JPS63215001A - 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 the functions of a variable thickness characteristic and a capacitor characteristic 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 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, the dielectric constant is large (α is large, and
It is an object of the present invention to provide a voltage-dependent nonlinear resistor ceramic composition that has a large surge resistance and a low intragranular resistance.

Means for Solving the Problems In order to solve the above problems, in the present invention, 5rTi0
3. Cax5rl-xTiO3 (0.001≦x≦0
．． 5).

BaySr+-yTiO3 (0.001≦y≦0.5)
.

MgzSr I-JiO3 (0.001≦z≦0.5)
(hereinafter referred to as the first component), at least one type of 90.000-99.998 mo, Nb2O5, Ta
205. WO3゜Dy203r Y2O3, La2.
s, CeO2, Sm2O3, Pr5ll+.

At least 1 of Nd203 (hereinafter referred to as the second component)
More than 0.001-5.000 mo1g of HfN
(hereinafter referred to as the third component) from 0.001 to 5.000 m
or containing 80.000% of the first component.
~99.997 molL second component 0.001-5. O
QOmoL$, third component 0.001-5. QOOso
l$, A120315btOs, Bad, Bed,
PbO, B2O3, CeO2+Cr2Q3. Fe2
O3, CdO, K2O, Cab, Co2O3, Cub
.

Cu2O, Litu, MgO, MnO2, MoO3,
Na2O, Nip.

nh2o3.5e02. AgtO, 5ift, Si
C, SrO, Tl2O.

ThO2*Tilt, V2O3, Bi2O3, W
At least one of O3, ZnO, ZrO2, and 5n02 (hereinafter referred to as the fourth component) from 0.001 to 1O,
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.

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 HfN 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, 5rCOa, CaCO5, BaC0a +
MgCO3 and TiOx are weighed to have the composition ratio shown in Table 1 below, mixed in a ball mill or the like for 40 hours, dried, and then calcined at 1000°C for 15 hours. ZrN and additives were weighed to the thus obtained calcined material 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 for 1 hour.
After adding 0 wt* and granulating it, it is molded into a disk shape of 10φXlt (nm+) with a press pressure of 1 (t/cat). Thereafter, the product is calcined in air at 1100° C. for 1 hour to remove the binder, and then fired at 1520° C. for 3 hours in a mixed gas of N2:H2=9:1. Furthermore, 1 in the air
After firing at 100° C. for 12 hours, a conductive paste such as Ag is applied by screen printing or the like, leaving the outer periphery on the open plane of the thus obtained sintered body 1 shown in FIGS. 1 and 2. 1. Baked at 600℃ for 5 minutes, electrode 2.
form 3.

Next, attach the lead wire (not shown) with solder etc.
Paint a resin such as epoxy (not shown).The characteristics of the element thus obtained are expressed as follows: a = 1/Log
A) (However, VIOIIA, VlmAi;! sotL
SotL 10mA.

This is the voltage applied across the device when a current of 1 mA is applied. ) was evaluated. In addition, the evaluation is based on the maximum pulse current value when the change in VlmA after applying the pulse current to the surge resistance j is within ±10.

(Margin below) Also, the first component 5rTi03゜CaxSr+-xTiO3 (0.001≦x≦0.5)
.

Ba, Sr +-zTiO3 (0.001≦y≦0.5
).

MgzSr+-zTtO3 (0.OQ1≦z≦0.5)
The range of x, y, and z is specified because if it is less than 0.0α1, 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 does not show any effect if it is less than 0.001 mo1g, and if the second component is less than 0.001 mo1g,
If it exceeds 0 mo1g, it segregates at the grain boundaries, suppresses the increase in resistance of the grain boundaries, and forms a second phase at one grain boundary, resulting in deterioration of properties. Further, if the third component is less than 0.0011 g, it will not be effective, and if it exceeds 5.000 mo, a second phase will be formed at the grain boundaries, resulting in deterioration of properties. If the fourth component is less than 0.001molg, it will not show any effect, and if it exceeds 5.00On+olyO, it will form a second phase at the grain boundaries, suppressing grain growth, increasing the resistance of the grain boundaries, but reducing the width of the grain boundaries. This is because the capacitance becomes smaller, the varistor voltage becomes higher, and the varistor becomes more susceptible to 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 one other person 1 - Sintered 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%, HfN 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%, HfN 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.