material having a pervoskite structure of the general formula:
  • M" II is selected from the group consisting essentially of Ca, Sr, Pb, Mg and mixtures thereof; M is selected from the group consisting essentially of Zr, Sn, and mixtures thereof; x and y are numerals ranging from 0 to l, i.e. ranging up to one, and z is a numeral ranging from 1.005 to 1.05.
  • This barium-titanate material is provided with at least two different doping substances, one of which predominantly effects N-conductivity on the interior of the crystallites and is selected from the grouping consisting of antimony (Sb), lanthanum (La), niobium (Nb), bismuth (Bi), cerium (Ce), neodymium (Nd), praseodymium (Pr), samarium (Sm) and tantalum (Ta) and the other of which predominantly effects P-conductivity at the surface layer of the crystallites and is selected from the group consisting of copper (Cu), iron (Fe), and manganese (Mn).
  • Sb antimony
  • La lanthanum
  • Nb niobium
  • Bi bismuth
  • Ce cerium
  • Nd neodymium
  • Pr praseodymium
  • Sm samarium
  • Ta tantalum
  • Another feature of the invention is to provide a polycrystalline (i.e., a plurality of bonded together crystallites) dielectric capacitor body wherein a plurality of insulating barrier layers are substantially uniformly distributed on the inside of the body and such layers are connected in series. Consequently, these insulating barrier layers provide a plurality of PN- transistions (i.e., PN-junctures) poled in blocking or passing directions.
  • a polycrystalline i.e., a plurality of bonded together crystallites
  • insulating barrier layers are substantially uniformly distributed on the inside of the body and such layers are connected in series. Consequently, these insulating barrier layers provide a plurality of PN- transistions (i.e., PN-junctures) poled in blocking or passing directions.
  • Another object of the invention is to provide a dielectric capacitor body and a method of making the same having inner barrier layers and a low temperature dependence.
  • FIG. 1 is a prospective elevational view, with parts broken away, illustrating a disc-shaped capacitor body constructed in accordance with the principles of the invention
  • FIG. 2 is an elevated sectional view, with parts broken away, of a tubular-shaped capacitor constructed in accordance with the principles of the invention
  • FIG. 3 is an elevational sectional view, with parts broken away, of a stack capacitor body constructed in accordance with the principles of the invention
  • FIG. 4 is a sectional fragmentary enlargement taken substantially at the encircled portion designated IV in FIGS. l-3;
  • FIG. 5 is a graphical illustration of the DK-value of capacitors of the invention as a function of temperature for different sintering conditions
  • FIG. 6 is a graphical illustration of the loss factor of the capacitors of the invention as a function of temperature for different sintering conditions.
  • FIGS. 7 and 8 are graphical illustrations of the DK-value and the tangent of the loss angle Bas a function of temperature for capacitors of the present invention as a function of sintering temperature.
  • the dielectric capacitor bodies of the invention are composed of a plurality of bonded crystallites in a ceramic form.
  • the crystallites are composed of bariumtitanate materials having a perovskite structure or lattice with a general formula of:
  • M is a material selected from the group consisting of Ca, Sr, Pb, Mg, and mixtures thereof; M is a material selected from the group consisting of Zr, Sn, and mixtures thereof; x and y are numerals ranging up to one; and z is a numeral in the range of 1.005 to 1.05.
  • the quantity of the quadrivalent perovskite forming ingredient is 0.5 to 5 mol. percent greater than the quantity of the bivalent perovskite forming ingredient.
  • barium-titanate crystallites contain at least two different doping substances, a first of which is selected from the group consisting essentially of Bi, Ce, La, Nb, Nd, Pr, Sb, Sm and Ta which tend to predominantly effect N-conductivity on the inside or interior of suchcrystallites; and the second of which is selected from the group consisting of Cu, Fe and Mn which tend to predominantly effect P-conductivity on the surface layer or outer peripheral portions of such crystallites.
  • the above defined dielectric capacitors of the invention have an increased insulating stability and a relatively low (and variable) dependence on voltage for the DK-value thereof in accordance with their application.
  • the amount of the doping substances are calculated on the basis of their respective oxides.
  • DK-values discussed hereinbefore and hereinafter in regard to both the known and the now disclosed capacitor bodies are the values for the dielectric constant (DK) and are conventionally designated far above the e-value (dielectric and are to the specified material. These DK-values are obtained by computing a dielectric constant (DK) through measurements of the capacity of such capacitors modified by the physical dimensions of the capacitor body.
  • DK dielectric constant
  • Control of crystalline growth (a process known to workers skilled in the art) or the addition of tin (with a correspondingly simultaneous shift of Curie Point) are utilized to insure that the crystallites of the instant invention are of a medium size in the range of 20 to 300 my. and preferably in the range of 100 to 300 mp. (millimicrons).
  • Such medium sized crystals exhibit an exceptionally large DK-value, however, the voltage dependence of the DK thereof tends to increase.
  • dielectric capacitors formed in accordance with the principles of the instant invention from the aforesaid medium sized crystals have exceptional utility, (or applicability) for example, as dielectric amplifiers.
  • antimony is utilized as the first doping substance (previously identified) effecting the N-conductivity in amounts ranging from 0.15 to 0.25 percent by weight calculated on the basis of Sb O Copper (Cu) is utilized as the preferred second doping substance (previously identified) effecting the P-conductivity in amounts ranging from 0.01 to 0.15 percent by weight calculated on the basis of CuO.
  • Sb antimony
  • Cu Copper
  • N-conductivity effecting doping substances i.e., Bi, Ce, La, Nb, Nd, Pr, Sb, Sm, Ta, etc.
  • P-conductivity effecting doping substances i.e., Cu, Fe, Mn, etc.
  • Curie temperatures of the materials utilized as the dielectric capacitors can be adjusted in a conventional manner.
  • these metals tend to individually and/or jointly function to shift the Curie temperature of the dielectric capacitor material toward a lower temperature.
  • the utilization of la lead as a M" metal in the aforesaid perovskite structure functions to increase the Curie temperatures to values above 120 C.
  • the ability to shift toward lower temperatures in accordance with the principles of the invention affords an added advantage of having the operating temperature range lie below the Curie temperature.
  • the Curie temperature of a particular composition is 10 C. (such as by inclusion of 20 mol. percent of tin), such as for material having the formula BaO-z(Ti Sn,, .,)O wherein z is a numeral ranging from 1.005 to 1.05
  • the operating temperature range lies from 0 C. to far in excess of C.
  • the dielectric capacitor bodies of the invention possess, particularly above the Curie temperature, a very high DK-value.
  • Such high DK-values because of the operating temperature is in the cubical range, simultaneously decrease the loss factor to a very low value and suppress a decrease of the DK-value for ferroelectric substances (achieved by the increased amount of P-conductivity effecting substances, i.e. Cu, Fe, Mn, etc.) in accordance with the Curie-Weiss law. Consequently, such dielectric capacitor materials have a relatively low temperature coefiicient.
  • the crystallites utilized in the formation of the dielectric capacitor bodies of the invention are preferably formed by intermixing suitable quantities of, for example, BaCO and TiO 5 (Ti0,-is generally derived from and utilized in' its raw ore form, i.ei rutile, anatase, or' mixtures thereof).
  • suitable quantities of, for example, BaCO and TiO 5 Ti0,-is generally derived from and utilized in' its raw ore form, i.ei rutile, anatase, or' mixtures thereof.
  • other perovskite starting materials such as(Ba Pb) Ti 0,; (Ba Ca Ti (Ba Sr) Ti 0,; Pb (Zr Ti) 0,, etc. can also be utilized.
  • the perovskitestarting materials are then intermixed with an N-conductivity'effecting doping substance, such as for example, Sb,0 in amounts ranging from 0.15 to 0.25 percent by weight and with a P-conductivity effecting
  • an N-conductivity'effecting doping substance such as for example, Sb,0
  • P-conductivity effecting such as for example, P-conductivity effecting
  • tor values can (as in the case of conventional capacitors) be readily attained through appropriate body shaping without the necessity of having to, produce barrier layers on the finished doping substance, such as for example, CuO in amounts ranging from"0.0l to 0.15 percent by weight.
  • This mixture is then generally uniformly pulverized, as by' grinding'ina ball mill for about'l 8 hours while adding about 0.5 mols. of water per mol. of mixture, dried and reacted (a solid-state reaction) at about 950 to 1 100 C.-An important factor in the preparation of the dielectric capacitor crystallites is the uniform initmate mixture of the materials and the attainment of an excess of TiO, (preferably attained through the so-called wet-grinding process described). More generally, (and mother words) it is important to obtain-an excess of about 0.5 to 5 mols. percent of them metals over the M" metals.
  • barrier layer capacitor crystallites having substantially equivalent qualities to those previously described may also be attained by utilizing a so-called' dry grinding (or mixing) process.
  • the dry grinding process achieves uniformityof the materials but several excess mols. percent of TiO, must be added to the initial mixture.
  • the reaction product is again thoroughly pulverized or ground, such as in a ball mill, with the addition of about 0.5 mols. of water (however, dry grinding is also suitable) per mol. or reaction product for approximately 18 hours'to achieve a fine-sized uniform particle mixture.
  • This mixture is then dried and combined, in conventional manner, with an organic binding agent, such as for example, polyvinyl alcohol.
  • This mixture is then pressed or formed into desired shape orconfiguration.
  • the shaped dielectric capacitor bodies are then subjected to a final sintering operation at about l300 to 1400 C.
  • the completed capacitor bodies exhibit the values specified in the tables set forth hereinafter inregard to the dielectric" constant DK, the tg8 (dielectric loss angle) and-the voltage strength.
  • an exeeptional'advantage of the invention consists in providing a material having an extremely .flargeapparent DK-value in: a form suitable for capacitor use.
  • Amspacitorformed from 'su'chniaterials results in'the formation of thin nonconductive layers at the surfaces or peripheries of crystallites, which have a well conducting polycrystalline (a plurality of such crystals bonded together) ceramic body.
  • This is, in contrast to the heretofore known barrier layer capacitors, a quasi-volume capacity I wherein a high dielectric strength is achieved (up-to 100 v./mm. in certain cases).
  • an additional advantage coupled therewith is that the new capacitor material allows the production of capacitor bodies having extremely small (smallest of all known capaciceramic body through various complicated processes.
  • the material of the invention allows the produc tion of so-called stacking or multilayer capacitors by, for example, applying spraying techniques (or other suitable techniques) to alternately spray thin ceramic layers.(composed of, for example, converted BaTiO, basementte metal oxide doping substances added thereto, such as the previously disclosed CuO and Sb,O, in a suitable liquid or viscous form) on top of one another and subjecting such a stack to a sintering operation-toform a parallelly connected electrical barrier layer capacitor body.
  • spraying techniques or other suitable techniques
  • FIG. 1 generally illustrates a disc-shaped capacitor body 1. which functions as a dielectric and is produced from the novel material of the invention.
  • Capacitor coats l2 and 13 are suitably fastened to this material and are provided with suitably fastened external connection means 14 and 15. a 1
  • FIG. 2 illustrates a tubular-shaped ceramic body 2!.
  • Ceramic body 21 functions as a tubular capacitor and is provided with coatings 22 and 23.
  • OuterIcurrent connection means 24 and 25 are suitably fastened to the coatings 22 and 23 respectively.
  • g Y i FIG. 3 illustrates a monolithic body 31 which is formed from a layer of ceramic materials of theinvention stacked on top of 'one another in a manner conventional to the formation of ceramic bodies.
  • the monolithic block 31 is divided by metallic layers 32and 33 which function as condenser coatings. Layers 32 and 33 are alternatively led to the two connecting sides.
  • Metal coatings 34 and 35 respectively, connect layers 32 and 33 with .oneanother.
  • FIG. 4 illustrates a'considerably'enlarged segment IV out of the ceramic bodies illustrated atFlGS. 1+3.
  • the interior of the crystallites have good N-conductivity characteristics.
  • the surface of the peripheral layers 42 are located in surtors) geometric dimensions. This' 'factor is extremely important in current .microtechniqu'e. applications.
  • a DK of 10 such as one having its Curie point shifted to a lowternperature
  • the capacitor materia'iof the invention offers a 0.3 and athickness of about 0:2
  • the first column enumerates the particular test in sequential order.
  • the second column identifies the form of titanium oxide utilized in the formation of barium-titanate.
  • Columns 3 and 4 specify the amounts of the indicated doping substance utilized.
  • the last threecolumns indicate'the electrical qualities of the particdlarmaterial. The values given are average values attained from measuring-40 bodies in the respective tests.
  • the DK-values'specitied in brackets below the average DK-valuesrep'resent the highest measured value attained with the highest CuO quantity specified in column 4 for the respective tests.
  • the CuO-quantit'y for the individual tests was varied within the two specified limits.
  • the last column includes a notation".parti ally conductive" to indicate capacitor only to a limited extent. I
  • Starting substance SbzOa, CuO, for the percent percent DK (in accordformation by by ance with the tgoi- S ecific resistance 5 (Ohm cm.) Test Number p31 thfo weight weight given definition) percent easurlng voltage 320 v./mm.
  • the graph illustrated at FIG. 5 shows the DK as a function of the temperature at different sintering conditions.
  • the abscissa specifies the temperature in degrees centigrade while the ordinate specifies the DK (in accordance with the definition given hereinbefore).
  • the material utilized is that of test 6 (identified in the above tables) and is a barium-titanate material (utilizing anatase as the raw material for titanium oxide) having 0.175 percent Sb ll and 0.04 percent CuO as the doping substances therein.
  • the measuring frequency was 1 kHz.
  • Curve 1 represents the DK of this material after it was sintered at 1350 C. for 30 minutes.
  • Curve 2 represents the DK of the material after it was subjected to sintering temperature at 1350" C. for after hour.
  • Curve 3 represents the DK of the material after it was sintered at 1360 C. for 2 hours.
  • the graph illustrated at FIG. 6 shows the loss factor as a function of the temperature at different sintering conditions.
  • the material tested, the measuring frequency, the sintering temperatures and times are substantially identical to those explained in conjunction with FIG. 5 and, therefore, the reference numerals on the curves are the same as those utilized in FIG. 5.
  • the graph illustrated at FIG. 7 shows the DK and the tangent of the loss angle 8 on the ordinate as a function of the temperature in degrees centigrade on the abscissa.
  • the material utilized was that of test 50 (identified in the above tables), and has the empirical formula of Ba0-z(Ti,, ,-,Sn,, .,)0 containing 0.15 percent by weight of Sb 0 and 0.03 percent by weight of CuO as the doping substances.
  • the measuring frequency was again 1 kHz.
  • Curve 5 represents the DK trend of the material after it was sintered at 1360 C. for 2 hours.
  • curve 6 represents the DK trend of the material after it was sintered at 1350 C. for 1 hour.
  • Curve 7 illustrates the trend of the tangent of the loss angle for the material after it was sintered at 13 60 C. forfhoufs and curve 8 illustrates the trend of the tangent of the loss angle for the material sintered at 1350 C. for 1 hour.
  • the graph illustrated in FIG. 8 also shows the DK and the tangent of the loss angle 5 on the ordinate as a function of temperature in degrees centigrade on the abscissa.
  • the material utilized corresponds to the material of test 46 (identified in the above tables) and has an empirical formula of BaO'z(Ti Sn .,)O containing 0.15 percent by weight of Sb O and 0.06 percent by weight of CuO. The material was subjected to sintering conditions at 1360-C. for 2 hours.
  • Curve 9 illustrates the trend of the DK and curve 10 illustrates the trend of the tangent of the loss angle.
  • a dielectric capacitor body composed of a plurality of joined together crystallites to form a ceramic body, said crystallites being composed of a barium-titanate material having a perovskite structure of the formula:
  • M is a material selected from the group consisting essentially of Ca, Sr, Pb, Mg, and mixtures thereof; M is a material selected from the group consisting essentially of Zr, Sn and mixtures thereof; x and y are numerals ranging up to one; and z is a numeral ranging from 1.005 to 1.05; said barium-titanate material including at least a first and a second doping substance, said first doping substance predominantly producing N-conductivity in the inside of said crystallites and said second doping substance predominatly producing P-condictivity in the surface layers of said crystallites, said first doping substance being present in amounts ranging from 1.5 to 2.5 times greater than the maximum quantity of the substance necessary for producing maximum conductivity in said barium-titanate material and said second doping substance being present in amounts ranging from 0.01 to 0.15 percent by weight determined on the basis of its oxide.
  • the first doping substance is a material selected from the group consisting essentially of Bi, Ce, La, Nb, Nd, Sb, Sm and Ta and the second doping substance is a material selected from ,the group consisting essentially of Cu, Fe, and Mn.
  • the dielectric capacitor as defined in claim 3 wherein the first doping substance is antimony and the amount thereof is calculated on the basis of Sb2O I 5.
  • a dielectric capacitor body composed of a polycrystalline ceramic body the crystallites composing said body consisting essentially of a barium-titanate perovskite material having the formula:
  • z is a numeral ranging from 1.005 to 1.05, said barium-titanate material including about 0.15 percent to 0.25 percent by weight Sb O predominantly producing N-conductivity in the inside of said crystallites and about 0.01 to 0.15 percent by weight of CuO predominantly producing P-conductivity in the surface layers of said crystallites.
  • the method of producing a dielectric capacitor body comprising: (1) forming a barium-titanate crystallite having a perovskite structure of the formula:
  • M is selected from the group consisting essentially of Ca, Sr, Pb, Mg and mixtures thereof; M" is selected from the group consisting essentially of Zr, Sn and mixtures thereof; x and y are numerals ranging up to one, and z is a numeral ranging from 1.005 to 1.05; (2) admixing at least a first and a second doping substance to said crystallites to achieve a substantially uniform intimate mixture thereof, said first doping substance predominantly producing N-conductivity in the inside of the crystallites, said second doping substance predominantly producing P-conductivity in the surface layers of said crystallites; (3) heating said mixture to a temperature in the range of 950 C. to 1100 C.
  • step (1) comprises uniformly intermixing an amount of BaCO and an amount of H0 in excess of the aforesaid BaCO amount, said excess amount being in the range of 0.5 to 5 mol. percent.
  • the first doping substance is a material selected from the group consisting essentially of Bi, Ce, La, Nb, Nd, Pr, Sb, Sm and Ta and the second doping substance is a material selected from the group consisting essentially of Cu, Fe, and Mn.
  • Curve 4 represents the same material after sintering at 1360 C.

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Cited By (20)

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US3670211A (en) * 1969-08-29 1972-06-13 Hitachi Ltd Switching condenser element for switching an alternating current
US4131903A (en) * 1976-08-03 1978-12-26 Siemens Aktiengesellschaft Capacitor dielectric with inner blocking layers and method for producing the same
US4149173A (en) * 1976-12-30 1979-04-10 Siemens Aktiengesellschaft Capacitor dielectric with internal barrier layers and a method for its production
US4148853A (en) * 1976-09-16 1979-04-10 Siemens Aktiengesellschaft Process for the manufacture of a capacitor dielectric with inner blocking layers
US4192840A (en) * 1976-08-03 1980-03-11 Siemens Aktiengesellschaft Method for producing a capacitor dielectric with inner blocking layers
EP0042009A1 (en) * 1980-06-11 1981-12-23 University of Illinois Foundation Internal boundary layer ceramic compositions and process for their production
US4397886A (en) * 1981-05-06 1983-08-09 Sprague Electric Company Method for making a ceramic intergranular barrier-layer capacitor
US4419310A (en) * 1981-05-06 1983-12-06 Sprague Electric Company SrTiO3 barrier layer capacitor
US5065274A (en) * 1989-11-27 1991-11-12 U.S. Philips Corp. Ceramic body of a dielectric material on the basis of barium titanate
US5142437A (en) * 1991-06-13 1992-08-25 Ramtron Corporation Conducting electrode layers for ferroelectric capacitors in integrated circuits and method
US5166759A (en) * 1989-03-15 1992-11-24 Matsushita Electric Industrial Co., Ltd. Semiconductor-type laminated ceramic capacitor with a grain boundary-insulated structure
US5191510A (en) * 1992-04-29 1993-03-02 Ramtron International Corporation Use of palladium as an adhesion layer and as an electrode in ferroelectric memory devices
US5206788A (en) * 1991-12-12 1993-04-27 Ramtron Corporation Series ferroelectric capacitor structure for monolithic integrated circuits and method
US5268006A (en) * 1989-03-15 1993-12-07 Matsushita Electric Industrial Co., Ltd. Ceramic capacitor with a grain boundary-insulated structure
US5361187A (en) * 1993-03-11 1994-11-01 Ferro Corporation Ceramic dielectric compositions and capacitors produced therefrom
US6204069B1 (en) 1993-03-31 2001-03-20 Texas Instruments Incorporated Lightly donor doped electrodes for high-dielectric-constant materials
US6242299B1 (en) 1999-04-01 2001-06-05 Ramtron International Corporation Barrier layer to protect a ferroelectric capacitor after contact has been made to the capacitor electrode
US8723654B2 (en) 2010-07-09 2014-05-13 Cypress Semiconductor Corporation Interrupt generation and acknowledgment for RFID
US9092582B2 (en) 2010-07-09 2015-07-28 Cypress Semiconductor Corporation Low power, low pin count interface for an RFID transponder
US9846664B2 (en) 2010-07-09 2017-12-19 Cypress Semiconductor Corporation RFID interface and interrupt

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JPS5517965A (en) * 1978-07-25 1980-02-07 Matsushita Electric Ind Co Ltd Porcelain dielectric substance and method of fabricating same
JPS56162820A (en) * 1980-05-20 1981-12-15 Kiyoshi Okazaki Vapor bank layered laminated ceramic capacitor and method of manufacturing same
GB2103422B (en) * 1981-07-30 1985-02-27 Standard Telephones Cables Ltd Ceramic capacitors
DE3235886A1 (de) * 1982-09-28 1984-03-29 Siemens AG, 1000 Berlin und 8000 München Verfahren zur herstellung einer sperrschicht-keramik
JPH0692268B2 (ja) * 1988-06-03 1994-11-16 日本油脂株式会社 還元再酸化型半導体セラミックコンデンサ素子
JPH06102573B2 (ja) * 1988-07-01 1994-12-14 日本油脂株式会社 還元再酸化型半導体セラミックコンデンサ用組成物
JP2642876B2 (ja) * 1994-08-11 1997-08-20 工業技術院長 チタン酸鉛系誘電体薄膜

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US3670211A (en) * 1969-08-29 1972-06-13 Hitachi Ltd Switching condenser element for switching an alternating current
US4131903A (en) * 1976-08-03 1978-12-26 Siemens Aktiengesellschaft Capacitor dielectric with inner blocking layers and method for producing the same
US4192840A (en) * 1976-08-03 1980-03-11 Siemens Aktiengesellschaft Method for producing a capacitor dielectric with inner blocking layers
US4148853A (en) * 1976-09-16 1979-04-10 Siemens Aktiengesellschaft Process for the manufacture of a capacitor dielectric with inner blocking layers
US4149173A (en) * 1976-12-30 1979-04-10 Siemens Aktiengesellschaft Capacitor dielectric with internal barrier layers and a method for its production
EP0042009A1 (en) * 1980-06-11 1981-12-23 University of Illinois Foundation Internal boundary layer ceramic compositions and process for their production
US4397886A (en) * 1981-05-06 1983-08-09 Sprague Electric Company Method for making a ceramic intergranular barrier-layer capacitor
US4419310A (en) * 1981-05-06 1983-12-06 Sprague Electric Company SrTiO3 barrier layer capacitor
US5166759A (en) * 1989-03-15 1992-11-24 Matsushita Electric Industrial Co., Ltd. Semiconductor-type laminated ceramic capacitor with a grain boundary-insulated structure
US5268006A (en) * 1989-03-15 1993-12-07 Matsushita Electric Industrial Co., Ltd. Ceramic capacitor with a grain boundary-insulated structure
US5065274A (en) * 1989-11-27 1991-11-12 U.S. Philips Corp. Ceramic body of a dielectric material on the basis of barium titanate
US5142437A (en) * 1991-06-13 1992-08-25 Ramtron Corporation Conducting electrode layers for ferroelectric capacitors in integrated circuits and method
US5206788A (en) * 1991-12-12 1993-04-27 Ramtron Corporation Series ferroelectric capacitor structure for monolithic integrated circuits and method
US5191510A (en) * 1992-04-29 1993-03-02 Ramtron International Corporation Use of palladium as an adhesion layer and as an electrode in ferroelectric memory devices
US5361187A (en) * 1993-03-11 1994-11-01 Ferro Corporation Ceramic dielectric compositions and capacitors produced therefrom
US6204069B1 (en) 1993-03-31 2001-03-20 Texas Instruments Incorporated Lightly donor doped electrodes for high-dielectric-constant materials
US6319542B1 (en) * 1993-03-31 2001-11-20 Texas Instruments Incorporated Lightly donor doped electrodes for high-dielectric-constant materials
US6593638B1 (en) * 1993-03-31 2003-07-15 Texas Instruments Incorporated Lightly donor doped electrodes for high-dielectric-constant materials
US6242299B1 (en) 1999-04-01 2001-06-05 Ramtron International Corporation Barrier layer to protect a ferroelectric capacitor after contact has been made to the capacitor electrode
US8723654B2 (en) 2010-07-09 2014-05-13 Cypress Semiconductor Corporation Interrupt generation and acknowledgment for RFID
US9092582B2 (en) 2010-07-09 2015-07-28 Cypress Semiconductor Corporation Low power, low pin count interface for an RFID transponder
US9846664B2 (en) 2010-07-09 2017-12-19 Cypress Semiconductor Corporation RFID interface and interrupt

Also Published As

Publication number Publication date
NL141690B (nl) 1974-03-15
DE1614605A1 (de) 1972-03-02
DE1614605B2 (de) 1974-06-27
FR1581387A (enrdf_load_stackoverflow) 1969-09-12
NL6812580A (enrdf_load_stackoverflow) 1969-03-24
YU31236B (en) 1973-02-28
GB1204436A (en) 1970-09-09

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