EP0723276A2 - Halbleitende Keramik mit negativem Temperaturkoeffizienten und diese verwendendes keramisches Halbleiterbauelement - Google Patents

Halbleitende Keramik mit negativem Temperaturkoeffizienten und diese verwendendes keramisches Halbleiterbauelement Download PDF

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Publication number
EP0723276A2
EP0723276A2 EP96100708A EP96100708A EP0723276A2 EP 0723276 A2 EP0723276 A2 EP 0723276A2 EP 96100708 A EP96100708 A EP 96100708A EP 96100708 A EP96100708 A EP 96100708A EP 0723276 A2 EP0723276 A2 EP 0723276A2
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EP
European Patent Office
Prior art keywords
ceramic
semiconductor ceramic
ycamn
type oxide
semiconductor
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.)
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Application number
EP96100708A
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English (en)
French (fr)
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EP0723276A3 (de
Inventor
Kenjiro c/o Murata Manufact. Co. Ltd. Mihara
Hideaki c/o Murata Manufact. Co. Ltd. Niimi
Terunobu c/o Murata Manufact. Co. Ltd. Ishikawa
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Murata Manufacturing Co Ltd
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Murata Manufacturing Co Ltd
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 Murata Manufacturing Co Ltd filed Critical Murata Manufacturing Co Ltd
Publication of EP0723276A2 publication Critical patent/EP0723276A2/de
Publication of EP0723276A3 publication Critical patent/EP0723276A3/de
Withdrawn legal-status Critical Current

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    • 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
    • H01C7/04—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 negative temperature coefficient
    • H01C7/042—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 negative temperature coefficient mainly consisting of inorganic non-metallic substances
    • H01C7/043—Oxides or oxidic compounds

Definitions

  • the present invention relates to a semiconductor ceramic having negative resistance/temperature characteristics and a semiconductor ceramic component utilizing the same.
  • Fig. 1 illustrates the appearance of a conventional semiconductor ceramic having negative resistance/temperature characteristics (hereinafter referred to as a negative characteristics thermistor).
  • a negative characteristics thermistor electrodes (not shown) are formed on both principal surfaces of a semiconductor ceramic (not shown) having negative resistance/temperature characteristics made of a spinel type oxide; terminals 3a and 3b are connected to the electrodes by solder (not shown); and the external surface of the oxide is coated with resin 4.
  • a switching power supply is subjected to an overcurrent, i.e., an initial rush current, when it is turned on.
  • the so-called negative characteristics thermistor is used to absorb such a rush current.
  • the negative characteristics thermistor exhibits high resistance at room temperature, and the resistance decreases as the temperature rises. Therefore, the rush current is suppressed immediately after energization, and the thermistor exhibits low resistance during steady state operation where the thermistor temperature has risen as a result of self-heating, which reduces power consumption.
  • Spinel oxide type ceramics have been used for such negative characteristics thermistors.
  • a negative characteristics thermistor When a negative characteristics thermistor is processed using an SMD, the self-heating of the negative characteristics thermistor causes a temperature rise of the circuit board to which it is connected. Since a conventional spinel oxide type negative characteristics thermistor has a B constant which is as small as 3000, and the resistance thereof at elevated temperatures is not sufficiently low which results in a more significant degree of self-heating during operation. As a result, it has been difficult to suppress the temperature rise at the circuit board.
  • a negative characteristics thermistor having low specific resistance made of a VO 2 type ceramic is excellent in preventing a rush current because it exhibits the characteristic of the specific resistance being abruptly decreased to 10 to 0.01 ⁇ cm at 80°C.
  • the shape of a VO 2 type ceramic is limited to a bead-like shape because such a ceramic is unstable and is manufactured using reduction firing followed by quenching. Further, since the allowable current value of such a ceramic is as small as several tens mA, it has not been possible to use it in a switching power supply through which a large current flows.
  • a chip type thermistor for current control that satisfies recent demands for more compact and lower profile devices is provided.
  • the thermistor of the present invention has low resistance at elevated temperatures to suppress its heat generation. A large current can be applied to the thermistor.
  • the inventors made an active study to find a device made of a material having negative resistance/temperature characteristics which had a specific resistance sufficiently low to fabricate the device in a chip-size, which had a B constant large enough to suppress the self-heating of the device, and which was suitable for current control.
  • compositions based on YCaMn type oxides have specific resistance of 1 ⁇ cm or less and a B constant of 4000 or more, and can provide satisfactory results in tests to examine practicality for the purpose of current control.
  • compositions are the type of materials described by Taguchi, Shimada et al. in Journal of Solid State Chemistry, Vol. 63, p.290 (1986). Those materials were studied as potential materials for the electrodes of fuel batteries, and the study was focused on their conductivity at high temperatures. Therefore, the study was intended for an application which is quite different from the intended application of the present invention wherein such materials are used for current control devices.
  • a negative characteristics thermistor made of a YCaMn type oxide ceramic.
  • a negative characteristics thermistor made of a YCaMn type oxide ceramic which is expressed by a general formula Y 1-x Ca x MnO 3 in which x is about 0.2 to 0.6.
  • a semiconductor ceramic component constituted by a ceramic body and electrodes formed on the ceramic body, the ceramic body being made of a YCaMn type oxide ceramic.
  • a negative characteristics thermistor according to the present invention is made of a YCaMn type oxide and has low specific resistance and a big B constant.
  • composition of a YCaMn type oxide allows a semiconductor ceramic component according to the present invention to have small specific resistance and a large B constant.
  • Fig. 1 shows the appearance of a conventional negative characteristics thermistor.
  • Fig. 2 is a perspective view of a semiconductor ceramic component according to the present invention.
  • Fig. 3 illustrates temperature rises caused by energization observed on a semiconductor ceramic component according to the present invention and a conventional semiconductor ceramic component.
  • Fig. 4 illustrates changes in the specific resistance of a semiconductor ceramic component according to the present invention caused by intermittent energization of the same.
  • electrodes 2a and 2b are formed on both ends of a semiconductor ceramic body 1 having negative resistance/temperature characteristics.
  • the materials Y 2 O 3 , CaCO 3 , and Mn 2 O 3 are prepared and weighed to provide the compositions shown on Table 1.
  • the resultant powders are subjected to wet mixing with purified water and zirconia balls for seven hours in a pot made of polyethylene. Thereafter, they are dried and are sintered for two hours at 1000°C.
  • the resultant sintered powders are combined with an organic binder, a solvent, a dispersant, and polystyrene particles and are subjected to wet mixing for five hours in a polyethylene pot again to obtain a slurry.
  • a ceramic green sheet having a thickness of 50 ⁇ m is formed from the slurry.
  • the green sheet is cut into predetermined dimensions, stacked and laminated, and contact-bonded to be finally formed in a size such that it has resistance of 8 1/2.
  • Table 1 Sample No. Y 1-x Ca x MnO 3 x Specific Resistance at 25°C ⁇ cm B Constant 25/50°C K 1 * 0 2800 5200 2 * 0.1 20 5000 3 0.2 1 4800 4 0.4 0.8 4400 5 0.6 0.4 4000 6 * 0.7 0.008 3000 7 * 1.0 less than 0.001 2700
  • the elements thus formed are dispersed on a firing sheath so that they do not overlap with each other. After being degreased at 400°C, they are fired at 1400°C in an atmosphere with a partial pressure of oxygen of 0.5 MPa or more to obtain a ceramic body.
  • the resultant ceramic body is chamfered by means of barrel polishing.
  • An electrode paste containing a conductive powder mainly composed of Ag is applied to the ends of the ceramic body and is baked at 800°C to form the electrodes of the semiconductor ceramic component.
  • a conventional semiconductor ceramic component as shown in Fig. 1 was fabricated as follows.
  • CO 3 O 4 , Mn 3 O 4 , and CuCO 3 are weighed to achieve a weight ratio of 6:3:1.
  • the product is combined with a binder and subjected to wet mixing and pulverization for seven hours in a polyethylene pot containing zirconia balls. After being dried, it is molded in the form of a disc so that it has resistance at room temperature of 8 ⁇ and is fired for two hours at 1250°C in the air. Then, electrodes are baked on both principal surfaces of the resultant disc-shaped ceramic body; terminals are soldered to the electrodes; and the external surface of the body is coated with resin.
  • Fig. 3 is a graph showing the results of an energization test in which the surface temperature (°C) of the semiconductor ceramic components and the value of the energizing current (A) are plotted along the vertical and horizontal axles, respectively.
  • the solid line and broken line indicate the results for the components according to the invention and the prior art, respectively.
  • the self-heating of the semiconductor ceramic component according to the present invention is significantly less than that of the conventional component.
  • Fig. 4 is a graph showing the results of an intermittent energization test in which the percentages of change in resistance and the number of times when the energization is performed and stopped are plotted. Intermittent energization was performed by repeating 10000 cycles of the application of a current of 5 A to samples according to the present invention for one minute and the removal of the current for five minutes, and changes in the resistance over time were measured. The measurement was made on 20 samples according to the present invention at each point in time, and the average, maximum, and minimum values were obtained. The graph indicates sufficient applicability of the invention to current control devices because there is almost no fluctuation of the percentage of change in resistance during the 10000 cycles of intermittent energization.
  • electrodes made of Ag is used in the present invention, the same characteristics can be obtained using Pt, Pd, Rh, or alloys obtained from them.

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  • Engineering & Computer Science (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Thermistors And Varistors (AREA)
  • Compositions Of Oxide Ceramics (AREA)
EP96100708A 1995-01-18 1996-01-18 Halbleitende Keramik mit negativem Temperaturkoeffizienten und diese verwendendes keramisches Halbleiterbauelement Withdrawn EP0723276A3 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP5870/95 1995-01-18
JP07005870A JP3141719B2 (ja) 1995-01-18 1995-01-18 負の抵抗温度特性を有する半導体セラミックとそれを用いた半導体セラミック部品

Publications (2)

Publication Number Publication Date
EP0723276A2 true EP0723276A2 (de) 1996-07-24
EP0723276A3 EP0723276A3 (de) 1997-06-18

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EP96100708A Withdrawn EP0723276A3 (de) 1995-01-18 1996-01-18 Halbleitende Keramik mit negativem Temperaturkoeffizienten und diese verwendendes keramisches Halbleiterbauelement

Country Status (4)

Country Link
EP (1) EP0723276A3 (de)
JP (1) JP3141719B2 (de)
KR (1) KR960030454A (de)
TW (1) TW293183B (de)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0798275A1 (de) * 1996-03-29 1997-10-01 Denso Corporation Verfahren zur Herstellung von Thermistoren und Werkstoff dafür
EP0917717A1 (de) * 1996-06-17 1999-05-26 Thermometrics, Inc. Sensoren und verfahren zu deren herstellung aus einem gemeinsamen wafer
US10134512B2 (en) 2015-06-04 2018-11-20 Murata Manufacturing Co., Ltd. Ceramic material and resistive element

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3553796A4 (de) * 2017-06-20 2020-12-16 Shibaura Electronics Co., Ltd. Thermistor-sinterkörper und thermistorelement
CN115925418A (zh) * 2022-12-14 2023-04-07 肇庆市金龙宝电子有限公司 一种低温ntc热敏电阻陶瓷及其制备方法

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0350770A2 (de) * 1988-07-14 1990-01-17 TDK Corporation Keramik-Halbleiter
JPH05229866A (ja) * 1992-02-19 1993-09-07 Murata Mfg Co Ltd Ｍｎ３ Ｏ４ 系磁器の焼成方法
JPH05258906A (ja) * 1992-03-13 1993-10-08 Tdk Corp チップ型サーミスタ
JPH07247165A (ja) * 1994-03-11 1995-09-26 Kyocera Corp 導電性セラミックス

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0350770A2 (de) * 1988-07-14 1990-01-17 TDK Corporation Keramik-Halbleiter
JPH05229866A (ja) * 1992-02-19 1993-09-07 Murata Mfg Co Ltd Ｍｎ３ Ｏ４ 系磁器の焼成方法
JPH05258906A (ja) * 1992-03-13 1993-10-08 Tdk Corp チップ型サーミスタ
JPH07247165A (ja) * 1994-03-11 1995-09-26 Kyocera Corp 導電性セラミックス

Non-Patent Citations (4)

* Cited by examiner, † Cited by third party
Title
JOURNAL OF SOLID STATE CHEMISTRY, MAY 1991, USA, vol. 92, no. 1, ISSN 0022-4596, pages 116-129, XP000646234 KOBAYASHI T ET AL: "Metal-insulator transition and thermoelectric properties in the system (R/sub 1-x/Ca/sub x/)MnO/sub 3- delta / (R:Tb, Ho, Y)" *
PATENT ABSTRACTS OF JAPAN vol. 017, no. 685 (C-1142), 15 December 1993 & JP 05 229866 A (MURATA MFG CO LTD), 7 September 1993, *
PATENT ABSTRACTS OF JAPAN vol. 018, no. 020 (E-1489), 13 January 1994 & JP 05 258906 A (TDK CORP), 8 October 1993, *
PATENT ABSTRACTS OF JAPAN vol. 95, no. 009 & JP 07 247165 A (KYOCERA CORP), 26 September 1995, *

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0798275A1 (de) * 1996-03-29 1997-10-01 Denso Corporation Verfahren zur Herstellung von Thermistoren und Werkstoff dafür
US5879750A (en) * 1996-03-29 1999-03-09 Denso Corporation Method for manufacturing thermistor materials and thermistors
EP0917717A1 (de) * 1996-06-17 1999-05-26 Thermometrics, Inc. Sensoren und verfahren zu deren herstellung aus einem gemeinsamen wafer
EP0917717A4 (de) * 1996-06-17 2000-11-08 Thermometrics Inc Sensoren und verfahren zu deren herstellung aus einem gemeinsamen wafer
US10134512B2 (en) 2015-06-04 2018-11-20 Murata Manufacturing Co., Ltd. Ceramic material and resistive element

Also Published As

Publication number Publication date
JP3141719B2 (ja) 2001-03-05
KR960030454A (ko) 1996-08-17
TW293183B (de) 1996-12-11
JPH08198674A (ja) 1996-08-06
EP0723276A3 (de) 1997-06-18

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