JPH01175702A - Voltage-dependent non-linear resistor having porcelain composition - Google Patents

Abstract

PURPOSE:To obtain a composition with a large dielectric constant, a large voltage non-linear index, a large surge withstand amount, and a low resistance within grain by using a substance which includes at least one kind out of SrTiO3, CaxSr1-xTiO3, BaySr1-yTiO3, and MgzSr1-zTiO3, at least one kind, out of Nb2O5, Ta2O5, WO3 etc., and Nn3N2 each in a specified amount. CONSTITUTION:A substance which contains at least one kind out of SrTiO3, CaxSr1-xTiO3 (0.001<=x<=0.5), BaySr1-yTiO3 (0.001<=y<=0.5), and MgzSr1-zTiO3 (0.001<=z<=0.5) in 90.000-99.998mol%, at least one kind out of Nb2O5, Ta2O5, WO3, Dy2O3, Y2O3, La2O3, CeO2, Sm2O3, Pr6O11, and Nd2O3 for 0.001-5.000mol%, and Mn3N2 in 0.001-5.000mol% is used. Or, a substance which contains in addition to the above each constituent, at least one kind out of Al2O3, Sb2O3, BaO, BeO, PbO, B2O3, CeO2, Cr2O3, Fe2O3, CdO, K2O, CaO, Co2O3, CuO, Cu2O, Li2O, MgO, MnO2, MoO3, Na2O, NiO etc., in 0.001-10.000mol% is used.

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 to protect 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 having 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.
ZnO-based varistors were used. The voltage-current characteristics of such a varistor can be approximately expressed as in the following equation.

I: (V/C; )” Here, E is the current, V is the voltage, C is a constant specific to the varistor, and α is the 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 60. 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 6 to 10%.

On the other hand, semiconductor capacitors with an apparent dielectric constant of about 5×10' and a tan δ of about 1 gu 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 5rTiO as its main component and having both varistor and capacitor properties has been developed and is used to protect semiconductor elements such as IC, I, and SI in electronic equipment such as microcomputers. There is.

The varistor whose main component is 5rTiO3 mentioned in 1. Problems to be Solved by the Invention is ZnO.
Although the dielectric constant is about 10 times higher than that of the varistor, it has the drawbacks of low voltage nonlinearity index (α) and surge resistance, and high intragranular resistance, which makes it unable to absorb high-frequency noise sufficiently. .

Therefore, an object of the present invention is to provide a voltage-dependent nonlinear resistor ceramic composition that has a large dielectric constant, a large α, a large surge resistance, and a low intragranular resistance.

In order to solve the problems described in "Means for Solving the Problems", the present invention uses 5rTi.
O, Cax5r1-xTiO5 (0,001≦x≦0.
5).

BaySr,, Tie, (0,001≦y≦0.5
).

Mg25r1-zTie, (0,001-zTiO3
(0.001≦z≦o, s) (hereinafter referred to as the first component) at least one type of 80.000 to 99.
997 mol%, Nb2O5, Ta205°WO5
, Dy2O3, Y2O3, La20. , CaO2°Sm, 03. Pr60. , , at least one type of Nd203 (hereinafter referred to as the second component) is 0.0
01-5.000 mol%9Mn3N2 (hereinafter referred to as third f
f minutes! : 0.001 to 5.000 mol%
1203.5b203. BaO
, Boo, Pbo.

B2O3, CeO2, Or, 03. Fe2O3,C
d, O, K2O.

CaO, Co2O3, CuO, Cu2O, Li2O, M
gO, MnO□.

MoO2, Na2O, NiO, Rh20. , 5ea2
．． Mug20°5in2. SiC, SrO, Tl2O,
The□, Tie2゜V O, Bi2O5, Ta2O
5, WO3, Dy2O3, Y2O3, No3. ZnO
, ZrO2, SnO2 (hereinafter referred to as the fourth component) at 0.001 to 10.000 mo
The present invention attempts to solve the problem by obtaining a voltage-dependent nonlinear resistor ceramic composition containing 1.

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 contributes to improving the dielectric constant, α, and 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 emits electrons. At the grain boundaries, oxides are formed by 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, inside the microparticles, oxygen diffusion is difficult to occur, so most Mn and N2 exist as nitrides, and even if oxygen diffuses into the inside of the particles, the valence of the nitrides changes and electrons are emitted. Therefore, it acts to suppress the increase in resistance due to oxidation. Therefore, the internal resistance of the particles can be made low.

Example The present invention will be specifically described below with reference to Examples.

5rCO5, CaCO3, BaCO3, JCO5, Ta
Weigh 2O5, WO3, Dy2O3, Y2O3, and TiO2 so that the composition ratio is as shown in Table 1 below,
After mixing for 40 hours with a ball mill etc. and drying,
Calcined for 15 hours at O''C.Mn5N2 and additives were weighed to the thus obtained calcined product so as to have the composition ratio shown in Table 1 below, mixed in a ball mill etc. for 20 hours, dried, and mixed with polyvinyl alcohol. 1 organic binder such as
After adding 0 wt% and granulating it, it is molded into a disk shape of 10φX 1ta with a press pressure of 1 (t/d). After calcination in air at 1000°C for 115 hours to remove the binder, the mixture was heated to 145°C in a mixed gas of N2:H2=9:1.
Bake for 13 hours at 0'C. Furthermore, 1200° in air
C. Sinter for 4 hours 1. Apply 5 g of conductive paste 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 electrode 2.3 is formed by coating and baking at 600° C. for 6 minutes. Next, the lead wires are attached using solder or the like, and a resin such as epoxy is applied. The characteristics of the device thus obtained are shown in Table 2 below. In addition, the dielectric constant is 1KHz
The intragranular resistance is evaluated by the impedance at the resonant frequency, and α is a = 1 / Log (Y, omA / vImA
) (However, -vImA + v+omA is 1mA
, is the voltage applied across the device when a current of 10 mA is applied. ) was evaluated. In addition, the surge resistance j1t is such that the change in vImA after applying a Nordic current is ±1o.
The evaluation is based on the maximum pulse current value within %.

(Left below) -Table 2- Comparative examples are shown for the US and India.

! , and the first component 5rT10. , CaxSr.
, Tie.

(○, o o 1-X S o, s ), BayS
r, -yTie3 (0,0014y 40.6)
, Mg2Sr, -2Tie3 (0,001-2 0.
The reason why the ranges of x, y, and z in 5) are defined is that 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. Moreover, the second component shows no effect at less than 0.0 Of 111014, s, o o.

This is because if it exceeds 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, resulting in deterioration of characteristics. Roughly speaking, if the third component is less than 0.001 mol4, it will not show any effect, and if it exceeds 5.000 mol, a second phase will be formed at the grain boundaries, resulting in deterioration of the properties. The fourth component has no effect if it is less than 0.001 mol, and if it exceeds 5.000 mol, it forms a second phase at the grain boundaries, suppressing grain growth, and increases the grain boundary resistance. As the width of the varistor 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 high frequency noise is absorbed and heat generation is small after a surge current is applied. Effects such as less deterioration of the element and increased surge resistance 111' can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a device according to the present invention, and FIG. 2 is a diagram showing a cross section of the device according to the present invention. 1... Sintered body, 2.3... Electrode. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 "/' /- \- \- Q-

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
9.998mol%, 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%, Mn_3N_2 0.
A voltage-dependent nonlinear resistor ceramic composition containing 001 to 5.000 mol%. (2) SrTiO_3, Ga_xSr_1_-_xTi
O_3 (0.001≦x≦0.5), BaySr_1_
−_yTiO_3 (0.001≦y≦0.5), Mg_
zSr_1_-_zTiO_3 (0.001≦z≦0.
5) at least one type from 80,000 to 99
．． 997mol%, Nb_2O_5, Ta_2O_5,
WO_3, Dy_2O_3, Y_2O_3, La_2O
_3, CeO_2, Sm_2O_3, Pr_6O_1_
1, Nd_2O_3 at least one type or more.
001-5.000 mol%, Mn_3N_2 0.0
01~5.000mol%, Al_2O_3, Sb_2
O_3, BaO, BeO, PbO, B_2O_3, Ce
O_2, Cr_2O_3, Fe_2O_3, CdO_2
, K_2O, CaO, Co_2O_3, CuO, Cu_
2O, Li_2O, MgO, MnO_2. MoO_3,
Na_2O, NiO, Rh_2O_3, SeO_2, A
g_2O, SiO_2, SiC, SrO, Tl_2O,
ThO_2, TiO_2, V_2O_5, Bi_2O_
3, 0.001 to 10.000 mo of at least one of WO_3, ZnO, ZrO_2, and SnO_2
A voltage-dependent nonlinear resistor ceramic composition containing 1%.