JPH08153604A - Manufacture of laminated type semiconductor ceramic element - Google Patents

Abstract

PURPOSE: To provide a laminates type semiconductor ceramic element with a good PTC characteristic with which a reoxidization treatment can be conducted at a low temperature, ohmic contact can be obtained between a ceramic layer and an inner electrode, a low resistance value can be obtained at room temperature and a large resistance fluctuation range can be obtained. CONSTITUTION: When a laminated type semiconductor ceramic element is manufactured, nickel oxide is used as the starting raw material for an internal electrode such a material as wet synthetic barium titanate semiconductor ceramic material which is sintered at 1000 to 1250 deg.C, and reoxidized at 500 to 1000 deg.C, is used for the raw material of ceramic layer, and fired at a low temperature.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a laminated semiconductor ceramic device having a positive resistance temperature characteristic (hereinafter referred to as "PTC characteristic").

[0002]

2. Description of the Related Art Semiconductor ceramic materials having PTC characteristics are generally based on barium titanate and are used for temperature control,
Widely used for current limitation, constant temperature heat generation, etc. In addition, in the above-mentioned applications, there is a demand for lower resistance in order to suppress power consumption. To meet such demand, for example, Japanese Laid-Open Patent Publication No. 57-60802 proposes a laminated semiconductor ceramic device. Has been done. In this laminated semiconductor ceramic element, ceramic layers containing barium titanate as a main component and internal electrodes made of a Pt-Pd alloy are alternately laminated and integrally fired. However, the above-mentioned laminated semiconductor ceramic element has a problem that it is difficult to obtain ohmic contact between the internal electrode and the ceramic layer, and the resistance value is significantly increased.

Nickel-based metals have been proposed as an alternative to the above internal electrode materials. In this case, since the electrode is oxidized in normal atmospheric firing, it is necessary to perform the reoxidation treatment at a temperature at which the nickel-based metal is not oxidized after the firing is performed once in the reducing atmosphere. However, even in this case, there is a case where ohmic contact between the ceramic layer and the internal electrode cannot be obtained during the reoxidation process, and there is a problem that the resistance value increases.

Further, even if ohmic contact is obtained, reoxidation occurs when a conventional semiconductor ceramic material requiring a firing temperature of 1300 ° C. or higher is used as illustrated in JP-A-6-151103. Since the processing temperature becomes high, there is a problem that the resistance change width becomes small.

[0005]

As described above, a multilayer semiconductor ceramic element which has ohmic contact between the ceramic layer and the internal electrode and has a low resistance and a sufficient resistance change width has not been obtained. . Therefore, an object of the present invention is to provide a multi-layer semiconductor ceramic device which has ohmic contact between a ceramic layer and an internal electrode, has a low resistance, and has a sufficient resistance change width.

[0006]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies in order to achieve the above-mentioned object. As a result, when performing reoxidation treatment after firing in a reducing atmosphere, the internal electrode Nickel oxide is used as a material, and is sintered at a temperature of 1000 ° C. or higher and 1250 ° C. or lower as a raw material for the semiconductor ceramic layer, and 5
By using a material that is reoxidized at a temperature of 00 ° C or higher and 1000 ° C or lower, 500 ° C or higher 1000
It has been found that ohmic contact is obtained between the ceramic layer and the internal electrode and the resistance change width is increased in the reoxidation treatment at a temperature of ℃ or below.

It is not clear why the PTC characteristics can be improved by changing nickel or nickel alloy used in the prior art to nickel oxide as the internal electrode material. The rise in resistance is suppressed and the range of resistance change is increased.

The nickel oxide used in the present invention is not particularly limited as long as it can be converted into a metal during firing in a reducing atmosphere, but since it is printed on a ceramic sheet as an internal electrode, the particle size is 5 μm or less, preferably. The thickness of 2 μm or less is used.

Further, in addition to the nickel oxide-based material, a material usually used as an electrode material, such as nickel, platinum or palladium, may be added to the above-mentioned internal electrode material within a range not impairing the characteristics of the present invention. It is possible. Further, it is also possible to add a glass component containing at least one element of boron and silicon, which is usually used for the purpose of improving the bondability with the ceramic layer, and a powder having the same or similar composition as that of the ceramic layer. It is possible within a range that does not impair

The raw material of the semiconductor ceramic layer is 1000 ° C. or more and 1250 ° C. or less, preferably 1 in a reducing atmosphere.
Sintered by firing at 100 ° C. or higher and 1200 ° C. or lower, and 500 ° C. or higher and 1000 ° C. or lower, preferably 7
A material that can be reoxidized at a temperature of 00 ° C to 900 ° C is used.

As a raw material for the semiconductor ceramic layer, a conventional 12
If a material that sinters at 50 ° C. or higher is used, a temperature of 1000 ° C. or higher is required in the subsequent reoxidation treatment step in order to obtain an element having PTC characteristics with a large resistance change width. If you reoxidize at very high temperature,
The internal electrodes oxidize, and a low resistance element cannot be obtained. Moreover, even if the above materials are used and fired at 1000 ° C. or less, sintering is insufficient and mechanically brittle, which is not preferable.

As a raw material for obtaining an element which is sufficiently sintered and exhibits excellent PTC characteristics, 1100 ° C. or higher and 1
A material that sinters at 200 ° C. or lower is preferable, and if a reoxidation process is performed at 700 ° C. or higher and 900 ° C. or lower using such a ceramic material, a laminated semiconductor ceramic element having a PTC characteristic with a larger resistance change width is obtained. can get.

When reoxidation is carried out under atmospheric conditions, it is usually carried out at 500 ° C. or higher and 1000 ° C. or lower. 900 ° C or higher 10
In the case of reoxidation at 00 ° C or lower, it is preferable to lower the oxygen partial pressure. On the contrary, at 500 ° C or higher and 700 ° C or lower, on the contrary, the oxygen partial pressure is increased, other oxidizing agents such as ozone are used, or oxygen is It is preferable to use them together.

[0014] As the raw material of the semiconductor ceramic layer of the present invention, specifically, for example, necessary to BaTiO _3, PbTiO ₃ for the purpose of Curie point shift, SrTi
Y, Nb, Sb, La, Dy, Ta, Bi, etc. are added as semiconducting agent elements to the main component to which O ₃ and CaTiO ₃ are added, and Mn, Cu, B, Si, Li, and
A material to which a property improving agent such as Na, K, Zn, Ni, Al, or Mg is added is preferable, but if a conventional product is used for the above material, firing at a high temperature of 1300 ° C. or higher is required. Therefore, if a fine-grained titanate is used as the main component, it becomes possible to sinter at 1000 ° C. or higher and 1250 ° C. or lower.

The fine particle material of the perovskite compound of titanate can be usually produced by the following steps. That is, when a solution or slurry of a titanium compound containing a semiconducting agent element is wet-reacted with an alkaline earth metal compound and calcined as necessary, semiconducting particles having an average particle diameter of 0.3 μm or less are obtained. It is possible to obtain a semiconductor powder having a perovskite type crystal structure that uniformly contains the agent.

The solution of a titanium compound containing a semiconducting element is a solution mixed in ionic or molecular units, for example, an aqueous solution of a chloride of titanium and a water-soluble compound of the semiconducting element, An organic solvent mixed solution of a titanium alkoxide and an alkoxide of a semiconducting element can be applied.
Specifically, for example, an aqueous hydrochloric acid solution of titanium tetrachloride or a titanium chloride solution partially substituted with a hydroxyl group and a chloride of a semiconducting agent element, titanium isopropoxide and isopropoxide of a semiconducting element For example, isopropyl alcohol solution.

The titanium compound slurry containing a semiconducting agent element means, for example, a hydroxide or a slurry of an oxide obtained by hydrolyzing a solution of a titanium compound containing a semiconducting element. . Specifically, for example, a semiconducting solution obtained by neutralizing and hydrolyzing an aqueous hydrochloric acid solution of titanium tetrachloride or a titanium chloride solution partially substituted with a hydroxyl group and a chloride of a semiconducting agent element with ammonia or the like. Examples include a hydrous titanium hydroxide slurry containing an agent element and a slurry obtained by adding water to an isopropyl alcohol solution of titanium isopropoxide and isopropoxide of a semiconducting agent element to cause hydrolysis.

As the alkaline earth metal compound, hydroxides, oxides, inorganic salts, organic alkaline earth metal compounds such as alkoxides and the like can be used.

When the solution or slurry of the titanium compound containing the semiconducting element is wet-reacted with the alkaline earth metal compound, for example, a hydrothermal reaction method, an alkoxide method, a coprecipitation calcination method or the like is applied. It is possible.

The hydrothermal reaction method is a method of obtaining a semiconducting agent element-containing titanate by thermal hydrolysis of a mixture of the above-mentioned compounds of titanium, a semiconducting agent element and an alkaline earth metal compound. Is. At this time, a solution prepared by previously dissolving a water-soluble alkaline earth metal compound such as barium chloride in an aqueous solution of titanium chloride and a water-soluble compound of a semiconductor element is heated in a strong alkali such as sodium hydroxide. It may be hydrolyzed.

The alkoxide method is a method in which an alkoxide of titanium, a semiconducting element, and an alkaline earth metal is mixed and dissolved in an organic solvent solution, and heat is applied to cause a reaction.

The coprecipitation calcination method is, for example, a solution of a water-soluble alkaline earth metal compound such as barium chloride dissolved in an aqueous solution of titanium chloride and a water-soluble compound of a semiconducting element, and oxalic acid. Is used to cause coprecipitation, and the resulting complex oxalate is calcined to obtain a semiconducting element-containing titanate.

Lead titanate is obtained by wet-reacting fine particle titanium oxide or titanium hydroxide containing a semiconducting element of 0.3 μm or less with lead oxide (PbO, Pb ₃ O _4, etc.) to obtain a precursor. After that, it can be obtained by carrying out a calcination reaction (JP-A-3-80117).

The method for forming a laminated ceramics is, for example, the same method as in JP-A-57-60802, and a ceramic material is formed into a sheet by using a doctor blade,
This can be done by screen printing the electrodes.

[0025]

According to the method for manufacturing a multilayer semiconductor ceramic device of the present invention, nickel oxide is used as the internal electrode material, and the raw material of the semiconductor ceramic layer is sintered at 1000 ° C. or higher and 1250 ° C. or lower, and 500 ° C. or higher. Since a material that can be reoxidized at 1000 ° C. or less is used, it is possible to obtain sufficient ohmic contact between the ceramic layer and the internal electrode by performing reoxidation treatment after firing in a reducing atmosphere, and it has good PTC characteristics. A laminated semiconductor ceramic device can be obtained.

[0026]

EXAMPLES The present invention will be further described with reference to examples. [Production Example of Titanate Used for Semiconductor Ceramic Material]

Production Example 1 Niobium-containing barium titanate aqueous solution of titanium chloride (containing 16.5% by weight of Ti)
A niobium pentachloride solution previously dissolved in hydrochloric acid was added to the above so that the Nb / Ti atomic ratio was 0.22%, and the solution was stirred and dissolved. Add pure water while stirring and add 1
After 0-fold dilution, 5% aqueous ammonia was added and mixed for 3 hours until pH 8 was reached, and a neutralization hydrolysis reaction was performed. The above neutralized slurry is subjected to suction filtration using a Buchner funnel and washed with water to give a water-containing cake, and pure water is added to the cake so that the cake has a concentration of 0.7 mol / l in terms of TiO _2. Turned into

While stirring the niobium-containing hydrous titanium hydroxide slurry described above, the reaction system was placed in a nitrogen atmosphere, and Ba (O 2
After H) ₂ · 8H ₂ O and Ba / Ti atomic ratio was added and mixed so as to be 1.4, the temperature was raised over a period of about 1 hour to boiling temperature, carried out for about 4 hours hydrothermal reaction at a temperature of 105 ° C. It was Then, after naturally cooling to room temperature, decantation was repeated, suction filtration using a Buchner funnel, and washing with water were performed.
Got a cake The cake obtained after the hydrothermal reaction was TiO ₂
Pure water was added and redispersed to a slurry of a concentration of 0.7 mol / l in terms of conversion. This barium / titanium-containing slurry was heated to 60 ° C. with stirring and maintained at that temperature for the purpose of adjusting the Ba / Ti atomic ratio by 10%.
The addition of acetic acid solution and sampling were repeated, composition analysis was performed using a fluorescent X-ray analyzer, the Ba / Ti atomic ratio was adjusted to 1.005, and this state was maintained for 1 hour.

The slurry having the adjusted Ba / Ti atomic ratio was then subjected to suction filtration using a Buchner funnel, washed with water, and dried. The particle diameter of the obtained powder was measured with a scanning electron microscope and the crystal shape was measured with an X-ray diffractometer. As a result, a barium titanate powder having a cubic perovskite crystal structure with an average particle diameter of 0.08 μm was obtained. It was a body. The above powder was further calcined at 800 ° C. for 2 hours to obtain a barium titanate perovskite type crystal fine powder containing niobium having an average particle diameter of 0.1 μm, wet pulverized with a ball mill for 5 hours, and dried. The powder after calcination was subjected to composition analysis using a fluorescent X-ray analyzer, and as a result, the Ba / Ti atomic ratio was 1.005 and the Nb / Ti atomic ratio was 0.22%.

Production Example 2 Yttrium-containing barium titanate aqueous solution of titanium chloride (containing 16.5% by weight of Ti)
A yttrium nitrate solution previously dissolved in hydrochloric acid was added to the above so that the Y / Ti atomic ratio was 0.3%, and the solution was stirred and dissolved. Add pure water while stirring and add 1
After 0-fold dilution, 5% aqueous ammonia was added and mixed for 3 hours until pH 8 was reached, and a neutralization hydrolysis reaction was performed. The above neutralized slurry is subjected to suction filtration using a Buchner funnel and washed with water to obtain a yttrium-containing water-containing titanium hydroxide cake, and the cake has a concentration of 0.7 mol / l in terms of TiO ₂ . Pure water was added to make a slurry.

The yttrium-containing hydrous titanium hydroxide slurry obtained above was stirred and the reaction system was placed in a nitrogen atmosphere so that Ba (OH) ₂ .8H ₂ O had a Ba / Ti atomic ratio of 1.4. After the addition and mixing, the temperature was raised to the boiling temperature over about 1 hour, and the hydrothermal reaction was performed at a temperature of 105 ° C. for about 4 hours. Then, after naturally cooling to room temperature, decantation was repeated, suction filtration using a Buchner funnel, and washing with water were performed. The cake obtained after the hydrothermal reaction is Ti
Pure water was added so as to have a concentration of 0.7 mol / l in terms of O _{2 and} redispersed to form a slurry.

The barium / titanium-containing slurry was heated to 60 ° C. with stirring and maintained at that temperature.
For the purpose of adjusting the Ba / Ti atomic ratio, addition of 10% acetic acid solution and sampling were repeated, composition analysis was performed using a fluorescent X-ray analyzer, and the Ba / Ti atomic ratio was adjusted to 1.000. Hold for 1 hour. The slurry having the adjusted Ba / Ti atomic ratio was then suction filtered using a Buchner funnel, washed with water, and dried. The obtained powder is
Further, it was calcined at 800 ° C. for 2 hours to obtain yttrium-containing barium titanate perovskite type crystal fine powder having an average particle diameter of 0.1 μm, wet pulverized with a ball mill for 5 hours, and dried. As a result of compositional analysis of the powder after calcination using a fluorescent X-ray analyzer, the Ba / Ti atomic ratio was 1.000 and the Y / Ti atomic ratio was 0.3%.

Production Example 3 Yttrium-containing strontium titanate Obtained in the same process as in Production Example 2 and converted into TiO ₂ in a value of 0.
The yttrium-containing hydrous titanium hydroxide slurry dispersed at a concentration of 7 mol / l was placed in a nitrogen atmosphere while stirring to make Sr (OH) ₂ .8H ₂ O have an Sr / Ti atomic ratio of 1.4. After such addition and mixing, the temperature was raised to the boiling temperature over about 1 hour, and the hydrothermal reaction was carried out at a temperature of 105 ° C. for about 4 hours. Then, after naturally cooling to room temperature, decantation was repeated, suction filtration using a Buchner funnel, and washing with water were performed. The cake obtained after the hydrothermal reaction is Ti
Pure water was added so as to have a concentration of 0.7 mol / l in terms of O _{2 and} redispersed to form a slurry.

This strontium / titanium-containing slurry was heated to 60 ° C. with stirring, and while maintaining this temperature, addition of 10% acetic acid solution and sampling were repeated to adjust the Sr / Ti atomic ratio, and fluorescence was added. The composition was analyzed using an X-ray analyzer, and the Sr / Ti atomic ratio was 1.000.
And the state was maintained for 1 hour. Above Sr / Ti
The slurry having the adjusted atomic ratio was then subjected to suction filtration using a Buchner funnel, washed with water, and dried. The obtained powder was further calcined at 800 ° C. for 2 hours to obtain yttrium-containing strontium titanate perovskite type crystal fine powder having an average particle diameter of 0.05 μm, wet pulverized with a ball mill for 5 hours, and dried. . The composition of the powder after calcination was S analyzed by an X-ray fluorescence analyzer,
The r / Ti atomic ratio was 1.000 and the Y / Ti atomic ratio was 0.3%.

Production Example 4 Yttrium-Containing Calcium Titanate Obtained in the same process as in Production Example 2 and converted to TiO ₂ of 0.
The yttrium-containing hydrous titanium hydroxide slurry dispersed at a concentration of 7 mol / l was placed in a nitrogen atmosphere while stirring to make Ca (OH) ₂ .8H ₂ O have a Ca / Ti atomic ratio of 1.000. After such addition and mixing, the temperature was raised to the boiling temperature over about 1 hour and refluxed at a temperature of 105 ° C. for about 4 hours. Then, naturally cool to room temperature, evaporate to dryness, and calcine at 800 ° C. for 2 hours,
Yttrium-containing calcium titanate perovskite type crystal fine powder having an average particle diameter of 0.13 μm was obtained, wet pulverized with a ball mill for 5 hours, and then dried. The obtained powder was subjected to composition analysis using a fluorescent X-ray analyzer,
The Ca / Ti atomic ratio was 1.000 and the Y / Ti atomic ratio was 0.3%.

Production Example 5 Yttrium-containing lead titanate Obtained in the same process as in Production Example 2 and converted to TiO ₂ in a quantity of 0.1.
After adding the Pb ₃ O ₄ to the yttrium-containing hydrous titanium hydroxide slurry dispersed at a concentration of 7 mol / l under stirring in a nitrogen atmosphere in the reaction system so that the Pb / Ti atomic ratio becomes 1.000, The temperature was raised to the boiling temperature over about 1 hour and refluxed at a temperature of 105 ° C. for about 4 hours. Then, the mixture was naturally cooled to room temperature, evaporated to dryness, and calcined at 500 ° C. for 2 hours to obtain a yttrium-containing lead titanate perovskite type crystal fine powder having an average particle diameter of 0.05 μm, which was then ball milled for 5 hours. After wet grinding, it was dried. As a result of composition analysis using an X-ray fluorescence analyzer, the obtained powder had a Pb / Ti atomic ratio of 1.000 and a Y / Ti atomic ratio of 0.3%.

[0037]

Example 1 A powder obtained by adding 0.02 atomic% of Mn to the niobium-containing barium titanate obtained in Production Example 1 was mixed with an organic binder, a solvent, and a dispersant to form a slurry, which was then subjected to a doctor blade method. Thus, a ceramic green sheet was formed.

An electrode paste was prepared by mixing a varnish with a powder of nickel acetate that had been calcined at 1000 ° C. to form nickel oxide, and the internal electrodes were printed on the ceramic green sheet.

After printing the electrodes, the green sheets were laminated so that the internal electrodes were alternately exposed to the left and right, and pressure-bonded and cut to obtain a laminate. The produced laminated body has a structure in which the ceramic green sheets sandwiched by the internal electrodes are laminated in five layers, and further the ceramic green sheets on which the internal electrodes are not printed are laminated as protective layers above and below this.

The above-mentioned laminated body is heated in the atmosphere for debinding, and then carbon monoxide / argon = 10 /
1175 ° C or 1200 ° C in 90 reducing atmosphere
The temperature was raised to 2 ° C., and each was fired for 2 hours. After firing, reoxidation treatment was performed in the air at a constant temperature of 500 to 1000 ° C. for 2 hours to obtain a sintered body. The obtained sintered body was coated with ohmic silver paste on the left and right side surfaces and baked in the atmosphere to form external electrodes so that each internal electrode could be energized.

Tables 1 and 2 show the characteristic test results of the laminated semiconductor ceramic elements obtained in the examples.
Table 1 shows the resistance value [Ω] of each sample at room temperature and the room temperature to 280 ° C. when the firing temperature was 1175 ° C. and the reoxidation treatment temperature was changed between 500 to 1000 ° C. at every 100 ° C. This shows the resistance change width. The resistance change width [digit] was calculated by the following equation. Resistance change width [digit] = Log ₁₀ (R ₂ / R ₁ ) where R ₂ is the maximum resistance value at room temperature to 280 ° C., R
₁ is the minimum resistance value at room temperature to 280 ° C. Table 2
Shows the results of the above characteristic test when the firing temperature was 1200 ° C.

[0042]

[Comparative Example 1] The same as Example 1 except that a commercial nickel paste using nickel metal as a raw material was used instead of the nickel oxide used in Example 1 as the internal electrodes printed on the ceramic green sheets. A multilayer semiconductor ceramic device was manufactured. Table 3 shows the characteristic test results of the multilayer semiconductor ceramic device obtained in Comparative Example 1.

[0043]

Comparative Example 2 Nickel oxide was used for the internal electrodes, and commercially available BaCO ₃ , TiO ₂ , Nb were used as raw materials for the ceramic layer.
₂ O ₅ and MnCO ₃ were mixed in the same composition as in Example 1,
Add 1.5 mol% of SiO ₂ and add ₂ at 1100 ℃.
A multilayer semiconductor ceramic element was manufactured using the powder obtained by calcination for a period of time. Table 4 shows the characteristic test results of the multilayer semiconductor ceramic device obtained in Comparative Example 2.

As is clear from Example 1 and Comparative Example 2,
When a conventional ceramic material is used and fired at 1300 ° C., only a small resistance temperature change width can be obtained. Even if the resistance temperature change width exceeds two digits, the resistance value also increases. . Further, as is clear from Example 1 and Comparative Example 1, when the low temperature sintered ceramic material was combined with the metallic nickel paste, the reoxidation treatment at 800 ° C. or higher increased the resistance value and could not be used. , 7
Even in the reoxidation treatment at 00 ° C. or lower, the corresponding characteristics were inferior as compared with the case of Example 1 using the nickel oxide and the low temperature sintered ceramic material.

[0045]

[Table 1]

[0046]

[Table 2]

[0047]

[Table 3]

[0048]

[Table 4]

[0049]

Example 2 The yttrium-containing barium titanate, the yttrium-containing strontium titanate, the yttrium-containing calcium titanate, and the yttrium-containing lead titanate prepared in each of the above-described Production Examples 2 to 5 were mixed with 0.3
Ba _0.68 Sr _0.06 Ca containing mol% yttrium
The composition was _0.01 Pb _0.25 TiO ₃ and boron nitride was added at 1.0 mol% and Mn was added at 0.08 mol%. The mixed powder was wet-mixed for 10 hours using a ball mill and dried to obtain a sample powder, and then a laminated body was prepared in the same manner as in Example 1. The produced laminate is heated in the air to be debindered, and then H ₂ / N
_In a reducing atmosphere of ₂ = 5/95, the temperature was raised to 1100 ° C. and firing was performed for 2 hours. 600 ~ 90 in the air after firing
A reoxidation treatment was performed at a constant temperature between 0 ° C. for 2 hours to obtain a sintered body. External electrodes were formed on the obtained sintered body in the same manner as in Example 1 and a characteristic test was conducted. The results are shown in Table 5.

[0050]

Comparative Example 3 Commercially available BaCO ₃ , SrCO ₃ , CaCO
₃ , lead oxide, TiO ₂ , and Y ₂ O ₃ were blended in the same manner as in the composition of Example 2, and further 1.0 mol% of boron nitride and 0.08 mol% of Mn were added. The mixed powder was wet-mixed for 10 hours using a ball mill, dried, and then calcined at 1100 ° C. for 2 hours to obtain a sample powder, and a laminate was prepared in the same manner as in Example 1. The produced laminate was heated in the air to be subjected to a binder removal treatment, and then heated to 1300 ° C. in a reducing atmosphere of H ₂ / N ₂ = 5/95 and baked for 2 hours. After that, reoxidation treatment was performed in the atmosphere at a constant temperature of 600 to 900 ° C. for 2 hours to obtain a sintered body. External electrodes were formed on the obtained sintered body in the same manner as in Example 1 and a characteristic test was conducted. The results are shown in Table 6.

[0051]

[Table 5]

[0052]

[Table 6]

As is clear from Tables 5 and 6, even when the high-temperature sintered ceramic material was used, only inferior characteristics were obtained as compared with the product of the present invention.

[0054]

As described above, in manufacturing the multilayer semiconductor ceramic device of the present invention, by using nickel oxide as the starting material for the internal electrodes, the resistance of the device at room temperature can be suppressed to a low level. By using a low-temperature sintered barium titanate-based semiconductor ceramic material as the raw material of the ceramic layer and firing at low temperature, it has the effect of sufficiently increasing the resistance change width even at a reoxidation treatment temperature of 500 ° C. or higher. .

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical indication C04B 35/64 M (72) Inventor Osamu Kobayashi 1-347 Funamachi, Taisho-ku, Osaka-shi, Osaka (72) Inventor Shuji Igarashi 754 Tsukui, Yokosuka City, Kanagawa Prefecture

Claims (2)

[Claims] 1. When manufacturing a multilayer semiconductor ceramic device obtained by alternately stacking semiconductor ceramic layers and internal electrodes, firing them in a reducing atmosphere, and then performing reoxidation treatment, nickel oxide is used as the metal material of the internal electrodes. And a material that is sintered at 1000 ° C. or higher and 1250 ° C. or lower and reoxidized at 500 ° C. or higher and 1000 ° C. or lower is used as a raw material for the semiconductor ceramic layer. . 2. As a raw material for a semiconductor ceramic layer, 11
The method for manufacturing a multilayer semiconductor ceramic device according to claim 1, wherein a material that is sintered at a temperature of 00 ° C. or higher and 1200 ° C. or lower and is reoxidized at a temperature of 700 ° C. or higher and 900 ° C. or lower is used.