JPS63215004A - 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)' 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 2nO varistors is as high as 50. Although such varistors have excellent performance in absorbing relatively high voltages, they have a low dielectric constant and small inherent capacitance, so they are difficult to absorb relatively low voltages below the varistor voltage. It 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 -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 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 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, in the present invention, Sr, Ti
O3, (CaXSr+-x)bTi03 (0,001≦
x≦0.5).

(BaySr+-y)cTi03(0,001≦y≦
0.5).

(MgzSrI-z)dTi03(0,001≦z≦0
．． 5) (0,950≦a, b, c, d<1.000) (
(hereinafter referred to as the first component)
0.000-99.998mol*, Nb20B,
Ta205. WO3゜Dy20s, v,, o, L
a2O3, CeO2, Sm20s, Pr5Ou.

At least 1 of Nd203 (hereinafter referred to as the second component)
More than 0.001~5.000s+ol$, Sc
N (hereinafter referred to as the third component) is 0.001-5.000
o + ol zero content, or the first component is 80.0
00-99.997 IIol zero, second component 0.001
-5.000mo1! , the third component is 0.001-5.0
00mol$, Al2O3,5b203. Bad,
Bed, PbO, B2O3, CeO2゜Cr2O3,
Fe2O3, CdO, K2O, Cab, CO2O3,
Cub.

CuxO, LizO, MgO, MnO2, MOO3, N
a2O, Nip.

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

Th02. TiO2, V2O5, Bi2O3, WO3
, znO, ZrO2, 5n02 (hereinafter referred to as the fourth component)
At least one of the following: 0.001 to io, 00
The purpose is to solve this problem by obtaining a voltage-dependent nonlinear resistor ceramic composition containing: 0mo12.

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 it is difficult for oxygen to diffuse inside the particles. 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, 5rC(h, CaCO3, [3aCO3, M
gCO3 and TiO2 were weighed so as 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 to the calcined material for 10 minutes.
After adding wtg and granulating it, it is molded into a disc shape of 10φXlt (mm) with a press pressure of Ht/car). 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.
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 (V IOImA / V I
IIA ) (However, V IOmA r V ImA are each 10 mA.

This is the voltage applied across the device when a current of ImA flows through it. ) was evaluated. Further, the surge resistance is evaluated based on the maximum pulse current value when the change in VIIIA after applying the pulse current is within ±10N.

(Hereafter, the rest is white) In addition, the first components are Sr and TiO3.

(CaxSr +-x)bTi03(0,001≦x≦
0.5).

(BaySr+-y)cTi03(0,001≦y≦
0.5).

(MgzSr I-z)dTiO3(0.001≦z
-≦0.5) (0,950≦a, b, c, d<1.00
The range of x, y, and z of 0) is specified because 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. Also, a,
The ranges of b, c, and d were specified because 1.0 causes lattice defects (and therefore does not promote semiconductor formation), and below 0.95 causes too much Ti and the formation of TiO2 crystals. This is because the structure becomes non-uniform and the properties deteriorate.Also, if the second component is less than 0.001 iol, it has no effect, and if it exceeds 5.000 iol, it segregates at the grain boundaries, causing high resistance at the grain boundaries. This suppresses the formation of a second phase at the grain boundaries, resulting in deterioration of properties.Furthermore, the third component is 0.0
01iol Less than zero shows no effect; 5.000iol
If it exceeds zero, a second phase is formed at the grain boundaries, resulting in deterioration of properties. Furthermore, the fourth component has no effect if it is less than 0.001 iol, and if it exceeds 5.000 iol, it will form a second phase at the grain boundaries, suppressing grain growth, and increasing the resistance of the grain boundaries. As the width becomes thicker, the capacitance becomes smaller and the varistor voltage becomes higher, making it less 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.

Effects of the Invention As shown above, according to the present invention, the dielectric constant α is large and the intragranular resistance is small, so there is little heat generation after a surge current is applied, so the deterioration of the element is small and the surge resistance is low. You can get the effect of becoming thicker.

[Brief explanation of the drawing]

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

Claims (2)

[Claims] (1) Sr_aTiO_3, (Ca_xSr_1_-_
x)_bTiO_3 (0.001≦x≦0.5), (B
a_ySr_1_-_y)_cTiO_3(0.001
≦y≦0.5), (Mg_zSr_1_−_z)_dT
iO_3 (0.001≦z≦0.5) (0.950≦a
, b, c, d<1.000) at 90.000 to 99.998 mol%, Nb_2O
_5, Ta_2O_5, WO_3, Dy_2O_3, Y
_2O_3, La_2O_3, CeO_2, Sm_2O
0.001 to 5.000 mol% of at least one of _3, Pr_6O_1_1, and Nd_2O_3;
A voltage-dependent nonlinear resistor ceramic composition containing 0.001 to 5.000 mol% of ScN. (2) Sr_aTiO_3, (Ca_xSr_1_-_
x)_bTiO_3 (0.001≦x≦0.5), (B
a_ySr_1_-_y)_cTiO_3(0.001
≦y≦0.5), (Mg_zSr_1_−_z)_dT
iO_3 (0.001≦z≦0.5) (0.950≦a
, b, c, d<1.000) at 80.000 to 99.997 mol%, Nb_2O
_5, Ta_2O_5, WO_3, Dy_2O_3, Y
_2O_3, La_2O_3, CeO_2, Sm_2O
0.001 to 5.000 mol% of at least one of _3, Pr_6O_1_1, and Nd_2O_3;
ScN 0.001-5.000 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, Cu
O, Cu_2O, Li_2O, MgO, MnO_2, M
oO_3Na_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, ZnO, ZrO_2, SnO_
0.001 to 10.0 of at least one of 2.
A voltage-dependent nonlinear resistor ceramic composition containing 00 mol%.