JPH03127404A - Porcelain composition for reduction re-oxidation semiconductor condenser - Google Patents

Abstract

PURPOSE:To obtain a porcelain composition excellent in various electric characteristics, in particular, in temperature characteristic by composing a reduction re-oxidation type semiconductor porcelain composition suitable for a surface layer type semiconductor magnetic condenser, out of a primary component of BaTiO3 and secondary components of Ta and Nd. CONSTITUTION:As a primary component, BaTiO3 is used, while, as secondary components 0.3-3.0mol% of Ta converted in Ta2O5 is used, as well as 0.3-3.0mol% of Nd, converted into Nd2O3 is used, so as to form a composition of (100-x-y).BaTiO3+x.Ta2O5+y.Nd2O3. In the component, Co is included by less than 0.8weight% (O excluded), converted into CO3O4, as well as Mn is included by less than 0.8weight% (O excluded), converted into MnCO3. In addition, Mn is included in this component by less than 0.50wt.% (O excluded) converted into MnCO3 so as to include SiO2 by less than 0.20wt.% (O excluded) in the component. In order to include these species, a ball mill made of synthetic resin is used, and, after they are mixed and granulated with an approximately 2% of PVA binder, they are formed into a disc with a pressure of approximately 3 ton/cm<2>.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a semiconductor ceramic composition, and more particularly to a reduced and reoxidized semiconductor ceramic composition passed through a surface layer type semiconductor ceramic capacitor.

[Conventional technology]

Semiconductor ceramic capacitors as passive electronic components are broadly classified into grain boundary layer type and surface layer type. Grain boundary layer type includes grain boundary insulated semiconductor ceramic capacitors, and surface layer type includes base layer capacitance type semiconductor ceramic capacitors and reduction recycle type. There are oxidized semiconductor ceramic capacitors, etc.

Each type has its own characteristics, but the grain boundary layer type has a smaller capacity than the base layer capacitive type, and the withstand voltage is lower than the reduced and reoxidized type.

The base capacitive type has poor frequency characteristics, large dielectric loss, and low withstand voltage.

[Problem to be solved by the invention]

1) The original reoxidized form has a volume per unit area fitc (μF
/cm''), the breakdown voltage value becomes smaller, the dielectric loss tan δ becomes larger, or the temperature characteristic of capacitance T-C becomes larger.

Therefore, an object of the present invention is to obtain a semiconductor ceramic composition suitable for a reduced reoxidation type semiconductor (R type capacitor), which has a large capacity per unit area, has a high withstand voltage, and has good temperature characteristics.

[Means to solve the problem]

Therefore, as a result of intensive research, the present inventors found that B.
(100-x-y) mol% of aTto 3, 0.3 to 3.0 mol% of X・"FaxOs as accessory components, and y-
Contains 0.3 to 3.0 mol% of Nds○3 (100-
X-)') ・BaTiO3+x-Ta*Os+y-
It has been found that a Ndx03-based semiconductor ceramic composition achieves the above object.

Furthermore, to the above components, add 0.8% by weight or less of cobalt in terms of CO3O4, or add manganese to MnCO
Add 0.50% or less in terms of SiO2
It has been found that the electrical properties of the semiconductor ceramic composition of the present invention can be further improved by adding 0.20% or less of .

[Effect]

The ceramic composition for a reduced and reoxidized semiconductor capacitor having the above composition has a large capacity per unit area, a high withstand voltage, and good temperature characteristics.

〔Example〕

The present invention will be described in detail.

BaCO3, TiO2, Ta205, N as starting materials
d2O3, CO3O4, MnCO3, 5in2 are weighed so that the component m-acid ratio after generation is as shown in Table 1 (see Figure 1X).

The weighed raw materials are wet-mixed by rotating them together with water and cobblestones for about 20 hours in a synthetic resin ball mill, for example (see Figure 1
reference).

Next, dehydrate and dry (see Figure 1
.

This is again rotated for about 20 hours with water and cobblestones in a synthetic resin bowl and pulverized (see FIG. 1, X).

After dehydration and drying again (see Figure 1
, into a 5 mm disk (see Figure 1, X).

The molded disk was stabilized at about 800°C for about 1 hour, and then PVA
Remove the solvent and remove the solvent (see X in Figure 1).

After desolvation, the formed disk was stabilized at 1300°C for 2 hours,
Main firing is performed to obtain dielectric porcelain (see Fig. 1, Xl).

The obtained ceramic body porcelain is stabilized for 2 hours in a reducing atmosphere such as a hydrogen gas atmosphere at 800'C to form a semiconductor porcelain (see FIG. 1X).

Silver paste to serve as electrodes is printed on both sides of this semiconductor ceramic disk (see FIG. 1, Xl).

This is stabilized again at 800°C for 2 hours in an oxidizing atmosphere, and a conductor layer is formed on the surface of the porcelain, and electrodes are formed to complete the reduction and reoxidation semiconductor capacitor (see Figure 1, Xl). ).

Regarding the semiconductor capacitor formed in this way,
The results of measuring the electrical characteristics are shown in Table 1 (see plate in Figure 1). Here, capacitance per unit area IC, dielectric loss ta
nδ is a value determined by IKIIz, IV and
! ! ! The edge resistance resistance is a value measured by applying a voltage of 25 V, and the temperature characteristic 'r-c' is a value measured by measuring the rate of change in capacitance from -25°C to 85°C with the capacitance at 20°C as a reference.

In addition, those marked with an x in Table 1 are outside the scope of this invention.

In the following margin, the reasons for limiting the composition of the ceramic composition for a reduced and reoxidized semiconductor capacitor of the present invention will be explained with reference to Table 1.

When Taz05 is less than 0.3 mol%, sintering may be insufficient (sample No. 01). 2.4), the capacitance C per unit area is low and tan δ is large, the DC breakdown voltage vb is small, and the temperature characteristics of the capacitance are also deteriorated (see sample No. 093).

On the other hand, if Taxes exceeds 3 mol %, the temperature characteristics deteriorate (see samples Nos. 14 and 16).

In addition, when Nd2O3 is less than 0.3 mol%, the capacity C
is low, the DC breakdown voltage vb is small, and the temperature characteristics are also deteriorated (see sample No. 015.16).

If Nd2O5 exceeds 3 mol%, temperature characteristics deteriorate (
See sample N011O1)4).

When CO3O4 exceeds 0.8% by weight, the capacity C per unit area is low and the temperature characteristics are also deteriorated (sample No.
(see 19).

Furthermore, when MnCCl3 exceeds 0.50% by weight, the insulation resistance IR1 DC breakdown voltage vb decreases (sample NO, 2
(See 3).

Further, when SiO2 exceeds 0.20% by weight, the capacitance C per unit area becomes low and the insulation resistance IR1 DC breakdown voltage vb becomes low (see sample No. 27).

Although it is possible to obtain a semiconductor ceramic composition having good electrical properties without adding each of the additives CO3O4, MnCO3, and 5i02, even better properties can be obtained by adding these additives. (See sample No. 17, 18, 21, 22, 25, 26).

〔Effect of the invention〕

Vlf for reduced and reoxidized semiconductor capacitors having the composition of the present invention
By forming a semiconductor capacitor using a T-type capacitor composition, it is possible to obtain excellent electrical characteristics, particularly excellent temperature characteristics.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the manufacturing process of an embodiment of the present invention.

Claims (4)

[Claims] (1) BaTiO_3 as the main component and tantalum as a subcomponent of 0.3 to 3.0 mol% in terms of Ta_2O_5
, 0.3 to 3.0 when neodymium is converted to Nd_2O_3.
(100-xy) characterized by containing 0 mol%
・BaTiO_3+x・Ta_2O_5+y・Nd_2
Ceramic composition for O_3-based reduced and reoxidized semiconductor capacitors. (2) The porcelain for reduced and reoxidized semiconductor capacitors according to claim (1), characterized in that it contains 0.8% by weight or less (excluding 0) of cobalt in terms of Co_3O_4 based on the component. Composition. (3) The ceramic composition for a reduced and reoxidized semiconductor capacitor according to claim (1), characterized in that it contains 0.50% by weight or less (excluding 0) of manganese in terms of MnCO_3 based on the component. thing. (4) Silicon oxide SiO_2 is 0.0% of the above components.
The ceramic composition for a reduced and reoxidized semiconductor capacitor according to claim 1, characterized in that it contains 20% by weight or less (excluding 0).