JPS5957414A - Composition for reduced reoxidized semiconductor porcelain condenser - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] Regarding the composition.

Conventionally, reduction and reoxidation type semiconductor ceramic capacitors are made of BaTi.
Rare earth elements, Nb, 1-Ra, etc. are added to O3-based porcelain, and the surface is converted into a semiconductor through reduction heat treatment in an oxidizing, neutral, or reducing atmosphere. One in which a silver electrode is formed is in practical use.

However, this type of capacitor has the drawback that increasing the capacitance reduces the breakdown voltage and increases dielectric loss, and conversely, increasing the breakdown voltage decreases the capacitance. In order to improve this drawback, in Japanese Patent Publication No. 56-40965, B.
aTi03 as a base material, Bi2031-4% by weight
, Zr021, 6-5 weighing device Mn0.01-0.10
The amount of X-1 (wt%
) S'y';
It has been proposed to use a reduced and reoxidized semiconductor ceramic composition characterized by a relationship of Z/X≦20% by weight. A reduction-reoxidation type semiconductor ceramic capacitor using this composition has a small size, large capacity, and low dielectric loss.
Although it exhibits excellent properties such as a high breakdown voltage, there are problems in that its applications are limited because of large variations in breakdown voltage and large dielectric loss at high frequencies (near l Mtlz ).

The present invention has been made in view of these problems, and has a high breakdown voltage with little variation, and a low induced loss at high frequencies! The object of the present invention is to provide a composition with which a reduced-reoxidation type semiconductor ceramic capacitor having a small size and large capacity can be obtained.

That is, the present invention provides (13a1-l'if) 'rl
lno3 (where l:, m is the mole fraction of each component, 0
．． 002<l<0006.1.02': m<1.08
) 85-95 mol%, (Ba, .S r o) Z
rO3 (however, o, t<n<o, 3) 5 to 15 mol% as a base, 1312031 to 4 mol%, Mn
The gist thereof is a composition for a reduced and reoxidized semiconductor ceramic capacitor containing 0.03 to 0.1% by weight.

In the present invention, the composition range is limited as described above for the following reason.

In other words, if the molar fraction l of ■ is less than 0002, the dielectric loss in the high frequency range will increase, and if it exceeds 0006, the variation in breakdown voltage will increase, and the minimum breakdown voltage (BDVml,) in the same lot will decrease. l from 0002 to 000
The range was set at 6. Further, the reason why the molar fraction (+n) of Ti is set to 1.03 to 1.08 is because when m is outside this range, the capacitance and/or breakdown voltage decreases.

(Ba1,5ro) Z, , The mole fraction (n) of Sr in 03 is set to 0.1 to 0.3 because n is less than 01, Bl)V, +1. This is because if o is not sufficiently close to -1 and exceeds 03, the capacitance will decrease.

In addition, the reason why the addition needle of l31203 was set to 1 to 4 times π% is because the porcelain is difficult to reduce if Bi2O3 is not 1% by weight, and the entire porcelain is easily reoxidized at the reoxidation temperature, so the capacitance This is because the capacitance becomes smaller when the ratio becomes smaller and exceeds 4%. Furthermore, the amount of Mn added is 003
The reason for setting the Mn content to 0.1% by weight is that if the Mn content is less than 0.03%, both the capacitance and insulation resistance will be small, and the breakdown voltage will also be small, and if it exceeds 0.1%, the capacitance will be This is because it becomes smaller.

Hereinafter, the present invention will be explained according to examples.

Example I Using Ba CO3, Y2O3 and T i O2 as raw materials, they were (Ba0998 Yo, 002)"' 1.
While adding weight and mixing so that the ring 1 composition ratio of 03°3 is 1', +3 a 903, S r CO3 and 10
00Kg/cJ pressure, diameter 10mm, thickness 0.5m
Form into a disk of m. After firing this in air at 1320° C., it is reduced to a semiconductor at 1200° C. for 2 hours in a reducing atmosphere consisting of 15% hydrogen and 85% nitrogen by volume, and then cooled as it is in the reducing atmosphere. Then, in the air 1
After applying silver paste to both surfaces of the semiconductor ceramic element obtained in this way, it was dried and baked for 5 minutes at 800°C in air; As a result, a capacitor was obtained which was made of a 11-oxidized semiconductor ceramic with a half-solid interior and an insulating layer formed by oxidation on the surface.

The capacitance, breakdown voltage (10) and dielectric loss tangent (Lan δ) of each of the thus obtained reduced and reoxidized semiconductor ceramic capacitors were measured.

The results are shown in Table 1 along with the composition. Please note (old)
~'(X) is the average value of breakdown voltage for 100 samples, and +Q is the lowest breakdown voltage among them.

Example 2 Same as Example 1 ("0.996 YO, 04)"
"J, 0503, (Bao, 8oSro2o) Z103
131203, and Mn
(in terms of MnO2) and were mixed in proportions not shown in Table 2 to obtain a reduced and reoxidized semiconductor ceramic capacitor in the same manner as in Example 1. Their capacitance, breakdown voltage, and dielectric loss tangent are
Shown in the table.

Comparative Example I Weigh and mix Is a Co3, 'l'' +02,
While making Te Ba-riO3 by calcining at 1150℃ for 2 hours, 13aCO3 and ZrO2 were weighed and mixed, and 115
Calcinate at 0°C for 2 hours to make 13a Z r O3.
13a'1. '+0390%)'v%, 13aZ
After adding a mixture of R0310% and l512033% by weight, 'I'+0210% by weight, MnQ, and Q5 weight, 35% of a binder (vinyl resin) was added and sized to form 10 diameter particles. , and was molded into a disk with a thickness of 0.5 mm.

This disk was fired, reduced and subjected to tetroxidation treatment under the same conditions as in Example 1, then coated with silver paste and baked at 8000C to form an electrode, thereby obtaining a reduction and reoxidation type semiconductor device capacitor. Its capacitance is 150nF/cJ, 13DV(x)
was l,lKV, 81)V(+ni+ri) was 0.41g, and tanδ(lMHy, ) was 18%.

Comparative Example 2 (13a Y )TiO prepared in Example 1
,9980,0021,03 0390 mol% and Ba Z r0 prepared in Comparative Example 1
310 mol%, Bi2032% by weight, Mn
A reduced and reoxidized semiconductor ceramic capacitor was obtained in the same manner as in Example 1 by adding 0.05 weight N% (in terms of MnO3). Its capacitance is 170 n F/ca, B1) V(x)
is 1, 2 Kv, BDV (min) is Q, 5KV, ta
llδ(l M[l z ) was 12%.

Comparative Example 3 Ba'ri 1.050390 mol% and (BaO, 8
A reduced and reoxidized semiconductor ceramic capacitor was obtained in the same manner as in Example 1 by adding 12032% by weight of I and 5% by weight of Mlo to a mixture of 10% by mole of 0SrO, 20) Zr03. Its capacitance is 150 n F/crR, BD
V (X) is 1.2KV, B I)V (min) is Q
, 5 KV, tan δ (l MtI z ) is 19
%Met.

As is clear from the results in Tables 1 and 2, the capacitor made of the reduced and reoxidized semiconductor ceramic composition according to the present invention has the same areal capacitance as the conventional capacitor of Comparative Example 1. Also, the minimum breakdown voltage is high, there is little variation in breakdown voltage, and the dielectric loss tangent at high frequencies is low, showing good characteristics. In addition, from the results of Comparative Examples 1 to 3, when a part of Ba is replaced with Y, the dielectric loss improves, and when a part of Ba is replaced with Sr, only the old) V (m1n) can be improved. Recognize.

f'i FF Applicant Representative of Murata Manufacturing Co., Ltd. Patent attorney Mr. Hajime and 1 other person 69

Claims (1)

[Claims] (1,1(13a1-jYz) T+m03(However, 0
．． 002≦l 0006.1.02<rn'<1. □
s) s 5 to 95 mol% and (Ha1', 5r
n) Zr03 (however, o, t'-n'-0,3
) 5 to 15 mol% to the substrate, and to this Bi2031-4
A composition for a reduction and reoxidation type semiconductor ceramic capacitor, which contains 0.03 to 0.1% by weight of Mn.