JPS63215018A - Voltage-dependent nonlinear resistor porcelain compound - 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 relates to a voltage-independent non-voltage device having capacitor characteristics and varistor characteristics for protecting semiconductors and circuits from abnormal high voltages, noise, and static electricity generated in electrical equipment and electronic equipment. The present invention relates to a linear resistor ceramic composition.

Conventional technology Conventionally, SiC varistors and Zn varistors, which have 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 in the following equation.

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

The α of SiC 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, their low dielectric constant and small inherent capacitance make them difficult to absorb relatively low voltages below the varistor voltage. shows almost no effect, and the dielectric loss tan δ is as large as 5 to 10%.

On the other hand, semiconductor capacitors with an apparent dielectric constant of about 5×10' and a tan δ of about 1% 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 may break down and no longer function as a capacitor.

Therefore, recently, a material containing 5rTi03 as a main component and having both variable-type characteristics and capacitor characteristics has been developed and is used to protect semiconductor elements such as TC and LSI in electronic devices such as microcomputers.

Problems to be Solved by the Invention Although the above-mentioned 5rTi03-based varistor has a dielectric constant about 10 times higher than that of the ZnO-based varistor, the voltage nonlinearity index (α) and surge resistance are small, and the intragranular resistance is low. Because of its high cost, it had the disadvantage of not being able to sufficiently absorb high-frequency noise.

Therefore, in the present invention, in addition to having a large dielectric constant and a large α,
The object of the present invention is to provide a voltage-dependent nonlinear resistor ceramic composition that has a large surge withstand capacity (-1 and low intragranular resistance).

Means for Solving the Problems In order to solve the above problems, in the present invention, 5rTi0
3. Ca, 5rI-, Ti03 (0.001≦x≦0
．． 5).

BaySr+-yTiO3 (0.001≦y≦0.5)
.

MgzSr t-zTiO3 (0.001≦z≦0.5
) (hereinafter referred to as the first component) 90.000-99.998 mo1g, Nbt05
．． Ta20B, WO3゜mouth y203. Y2O3
, La2O3, Cen2. 512031 Pr60
eye.

At least one of NdxOs (hereinafter referred to as the second component)
More than type 0.001=5.000+gol*, Zr
N (hereinafter referred to as the third component) is o, oot ~ 5.0OO
io or containing 80,000 of the first component.
-99.997sol zero, second component 0.001=5.
OOOmol$, third component 0.001=5.000
*oH5A1203.5b203. Bad, Bed
, PbO, B2O3, Ce0g.

Cr2O5, Fe2e3. CdO, K2O, Cab,
CO2031Cub.

Cu2O, Li2O, MgO, MnO2, MoO3, N
a2O, Nip.

Rh2O3,5e02. Ag2O,5i02. Si
C, SrO, Tl2O.

Th02. TiO2, V2O5, Bi2O3, WO:
+, ZnO+ At least one type of ZrO2, 5n02 (hereinafter referred to as the fourth component) from 0.001 to 10
The present invention attempts to solve this problem by obtaining a voltage-dependent nonlinear resistor ceramic composition containing OOOmo 18.

Function: In the above invention, the first component is the main component, and the second component is mainly a metal oxide that promotes semiconductor formation. Further, the third component contributes to improving the dielectric constant and intragranular resistance, and the fourth component is the dielectric constant, α.

Contributes to improving surge resistance. In particular, the third component is uniformly dispersed throughout the device, and is a nitride at the time of addition, but when heat treated in air after reduction firing, it changes to an oxide, and a reaction occurs that releases electrons. That is, oxides are formed at the grain boundaries due to the large amount of oxygen that has diffused, and the emitted electrons are captured by oxygen ions, making the grain boundaries insulating. On the other hand, most of the ZrN exists as a nitride inside the particle because it is difficult for oxygen to diffuse inside the particle. It acts to suppress resistance. Therefore, the internal resistance of the particles can be made low.

Example EXAMPLES The present invention will be described in detail below using examples.

First, SrCO3, CaCO3, BaCO3, MgCO
3. Weigh TiO2 so that the composition ratio is as shown in Table 1 below, mix it in a ball mill etc. for 40 hours, dry it, and then
Calcinate at 000°C for 15 hours. ZrN and additives were weighed to the thus obtained calcined product so as to have the composition ratio shown in Table 1 below, mixed in a ball mill etc. for 24 hours, dried, and then a binder such as polyvinyl alcohol was added with 10% zero. After granulation, 1 (t/cd) press pressure
Form into a disk shape of 0φX1t (+w). After that, after performing calcination in air at 1100℃ for 1 hour to remove the binder,
1520℃ in a mixed gas of N2:H2=9:1,
Bake for 3 hours. Further, the sintered body 1 shown in FIGS. 1 and 2 was fired in air for 12 hours at 1100°C, and a conductive paste such as Ag was applied so as to leave the outer periphery on both sides of the sintered body 1 shown in FIGS. 1 and 2. Apply by screen printing etc., 6
The electrodes 2 and 3 are formed by baking at 00° C. for 5 minutes.

Next, attach the lead wire (not shown) with solder etc.
Apply a resin such as epoxy (not shown). The characteristics of the device thus obtained are shown in Table 2 below. The dielectric constant is calculated from the capacitance at IKHz, the intragranular resistance (ESR) is evaluated by the impedance at the resonant frequency, and α is a = 1 / Log (VIOIIA/V
IIIA) (However, VIOIIIA, V+@A
Lt soreso t'L10mA.

This is the voltage applied across the device when a current of 1 mA is applied. ) was evaluated. Further, the evaluation is based on the maximum pulsed current value when the change in VImA after applying the pulsed current of surge tolerance 1 is within ±10 zero.

(Margin below) In addition, the first component 5rTi03°Ca, Sr1-xTiO2 (0,001≦x≦0.5
).

BaVSrl-yTiO3 (0.001≦y≦0.5)
.

Mg, 5r1-, Ti03 (0.001≦z≦O, -5
) is specified because if it is less than 0.011, no effect will be shown, and if it exceeds 0.5, grain growth and semiconducting will be suppressed and the characteristics will deteriorate. In addition, the second component has no effect when less than 0.001 mo1g, and 5.0 mo1g is less than 0.001 mo1g.
If it exceeds 00 mol*, it segregates at the grain boundaries, suppresses the increase in resistance of the grain boundaries, and forms a second phase at the grain boundaries, resulting in deterioration of properties. Further, the third component does not show the Teha effect when it is less than 0.001 io1g, and when it exceeds 5.000 mol$, a second phase is formed at the grain boundaries and the properties are deteriorated.

The fourth component has no effect if it is less than 0.00 In+ol*, and if it exceeds 5.000 mol, it forms a second phase at the grain boundaries, suppressing grain growth, and increases the resistance of the grain boundaries. As the width becomes thicker, the capacitance becomes smaller, the varistor voltage becomes higher, and the varistor becomes weaker against surges.

In this example, only some combinations of additives were shown, but it was confirmed that other combinations of additives had similar effects.

Effect of the invention As shown above, according to the present invention, the dielectric constant.

Since α is large and the intragranular resistance is small, less heat is generated after a surge current is applied, resulting in less deterioration of the element and increased surge resistance.

[Brief explanation of the drawing]

FIG. 1 is a top view showing an element according to the invention, and FIG. 2 is a sectional view of the element according to the invention. 1... Sintered body, 2, 3... Electrode. Name of agent Patent attorney Toshio Nakao and 1 other person 1 - Burnt body 2.3 - Electrode Figure 1 Figure 2

Claims (2)

[Claims] (1) SrTiO_3, Ca_xSr_1_-_xTi
O_3 (0.001≦x≦0.5), Ba_ySr_1
____yTiO_3 (0.001≦y≦0.5), Mg
_zSr_1_−_zTiO_3 (0.001≦z≦0
．． 90.000 to 9 for at least one of the following
9.998 mol%, Nb_2O_5, Ta_2O_5
, WO_3, Dy_2O_3, Y_2O_3, La_2
O_3, CeO_2, Sm_2O_3, Pr_6O_1
At least one of _1, Nd_2O_3 is 0
．． 001-5.000 mol%, ZrN 0.001-5.001 mol%
A voltage-dependent nonlinear resistor ceramic composition containing 5.000 mol%. (2) SrTiO_3, Ca_xSr_1_-_xTi
O_3 (0.001≦x≦0.5), Ba_ySr_1
____yTiO_3 (0.001≦y≦0.5), Mg
_zSr_1_−_zTiO_3 (0.001≦z≦0
．． 80.000-9 for at least one of the following
9.997 mol%, Nb_2O_5, Ta_2O_5
, WO_3, Dy_2O_3, Y_2O_3, La_2
O_3, CeO_2, Sm_2O_3, Pr_6O_1
At least one of _1, Nd_2O_3 is 0
．． 001-5.000 mol%, ZrN 0.001-5.001 mol%
5.000 mol%, Al_2O_3, Sb_2O_3
, BaO, BeO, PbO, B_2O_3, CeO_2
, Cr_2O_3, Fe_2O_3, CdO, K_2O
, CaO, Co_2O_3, CuO, Cu_2O, Li
_2O, MgO, MnO_2, MoO_3, Na_2O
, NiO, Rh_2O_3, SeO_2, Ag_2O,
SiO_2, SiC, SrO, Tl_2O, ThO_2
, TiO_2, V_2O_5, Bi_2O_3, WO_
3. A voltage-dependent nonlinear resistor ceramic composition containing 0.001 to 10.000 mol% of at least one of ZnO, ZrO_2, and SnO_2.