JPS63215019A - 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, ■ 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 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 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 5rTiOs 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. ing.

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, 5raTi
Os, (2) SraTiO3, (CaxSr1-x)
bTi03 (0,001≦x≦0.5).

(BaySr+-y)cTiO3(0.001≦y≦
0.5).

(MgzSr I-z)dTi03(0,001≦z
≦0.5) (0,950≦a, b, c, d<1.000
) (hereinafter referred to as the first component) of 90.000 to 99.998 iol*, Nb20B
, Ta20B, WO3゜口y2(h, Y2O3
, La2O3, CeO2, 5s203. Pr60th.

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) is 0.001-5.000i
o1* or the first component is 80.000
-99.997solK, second component 0.001-5.
00th centroid, 0.001-5.000iol of the third component
*, Al2O3,5b203. Bad, Bed,
PbO, FhOs+ CeO2゜Cr203, Fe
tOs + CdO, 20 * Can + CO2
O3* CuO#Cu2O,Litu, MgO,Mn
Ox, MOO3, Na2O, Nip.

Rh20t, 5ea2. AgtO, 5ift, S
iC, SrO, Tl2O.

Th02. Ti12. V2O5, Bit'3. W
At least one of Os, ZnO, Zr(h, 5nO2 (hereinafter referred to as the fourth component)) in an amount of 0.001 to 1O
,000 mo1g of the voltage dependent nonlinear resistor ceramic composition.

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, SrCO3, CaCO3, BaCO3, MgCO
3. Weigh TiO2 so that it has the composition ratio 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. ZrN and additives were weighed to the thus obtained calcined product so as to have the composition ratio shown in Table 1 below, mixed for 24 hours using a ball mill, dried, and then mixed with a binder such as polyvinyl alcohol for 10 wt$.
After adding and granulating, it is molded into a disk shape of 10φ×1t(+a) with a press pressure of 1(t/cvJ). Thereafter, the binder was removed by calcination at 1100°C in air for 1 hour, and then at 1520°C in a mixed gas of N2:H2=9:1.
, bake for 3 hours. Furthermore, in air at 1100℃, 12
After firing for a time, a conductive paste such as Ag is applied by screen printing or the like, leaving the outer periphery on both planes of the sintered body 1 thus obtained as shown in FIGS. 1 and 2,
The electrodes 2 and 3 are formed by firing at 600° C. for 5 minutes.

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 (V IOImA / V II
IIA) (However, VIOmA + VlmA are each 10 mA.

This is the voltage applied to both ends of the element when a current of In+A flows through it. ) was evaluated. Further, the surge resistance is evaluated based on the maximum pulse current value when the change in VlmA after applying the pulse current is within ±10 zero.

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

(CaxSr+-x)bTi03(0,001:ii;
x≦0.5).

(BaySr 1-y ). Tifh(0,001≦y
≦0.5).

(MgzSr+-z)dTi03(0,001≦i≦0
．． 5) The range of X, Y + Z (0,950≦a,b,c,d<1.000) was specified because if it is less than 0.001, it will not show any effect, and if it exceeds 0.5, grain growth will occur. This is because semiconductor formation is suppressed and the characteristics deteriorate. Also, at b
*The range of Cp d was specified because 1.0 causes lattice defects (therefore, semiconductor formation is not promoted, and 0.95
This is because if it becomes smaller, Ti will be excessive and TiO2 crystals will be formed, the structure will become non-uniform and the characteristics will deteriorate. In addition, the second component has no effect if it is less than 0.001 mol, and if it exceeds 5.000 mol, it segregates at the grain boundaries, suppresses the increase in resistance of the grain boundaries, and forms a second phase at the grain boundaries. The characteristics deteriorate. Furthermore, the third component is 0.
001 mol less than zero, no effect is shown, 5.000 mol
When f exceeds zero, a second phase is formed at grain boundaries, resulting in deterioration of characteristics. And the fourth component is 0.001mol1g
If it is less than 5.00On+O, it will not be effective, and if it exceeds 1g of 5.00On+O, a second phase will be formed at the grain boundaries and grain growth will be suppressed, and the resistance of the grain boundaries will increase, but the width of the grain boundaries will become thicker, so the capacitance will decrease. This is because the varistor voltage 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 (
Since the intragranular resistance is small, there is less heat generation after a surge current is applied, so that the effect of reducing element deterioration and increasing surge resistance can be obtained.

[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 idiot 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 HfN. (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;
HfN 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%.