EP0065806B1 - Résistance dépendant de la tension et procédé pour sa fabrication - Google Patents
Résistance dépendant de la tension et procédé pour sa fabrication Download PDFInfo
- Publication number
- EP0065806B1 EP0065806B1 EP82200615A EP82200615A EP0065806B1 EP 0065806 B1 EP0065806 B1 EP 0065806B1 EP 82200615 A EP82200615 A EP 82200615A EP 82200615 A EP82200615 A EP 82200615A EP 0065806 B1 EP0065806 B1 EP 0065806B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- metal oxide
- sintered body
- voltage
- metal
- dependent resistor
- 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.)
- Expired
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Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01C—RESISTORS
- H01C7/00—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material
- H01C7/10—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material voltage responsive, i.e. varistors
- H01C7/105—Varistor cores
- H01C7/108—Metal oxide
- H01C7/115—Titanium dioxide- or titanate type
Definitions
- the invention relates to a voltage-dependent resistor with a ceramic sintered body based on a polycrystalline, alkaline earth metal titanate doped with a small amount of a metal oxide to produce an N-type conductivity, with electrodes arranged on opposing surfaces, and a method for producing such a resistor.
- a voltage-dependent resistor is known from German patent application P 30 19 969.0, which is based on N-doped strontium titanate, to which a small proportion of a lead germanate phase was added before sintering, which leads to the formation of insulating grain boundary layers in the polycrystalline structure of the sintered body.
- This known resistance is because of its relatively high field strength - a current density z. B. of about 3 mAlcm 2 results only in fields of about 6 kV / cm - can only be used to a limited extent; he is e.g. B. Not suitable for modern semiconductor circuits that work with low voltages.
- the invention has for its object to develop a voltage-dependent resistor according to the preamble of the claim and a method for its production such that a voltage-dependent resistor with a low field strength is obtained.
- a method for producing a voltage-dependent resistor with a ceramic sintered body based on a polycrystalline, alkaline earth metal titanate doped with a small amount of a metal oxide to produce an N-type conductivity is characterized in that the sintered body with a perovskite structure is first produced in a reducing atmosphere by producing it Sintered body is then covered on its surface to form an insulating layer on the grain edge layers of the polycrystalline perovskite phase with a suspension containing at least one metal oxide or a metal oxide compound, the metal oxide or metal oxide compound having a lower melting point than the perovskite phase, the polycrystalline perovskite phase on the other Grain edge layers well wetted and showing reversible breakthrough phenomena during field strengths during operation of the component, after which the sintered body in an oxidizing atmosphere, preferably in air, b at a temperature which is above the melting point of the suspension component (s).
- the alkaline earth metal titanate is reacted by reacting SrC0 3 with Ti0 2 in a molar ratio of 1: 1.001 to 1: 1.02 with the addition of the doping metals in the form of their oxides in an amount of 0.05 to a maximum of 60 mol% of the constituent to be substituted after grinding and presintering for 15 h at 1,150 ° C. in air.
- this is made from 90 for 4 h at a temperature of 1,460 ° C. in a reducing atmosphere consisting of mixed gas saturated with water vapor Vol.% N 2 and 10 vol.% H 2 sintered.
- La 2 0 3 , Nb 2 0 5 or W0 3 are used as the doping metal oxide and Bi 2 0 3 as the metal oxide to be diffused in, or lead germanate Pb 5 Ge 3 O 11 is used as the metal oxide compound to be diffused in.
- La 3 + , Nb s + and W 6+ ions have proven to be particularly suitable for N doping.
- other dopings are also conceivable, e.g. B. other rare earth metal ions such as Sm 3+ or Y 3+ ; instead of Nb 5+ , Ta 5+ , As 5+ or Sb 5+ and instead of W 6+ , Mo 6+ and U 6+ can be used.
- the doping ions are installed either on Sr or Ti sites in the perovskite lattice.
- a suspension with at least one metal oxide that melts relatively low with respect to the sintered body or at least one metal oxide compound that melts relatively low with respect to the sintered body e.g. B. Bi 2 0 3 or lead germanate Pb 5 Ge 3 O 11 , applied in an organic binder and baked under oxidizing conditions at temperatures around or above 900 ° C, the applied molten metal oxide or the metal oxide compound diffuses preferably along the grain boundaries into the semiconducting ceramic and creates highly insulating grain boundary layers there.
- the voltage across a varistor of composition is Sr (Ti 0.996 W 0.004 ) O 3 .
- 0.0TiO 2 with a diffused phase of Bi 2 O 3 at 1 mA and 30 mA depending on the temperature.
- a liquid sintering phase is formed with the SrTi0 3 at a sintering above 1 400 ° C - it can be assumed that this is the eutectic SrTi0 3 -Ti0 2 occurring at ⁇ 1 440 ° C, which is caused by the addition of Dopants can also occur at lower temperatures.
- a liquid sintering phase of this type promotes coarse grain growth, which, as already stated, is desirable.
- the raw materials are weighed in an amount corresponding to the desired composition and 2 hours in a ball mill, e.g. B. agate, wet mixed. This is followed by presintering at 1,150 ° C for 15 h.
- the pre-sintered powders are ground again wet (1 h in a ball mill, e.g. made of agate).
- the millbase is then dried, and the powders thus obtained are then removed using a suitable binder, e.g. B. a 10% aqueous polyvinyl alcohol solution, granulated.
- the granules are molded articles suitable for ceramic resistors, for. B.
- sintering it is remarkable that coarse-grained structures preferably occur at sintering temperatures above 1,440 ° C.
- the reducing sintering should take place in a tightly closing furnace, e.g. B. a tube furnace is suitable. Excess reducing gas should expediently flow out via a bubble counter in order to create a constant sintering atmosphere.
- Sintered bodies produced in this way are semiconducting and no longer show open porosity.
- the insulating grain edge layers are by diffusing at least one molten metal oxide or at least one metal oxide compound, for. B. Bi 2 0 3 or lead germanate Pb 5 Ge 3 O 11 , generated in air.
- the metal oxide or the metal oxide compound is first suspended in a binder based on polyvinyl acetate and applied to the already sintered ceramic.
- the suspended metal oxide or the suspended metal oxide compound is then baked into the sintered body by a tempering process at a temperature at which they are in the molten state.
- the minimum annealing temperature was a temperature slightly above the melting point of the metal oxide used or the used metal oxide compound determined.
- the amounts of the metal oxides or metal oxide compounds diffused into the sintered body were determined in parallel experiments by weighing the sintered bodies before applying the suspension, after burning out the binder in air at 600 ° C. and after tempering.
- the heating-up and cooling-down times were uniformly 100 minutes for all tests.
- electrodes made of suitable metals, preferably gold, e.g. B. by vapor deposition.
- a suitable adhesive layer as an intermediate layer between the ceramic and the electrode metal on the ceramic sintered body; e.g. B. a Cr-Ni layer is suitable.
- x results from the solubility limit of La in the perovskite phase.
- Different operating voltages of the finished component can, however, be set by different thickness of the components.
- the sintered bodies treated with a diffusion phase made of Bi 203 show the normal VDR dependence superimposed on a negative resistance range, ie, the voltage across the component decreases with increasing current, which can be advantageous in certain applications, since this is practically a value for the current index ⁇ ⁇ 0 corresponds (for this, reference is made to FIG. 2).
- An overvoltage is thereby not only limited to a certain value, but additional energy is absorbed in the component as the current decreases as the current increases.
- This property of the sintered body treated with Bi 2 0 3 is only partially caused by the heating and the associated decrease in resistance of the components. This is shown in FIG. 3, in which the voltage across the component was plotted at 1 mA and 30 mA as a function of the temperature. The 30 mA values were measured by short current pulses, so that self-heating by the measuring current is negligible.
Landscapes
- Engineering & Computer Science (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Compositions Of Oxide Ceramics (AREA)
- Thermistors And Varistors (AREA)
Claims (18)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE19813121289 DE3121289A1 (de) | 1981-05-29 | 1981-05-29 | Spannungsabhaengiger widerstand und verfahren zu seiner herstellung |
DE3121289 | 1981-05-29 |
Publications (3)
Publication Number | Publication Date |
---|---|
EP0065806A2 EP0065806A2 (fr) | 1982-12-01 |
EP0065806A3 EP0065806A3 (en) | 1983-05-04 |
EP0065806B1 true EP0065806B1 (fr) | 1985-11-21 |
Family
ID=6133437
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP82200615A Expired EP0065806B1 (fr) | 1981-05-29 | 1982-05-19 | Résistance dépendant de la tension et procédé pour sa fabrication |
Country Status (4)
Country | Link |
---|---|
US (2) | US4581159A (fr) |
EP (1) | EP0065806B1 (fr) |
JP (1) | JPS57199202A (fr) |
DE (2) | DE3121289A1 (fr) |
Families Citing this family (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS59188103A (ja) * | 1983-04-08 | 1984-10-25 | 株式会社村田製作所 | 電圧非直線抵抗体用磁器組成物 |
DE3523681A1 (de) * | 1985-07-03 | 1987-01-08 | Philips Patentverwaltung | Verfahren zur herstellung keramischer sinterkoerper |
JPH0670884B2 (ja) * | 1986-12-27 | 1994-09-07 | 株式会社住友金属セラミックス | マイクロ波用誘電体磁器組成物 |
US5225126A (en) * | 1991-10-03 | 1993-07-06 | Alfred University | Piezoresistive sensor |
DE10026258B4 (de) * | 2000-05-26 | 2004-03-25 | Epcos Ag | Keramisches Material, keramisches Bauelement mit dem keramischen Material und Verwendung des keramischen Bauelements |
DE102007010239A1 (de) | 2007-03-02 | 2008-09-04 | Epcos Ag | Piezoelektrisches Material, Vielschicht-Aktuator und Verfahren zur Herstellung eines piezoelektrischen Bauelements |
DE102009058795A1 (de) * | 2009-12-18 | 2011-06-22 | Epcos Ag, 81669 | Piezoelektrisches Keramikmaterial, Verfahren zur Herstellung des piezoelektrischen Keramikmaterials, piezoelektrisches Vielschichtbauelement und Verfahren zur Herstellung des piezoelektrischen Vielschichtbauelements |
US10529472B2 (en) | 2017-12-01 | 2020-01-07 | Avx Corporation | Low aspect ratio varistor |
Family Cites Families (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
NL301822A (fr) * | 1963-12-13 | |||
US3561106A (en) * | 1968-07-03 | 1971-02-09 | Univ Iowa State Res Found Inc | Barrier layer circuit element and method of forming |
US3933668A (en) * | 1973-07-16 | 1976-01-20 | Sony Corporation | Intergranular insulation type polycrystalline ceramic semiconductive composition |
GB1556638A (en) * | 1977-02-09 | 1979-11-28 | Matsushita Electric Ind Co Ltd | Method for manufacturing a ceramic electronic component |
US4237084A (en) * | 1979-03-26 | 1980-12-02 | University Of Illinois Foundation | Method of producing internal boundary layer ceramic compositions |
JPS56169316A (en) * | 1980-05-30 | 1981-12-26 | Matsushita Electric Ind Co Ltd | Composition functional element and method of producing same |
JPS5735303A (en) * | 1980-07-30 | 1982-02-25 | Taiyo Yuden Kk | Voltage vs current characteristic nonlinear semiconductor porcelain composition and method of producing same |
US4347167A (en) * | 1980-10-01 | 1982-08-31 | University Of Illinois Foundation | Fine-grain semiconducting ceramic compositions |
US4419310A (en) * | 1981-05-06 | 1983-12-06 | Sprague Electric Company | SrTiO3 barrier layer capacitor |
JPS58103116A (ja) * | 1981-12-16 | 1983-06-20 | 太陽誘電株式会社 | コンデンサ用半導体磁器 |
JPS5891602A (ja) * | 1981-11-26 | 1983-05-31 | 太陽誘電株式会社 | 電圧非直線磁器組成物 |
US4436650A (en) * | 1982-07-14 | 1984-03-13 | Gte Laboratories Incorporated | Low voltage ceramic varistor |
-
1981
- 1981-05-29 DE DE19813121289 patent/DE3121289A1/de not_active Withdrawn
-
1982
- 1982-05-19 EP EP82200615A patent/EP0065806B1/fr not_active Expired
- 1982-05-19 DE DE8282200615T patent/DE3267542D1/de not_active Expired
- 1982-05-28 US US06/382,910 patent/US4581159A/en not_active Expired - Fee Related
- 1982-05-28 JP JP57090029A patent/JPS57199202A/ja active Granted
-
1985
- 1985-07-11 US US06/753,757 patent/US4692289A/en not_active Expired - Fee Related
Also Published As
Publication number | Publication date |
---|---|
DE3121289A1 (de) | 1982-12-23 |
DE3267542D1 (en) | 1986-01-02 |
EP0065806A3 (en) | 1983-05-04 |
US4581159A (en) | 1986-04-08 |
JPH0236041B2 (fr) | 1990-08-15 |
US4692289A (en) | 1987-09-08 |
EP0065806A2 (fr) | 1982-12-01 |
JPS57199202A (en) | 1982-12-07 |
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