JPH01226120A - Voltage-dependent non-linear resistor ceramic composition - Google Patents

Abstract

PURPOSE:To increase dielectric constant, voltage non-linearity index, surge withstand amount, etc., by incorporating a third element Co3N2 in a voltage- dependent non-linear resistor ceramic composition consisting of the main element of a first element SrTiO3 and metal oxide of a second element. CONSTITUTION:A third element Co3N2 of 0.001-5.000mol% is contained within a voltage-dependent non-linear resistor ceramic composition consisting of the main element of a first element of 90.000-99.998mol% and the metal oxide of a second element of 0.001-5.000mol%. The first element consists of at least one type out of SrTiO3, CaXSr1-XTiO3(0.001<=X<=0.5), BaySr1-YTiO3(0.001<=Y<=0.5), MgzSr1-ZTiO3(0.001<=Z<=0.5). The second constituent consists of at least one type out of Nb2O5, Ta2O5, WO3, Dy2O3, La2O3, CeO2, Sm2O3, Pr6O11, and Nd2O3. It allows the dielectric constant, voltage non-linear index, surge withstand amount, etc., to be increased.

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.

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

The α of SiC varistors is about 2 to 7, and the α of some ZnO-based varistors is as high as 50. Varistors have excellent performance in absorbing relatively high voltages, but due to their low dielectric constant and small inherent capacitance, they cannot absorb relatively low voltages below the varistor voltage. shows almost no effect, and dielectric loss tan%%% 5 to 10%
It's big.

On the other hand, semiconductor capacitors with an apparent dielectric constant of about 5.times.10' and a tan .delta. of about 1 inch 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 varistor and capacitor properties has been developed and is used to protect semiconductor elements such as ICs and LSIs in electronic devices such as microcomputers.

Problems to be Solved by the Invention Although the above-mentioned 5rTi05-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 high. Therefore, it had the disadvantage of not being able to sufficiently absorb high-frequency noise.

Therefore, an object of the present invention is to provide a voltage-dependent nonlinear resistor ceramic composition that has a high dielectric constant, a large α, a large surge resistance, and a low intragranular resistance.

Means for Solving the Problems In order to solve the above problems, the present invention uses 5rTiO5
,y2O3,Oaz Srj -zT103 (0.0
01-xTiO3 (0.001≦x≦O, E5).

BaySr j −yTlos (0.001≦y≦0
．． 5).

MgzSrl -zTi05 (0.001≦z≦0.
5) At least one type (hereinafter referred to as the first component) of 80.000 to 99.997 mol%, Nb2O5
, WO3, Dy2O3, Y2O3, Ta205゜WO5
r ”!205 +Y2O3+ ”205 + C
eO2+8m2O3+Pr60H, at least one of Na2O5 (hereinafter referred to as the second component) at 0.00%
1-5. OOOmol%, Go3N2 (hereinafter referred to as the third component) from 0.001 to 5, WO3, Dy2O3,
Y2O3, OOOmol%, or the first component is 80.000 to 99.997no1% and the second component is 0.001 to 5.0%. OOomol%, the third component is O, OCN~5. ooo mol%, plus Ad2
03.5b20. .

BaO, BeO, PbO, B2O3, CeO2, Gr2
03゜Fe2O3, CdO, K2O, CaO, Co2O
3.CuO.

Cu2O, Li2O, MgO, MnO2, MoO2, N
a2O.

NiO, Rh2O3, 5e02, Ag2O, 5i
02. SiC.

SrO, Td20, Th02, TiO2, V2
O5, WO3, Dy2O3, Y2O3, Bi2O3゜W
At least one of O, ZnO, ZrO2, and 5n02 (hereinafter referred to as the fourth component) is 0.001 to 1
The purpose is to solve this problem by obtaining a voltage-dependent nonlinear resistor ceramic composition containing 0.000 mol%.

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.

This 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 heated in air after firing the ring element, it changes to an oxide and emits 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, inside the particle, oxygen diffusion is difficult to occur, so most of the Co 3N 2 nitride remains, and even if oxygen diffuses into the particle, the valence of the nitride changes and electrons are emitted. Therefore, it acts to suppress the increase in resistance due to oxidation. Therefore, the internal resistance of the particles can be made low.

Example The present invention will be specifically described below with reference to Examples.

First, SrCO3, CaCO3, BaCO3, ygco
, .

Ti02 was weighed to have the composition ratio shown in Table 1 below, mixed in a ball mill etc. for 40 hours, dried, and then
Calcinate at 000°C for 15 hours. Fe2N 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 10wt% of an organic binder such as polyvinyl alcohol was added. After granulation, it is molded into a disk shape of 10φ×1 (II) with a press pressure of 1 (t/Cm). Next, the binder is removed by calcination at 1050°C in air for 1 hour, and then fired at 1400°C for 16 hours in a mixed gas of N2:H2=9:1. Additionally, 10 in the air
Fig. 1 was obtained by firing at 80°C for 914 hours.

A conductive paste such as Ag is applied by screen printing or the like so as to leave the outer periphery on the side plane of the sintered body 1 shown in FIG. 2, and is fired at 600° C. for 5 minutes to form electrodes 2 and 3. Next, although not shown, lead wires are attached using solder or the like, and a resin such as epoxy is applied. The characteristics of the device thus obtained are shown in Table 2 below. In Table 2, 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 α'''' / ''g (''+ o mh/Vlz
l) (However, “ImA + v+OmA is 1mA,
This is the voltage applied to both ends of the element when a current of 1 ohmA is applied. ) was evaluated. Further, the surge resistance is evaluated based on the maximum pulse current value when the change in Win after applying the pulse current is within ±10%.

(The following is a margin) Table 1〉 *mark indicates a comparative example * mark indicates a comparative example In addition, the first component 5rTi03, CazSr, -
zTi05(o, oo1-xTiO3(0.001≦x
≦0, 6), BaySr + yT103
(0.001≦y≦0.5), MgzSrl −z
x+' of TiO3 (o, ool ≦z≦0.5)! +
The reason for specifying the range of z is that if it is less than 0.001, no effect will be shown, and if it exceeds 0.5, grain growth and semiconducting will be suppressed and the characteristics will deteriorate. Furthermore, the second component is 0
,001 mol, no effect is shown, s,oo.

If it exceeds mol%, it will segregate at the grain boundaries, suppress the increase in resistance of the grain boundaries, and form a second phase at the grain boundaries, resulting in deterioration of properties. If the third component is less than 0.001 mol%, it will not be effective, and if it exceeds 5,000 mol%, a second phase will be formed at the grain boundaries, resulting in deterioration of the properties.

Furthermore, if the fourth component is less than 0.001 mol%, it has no effect, 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, but As the width of the field becomes thicker, the capacitance becomes smaller and the varistor voltage becomes higher, making it more vulnerable to surges.

In this example, only some combinations of additives were shown, but it was confirmed that other combinations of additives had similar effects as long as they were within the required range.

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

Because the voltage nonlinearity index α is large and the intragranular resistance is small, it absorbs high-frequency noise and generates little heat after a surge current is applied, resulting in less element deterioration and higher surge resistance. can get.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing an element according to the invention, and FIG. 2 is a sectional view showing an element according to the invention. 1... Sintered body, 2, 3... Electrode.

Claims (2)

[Claims] (1) SrTiO_36, Ca_xSr_1_-_xT
iO_3(0.001≦x≦0.5), Ba_ySr_
1_-_yTiO_3 (0.001≦y≦0.5), M
g_zSr_1_−_zTiO_3(0.001≦z≦
0.5) at least one type from 90,000~
99.998mol%, Nb_2O_5, Ta_2O_
5, WO_3, Dy_2O_5, y_2O_3, La_
2O_3, CeO_2, Sm_2O_3, Pr_6O_
1_1, Nd_2O_3, and 0.001 to 5.000 mol% of Co_3N_2. (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%, Co_3N_2 0.
001-5.000 mol%, Al_2O_3, Sb_
2O_3, BaO, BeO, PbO, B_2O_3, C
eO_2, Cr_2O_3, Fe_2O_3, CdO,
K_2O, CaO, Ce_2O_3, CuO, Cu_2
O, Li_2O, MgO, MnO_2, MoO_3, N
a_2O, NiO, Rh_2O_3, SeO_2, Ag
_2O, SiO_2, SiC, SrO, Tl_2O, T
hO_2, TiO_2, V_2O_5, Bi_2O_3
, WO_3, ZnO, ZrO_2, SnO_2 in an amount of 0.001 to 10.000 mol.
A voltage-dependent nonlinear resistor ceramic composition containing %.