JPS63215002A - 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.

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 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 5rTi (h) 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. There is.

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,
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, (2) SraTiO3, (CaxSr1-x)b
Tio 3 (0,001≦x≦0.5).

(Ba, Sr I-y)cTio3(0.001≦y
≦0.5).

(MgzSr+-z)dTiQ3(0,001≦z≦0
．． 5) (0,950≦a, b, c, d<1.000) (
(hereinafter referred to as the first component)
0.000-99.998ioIJ, Nb2O5,T
atOs, WO3゜[1y203. Y2O3, La
2O5,Cen2. Sm2O3, PraO*Nd2
0.001-5.000 mol of at least one of 0.03 (hereinafter referred to as the second component) and 0.001-5.000 sol$ of TiN (hereinafter referred to as the third component), or The first component is 80.000-99.
997mol$, second component 0.001-5.000n
o1g, third component 0.001-5.000a+ol*
.

Al2O3,5b203, Y2O3, BaOtBe
O* PbO+ has y CeF rCr203.
Fe2O3, CdO, K2O, Cab, Co2O3
,Cub.

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

Rh203r 5e02+ Ag2O+ 5iOz p
StC* SrO+ Tl2O+Th02, Ti
O2, V2O5, Bi2O3, WO3, ZnO, ZrO
We attempted to solve the problem by obtaining a voltage-dependent nonlinear resistor ceramic composition containing 0.001-10.000 sol$ of at least one of 2.5n02 (hereinafter referred to as the fourth component). It is something to do.

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 although Ti is trivalent at the time of addition,
After reduction firing, heat treatment in air causes a reaction to change to tetravalent and release electrons. That is, TiO2 is formed by a large amount of oxygen that has diffused in the grain boundary portion, and the emitted electrons are captured by oxygen ions and the grain boundary is insulated. On the other hand, most of the Ti in TiN remains trivalent because it is difficult for oxygen to diffuse inside the particles, and even if oxygen diffuses into the inside of the particles, the trivalent Ti changes to tetravalent Ti and loses electrons. Since it is released, it has the effect of suppressing the increase in resistance due to oxidation. 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, CaCO5, BaCO3, MgC
Weigh O5, Ti (h) so that the composition ratio is as shown in Table 1 below, mix in a ball mill etc. for 40 hours, and after drying,
Calcinate at 1000°C for 15 hours. ZrN and additives were weighed to the thus obtained calcined product so that the composition ratio was as shown in Table 1 below, mixed for 24 hours using a ball mill, dried, and then 10 wt of a binder such as polyvinyl alcohol was added.
After adding $ and granulating it, it is molded into a disk shape of 10φXlt (mm) with a press pressure of l (t/c+J'). After that, the binder was removed by calcination in air at 1100°C for 1 hour, and then the binder was removed by calcination in a mixed gas of N2:H2=9:1.
Bake at 520°C for 3 hours. Furthermore, 1100 in the air
℃ for 12 hours, thus obtained Fig. 1,
A conductive paste such as Ag is applied by screen printing or the like so as to leave the outer periphery on both sides of the sintered body 1 shown in FIG. 2, and is fired 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 paper-resistance (ESR) is evaluated by the impedance at the resonant frequency, and α is a = 1 / Log (V l0IIA / VI
IIA > (However, VIO, A+ VlmA are each 10 mA.

This is the voltage applied across the device when a current of 1 mA is applied. ) 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.

(Margin below) Also, the first component 5raTiO3゜(2)SraTiO3, (CaxSr1-x)bTi0
3 (0,001≦x≦0.5).

(BaySr l-y)cTlo3(0.001≦y
≦0.5).

(MgzSr+-z)dTiO3(0.0OL≦i≦
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*
The reason why the range of b*C*d was defined is that 1.0 is difficult to generate lattice defects, so semiconductor formation is not promoted, and 0.
If it is less than 95, Ti is too much and TiO2
This is because crystals are formed, the structure becomes non-uniform, and the properties 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 does not show any effect at less than 0.001 mol$, and 5. OOO
If the mol exceeds zero, a second phase is formed at grain boundaries, resulting in deterioration of properties. And the fourth component is O, OO1mo
If it is less than l$, no effect is shown, and if it exceeds 5.000s+o1g, a second phase is formed at the grain boundaries, grain growth is suppressed, and the resistance of the grain boundaries becomes high (although the width of the grain boundaries becomes thick). The capacitance is small, the varistor voltage is high, and it is 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, 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 and 1 other person 1 - 2.3 = t 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 TiN. (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;
0.001 to 5.000 mol% TiN, 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%.