WO2012111385A1 - Positive temperature-coefficient thermistor - Google Patents

Positive temperature-coefficient thermistor Download PDF

Info

Publication number
WO2012111385A1
WO2012111385A1 PCT/JP2012/051331 JP2012051331W WO2012111385A1 WO 2012111385 A1 WO2012111385 A1 WO 2012111385A1 JP 2012051331 W JP2012051331 W JP 2012051331W WO 2012111385 A1 WO2012111385 A1 WO 2012111385A1
Authority
WO
WIPO (PCT)
Prior art keywords
thermistor
thick film
alumina substrate
semiconductor ceramic
amount
Prior art date
Application number
PCT/JP2012/051331
Other languages
French (fr)
Japanese (ja)
Inventor
朗人 内藤
新見　秀明
Original Assignee
株式会社村田製作所
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by 株式会社村田製作所 filed Critical 株式会社村田製作所
Publication of WO2012111385A1 publication Critical patent/WO2012111385A1/en

Links

Images

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
    • H01C7/02—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 having positive temperature coefficient
    • H01C7/022—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 having positive temperature coefficient mainly consisting of non-metallic substances
    • H01C7/023—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 having positive temperature coefficient mainly consisting of non-metallic substances containing oxides or oxidic compounds, e.g. ferrites
    • H01C7/025—Perovskites, e.g. titanates
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01C—RESISTORS
    • H01C1/00—Details
    • H01C1/14—Terminals or tapping points or electrodes specially adapted for resistors; Arrangements of terminals or tapping points or electrodes on resistors
    • H01C1/1406—Terminals or electrodes formed on resistive elements having positive temperature coefficient
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B3/00—Ohmic-resistance heating
    • H05B3/10—Heater elements characterised by the composition or nature of the materials or by the arrangement of the conductor
    • H05B3/12—Heater elements characterised by the composition or nature of the materials or by the arrangement of the conductor characterised by the composition or nature of the conductive material
    • H05B3/14—Heater elements characterised by the composition or nature of the materials or by the arrangement of the conductor characterised by the composition or nature of the conductive material the material being non-metallic
    • H05B3/141—Conductive ceramics, e.g. metal oxides, metal carbides, barium titanate, ferrites, zirconia, vitrous compounds
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B2203/00—Aspects relating to Ohmic resistive heating covered by group H05B3/00
    • H05B2203/02—Heaters using heating elements having a positive temperature coefficient

Definitions

  • the present invention relates to a positive temperature coefficient thermistor, and more particularly to a positive temperature coefficient thermistor suitable for use as a heating element through which a large current flows.
  • a thermistor composed of a semiconductor ceramic having a positive resistance temperature characteristic (PTC characteristic), that is, a positive temperature coefficient thermistor is widely used as a heating element, for example.
  • a heating element using a positive temperature coefficient thermistor is advantageous in that it has a self-control function and thus does not require an external control circuit.
  • a positive temperature coefficient thermistor used as a heating element is usually provided with an element body made of a single-plate-shaped semiconductor ceramic obtained by pressure-molding and firing a barium titanate-based semiconductor powder.
  • the semiconductor ceramic exhibiting the thermistor characteristics is preferably in the form of a film.
  • Patent Document 1 Japanese Patent Application Laid-Open No. 55-130101
  • Patent Document 1 Ni, Al and / or RuO 2 powder and glass frit are added to barium titanate semiconductor ceramic powder, and a paste-like mixture using an organic binder is applied onto an insulating substrate.
  • a thick-film positive characteristic semiconductor element obtained by firing at 600 to 1000 ° C. after being formed into a thick film is described.
  • the area resistance at room temperature of the obtained thick film type positive characteristic semiconductor element is in the range of 150 to 700 ⁇ / cm 2 .
  • the resistivity is 15 k ⁇ ⁇ cm to 70 k ⁇ ⁇ cm, which is a considerably high resistivity.
  • the thickness is less than 0.1 mm, a higher resistivity is exhibited.
  • Patent Document 1 suggests that the sheet resistance can be controlled by changing the addition amount of the conductive particles.
  • the addition amount of the conductive particles is variable. The range is limited. Therefore, the increase in resistivity by increasing the addition amount of conductive particles cannot be expected so much.
  • Patent Document 2 Japanese Patent Application Laid-Open No. 11-246268
  • Patent Document 2 contains a boron oxide in a barium titanate-based semiconductor sintered body, and an oxide composed of at least one selected from barium, strontium, calcium, yttrium, and a rare earth element.
  • boron element (assumed to be B) is in an atomic ratio of 0.005 ⁇ B / ⁇ ⁇ 0.50, 1 ⁇ B / ( ⁇ ) ⁇ 4 (where ⁇ is in the semiconductor ceramic)
  • the total amount of barium, strontium, calcium, yttrium, and rare earth elements contained in the semiconductor; ⁇ : the total amount of titanium, tin, zirconium, niobium, tungsten, and antimony contained in the semiconductor ceramic) is disclosed. Has been.
  • Patent Document 2 discloses a single-plate semiconductor ceramic element obtained by firing at a temperature of 1000 ° C. or lower.
  • Patent Document 2 only discloses a single-plate semiconductor ceramic element, and does not disclose any film-like heating element. That is, Patent Document 2 does not demonstrate whether a thick film can be sintered after a thick film serving as a heating element is formed on an insulating ceramic substrate such as an alumina substrate. In addition, when a semiconductor ceramic is fired in a thick film state on an insulator ceramic substrate, the thick film as a sintered body can have low resistance, or no peeling or the like occurs between the insulator ceramic substrate and high There are further issues to be pursued, such as whether adhesion can be secured.
  • an object of the present invention is to achieve a low resistance while having a form in which a thick film serving as a heat source is formed on an insulating ceramic substrate, and thus it is possible to energize a large current.
  • An object of the present invention is to provide a positive temperature coefficient thermistor having excellent adhesion between a ceramic substrate and a thick film.
  • an alumina substrate is used as the insulator ceramic substrate.
  • the present inventors have found that low resistance can be realized when the amount of sodium in the alumina substrate and the amount of donor and manganese in the barium titanate-based semiconductor ceramic exhibit a certain relationship, leading to the present invention. It is a thing.
  • a positive temperature coefficient thermistor according to the present invention includes an alumina substrate, a thermistor thick film having a positive resistance temperature characteristic formed on the alumina substrate, and in contact with the thermistor thick film and sandwiching at least a part of the thermistor thick film. Although it is provided with at least one pair of electrodes which oppose, in order to solve the technical problem mentioned above, it is characterized by providing the following structures.
  • the above thermistor thick film is characterized by comprising a sintered body of a semiconductor ceramic mainly composed of barium titanate.
  • the total amount of donors contained in the sintered body of the semiconductor ceramic was expressed as x when expressed by the donor / Ti atomic ratio, and the amount of Mn contained in the sintered body of the semiconductor ceramic was expressed by the Mn / Ti atomic ratio.
  • y when the amount of Na in the alumina substrate is expressed by the Na / Al atomic ratio, z 0.0008 ⁇ (x ⁇ 0.5y ⁇ 0.5z) ⁇ 0.004, 0 ⁇ y ⁇ 0.007, and 0 ⁇ z ⁇ 0.002.
  • the semiconductor ceramic preferably contains at least boron element as a subcomponent.
  • the donor is preferably a rare earth element.
  • the amount of Na in the alumina substrate and the amount of donor and the amount of Mn in the barium titanate semiconductor ceramic are selected as described above.
  • a positive temperature coefficient thermistor with low resistance can be obtained.
  • the semiconductor ceramic constituting the thermistor thick film is in a state where the crystal particles are in surface contact with each other by sintering, the contact area between the particles can be widened. This also contributes to a reduction in resistance. That is, the resistance can be reduced as compared with the case where the semiconductor powder particles and the conductive particles are simply glued so as to be in point contact, as in the above-described Patent Document 1.
  • the semiconductor ceramic constituting the thermistor thick film contains at least boron element as an accessory component, it can be surely sintered at a temperature of about 1000 ° C. or lower. Therefore, it is possible to easily realize a positive temperature coefficient thermistor having a structure in which a thermistor thick film made of a semiconductor ceramic sintered body is formed on an alumina substrate, that is, a form suitable as a heating element for large current.
  • FIG. 2 is an enlarged sectional view taken along line II-II in FIG. It is a top view which shows the positive temperature coefficient thermistor 11 as a sample produced in the experiment example.
  • Table 1 prepared in the experimental example, those containing “Sm” as “Ln” show the relationship between “x (Sm / Ti ratio)” and “z (Na / Al ratio)”.
  • FIG. Of the samples shown in Table 2 prepared in the experimental example, those containing “Sm” as “Ln” show the relationship between “x (Sm / Ti ratio)” and “y (Mn / Ti ratio)”.
  • a positive temperature coefficient thermistor 1 according to an embodiment of the present invention will be described with reference to FIGS.
  • the positive temperature coefficient thermistor 1 is in contact with the alumina substrate 2, the thermistor thick film 3 formed on the alumina substrate 2 and exhibiting the PTC characteristic, and the thermistor thick film 3 with at least a part of the thermistor thick film 3 interposed therebetween. And at least one pair of electrodes 4 and 5. Further, although not shown, a protective film may be formed on the alumina substrate 2 so as to cover the thermistor thick film 3 and the electrodes 4 and 5.
  • the thermistor thick film 3 is ABO 3 (A always contains barium and may further contain at least one selected from strontium, calcium, lead and rare earth elements. B necessarily contains titanium, and further contains tin, zirconium. , Niobium, tungsten, and antimony may be included.) And a sintered body of a semiconductor ceramic having a barium titanate (BaTiO 3 ) system as a main component.
  • ABO 3 A always contains barium and may further contain at least one selected from strontium, calcium, lead and rare earth elements.
  • B necessarily contains titanium, and further contains tin, zirconium. , Niobium, tungsten, and antimony may be included.
  • This semiconductor ceramic preferably contains at least boron element as a subcomponent. Boron acts to enable low-temperature firing.
  • the A content is ⁇ in atomic ratio
  • the B content is ⁇ in atomic ratio
  • the boron element content Is the atomic ratio ⁇ , 0.05 ⁇ ⁇ / ⁇ ⁇ 1.5, and 1 ⁇ ⁇ / ( ⁇ ) ⁇ 4 It is preferable to satisfy the following condition.
  • the boron element contained in the semiconductor ceramic of the present invention exists in the form of an oxide represented by B 2 BaO 4 or B 2 O 3 dissolved in the main component represented by BaTiO 3 ceramic. It may be a thing, and if it contains a boron element, it will not be limited to the said form.
  • elements other than boron may be added as subcomponents of the semiconductor ceramic.
  • the sintered body of a semiconductor ceramic is x when the total amount of donors contained therein is represented by the donor / Ti atomic ratio, and y when the amount of Mn contained therein is represented by the Mn / Ti atomic ratio.
  • the amount of Na in the alumina substrate is expressed as Na / Al atomic ratio, and z, 0.0008 ⁇ (x ⁇ 0.5y ⁇ 0.5z) ⁇ 0.004, 0 ⁇ y ⁇ 0.007, and 0 ⁇ z ⁇ 0.002.
  • the resistivity thermistor 1 can achieve a low resistivity of, for example, less than 10 k ⁇ ⁇ cm at room temperature. Furthermore, high adhesion can be obtained between the alumina substrate 2 and the thermistor thick film 3.
  • Mn serves as an acceptor for BaTiO 3 -based semiconductor ceramics
  • Na also serves as an acceptor like Mn, so that Mn and Na reduce the effect of the donor. It is done. That is, the resistance can be lowered by adding an appropriate amount of donor to the BaTiO 3 based semiconductor ceramic. However, if Na or Mn is present, the effect of the donor is weakened, so that the appropriate amount of donor is shifted to a larger amount. Is shown.
  • Na does not exist in the BaTiO 3 -based semiconductor ceramic before firing, and it is intended to be included in the alumina substrate or contained as an impurity. Regarding Na, it is considered that it influences because it diffuses from the alumina substrate into the BaTiO 3 based semiconductor ceramic during firing.
  • rare earth elements such as La, Y, Sm, Ce, Dy, Gd and the like shown in JP 2001-326102 A, Nb, Ta, Bi, Sb, W, and the like can be used. .
  • the thermistor thick film 3 has a thickness of 1 ⁇ m or more, for example.
  • a semiconductor ceramic paste formed by mixing semiconductor ceramic powder with varnish is prepared, and this semiconductor ceramic paste is applied onto the alumina substrate 2 or a doctor blade on the alumina substrate 2. After the method or the like is applied to form a sheet, the firing process may be performed.
  • the electrodes 4 and 5 have a portion located on the thermistor thick film 3 as well shown in FIG. As shown well in FIG. 1, the first electrode 4 is formed along the longitudinal direction of the thermistor thick film 3 having a rectangular planar shape. On the other hand, the second electrode 5 is positioned so as to face the first electrode 4 with a predetermined distance from the first electrode 4. Further, the electrodes 4 and 5 respectively form wide lead portions 6 and 7 at respective end portions, and these lead portions 6 and 7 are located on one end side of the insulating ceramic substrate 2. .
  • the electrodes 4 and 5 are made of a material capable of making ohmic contact with the thermistor thick film 3.
  • a material of the electrodes 4 and 5 for example, a base metal such as Ni, Cu, or Al or an alloy thereof, or ohmic Ag that is ohmicized by addition of a base metal is used.
  • a thin film forming method such as sputtering or vapor deposition, or a thick film method in which a conductive paste is applied and baked can be applied.
  • the positive temperature coefficient thermistor 1 has a structure in which a thermistor thick film 3 is formed in a long pattern on an elongated alumina substrate 2 (that is, an aspect ratio is large). is doing. Therefore, there is a problem that peeling is likely to occur between the alumina substrate 2 and the thermistor thick film 3 due to differences in the respective linear expansion coefficients.
  • high adhesion can be ensured between the alumina substrate 2 and the thermistor thick film 3, and therefore, peeling can be prevented. Accordingly, the present invention becomes more significant particularly when the positive temperature coefficient thermistor has a form in which a long thermistor thick film is formed on a long insulator ceramic substrate as shown in FIG.
  • the above prepared powder was pulverized with PSZ balls in water for 5 hours using a ball mill, and then calcined at a temperature of 1000 ° C. for 2 hours.
  • MnCO 3 was added to obtain a mixture having the following composition.
  • Tables 1 and 2 also show the value of “x ⁇ 0.5y ⁇ 0.5z” for each sample.
  • varnish was added to the above mixture to form a paste, which was then applied onto an alumina substrate and fired at a temperature of 1050 ° C. for 2 hours to obtain a thermistor thick film made of a sintered ceramic ceramic.
  • the thickness t of the thermistor thick film after firing was 100 ⁇ m.
  • a pair of electrodes 14 is formed on the alumina substrate 12 so as to cover each end of the thermistor thick film 13 formed on the alumina substrate 12. And a positive temperature coefficient thermistor 11 as a sample was obtained.
  • room temperature resistivity was measured for each of the obtained samples.
  • Room temperature resistivity is measured by the two-terminal method when a DC voltage of 1 V is applied at a room temperature of 25 ° C.
  • room temperature resistivity when it was 10 k ⁇ ⁇ cm or more, it was determined to be defective.
  • the “room temperature resistivity” It was as high as 10 k ⁇ ⁇ cm or more.
  • the “room temperature resistivity” is as high as 10 k ⁇ ⁇ cm or more.
  • the “room temperature resistivity” is as high as 10 k ⁇ ⁇ cm or more.
  • FIG. 4 is a diagram showing the relationship between “x (Sm / Ti ratio)” and “z (Na / Al ratio)” for samples including “Sm” as “Ln” among the samples shown in Table 1. It is.
  • FIG. 5 is a diagram showing the relationship between “x (Sm / Ti ratio)” and “y (Mn / Ti ratio)” for samples including “Sm” as “Ln” among the samples shown in Table 2. It is. 4 and 5, it is shown that the area surrounded by the line has a composition within the scope of the present invention.

Abstract

The present invention lowers the resistance of a positive temperature-coefficient thermistor having an embodiment wherein a thermistor thick film that is a heat source is formed on an alumina substrate. The positive temperature-coefficient thermistor (1) is provided with: an alumina substrate (2); a thermistor thick film (3) exhibiting PTC characteristics and formed on the alumina substrate (2); and a pair of electrodes (4, 5) that face each other sandwiching at least a portion of the thermistor thick film (3). The thermistor thick film (3) comprises a sintered body of a semiconductor ceramic having barium titanate as the primary component, and when the total donor quantity contained in the sintered body as a donor/Ti atom ratio is x, the amount of Mn as an Mn/Ti atom ratio is y, and the amount of Na in the alumina substrate (2) as an Na/Al atom ratio is z, the conditions 0.0008 ≤ (x-0.5y-0.5z) ≤ 0.004, 0 ≤ y ≤ 0.007, and 0 < z ≤ 0.002 are satisfied.

Description

正特性サーミスタPositive temperature coefficient thermistor
　この発明は、正特性サーミスタに関するもので、特に、大電流が流れる発熱体としての用途に適した正特性サーミスタに関するものである。 The present invention relates to a positive temperature coefficient thermistor, and more particularly to a positive temperature coefficient thermistor suitable for use as a heating element through which a large current flows.
　正の抵抗温度特性（ＰＴＣ特性）を有する半導体セラミックをもって構成されたサーミスタ、すなわち正特性サーミスタは、たとえば発熱体として広く利用されている。正特性サーミスタを利用した発熱体は、自己制御機能を有し、よって外部の制御回路を必要としない点で有利である。 A thermistor composed of a semiconductor ceramic having a positive resistance temperature characteristic (PTC characteristic), that is, a positive temperature coefficient thermistor is widely used as a heating element, for example. A heating element using a positive temperature coefficient thermistor is advantageous in that it has a self-control function and thus does not require an external control circuit.
　発熱体として用いられる正特性サーミスタは、通常、チタン酸バリウム系半導体粉末を加圧成形した後、焼成することによって得られた、単板形状の半導体セラミックからなる素子本体を備えている。しかし、正特性サーミスタが大面積の発熱体として用いられる場合には、サーミスタ特性を示す半導体セラミックは膜状の形態とされることが好ましい。 A positive temperature coefficient thermistor used as a heating element is usually provided with an element body made of a single-plate-shaped semiconductor ceramic obtained by pressure-molding and firing a barium titanate-based semiconductor powder. However, when the positive temperature coefficient thermistor is used as a large-area heating element, the semiconductor ceramic exhibiting the thermistor characteristics is preferably in the form of a film.
　このような膜状の発熱源を有する半導体素子としては、たとえば、特開昭５５－１３０１０１号公報（特許文献１）に記載されたものがある。 As a semiconductor element having such a film-like heat generation source, for example, there is one described in Japanese Patent Application Laid-Open No. 55-130101 (Patent Document 1).
　特許文献１には、チタン酸バリウム系半導体セラミック粉末に、Ｎｉ、Ａｌおよび／またはＲｕＯ２粉末とガラスフリットとを加え、有機結合剤を用いてペースト状にした混合物を絶縁性基板上に塗布して厚膜状に成形した後、６００～１０００℃で焼成することによって得られた、厚膜型正特性半導体素子が記載されている。 In Patent Document 1, Ni, Al and / or RuO 2 powder and glass frit are added to barium titanate semiconductor ceramic powder, and a paste-like mixture using an organic binder is applied onto an insulating substrate. A thick-film positive characteristic semiconductor element obtained by firing at 600 to 1000 ° C. after being formed into a thick film is described.
　しかしながら、特許文献１に記載の厚膜型正特性半導体素子では、チタン酸バリウム系半導体セラミック粉末粒子とＮｉ粉末等の導電性粒子とは、焼結するのではなく、単にガラスで糊付けされた状態にすぎないため、個々の粒子の結合が点接触となり、低抵抗化が困難である。このため、発熱体などに使用される場合において、大電流を通電できず、極めて狭い範囲での実用化しかできない。 However, in the thick film type positive characteristic semiconductor element described in Patent Document 1, the barium titanate-based semiconductor ceramic powder particles and the conductive particles such as Ni powder are not sintered but are simply glued with glass. Therefore, the bonding of individual particles becomes point contact, and it is difficult to reduce resistance. For this reason, when it is used for a heating element or the like, a large current cannot be applied, and it can only be put into practical use within an extremely narrow range.
　事実、特許文献１に記載の実施例では、得られた厚膜型正特性半導体素子の室温における面積抵抗は１５０～７００Ω／ｃｍ２の範囲にあり、同文献第３頁左上欄第１６～１７行の「厚さが０．１ｍｍ以下」という文言を根拠に、厚さ０．１ｍｍで計算すると、抵抗率が１５ｋΩ・ｃｍ～７０ｋΩ・ｃｍとなり、かなりの高抵抗率となる。ここで、もし、厚みが０．１ｍｍより薄い場合は、さらに高い抵抗率を示すことになる。 In fact, in the example described in Patent Document 1, the area resistance at room temperature of the obtained thick film type positive characteristic semiconductor element is in the range of 150 to 700 Ω / cm 2 . Based on the phrase “thickness is 0.1 mm or less” in the row, when the calculation is performed with a thickness of 0.1 mm, the resistivity is 15 kΩ · cm to 70 kΩ · cm, which is a considerably high resistivity. Here, if the thickness is less than 0.1 mm, a higher resistivity is exhibited.
　なお、特許文献１は、導電性粒子の添加量を変えることによって面積抵抗の制御が可能であることを示唆しているが、良好なＰＴＣ特性を維持するため、導電性粒子の添加量の可変範囲は限られている。よって、導電性粒子の添加量を増やすことによる抵抗率の増大はそれほど望めない。 Note that Patent Document 1 suggests that the sheet resistance can be controlled by changing the addition amount of the conductive particles. However, in order to maintain good PTC characteristics, the addition amount of the conductive particles is variable. The range is limited. Therefore, the increase in resistivity by increasing the addition amount of conductive particles cannot be expected so much.
　他方、膜状の発熱体ではなく、単板形状の発熱体として用いられる半導体セラミック素子が、たとえば特開平１１－２４６２６８号公報（特許文献２）に記載されている。 On the other hand, a semiconductor ceramic element used not as a film-like heating element but as a single-plate heating element is described in, for example, Japanese Patent Application Laid-Open No. 11-246268 (Patent Document 2).
　特許文献２には、チタン酸バリウム系の半導体焼結体中に、ホウ素酸化物を含有し、バリウム、ストロンチウム、カルシウム、イットリウム、希土類元素の中から選ばれる少なくとも１種類からなる酸化物を含有しした半導体セラミックであって、ホウ素元素（Ｂとする）が原子比で、０．００５≦Ｂ／β≦０．５０、１≦Ｂ／（α－β）≦４（ただし、α：半導体セラミック中に含まれるバリウム、ストロンチウム、カルシウム、イットリウム、希土類元素の総量；β：半導体セラミック中に含まれるチタン、錫、ジルコニウム、ニオブ、タングステン、アンチモンの総量）となるように添加されている半導体セラミックが開示されている。 Patent Document 2 contains a boron oxide in a barium titanate-based semiconductor sintered body, and an oxide composed of at least one selected from barium, strontium, calcium, yttrium, and a rare earth element. In the semiconductor ceramic, boron element (assumed to be B) is in an atomic ratio of 0.005 ≦ B / β ≦ 0.50, 1 ≦ B / (α−β) ≦ 4 (where α is in the semiconductor ceramic) The total amount of barium, strontium, calcium, yttrium, and rare earth elements contained in the semiconductor; β: the total amount of titanium, tin, zirconium, niobium, tungsten, and antimony contained in the semiconductor ceramic) is disclosed. Has been.
　特許文献２には、また、１０００℃以下の温度で焼成して得られた単板形状の半導体セラミック素子が開示されている。 Patent Document 2 discloses a single-plate semiconductor ceramic element obtained by firing at a temperature of 1000 ° C. or lower.
　しかしながら、特許文献２では、単板形状の半導体セラミック素子が開示されているのみで、膜状の発熱体については一切開示されていない。すなわち、特許文献２では、アルミナ基板などの絶縁体セラミック基板上に発熱体となる厚膜を形成した後、この厚膜を焼結できるかどうかは実証されていない。また、半導体セラミックを絶縁体セラミック基板上において厚膜状態で焼成したとき、焼結体としての厚膜が低抵抗となり得るか、あるいは、絶縁体セラミック基板との間で剥離等が生じず、高い密着性を確保できるか、など、さらに追求すべき課題がある。 However, Patent Document 2 only discloses a single-plate semiconductor ceramic element, and does not disclose any film-like heating element. That is, Patent Document 2 does not demonstrate whether a thick film can be sintered after a thick film serving as a heating element is formed on an insulating ceramic substrate such as an alumina substrate. In addition, when a semiconductor ceramic is fired in a thick film state on an insulator ceramic substrate, the thick film as a sintered body can have low resistance, or no peeling or the like occurs between the insulator ceramic substrate and high There are further issues to be pursued, such as whether adhesion can be secured.
特開昭５５－１３０１０１号公報JP-A-55-130101 特開平１１－２４６２６８号公報Japanese Patent Laid-Open No. 11-246268
　そこで、この発明の目的は、絶縁体セラミック基板上に発熱源となる厚膜が形成された形態を有しながら、低抵抗化が図られ、よって大電流の通電が可能であり、しかも絶縁体セラミック基板と厚膜との間での密着性に優れた、正特性サーミスタを提供しようとすることである。 Accordingly, an object of the present invention is to achieve a low resistance while having a form in which a thick film serving as a heat source is formed on an insulating ceramic substrate, and thus it is possible to energize a large current. An object of the present invention is to provide a positive temperature coefficient thermistor having excellent adhesion between a ceramic substrate and a thick film.
　この発明では、絶縁体セラミック基板として、アルミナ基板が用いられる。 In this invention, an alumina substrate is used as the insulator ceramic substrate.
　そして、本件発明者は、アルミナ基板中のナトリウム量、ならびにチタン酸バリウム系半導体セラミック中のドナー量およびマンガン量が一定の関係を示す場合に低抵抗を実現できることを見出し、この発明をなすに至ったものである。 The present inventors have found that low resistance can be realized when the amount of sodium in the alumina substrate and the amount of donor and manganese in the barium titanate-based semiconductor ceramic exhibit a certain relationship, leading to the present invention. It is a thing.
　この発明に係る正特性サーミスタは、アルミナ基板と、アルミナ基板上に形成された、正の抵抗温度特性を示すサーミスタ厚膜と、サーミスタ厚膜に接し、かつサーミスタ厚膜の少なくとも一部を挟んで対向する、少なくとも１対の電極とを備えるものであるが、上述した技術的課題を解決するため、次のような構成を備えることを特徴としている。 A positive temperature coefficient thermistor according to the present invention includes an alumina substrate, a thermistor thick film having a positive resistance temperature characteristic formed on the alumina substrate, and in contact with the thermistor thick film and sandwiching at least a part of the thermistor thick film. Although it is provided with at least one pair of electrodes which oppose, in order to solve the technical problem mentioned above, it is characterized by providing the following structures.
　上記サーミスタ厚膜は、チタン酸バリウム系を主成分とする半導体セラミックの焼結体からなることを特徴としている。 The above thermistor thick film is characterized by comprising a sintered body of a semiconductor ceramic mainly composed of barium titanate.
　そして、半導体セラミックの焼結体に含まれるドナーの総量を、ドナー／Ｔｉ原子比で表わしたとき、ｘとし、半導体セラミックの焼結体に含まれるＭｎ量を、Ｍｎ／Ｔｉ原子比で表わしたとき、ｙとし、アルミナ基板中のＮａ量を、Ｎａ／Ａｌ原子比で表わしたとき、ｚとしたとき、
　０．０００８≦（ｘ－０．５ｙ－０．５ｚ）≦０．００４、
　０≦ｙ≦０．００７、および
　０＜ｚ≦０．００２
の条件を満たすことをさらなる特徴としている。 The total amount of donors contained in the sintered body of the semiconductor ceramic was expressed as x when expressed by the donor / Ti atomic ratio, and the amount of Mn contained in the sintered body of the semiconductor ceramic was expressed by the Mn / Ti atomic ratio. And y, when the amount of Na in the alumina substrate is expressed by the Na / Al atomic ratio, z
0.0008 ≦ (x−0.5y−0.5z) ≦ 0.004,
0 ≦ y ≦ 0.007, and 0 <z ≦ 0.002.
A further feature is that the above condition is satisfied.
　上記半導体セラミックは、副成分として少なくともホウ素元素を含むことが好ましい。 The semiconductor ceramic preferably contains at least boron element as a subcomponent.
　上記ドナーは、好ましくは、希土類元素である。 The donor is preferably a rare earth element.
　この発明によれば、アルミナ基板中のＮａ量、ならびにチタン酸バリウム系半導体セラミック中のドナー量およびＭｎ量が上述のような関係に選ばれているので、後述する実験例によって明らかにされるように、低抵抗化が図られた正特性サーミスタを得ることができる。 According to the present invention, the amount of Na in the alumina substrate and the amount of donor and the amount of Mn in the barium titanate semiconductor ceramic are selected as described above. In addition, a positive temperature coefficient thermistor with low resistance can be obtained.
　また、サーミスタ厚膜を構成する半導体セラミックは、焼結により、結晶粒子同士が面接触した状態となっているので、粒子間の接触面積を広くすることができる。このことも、低抵抗化に寄与する。すなわち、前述の特許文献１に記載のもののように、半導体粉末粒子および導電性粒子が点接触するように単に糊付けされているような状態のものに比べて、低抵抗化を図ることができる。 In addition, since the semiconductor ceramic constituting the thermistor thick film is in a state where the crystal particles are in surface contact with each other by sintering, the contact area between the particles can be widened. This also contributes to a reduction in resistance. That is, the resistance can be reduced as compared with the case where the semiconductor powder particles and the conductive particles are simply glued so as to be in point contact, as in the above-described Patent Document 1.
　さらに、この発明によれば、アルミナ基板とサーミスタ厚膜との間で高い密着性を得ることができ、よって剥離等の問題を招きにくくすることができる。 Furthermore, according to the present invention, it is possible to obtain high adhesion between the alumina substrate and the thermistor thick film, thereby making it difficult to cause problems such as peeling.
　この発明において、サーミスタ厚膜を構成する半導体セラミックが、副成分として少なくともホウ素元素を含んでいると、１０００℃程度またはそれより低い温度で確実に焼結させることができる。よって、半導体セラミック焼結体からなるサーミスタ厚膜をアルミナ基板上に形成した構造、すなわち大電流用の発熱体として適した形態の正特性サーミスタを容易に実現することができる。 In the present invention, if the semiconductor ceramic constituting the thermistor thick film contains at least boron element as an accessory component, it can be surely sintered at a temperature of about 1000 ° C. or lower. Therefore, it is possible to easily realize a positive temperature coefficient thermistor having a structure in which a thermistor thick film made of a semiconductor ceramic sintered body is formed on an alumina substrate, that is, a form suitable as a heating element for large current.
この発明の一実施形態による正特性サーミスタ１を示す平面図である。It is a top view which shows the positive temperature coefficient thermistor 1 by one Embodiment of this invention. 図１の線II－IIに沿う拡大断面図である。FIG. 2 is an enlarged sectional view taken along line II-II in FIG. 実験例において作製した試料としての正特性サーミスタ１１を示す平面図である。It is a top view which shows the positive temperature coefficient thermistor 11 as a sample produced in the experiment example. 実験例において作製した表１に示した試料のうち、「Ｌｎ」として「Ｓｍ」を含むものについて、「ｘ（Ｓｍ／Ｔｉ比）」と「ｚ（Ｎａ／Ａｌ比）」との関係を示す図である。Of the samples shown in Table 1 prepared in the experimental example, those containing “Sm” as “Ln” show the relationship between “x (Sm / Ti ratio)” and “z (Na / Al ratio)”. FIG. 実験例において作製した表２に示した試料のうち、「Ｌｎ」として「Ｓｍ」を含むものについて、「ｘ（Ｓｍ／Ｔｉ比）」と「ｙ（Ｍｎ／Ｔｉ比）」との関係を示す図である。Of the samples shown in Table 2 prepared in the experimental example, those containing “Sm” as “Ln” show the relationship between “x (Sm / Ti ratio)” and “y (Mn / Ti ratio)”. FIG.
　図１および図２を参照して、この発明の一実施形態による正特性サーミスタ１について説明する。 A positive temperature coefficient thermistor 1 according to an embodiment of the present invention will be described with reference to FIGS.
　正特性サーミスタ１は、アルミナ基板２と、アルミナ基板２上に形成された、ＰＴＣ特性を示すサーミスタ厚膜３と、サーミスタ厚膜３に接し、かつサーミスタ厚膜３の少なくとも一部を挟んで対向する、少なくとも１対の電極４および５とを備えている。さらに、図示しないが、アルミナ基板２上には、サーミスタ厚膜３ならびに電極４および５を覆うように、保護膜が形成されてもよい。 The positive temperature coefficient thermistor 1 is in contact with the alumina substrate 2, the thermistor thick film 3 formed on the alumina substrate 2 and exhibiting the PTC characteristic, and the thermistor thick film 3 with at least a part of the thermistor thick film 3 interposed therebetween. And at least one pair of electrodes 4 and 5. Further, although not shown, a protective film may be formed on the alumina substrate 2 so as to cover the thermistor thick film 3 and the electrodes 4 and 5.
　サーミスタ厚膜３は、ＡＢＯ３（Ａは、バリウムを必ず含み、さらにストロンチウム、カルシウム、鉛および希土類元素から選ばれる少なくとも１種を含むことがある。Ｂは、チタンを必ず含み、さらに錫、ジルコニウム、ニオブ、タングステンおよびアンチモンから選ばれる少なくとも１種を含むことがある。）で表わされるチタン酸バリウム（ＢａＴｉＯ３）系を主成分とする半導体セラミックの焼結体からなる。 The thermistor thick film 3 is ABO 3 (A always contains barium and may further contain at least one selected from strontium, calcium, lead and rare earth elements. B necessarily contains titanium, and further contains tin, zirconium. , Niobium, tungsten, and antimony may be included.) And a sintered body of a semiconductor ceramic having a barium titanate (BaTiO 3 ) system as a main component.
　この半導体セラミックは、副成分として少なくともホウ素元素を含むことが好ましい。ホウ素は、低温焼成を可能とするように作用するものであるが、半導体セラミックにおける、上記Ａの含有量を原子比でα、上記Ｂの含有量を原子比でβ、およびホウ素元素の含有量を原子比でγとしたとき、
　０．０５≦γ／β≦１．５、および
　１≦γ／（α－β）≦４
の条件を満たすようにされることが好ましい。 This semiconductor ceramic preferably contains at least boron element as a subcomponent. Boron acts to enable low-temperature firing. In the semiconductor ceramic, the A content is α in atomic ratio, the B content is β in atomic ratio, and the boron element content. Is the atomic ratio γ,
0.05 ≦ γ / β ≦ 1.5, and 1 ≦ γ / (α−β) ≦ 4
It is preferable to satisfy the following condition.
　この発明の半導体セラミックに含まれるホウ素元素は、ＢａＴｉＯ３系セラミックで表わされる主成分に固溶しているもの、Ｂ２ＢａＯ４あるいはＢ２Ｏ３で示される酸化物の状態で存在しているものであってもよく、ホウ素元素を含有していれば、上記形態に限定されるものではない。 The boron element contained in the semiconductor ceramic of the present invention exists in the form of an oxide represented by B 2 BaO 4 or B 2 O 3 dissolved in the main component represented by BaTiO 3 ceramic. It may be a thing, and if it contains a boron element, it will not be limited to the said form.
　なお、低温焼成を可能とするため、ホウ素以外の元素が半導体セラミックの副成分として添加されてもよい。 In order to enable low-temperature firing, elements other than boron may be added as subcomponents of the semiconductor ceramic.
　半導体セラミックの焼結体は、そこに含まれるドナーの総量を、ドナー／Ｔｉ原子比で表わしたとき、ｘとし、そこに含まれるＭｎ量を、Ｍｎ／Ｔｉ原子比で表わしたとき、ｙとし、アルミナ基板中のＮａ量を、Ｎａ／Ａｌ原子比で表わしたとき、ｚとしたとき、
　０．０００８≦（ｘ－０．５ｙ－０．５ｚ）≦０．００４、
　０≦ｙ≦０．００７、および
　０＜ｚ≦０．００２
の条件を満たすようにされる。 The sintered body of a semiconductor ceramic is x when the total amount of donors contained therein is represented by the donor / Ti atomic ratio, and y when the amount of Mn contained therein is represented by the Mn / Ti atomic ratio. When the amount of Na in the alumina substrate is expressed as Na / Al atomic ratio, and z,
0.0008 ≦ (x−0.5y−0.5z) ≦ 0.004,
0 ≦ y ≦ 0.007, and 0 <z ≦ 0.002.
To meet the requirements of
　上記の条件を満たすことによって、正特性サーミスタ１において、室温でたとえば１０ｋΩ・ｃｍ未満といった低い抵抗率を実現することができる。さらに、アルミナ基板２とサーミスタ厚膜３との間で高い密着性を得ることができる。 By satisfying the above conditions, the resistivity thermistor 1 can achieve a low resistivity of, for example, less than 10 kΩ · cm at room temperature. Furthermore, high adhesion can be obtained between the alumina substrate 2 and the thermistor thick film 3.
　上記（ｘ－０．５ｙ－０．５ｚ）の値が０．０００８未満では、ＢａＴｉＯ３系半導体セラミックの抵抗率が高くなり、他方、０．００４を超えても、同様に高抵抗率となる。 If the value of (x−0.5y−0.5z) is less than 0.0008, the resistivity of the BaTiO 3 based semiconductor ceramic is high, and if it exceeds 0.004, the resistivity is similarly high. .
　これは、ＢａＴｉＯ３系半導体セラミックに対して、Ｍｎがアクセプタとなり、また、Ｎａも、Ｍｎと同様、アクセプタ的な役割を果たすので、これらＭｎおよびＮａがドナーの効果を減殺するためであると考えられる。すなわち、ＢａＴｉＯ３系半導体セラミックに適量のドナーを添加することで低抵抗化が可能であるが、ＮａやＭｎが存在すると、ドナーの効果を弱めるため、ドナーの適量がより多い方へシフトすることを示している。 This is because Mn serves as an acceptor for BaTiO 3 -based semiconductor ceramics, and Na also serves as an acceptor like Mn, so that Mn and Na reduce the effect of the donor. It is done. That is, the resistance can be lowered by adding an appropriate amount of donor to the BaTiO 3 based semiconductor ceramic. However, if Na or Mn is present, the effect of the donor is weakened, so that the appropriate amount of donor is shifted to a larger amount. Is shown.
　なお、Ｎａに関しては、焼成前にはＢａＴｉＯ３系半導体セラミック中には存在せず、アルミナ基板に敢えて含有したものも、不純物として含有するものも対象となる。Ｎａに関しては、焼成中にアルミナ基板からＢａＴｉＯ３系半導体セラミック中に拡散するために影響するものと考える。 Note that Na does not exist in the BaTiO 3 -based semiconductor ceramic before firing, and it is intended to be included in the alumina substrate or contained as an impurity. Regarding Na, it is considered that it influences because it diffuses from the alumina substrate into the BaTiO 3 based semiconductor ceramic during firing.
　また、Ｍｎ量に相当するｙが０．００７を超え、あるいは、Ｎａ量に相当するｚが０．００２を超えると、ドナー量をより多くするだけでは補正しきれなくなり、ドナー量によらず高抵抗化してしまう。なお、Ｍｎについては、含有されないこともある。 Further, when y corresponding to the amount of Mn exceeds 0.007 or z corresponding to the amount of Na exceeds 0.002, it cannot be corrected only by increasing the amount of donor, and it is high regardless of the amount of donor. It becomes resistance. Note that Mn may not be contained.
　ドナー元素としては、特開２００１－３２６１０２号公報などで示されているＬａ、Ｙ、Ｓｍ、Ｃｅ、Ｄｙ、Ｇｄなどの希土類元素や、Ｎｂ、Ｔａ、Ｂｉ、Ｓｂ、Ｗなどを用いることができる。 As the donor element, rare earth elements such as La, Y, Sm, Ce, Dy, Gd and the like shown in JP 2001-326102 A, Nb, Ta, Bi, Sb, W, and the like can be used. .
　サーミスタ厚膜３は、たとえば１μｍ以上の厚みを有している。サーミスタ厚膜３を形成するため、たとえば、半導体セラミック粉末にワニスを混合して形成した半導体セラミックペーストを用意し、この半導体セラミックペーストをアルミナ基板２上に塗布するか、アルミナ基板２上でドクターブレード法等を適用してシート状に成形するかした後、焼成工程を実施するようにすればよい。 The thermistor thick film 3 has a thickness of 1 μm or more, for example. In order to form the thermistor thick film 3, for example, a semiconductor ceramic paste formed by mixing semiconductor ceramic powder with varnish is prepared, and this semiconductor ceramic paste is applied onto the alumina substrate 2 or a doctor blade on the alumina substrate 2. After the method or the like is applied to form a sheet, the firing process may be performed.
　電極４および５は、図２によく示されているように、サーミスタ厚膜３上に位置する部分を有している。第１の電極４は、図１によく示されているように、矩形の平面形状を有するサーミスタ厚膜３の長手方向に沿うように形成されている。他方、第２の電極５は、第１の電極４に対して所定の間隔を隔てながら、第１の電極４に対向するように位置している。また、電極４および５は、それぞれ、各々の端部において幅広の引出し部６および７を形成しており、これら引出し部６および７は、絶縁体セラミック基板２の一方端側に位置している。 The electrodes 4 and 5 have a portion located on the thermistor thick film 3 as well shown in FIG. As shown well in FIG. 1, the first electrode 4 is formed along the longitudinal direction of the thermistor thick film 3 having a rectangular planar shape. On the other hand, the second electrode 5 is positioned so as to face the first electrode 4 with a predetermined distance from the first electrode 4. Further, the electrodes 4 and 5 respectively form wide lead portions 6 and 7 at respective end portions, and these lead portions 6 and 7 are located on one end side of the insulating ceramic substrate 2. .
　電極４および５は、サーミスタ厚膜３との間でオーミック接触が取れる材料から構成される。電極４および５の材料としては、たとえば、Ｎｉ、Ｃｕ、Ａｌ等の卑金属またはその合金、あるいは卑金属添加によりオーミック化されたオーミックＡｇ等が用いられる。 The electrodes 4 and 5 are made of a material capable of making ohmic contact with the thermistor thick film 3. As a material of the electrodes 4 and 5, for example, a base metal such as Ni, Cu, or Al or an alloy thereof, or ohmic Ag that is ohmicized by addition of a base metal is used.
　電極４および５を形成するにあたっては、たとえば、スパッタリング、蒸着等の薄膜形成法、または導電性ペーストを塗布して焼き付ける厚膜法を適用することができる。 In forming the electrodes 4 and 5, for example, a thin film forming method such as sputtering or vapor deposition, or a thick film method in which a conductive paste is applied and baked can be applied.
　図示した正特性サーミスタ１は、特に図１からわかるように、長尺状の（すなわち、アスペクト比が大きい）アルミナ基板２上にサーミスタ厚膜３が長尺状のパターンをもって形成された構造を有している。そのため、アルミナ基板２とサーミスタ厚膜３との間で、各々の線膨張係数の違い等が原因となって剥がれが生じやすいという課題がある。しかし、この発明によれば、アルミナ基板２とサーミスタ厚膜３との間で高い密着性を確保でき、よって、剥がれが生じにくくすることができる。したがって、この発明は、特に、正特性サーミスタが図１に示すような長尺の絶縁体セラミック基板上に長尺のサーミスタ厚膜が形成された形態を有するとき、より意義深いものとなる。 As shown in FIG. 1, the positive temperature coefficient thermistor 1 has a structure in which a thermistor thick film 3 is formed in a long pattern on an elongated alumina substrate 2 (that is, an aspect ratio is large). is doing. Therefore, there is a problem that peeling is likely to occur between the alumina substrate 2 and the thermistor thick film 3 due to differences in the respective linear expansion coefficients. However, according to the present invention, high adhesion can be ensured between the alumina substrate 2 and the thermistor thick film 3, and therefore, peeling can be prevented. Accordingly, the present invention becomes more significant particularly when the positive temperature coefficient thermistor has a form in which a long thermistor thick film is formed on a long insulator ceramic substrate as shown in FIG.
　次に、この発明の効果を確認するために実施した実験例について説明する。 Next, experimental examples carried out to confirm the effects of the present invention will be described.
　［実験例１］
　まず、ＢａＣＯ３、ＴｉＯ２、ならびに、ドナーとなる希土類元素酸化物：Ｌｎ２Ｏ３としてのＳｍ２Ｏ３、Ｙ２Ｏ３およびＮｄ２Ｏ３の各粉末を用意し、これら粉末を（Ｂａ１－ｘＬｎｘ）ＴｉＯ３となるように調合した。ここで、ｘは、ドナーの総量をドナー／Ｔｉ原子比で表わしたものであるが、表１および表２の「ｘ」の欄に示されている。 [Experimental Example 1]
First, BaCO 3 , TiO 2 , and rare earth element oxides serving as donors: Sm 2 O 3 , Y 2 O 3 and Nd 2 O 3 as Ln 2 O 3 were prepared. 1-x Ln x ) TiO 3 was prepared. Here, x represents the total amount of donor in terms of donor / Ti atomic ratio, and is shown in the column “x” in Tables 1 and 2.
　次いで、上記調合粉末を、ボールミルを用いて、水中でＰＳＺボールとともに５時間粉砕した後、１０００℃の温度で２時間仮焼した。得られた仮焼粉に、ＢＮとＢａＣＯ３とを添加するとともに、表１および表２の「ｙ」（Ｍｎ量を、Ｍｎ／Ｔｉ原子比で表わしたもの）の欄に示す添加量をもって、ＭｎＣＯ３を添加して、以下の組成のような混合物を得た。 Next, the above prepared powder was pulverized with PSZ balls in water for 5 hours using a ball mill, and then calcined at a temperature of 1000 ° C. for 2 hours. In addition to adding BN and BaCO 3 to the calcined powder obtained, with the addition amount shown in the column of “y” in Table 1 and Table 2 (Mn amount expressed in Mn / Ti atomic ratio), MnCO 3 was added to obtain a mixture having the following composition.
　（Ｂａ１－ｘＬｎｘ）ＴｉＯ３＋０．３ＢＮ＋０．１５ＢａＣＯ３＋ｙＭｎＣＯ３
　他方、表１および表２の「ｚ」（アルミナ基板中のＮａ量をＮａ／Ａｌ原子比で表わしたもの）となるＮａ量を有するアルミナ基板を用意した。 (Ba 1-x Ln x ) TiO 3 + 0.3BN + 0.15BaCO 3 + yMnCO 3
On the other hand, an alumina substrate having an amount of Na corresponding to “z” in Tables 1 and 2 (the amount of Na in the alumina substrate expressed by the Na / Al atomic ratio) was prepared.
　表１および表２には、各試料についての「ｘ－０．５ｙ－０．５ｚ」の値も示されている。 Tables 1 and 2 also show the value of “x−0.5y−0.5z” for each sample.
　次に、上記混合物にワニスを添加し、ペースト化した後、アルミナ基板上に塗布して１０５０℃の温度で２時間焼成して、半導体セラミックの焼結体からなるサーミスタ厚膜を得た。焼成後のサーミスタ厚膜の厚みｔは１００μｍであった。 Next, varnish was added to the above mixture to form a paste, which was then applied onto an alumina substrate and fired at a temperature of 1050 ° C. for 2 hours to obtain a thermistor thick film made of a sintered ceramic ceramic. The thickness t of the thermistor thick film after firing was 100 μm.
　次に、Ｎｉスパッタリングを実施することによって、図３に示すように、アルミナ基板１２上に形成された上記サーミスタ厚膜１３の各端部を覆う状態で、アルミナ基板１２上に１対の電極１４および１５を形成し、試料となる正特性サーミスタ１１を得た。 Next, by performing Ni sputtering, as shown in FIG. 3, a pair of electrodes 14 is formed on the alumina substrate 12 so as to cover each end of the thermistor thick film 13 formed on the alumina substrate 12. And a positive temperature coefficient thermistor 11 as a sample was obtained.
　次に、表１および表２に示すように、得られた各試料について、「室温抵抗率」を測定した。「室温抵抗率」は、室温２５℃において、１Ｖの直流電圧を印加した際の抵抗率を２端子法で測定したものである。この「室温抵抗率」に関して、１０ｋΩ・ｃｍ以上の場合、不良と判定した。 Next, as shown in Tables 1 and 2, “room temperature resistivity” was measured for each of the obtained samples. “Room temperature resistivity” is measured by the two-terminal method when a DC voltage of 1 V is applied at a room temperature of 25 ° C. Regarding this “room temperature resistivity”, when it was 10 kΩ · cm or more, it was determined to be defective.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　表１および表２において、試料番号に＊を付したものは、この発明の範囲外の比較例である。なお、表１に示した試料と表２に示した試料とは、前者が半導体セラミック中にＭｎを含まず、後者がＭｎを含む点で区別される。 In Tables 1 and 2, the sample numbers marked with * are comparative examples outside the scope of the present invention. The samples shown in Table 1 and the samples shown in Table 2 are distinguished in that the former does not contain Mn in the semiconductor ceramic and the latter contains Mn.
　表１および表２に示すように、この発明の範囲内の試料２～４、７～９、１２～１４、１７～１９、２２～２４、２９～３３、３５～３９、４２～４４、４７～４９、５２～５４、５７～５９、６２～６４、６９～７２、および７４～７７によれば、「室温抵抗率」を１０ｋΩ・ｃｍ未満と低くすることができる。これらの試料は、０．０００８≦（ｘ－０．５ｙ－０．５ｚ）≦０．００４、０≦ｙ≦０．００７、および０＜ｚ≦０．００２の条件を満たしている。 As shown in Tables 1 and 2, Samples 2 to 4, 7 to 9, 12 to 14, 17 to 19, 22 to 24, 29 to 33, 35 to 39, 42 to 44, 47 within the scope of the present invention. According to ˜49, 52 to 54, 57 to 59, 62 to 64, 69 to 72, and 74 to 77, the “room temperature resistivity” can be lowered to less than 10 kΩ · cm. These samples satisfy the following conditions: 0.0008 ≦ (x−0.5y−0.5z) ≦ 0.004, 0 ≦ y ≦ 0.007, and 0 <z ≦ 0.002.
　また、上記のこの発明の範囲内の試料については、表１および表２には示されていないが、サーミスタ厚膜がアルミナ基板から剥がれることもなかった。 Further, although the samples within the scope of the present invention are not shown in Tables 1 and 2, the thermistor thick film was not peeled off from the alumina substrate.
　これらに対して、「ｘ－０．５ｙ－０．５ｚ」の値が０．０００８未満の試料１、６、１１、１６、２１、４１、４６、５１、５６および６１では、「室温抵抗率」が１０ｋΩ・ｃｍ以上と高くなった。 On the other hand, in the samples 1, 6, 11, 16, 21, 41, 46, 51, 56 and 61 in which the value of “x−0.5y−0.5z” is less than 0.0008, “room temperature resistivity” Was increased to 10 kΩ · cm or more.
　同様に、「ｘ－０．５ｙ－０．５ｚ」の値が０．００４を超える試料５、１０、１５、２０、２５、４５、５０、５５、６０および６５でも、「室温抵抗率」が１０ｋΩ・ｃｍ以上と高くなった。 Similarly, in the samples 5, 10, 15, 20, 25, 45, 50, 55, 60 and 65 in which the value of “x−0.5y−0.5z” exceeds 0.004, the “room temperature resistivity” It was as high as 10 kΩ · cm or more.
　また、「ｙ」が０．００７を超える試料６６～６８、７３および７８でも、「室温抵抗率」が１０ｋΩ・ｃｍ以上と高くなった。 Also, in the samples 66 to 68, 73 and 78 in which “y” exceeds 0.007, the “room temperature resistivity” is as high as 10 kΩ · cm or more.
　また、「ｚ」が０．００２を超える試料２６～２８、３４、４０でも、「室温抵抗率」が１０ｋΩ・ｃｍ以上と高くなった。 In addition, even in the samples 26 to 28, 34, and 40 where “z” exceeds 0.002, the “room temperature resistivity” is as high as 10 kΩ · cm or more.
　図４は、表１に示した試料のうち、「Ｌｎ」として「Ｓｍ」を含むものについて、「ｘ（Ｓｍ／Ｔｉ比）」と「ｚ（Ｎａ／Ａｌ比）」との関係を示す図である。図５は、表２に示した試料のうち、「Ｌｎ」として「Ｓｍ」を含むものについて、「ｘ（Ｓｍ／Ｔｉ比）」と「ｙ（Ｍｎ／Ｔｉ比）」との関係を示す図である。図４および図５において、線で囲まれた領域がこの発明の範囲内の組成であることを示している。 FIG. 4 is a diagram showing the relationship between “x (Sm / Ti ratio)” and “z (Na / Al ratio)” for samples including “Sm” as “Ln” among the samples shown in Table 1. It is. FIG. 5 is a diagram showing the relationship between “x (Sm / Ti ratio)” and “y (Mn / Ti ratio)” for samples including “Sm” as “Ln” among the samples shown in Table 2. It is. 4 and 5, it is shown that the area surrounded by the line has a composition within the scope of the present invention.
１，１１　正特性サーミスタ
２，１２　アルミナ基板
３，１３　サーミスタ厚膜
４，５，１４，１５　電極 1, 11 Positive temperature coefficient thermistor 2, 12 Alumina substrate 3, 13 Thermistor thick film 4, 5, 14, 15 Electrode

Claims (3)

  1. 　アルミナ基板と、
    　前記アルミナ基板上に形成された、正の抵抗温度特性を示すサーミスタ厚膜と、
    　前記サーミスタ厚膜に接し、かつ前記サーミスタ厚膜の少なくとも一部を挟んで対向する、少なくとも１対の電極と
    を備え、
    　前記サーミスタ厚膜は、チタン酸バリウム系を主成分とする半導体セラミックの焼結体からなり、
    　前記半導体セラミックの焼結体に含まれるドナーの総量を、ドナー／Ｔｉ原子比で表わしたとき、ｘとし、前記半導体セラミックの焼結体に含まれるＭｎ量を、Ｍｎ／Ｔｉ原子比で表わしたとき、ｙとし、前記アルミナ基板中のＮａ量を、Ｎａ／Ａｌ原子比で表わしたとき、ｚとしたとき、
    　０．０００８≦（ｘ－０．５ｙ－０．５ｚ）≦０．００４、
    　０≦ｙ≦０．００７、および
    　０＜ｚ≦０．００２
    の条件を満たす、
    正特性サーミスタ。     An alumina substrate;
    A thermistor thick film having a positive resistance temperature characteristic formed on the alumina substrate;
    And at least one pair of electrodes that are in contact with the thermistor thick film and face each other with at least a part of the thermistor thick film interposed therebetween,
    The thermistor thick film is composed of a sintered body of a semiconductor ceramic whose main component is a barium titanate system,
    When the total amount of donors contained in the sintered body of the semiconductor ceramic is represented by a donor / Ti atomic ratio, x is represented, and the amount of Mn contained in the sintered body of the semiconductor ceramic is represented by an Mn / Ti atomic ratio. And y, when the amount of Na in the alumina substrate is expressed as Na / Al atomic ratio, z
    0.0008 ≦ (x−0.5y−0.5z) ≦ 0.004,
    0 ≦ y ≦ 0.007, and 0 <z ≦ 0.002.
    Satisfying the conditions of
    Positive characteristic thermistor.
  2. 　前記半導体セラミックは、副成分として少なくともホウ素元素を含む、請求項１に記載の正特性サーミスタ。 2. The positive temperature coefficient thermistor according to claim 1, wherein the semiconductor ceramic contains at least a boron element as a subcomponent.
  3. 　前記ドナーは希土類元素である、請求項１または２に記載の正特性サーミスタ。 The positive temperature coefficient thermistor according to claim 1 or 2, wherein the donor is a rare earth element.
PCT/JP2012/051331 2011-02-17 2012-01-23 Positive temperature-coefficient thermistor WO2012111385A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2011-031570 2011-02-17
JP2011031570 2011-02-17

Publications (1)

Publication Number Publication Date
WO2012111385A1 true WO2012111385A1 (en) 2012-08-23

Family

ID=46672324

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2012/051331 WO2012111385A1 (en) 2011-02-17 2012-01-23 Positive temperature-coefficient thermistor

Country Status (1)

Country Link
WO (1) WO2012111385A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102017101946A1 (en) 2017-02-01 2018-08-02 Epcos Ag PTC heater with reduced inrush current

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS55130101A (en) * 1979-03-30 1980-10-08 Tokyo Shibaura Electric Co Method of manufacting thick film positive temperature coefficient semiconductor element
JPH11246268A (en) * 1998-03-05 1999-09-14 Murata Mfg Co Ltd Semiconductor ceramic and semiconductor ceramic device
JP2002076609A (en) * 2000-08-25 2002-03-15 Kyocera Corp Circuit board
JP2008169453A (en) * 2007-01-15 2008-07-24 Dowa Electronics Materials Co Ltd Silver particle-dispersed liquid, and method for producing the same

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS55130101A (en) * 1979-03-30 1980-10-08 Tokyo Shibaura Electric Co Method of manufacting thick film positive temperature coefficient semiconductor element
JPH11246268A (en) * 1998-03-05 1999-09-14 Murata Mfg Co Ltd Semiconductor ceramic and semiconductor ceramic device
JP2002076609A (en) * 2000-08-25 2002-03-15 Kyocera Corp Circuit board
JP2008169453A (en) * 2007-01-15 2008-07-24 Dowa Electronics Materials Co Ltd Silver particle-dispersed liquid, and method for producing the same

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102017101946A1 (en) 2017-02-01 2018-08-02 Epcos Ag PTC heater with reduced inrush current

Similar Documents

Publication Publication Date Title
JP5099011B2 (en) Barium titanate-based semiconductor ceramic composition and PTC element using the same
JP5327556B2 (en) Semiconductor ceramic and positive temperature coefficient thermistor
US9666369B2 (en) Dielectric ceramic composition and multilayer ceramic capacitor containing the same
JP6424728B2 (en) Semiconductor porcelain composition and PTC thermistor
US9530547B2 (en) Laminated PTC thermistor element
JP6915222B2 (en) Dielectric composition and multilayer ceramic capacitors containing it
US9799451B2 (en) Dielectric composition and multilayer ceramic capacitor containing the same
JP2016108217A (en) Dielectric ceramic composition, and multilayer ceramic capacitor including the same
JP2008130770A (en) Electronic component and manufacturing method thereof
EP3127889A1 (en) Semiconductor ceramic composition and ptc thermistor
JP5420603B2 (en) Reduction-resistant dielectric composition and ceramic electronic component including the same
JP4710096B2 (en) Multilayer positive temperature coefficient thermistor
JP4792900B2 (en) Porcelain composition for varistor and laminated varistor
JP7196906B2 (en) Dielectric porcelain composition and ceramic electronic parts
WO2012111385A1 (en) Positive temperature-coefficient thermistor
JP6102405B2 (en) Dielectric porcelain composition and dielectric element
JP4788274B2 (en) Oxide conductor porcelain and resistor having CTR characteristics
WO2012111386A1 (en) Positive temperature-coefficient thermistor
US8390421B2 (en) Semiconductor ceramic and positive-coefficient characteristic thermistor
WO2013065373A1 (en) Semiconductor ceramic, and ptc thermistor using same
JP2014072374A (en) Barium titanate-based semiconductor porcelain composition and ptc thermistor using the same
JPH11340090A (en) Manufacture of grain boundary insulated multilayer ceramic capacitor
US20140247107A1 (en) Barium titanate semiconductor ceramic and ptc thermistor using the same
JPH04115409A (en) Non-reducing dielectric ceramic composite
JP2016184694A (en) Semiconductor ceramic composition and ptc thermistor

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 12746575

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 12746575

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: JP