JPH0818862B2 - Semiconductor porcelain composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is suitable for semiconductor ceramic capacitors, particularly grain boundary insulation type semiconductor ceramic capacitors, SrTiO ₃ —CaTiO ₃ —BaTiO ₃ —Y ₂
O ₃ relates -Nb ₂ O ₅ based semiconductor ceramic composition.

[Conventional technology]

Conventional semiconductor porcelain capacitors are classified into surface layer types such as reduction / reoxidation type and weir layer capacitance type, and grain boundary layer types are roughly classified into grain boundary insulating types.

However, the medium grain boundary insulation type of these various semiconductor porcelain capacitors does not have a larger capacity than the weir layer capacity type, and has a lower withstand voltage than the reduction / reoxidation type. The weir layer capacitive type has poor frequency characteristics and a large dielectric loss tan δ,
Withstand voltage is small. The reductive reoxidation type has poor frequency characteristics, large temperature characteristics, and large dielectric loss tan δ. There were drawbacks.

[Problems to be solved by the invention]

As described above, the various conventional semiconductor ceramic capacitors have various drawbacks.

The present invention is intended to obtain a semiconductor ceramic composition having a high dielectric constant ε _s , good frequency characteristics and temperature characteristics, and a small dielectric loss tan δ in a semiconductor ceramic capacitor, particularly a grain boundary insulation type semiconductor ceramic capacitor. Is. That is, with respect to the main component SrTiO ₃ , by adding CaTiO ₃ as a sub-component, the appropriate range width of the SrO / TiO ₂ ratio is expanded, and
By adding BaTiO ₃ , MnO, and SiO ₂ , it was possible to obtain a semiconductor ceramic composition having a high insulation resistance IR.

[Means for solving problems]

The present invention provides a semiconductor porcelain composition having (100-xy)
・ SrtiO ₃ as the main component and x ・ CaTiO ₃ , y ・
BaTiO ₃ 1.0 ≦ x ≦ 20.0mol% (however, x changes the upper limit depending on the SrO / TiO ₂ ratio) 1.0 ≦ y ≦ 3.0mol%, and 0.1
0 ≦ Y ₂ O ₃ ≦ 1.0 mol%, 0.10 ≦ Nb ₂ O ₅ ≦ 0.4 mol% (100−x−y) · SrTiO ₃ + x · CaTiO ₃
+ Y · BaTiO ₃ + Y ₂ O ₃ + Nb ₂ O ₅ based semiconductor ceramic composition is used.

Further, with respect to the main component in the semiconductor porcelain composition,
Furthermore, manganese is converted to MnO by 0.02 to 0.2 mol% and S
A semiconductor porcelain composition characterized by containing 0.01 to 0.6 mol% of iO ₂ can be used.

〔Example〕

SrCO ₃ , CaCO ₃ , BaCO ₃ , TiO ₂ , MnCO ₃ , SiO ₂ as starting materials
And, Y ₂ O ₃ and Nb ₂ O ₅ were used as semiconducting agents and weighed so that the composition ratio shown in Table 1 or 2 was obtained, and these raw material compositions were mixed with water and cobblestone in a synthetic resin ball mill. Is added and wet mixing and stirring are performed for 20 hours. Then dehydrated and dried, 1200
℃, the rising and falling temperature of 200 ℃ / hr Stabilized for 2 hours, and calcined to cause chemical reaction. In a ball mill, add water and boulders again and crush and mix for 20 hours. This was dewatered and dried by adding PVA as 2% by weight of an organic binder, a granulated powder subjected to granulating sized 10φ × 0.5tmm the powder molding pressure of about 3 ton / cm ²
It is molded into a disk shape. This molded product was debindered at 800 ° C for 1 hour, and it was placed in a reducing gas stream (H ₂ + N ₂ atmosphere).
Main-baking is performed at 1450 ° C for about 2 hours to form a semiconductor. The semiconductor porcelain element obtained in this way is 8.5φ × 0.4tmm,
Bi ₂ O ₃ --CuO system frit paste was coated on both sides of this as a diffusion material by 3 mg screen printing, and this was applied in air for 115
Heat treatment is performed at 0 ° C. for 2 hours to obtain a semiconductor porcelain having an insulating layer formed on a crystal grain boundary. An Ag paste was screen-printed on both sides of this porcelain element and baked at about 800 ° C. to obtain a grain boundary insulating semiconductor porcelain composition having electrodes formed thereon.

Tables 1 and 2 show the results of measuring the electrical characteristics of each sample thus obtained. Where permittivity εs
And the dielectric loss tan δ was measured at a frequency of 1KHz and 1V. The insulation resistance IR was measured at room temperature of 20 ° C. by applying a DC voltage of 25V.

As is clear from Tables 1 and 2, those within the range of the present invention have a high dielectric constant εs of about 50,000 or more, a low dielectric loss tan δ of 1.0% or less, and an insulation resistance IR. Indicates a high value. Next, the reasons for limiting the composition ratio will be described.

If the content of CaTiO ₃ is less than 1.0 mol%, the insulation resistance IR and DC breakdown voltage E _b are low (No.4,5,6). CaTiO ₃ 1.0 to 20.0 mol%
The proper range of SrO / TiO ₂ ratio (0.030) becomes wider in the range of (N
o.7,8,11,12,13,15,16,18,19). However, CaTiO ₃ 1.0 mol
Below 0.90 SrO / TiO ₂ , CaTiO ₃ below 5.0 mol% SrO / TiO
₂ ratio 0.980, CaTiO ₃ less than 10.0 mol% SrO / TiO ₂ ratio 0.970
IR and _Eb are low (No.10,14,17). When CaTiO ₃ exceeds 20.0 mol%, the dielectric constant εs decreases and the dielectric loss tan δ increases (No. 9, 20). When BaTiO ₃ is less than 1.0 mol%, insulation resistance IR and DC breakdown voltage E _b are low (No.23, 24, 25), and when it exceeds 3.0 mol%, dielectric constant εs decreases and dielectric loss tan δ increases. It gets bigger (No.28). Dielectric constant εs is low in sole addition of Y ₂ O ₃ and Nb ₂ O ₅ (No.29,30), also a Y ₂ O ₃
Even in the case of adding Nb ₂ O ₅ in combination, the effect of increasing the dielectric constant εs and the DC breakdown voltage E _b is not significant when the content of each is less than 0.1 mol% (No. 3
0,31,32,40). When Y ₂ O ₃ exceeds 1.0 mol%, the dielectric constant εs decreases (No. 44, 45). When Nb ₂ O ₅ exceeds 0.4 mol%, the dielectric constant εs decreases (No. 35, 43). Next, Table 2 shows MnO and S
The case where iO ₂ was further added is shown, and No. 46 is a control sample. The effect of increasing the insulation resistance IR is not remarkable when MnO or SiO ₂ is added alone (No. 47, 48, 49, 50, 51, 52, 53). With MnO
The dielectric loss tan δ becomes higher when MnO exceeds 0.2 mol% even when SiO ₂ is added in combination (No. 61, 62, 63). In addition, SiO ₂
If it exceeds 0.6 mol%, the dielectric constant εs will decrease (No.56,60,6
3).

〔The invention's effect〕

Of the present invention (100-x-y) · SrtiO 3 + x · CaTiO 3 + y
・ According to the BaTiO ₃ + Y ₂ O ₃ + Nb ₂ O ₅ based semiconductor porcelain composition, S
iO 0.970 to 1.000 moles, TiO ₂ 1.000 moles of the main component SrTiO ₃ as a sub-component x · CaTiO ₃ , y · BaTiO ₃
Furthermore, composite addition of Y ₂ O ₃ and Nb ₂ O ₅ (0.1 ≦ x ≦ 20.0) (however, the upper limit of x changes depending on the SrO / TiO ₂ ratio), (0.05
≦ y ≦ 3.0), (0.10 ≦ Y ₂ O ₃ ≦ 1.0), (0.10 ≦ Nb ₂ O ₅ ≦
0.4), the dielectric constant εs is high and the dielectric loss t
Since an anδ is small and a semiconductor porcelain composition having a high insulation resistance IR and a high DC breakdown voltage E _b can be obtained, it is possible to miniaturize the porcelain capacitor element, that is, a conventional 10φ substrate with 10 ⁵ PF can be manufactured with 8φ substrate It became so. Furthermore, SrO / TiO ₂
Since the suitable range of the ratio can be expanded, the manufacturing work is facilitated, mass production is possible, the manufacturing cost can be reduced, and the industrial advantage is great. In addition, MnO is 0.02
~0.20mol%, in which it was possible to further improve the DC breakdown voltage E _b and the insulation resistance IR of SiO ₂ to 0.01～0.6Mol% composite addition.

Claims (3)

[Claims] 1. A main component of (100-xy) .SrTiO ₃
rO 0.970-1.000 mol, composed of the ratio of TiO ₂ 1.000 mol,
CaTiO ₃ added as an accessory component has a typical value of SrO of 1.000 and 0.99.
5.0-20.0, 1.0 for 0, 0.980, 0.970 mol respectively
〜20.0, 5.0〜20.0, 10.0〜20.0mol%, BaTiO ₃ 1.0〜3.0mol%, Yttrium Y ₂ O
₃ in terms of converting 0.1 to 1.0 mol% and the niobium Nb ₂ O _5, characterized in that it contains, respectively 0.1～0.4Mol% by (100-x-y) · SrTiO 3 + x · CaTiO 3 + y · BaTiO ₃ + Y
₂ O ₃ + Nb ₂ O ₅ based semiconductor porcelain composition. 2. The semiconductor porcelain composition according to claim 1, wherein the main component contains 0.02 to 0.20 mol of manganese and 0.01 to 0.6 mol% of SiO ₂ in terms of MnO. Stuff. 3. The Bi according to claim 1 or 2, wherein Bi is unevenly distributed in a grain boundary of a semiconductor ceramic formed by molding and sintering the composition containing the main component and the subcomponent. The semiconductor porcelain composition of.