JPS63215005A - 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.

I=(V/C)a Here, I is current, ■ is 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, they have a low dielectric constant (and low inherent capacitance), so they are difficult to absorb relatively low voltages below the varistor voltage. However, 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 5rTi (h)-based varistors have a dielectric constant about 10 times higher than ZnO-based varistors, their voltage nonlinearity index (α) and surge resistance are small, and Because of its high resistance, it had the disadvantage of not being able to absorb high-frequency noise sufficiently.

Therefore, in the present invention, in addition to having a large dielectric constant and a large α,
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, the present invention uses 5rTiO
s, CaxSr+-xTiO2(2)SrTiO3,
CaxSr1-xTiO3 (0.001≦x≦0.5)
.

BaySr+-yTio3(2)SrTiO3, Cax
Sr1-xTiO3 (0.0 old≦y≦0.5).

Mg25rl-, Ti(h(2)SrTiO3, Cax
Among Sr1-xTiO3 (0.001≦z≦0.5) (hereinafter referred to as the first component), one or more types are 90.
000=99.998mol*, Nb20B, T
a205, WO3.

Mouth yxOs, Y2O3, La2.3. Cen2
．． 51203. Pre(L+.

At least 1 of Nd203 (hereinafter referred to as the second component)
More than type 0.001=5.0OOs+olK, Sc
N (hereinafter referred to as the third component) is 0.001 to 5.000
or contains 80.000 of the first component.
-99.997 moth, second component 0.001 mo1$
, the third component is 0.001-5.000 mo, Al2O
3,5b203. Bad, Bed, PbO, B2
O3, Cent.

Cr2O5, Fe2O3, CdO, K2O, Cab,
CO2O3, Cub.

Cu2O, Li2O, MgO, Mn0g, Mo53.
Na2O, Nip.

Rh2o3+ 5e02* Ag2O,5i02r S
tC+ SrO, Tl2O+Th02, TiO2,
V2O6, Bi2O3, WO3, ZnO, ZrO2, 5
A small amount of n02 (hereinafter referred to as the fourth component) (0.00 for one or more types) (2) SrTiO3, CaxSr1-
The present invention attempts to solve this problem by obtaining a voltage-dependent nonlinear resistor ceramic composition containing xTiO3 (0.00*ol).

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 ScN exists as a nitride because oxygen diffusion occurs inside the particles, and even if oxygen diffuses to the inside of the particles, it will change its valence and release electrons, resulting in oxidation. It has the effect of suppressing high 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, 5rCO3r CaCO3, BaCO3, MgC
Weigh O5 and TiOx so that they have the composition ratio shown in Table 1 below, mix them in a ball mill etc. for 40 hours, dry them, and then
Calcinate at 1000°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 2 below, mixed in a ball mill etc. for 24 hours, dried, and then 10wt of a binder such as polyvinyl alcohol was added.
After adding zero and granulating, it is molded into a disk shape of 10φXlt (m) with a press pressure of 1 (t/c+j). After that, the binder was removed by calcination in air at 1100°C for 1 hour, and then 152
Bake at 0°C for 3 hours. Furthermore, at 1100℃ in air,
After baking for 12 hours, the thus obtained Fig. 1 and Fig. 2
The Ag
A conductive paste such as the above is applied by screen printing or the like and baked at 600° C. for 5 minutes to form electrodes 2 and 3.

Next, attach the lead wire (not shown) with solder etc.
A resin such as epoxy (not shown) is applied.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 (V 1011A/VI
IIIA) (However, VIOIIAI V+m^Lt
10 IIA each.

This is the voltage applied across the device when a current of 1n+A flows through it. ) was evaluated. Further, the surge resistance is evaluated based on the maximum pulse current value when the change in VImA after applying the pulse current is within a ±10 window.

(Hereafter, the rest is white) In addition, the first component 5rTi (h.

Cax5rI-xTiO2(2)SrTiO3, Cax
Sr1-xTiO3 (0.001≦x≦0.5).

BaySr t-yTiO3 (0.001≦y≦0.5
).

Mg, 5rl-, Ti03(2)SrTiO3, Cax
x of Sr1-xTiO3 (0.001≦z≦0.5),
The reason for specifying the range of y and z is that if it is less than 0.0 (11), no effect will be shown, and if it exceeds 0.5, grain growth and semiconducting will be suppressed and the characteristics will deteriorate. is 0
．． No effect is shown below 001mol$, 5.000m
If it exceeds o1g, 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. Furthermore, the third component is 0.001 moI! If it is less than 5.0001101, no effect will be exhibited, and if it exceeds 5.0001101, a second phase will be formed at the grain boundaries, resulting in deterioration of properties. When the fourth component is less than 0.001 io1*, it does not show any effect, and when it exceeds 5.000 mol*, it forms a second phase at the grain boundaries, suppressing grain growth, and the resistance of the grain boundaries becomes high (although the grain boundary As the width of the varistor becomes thicker, the capacitance becomes smaller, the varistor voltage becomes high, and the varistor becomes weak 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-Chart 2.3-1 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
_zSn_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%, ScN 0.001-5.000 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%, ScN 0.001-5.000 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, Ti_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.