JPS63215007A - 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 is 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 and electronic devices. The present invention relates to a linear resistor ceramic composition.

Conventional technology Conventionally, SiC varistors and 2n
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, they have a low dielectric constant (and low inherent capacitance), so they are 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.

Recently, a product containing 5rTi03 as its 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 equipment such as microphones and computers. .

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 purpose of the present invention is to provide a voltage-dependent nonlinear resistor ceramic composition with high surge resistance and low intragranular resistance.

Means for Solving the Problems In order to solve the above problems, in the present invention, Sr, Ti
O3, (2) SraTiO3, (CaxSr1 -x)
bTio 3 (0,001≦x≦0.5).

(BaySrI-y)cTioi(0,001≦y
≦0.5).

(MgzSr+-z)dTi03(0,0 old≦z≦0
．． 5) (0,950≦a, b, c, d<1.000) (
(hereinafter referred to as the first component)
0.000~99.998so1g, Nb2O5, T
a20B, WO3.

mouth y203. Y2O3, La2. s, Ce0z
, 51203. Pr5O mouth.

At least 1 of Nd203 (hereinafter referred to as the second component)
More than 0.001-5.000ao1g, NbN
(hereinafter referred to as the third component) is 0.001-5.000a
ol* or the first component is 80.000
=99.997mol*, second component 0.001-5.
000mo1*, third component 0.001=5.000g
Go eyes, ^1203.5btOs, Bad, Bed
, PbO, B2O3, Cent.

Cr2O3, Fe20s, CdO, K2O, Cab,
CO2O3, Cub.

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

Rh20i, 5eOz, AgtO, SiO2, Si
C, SrO, Tl2O.

ThOx, Tin2. V2O5, Bi2O2, W
At least one of Os, ZnO, Zr0t, and 5nOt (hereinafter referred to as the fourth component) in a concentration of 0.001 to 1
The present invention attempts to solve this problem by obtaining a voltage-dependent nonlinear resistor ceramic composition containing 0.000 solK.

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. -Also, 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 NbN exists as a nitride inside the particles 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, 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. To the thus obtained calcined product, lrN and additives were weighed so as to have the composition ratio shown in Table 1 below, mixed in a ball mill etc. for 24 hours, dried, and then 10 wt of a binder such as polyvinyl alcohol was added. After granulation, it is molded into a disk shape of 10φxlt (im+) with a press pressure of 1<tlcd). 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. Note that 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/VIII
A) (However, VIOIIAT V + sA has 1 each
0mA.

This is the voltage that is applied across the device when a current of 1i+A is applied. ) 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 ±10z.

(Margin below) Also, the first component 5raTi03゜(2)SraTiO3, (CaxSr1-x)bTi0
3 (0,001≦×≦0.5).

(BaySr+-y)cTi03(0,001≦y≦
0.5).

(Mg2Sr+-z)aTi03(0,001≦Z≦
0.5) (0,950≦a, b, c, d<1.000)
The range of x, y, and z 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, b,
The ranges of c and d were specified because when 1.0, lattice defects are hard to occur and semiconductor formation is not promoted, and when it is less than 0.95, Ti0p crystals are formed due to too much Ti and the structure is deteriorated. This is because it becomes non-uniform and the characteristics deteriorate.

Furthermore, if the second component is less than 0.001 mo19, it will not show any effect; If it exceeds OOOmol$, 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. Furthermore, the third component is 0.00
Less than 1 mol* shows no effect, 5.00 On+ol
If the value exceeds *, a second phase is formed at the grain boundaries, resulting in deterioration of properties. The fourth component has no effect if it is less than 0.001mol1g, and if it exceeds 5.00On+ol0, it forms a second phase at the grain boundaries, suppressing grain growth, and the resistance of the grain boundaries becomes high (although the width of the grain boundaries This is because the varistor becomes thicker, the capacitance becomes smaller, the varistor voltage becomes higher, and the varistor becomes 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.

Effects of the Invention As shown above, according to the present invention, the dielectric constant α is large (
Since the intragranular resistance is small, there is less heat generation 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 1 person 1 - Charging body 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 NbN. (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;
NbN 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_3, Na_2O, NiO, Rh_2O_3, Se
O_2, Ag_2O, SiO_2, SiC, SrO, T
l_2O, ThO_2, TiO_2, V_2O_5, B
i_2O_3, WO_3, ZnO, ZrO_2, SnO
At least one type of _2 from 0.001 to 10.
A voltage-dependent nonlinear resistor ceramic composition containing 000 mol%.