JPS625606A - Voltage depending non-linear resistor ceramic composition - 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 Field of Industrial Application The present invention is applicable to S for protecting semiconductors and circuits from abnormal high voltage, noise, and static electricity generated in electrical equipment and electronic equipment.
5rTi05 with r/Ti = 1.05-0.95.

CaxSr1-xTiO3 (○, ○o1≦x≦0.4)
.

Ba, 5r1-, Tic)5 (0.001≦y≦
0.4).

Mg, 5r1-TxTiO3 (0.001≦z≦0.4
) The present invention relates to a voltage-dependent nonlinear resistor ceramic composition containing at least one of the following as a main component.

Conventional technology Traditionally, S-G varistors and Zn varistors with voltage-dependent nonlinear resistance characteristics have been used to absorb abnormally high voltages, remove noise, eliminate sparks, and counter static electricity in various electrical and electronic devices.
O-type varistors were used. The voltage-current characteristics of such a varistor can be approximately expressed as follows.

I=(V/C)(! Here, engineering is the current, ■ is the voltage, C is a constant specific to the varistor, and α is the voltage nonlinear index.

The α of S/G varistors is about 2 to 7, and the α of some ZnO-based varistors is as high as 50. Although such varistors have excellent performance in absorbing relatively high voltages, they have a low dielectric constant and a small inherent capacitance1, so they cannot be used with low voltages below the varistor voltage or with high frequencies (e.g. It has almost no effect on absorption of noise (such as noise), and the dielectric loss is as large as 6 to 10 factors.

On the other hand, semiconductor capacitors with an apparent dielectric constant of about 5×10 4 and a tan δ of about 1 factor are used to remove these low voltage noises. However, if a voltage or current exceeding a certain limit is applied to such a semiconductor capacitor due to a surge or the like, it will be destroyed or will no longer function as a capacitor. Therefore, in recent years, 5rTi
Products that have O3 as the main component and have both varistor and capacitor characteristics have been developed, but they meet the requirements of low varistor voltage, high α, high dielectric constant, and high surge resistance. A product that satisfies all the characteristics has not yet been obtained.

The problem that the invention aims to solve This causes noise in semiconductors and circuits.

To protect against static electricity, the varistor voltage is low, α,
Elements with high dielectric constant, high surge resistance, and excellent noise attenuation characteristics are required.

The present invention seeks to provide a device composition that simultaneously satisfies all of these required characteristics.

Means for Solving the Problems In order to solve the above problems, in the present invention, Sr/Ti
= 1.05-0.95 5rTiO,.

CaxSr1-xTiO3 (0.001≦x≦0.4
).

BaySrl-yTi05 (0.001≦y≦0.
4).

Mg, Sr, -, L'rio3 (0.001≦z≦0
．． Sc
,Y.

La, Ce, Pr, Nd, Pm,
Sm, Eu, Gd, Tb.

Dy, Ho, Er, Tm, Yb,
Lu, Nb, Ta, W.

The present invention attempts to solve the above-mentioned problems by obtaining a voltage-dependent nonlinear resistor ceramic composition containing at least one type of fluoride such as Ce or Tl.

Function Generally, to convert 5rTiO5 into a semiconductor, a semiconductor conversion accelerator is added and reduction firing is performed, but depending on the type of semiconductor conversion accelerator, semiconducting does not progress much with this alone, and the specific resistance after reduction firing is 1.0Ω・It is slightly higher than before and after the varistor voltage is increased, which has a negative effect on electrical characteristics such as lowering the dielectric constant and lowering the surge resistance.

The reason for this is that the reaction between the semiconductor accelerator and sr'r process 05 is not sufficiently occurring. In general, oxides are manufactured by heat-treating salts at high temperatures, so they are thermally stable, and because oxygen and metal elements form highly covalent bonds, reactions with other substances are relatively unlikely. Hateful. Furthermore, even if oxygen is dissociated and sr'rio5 reacts with the metal element, the dissociated oxygen itself is highly active and thus works to suppress semiconductor formation.

Therefore, in order to convert 5rTi○5 into a semiconductor more efficiently, it is necessary that the semiconductor conversion accelerator has high activity and is not an oxide. Fluoride is the most suitable for this purpose, and exhibits several times the activity compared to oxides.

By using fluoride in this way, 5rTi0
Since it is possible to further improve the semiconductor structure of 5, it is possible to reduce characteristics due to particle resistance, for example, lower the varistor voltage, increase the dielectric constant, and increase the surge resistance.

Furthermore, since liquid phase sintering occurs by adding SiO□, sintering can be performed at a lower temperature.

The particle size can also be increased to around 100 μm, which is effective in reducing the varistor voltage.

Furthermore, the fourth component is T: , Fe2O2, Co2O
3.

NiO, MnO2, cr2o5, Ag2O, C
uO, MoO3゜BeO, Li2O, Na2O, ZrO
□, PbO, ZnO.

P2O5+ 5b205 t P2O5+ Bx205
By adding all of tmu1205, these segregate at the grain boundaries and make the grain boundaries high in resistance. Therefore, it is possible to improve the varistor characteristics by increasing the nonlinearity and increasing the surge resistance.

Example The present invention will be specifically explained below by giving examples.

5rCO5, CaCO3, BaCO3, Mgc0. ,
TiO2 was weighed to have the composition ratio shown in Table 1 below, mixed with a ball for 50 hours, dried, and then
Calcinate at 000'C for 1 hour.The thus obtained calcined product is weighed to have the composition ratio shown in Table 1 below, mixed for 24 hours in a ball mill, etc., dried, and then mixed with a binder such as polyvinyl alcohol. After adding 10wt% and granulating it, -1't, 10φaX with a press pressure of /CyA
Shape into a 1fi disc.

This molded body was temporarily phosphorized at 100Q'C for 2 hours, the binder was removed, and then fired at 1500°C for 3 hours in a mixed gas of +N2:H2=9:1. Roughly calcined in air at 12oo'C for 6 hours, the thus obtained first
A conductive paste such as Ag is screen printed leaving the outer periphery on both planes of the sintered body 1 shown in Figs.
oooC・6 minutes of baking to form electrode 2.3.

Next, attach the lead wires using solder, etc., and apply resin coating such as epoxy.

The characteristics of the device thus obtained are shown in Table 2 below.

In addition, it is calculated from the capacitance at dielectric constant [IKHz], and the surge withstand capacity is calculated when the change in vlmA (voltage when 1 mA current is passed) after applying a pulsed current is within ±10 coefficient. Evaluation is based on the maximum pulse current value at a certain time.

(Left below) Effects of the Invention As stated above, when fluoride is used as a semiconducting substance, semiconducting is promoted more than when using oxide, and the resistance of particles can be further lowered. Since the barrier generated in the field becomes relatively high, α becomes large. In addition, since the particles have low resistance, they are less susceptible to damage from electrical energy and can be highly resistant to surges.

The amount of fluoride added was specified as 0.001 m
No effect is shown below 10.000 mol%
If this value is exceeded, the fluoride will react with the substrate and sheath when it is decomposed, so it is difficult to make a product that maintains a predetermined shape.This is because undecomposed fluoride tends to remain, leading to deterioration of varistor characteristics.

In addition, although only some fluorides were shown in the examples, it was confirmed that other fluorides had similar effects.

In addition, this effect clearly appears when using the 5 main ingredients.
The Sr/Ti ratio of rTi05 is in the range of 1.05 to 0.95, otherwise it is difficult to obtain a uniform structure, which is not preferable because the varistor properties, especially the surge resistance, become extremely low.

Also, the ratio of substitution with Sr%&, Mg, and B& is.

For example, when expressed as Cax5r, -xTiO, the value of X is preferably 0, and V'h is preferably Oo1 to 0.4. That is, 0.
If it is less than 0.001, the effect of substitution will not be exhibited, and if it exceeds 0.4, the particle size will become small and both the varistor characteristics and capacitor characteristics will deteriorate, which is not desirable.

As described above, according to the present invention, by using fluoride, the characteristics such as low varistor voltage, large α, large dielectric constant (small tan δ, and high surge resistance) can be simultaneously satisfied. be able to.

Therefore, it is effective against comparatively low voltage surges and noise, and can attenuate and absorb input noise to a level that causes no problem in actual use of the CU.

As described above, by using the element according to the present invention, it is possible to replace a conventional large-sized noise filter circuit with a single element, making it possible to downsize the circuit and reduce costs. Therefore, the practical effect is extremely large.

[Brief explanation of drawings]

FIGS. 1 and 2 are a plan view and a cross-sectional view showing an embodiment of a voltage-dependent nonlinear resistor element according to the present invention. ···electrode. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure E - Akatsuki Piece Monster 2.3-11 Favorite Man 2 Figure

Claims (3)

[Claims] (1) SrTiO_ with Sr/Ti=1.05-0.95
3, Ca_xSr_1_-_xTiO_3 (0.001
≦x≦0.4), Ba_ySr_1_−_yTiO_3
(0.001≦y≦0.4), Mg_zSr_1_-_
The main component is at least one of zTiO_3 (0.001≦z≦0.4), Sc, Y, La, Ce,
Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, H
o, Er, Tm, Yb, Lu, Nb, Ta, W, Ge,
At least one type of Tl fluoride from 0.001 to
A voltage-dependent nonlinear resistor ceramic composition containing 10.000 mol % of the additive. (2) SrTiO_ with Sr/Ti=1.05-0.95
3, Ca_xSr_1_-_xTiO_3 (0.001
≦x≦0.4), Ba_ySr_1_−_yTiO_3
(0.001≦y≦0.4), Mg_zSr_1_-_
The main component is at least one of zTiO_3 (0.001≦z≦0.4), Sc, Y, La, Ce,
Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, H
o, Er, Tm, Yb, Lu, Nb, Ta, W, Ge,
At least one type of Tl fluoride from 0.001 to
10.000 mol%, 0.001 to 10 SiO_2
．． A voltage-dependent nonlinear resistor ceramic composition containing 000 mol% of the additive. (3) SrTiO_ with Sr/Ti=1.05-0.95
3, Ca_xSr_1_-_xTiO_3 (0.001
≦x≦0.4), Ba_ySr_1_−_yTiO_3
(0.001≦y≦0.4), Mg_zSr_1_-_
The main component is at least one of zTiO_3 (0.001≦z≦0.4), Sc, Y, La, Ce,
Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, H
o, Er, Tm, Yb, Lu, Nb, Ta, W, Ge,
At least one type of Tl fluoride from 0.001 to
10.000 mol%, 0.001 to 10 SiO_2
．． 000mol%, Fe_2O_3, Co_2O_3,
NiO, MnO_2, Cr_2O_3, Ag_2O, C
uO, MoO_3, BeO, Li_2O, Na_2O,
ZrO_2, PbO, ZnO, P_2O_5, Sb_2
O_3, V_2O_5, Bi_2O_3, Al_2O_
0.001 to 7.00 for at least one of 3.
A voltage-dependent nonlinear resistor ceramic composition containing 0 mol% of the additive.