JPS6348802A - Porcelain compound for voltage dependent nonlinear resistor - Google Patents

Abstract

(57) [Abstract] 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 provides a (CaxSr, -x)yTie for protecting semiconductors and circuits from abnormal high voltages, noise, and static electricity generated in electrical and electronic equipment.

(0.○01≦x≦0.4, 0.96≦y<1.O○
)(Ba, Sr, -a)b Tie3(QOO1
≦a≦Q4, Q95≦b(1,00) (MgoSr,
+c), Tie.

(QOO1≦c≦Q4, Q95≦d(1,00) The present invention relates to a voltage-dependent nonlinear resistor ceramic composition having as main components.

Conventional technology SiG varistors and ZnO 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.
A type of barista was used. The voltage-current characteristics of such a varistor can be approximately expressed as the following formula: OI: (v/c)a Here, 〇 is the current, ■ is the voltage, and C is a constant specific to the varistor. α is the voltage nonlinearity index.

The α of SiO 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, their low dielectric constant and small inherent capacitance prevent them from absorbing low voltages below the varistor voltage or high frequencies (e.g. It has little effect on absorbing noise (such as noise), and has a large dielectric loss tan δ of 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 inch 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 will be destroyed or will no longer function as a capacitor. Therefore, in recent years, 5r
A device that has TiO5 as its main component and has both varistor and capacitor characteristics has been developed, but it has all the required features such as low varistor voltage, large α, large dielectric constant, and high surge resistance. A product that satisfies these characteristics has not yet been obtained.

Problems to be Solved by the Invention In order to protect semiconductors and circuits from noise and static electricity, it is necessary to simultaneously satisfy characteristics such as low varistor voltage, high α, dielectric constant, and high surge resistance.

Conventional varistors are designed to absorb high-voltage surges, so they are not effective against noise or static electricity caused by low varistor voltages, and their low dielectric constant makes them poorly responsive to sharp-rising pulses. It had such problems.

The present invention solves these problems, and has varistor characteristics, a large dielectric constant, good responsiveness to pulses with a sharp rise, and a voltage-independent non-voltage device that efficiently removes noise and static electricity. An object of the present invention is to provide a linear resistor ceramic composition. Means for Solving the Problems In order to solve the above problems, the present invention provides
S r 1-x )y T i Os (0.001≦
x≦0.4.095≦y (1,95≦d<1.00) (
BaaSr1 -a )bTzO3(Q○01≦4≦04.0.95≦b(
1,95≦d<1.00) (Mg osr , -c), Tl05 (0.001≦c≦0.
4, at least one type among Q95≦d(1,00) s s, o o o ~ 99.997 moj%,
Y2O3, YF3. Nb2O5, T2L2O3, Y
F3, Nb2O5, Ta2O5, La2O5゜La2O
0.001 to 2.00 of at least one of 3.
0m0J%, Co2O3, CuO, Ag2O (7)
At least one of these from 0.001 to 5.000
mol%.

BaO is o, 95≦d<1.001'-ts, 95≦d
A voltage-dependent nonlinear resistor ceramic composition containing <1.000rno1% is obtained.

Function Generally, in order to convert 5rTiO into a semiconductor, a semiconducting promoter is added and reduction firing is performed, but depending on the type of the semiconducting promoter, the semiconducting may not proceed much with this alone.

Therefore, Sr in 5rTiO5 should be replaced with other elements, such as Ca.
, Ba, Mg, etc., causes distortion in the crystal structure and promotes semiconductor formation. Also, Sr relative to Ti
By making the proportions of , Ca, Ba, and Mg T1 in excess of the stoichiometric ratio, lattice defects are generated and promoted in the semiconductor device, and at the same time, grain growth is promoted.

Therefore, 5rTiO, and Sr are combined with Ca, Ba, M
The fine structure and properties of the final sintered body are significantly different from those in which Ti is substituted with g or the like and Ti is made excessive, and the composition is considered to be a different composition.

Next, CO20s * Cu O, A g 20 r
When BaO is added, these segregate at grain boundaries, making the grain boundaries high in resistance and exhibiting varistor properties.

Furthermore, B2O5, NiO, MoO2, Beo,
Fe2O3゜LiO, CrOPbO, CaO, TiO
2, P2O5, St+20. .

2 2 3 T Mu β2o3. When v205 is added, the varistor properties are improved because they segregate at the grain boundaries and increase the height of the barrier formed at the grain boundaries.

The high-resistance layer at the grain boundaries thus formed has a large dielectric constant and is thin in width, so that a large capacitance can be obtained.

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

5rCO, , CaCO3, BaCO3, MgC0. , T
Weigh iO2 so that it has the composition ratio shown in Table 1 below, mix it in a ball mill etc. for 60 hours, dry it, and then
Calcinate at 00°C for 10 hours. Additives were weighed to the thus obtained calcined product so that the composition ratio shown in Table 1 below was obtained, mixed for 24 hours using a ball mill, etc., dried, and then 10 wt% of a binder such as polyvinyl alcohol was added to produce the product. After graining, 10φm with a press pressure of 1t/ClTl
Shape into a disk shape of X 1 tM.

Next, after calcining in air at 1000℃ for 2 hours to remove the binder,
Bake at 00°C for 3 hours. Roughly 1200℃ in air
The sintered body 1 shown in FIGS. 1 and 2 thus obtained was screen-printed with a conductive paste such as Ag, leaving the outer periphery on both planes, and baked at 600°C for 6 hours. Partial firing is performed to form electrodes 2.3. Next, the lead wires are attached using solder or the like and coated with resin such as epoxy.

The characteristics of the device thus obtained are shown in Table 2 below.

Note that the dielectric constant in Table 2 is calculated from the capacitance at 1 KHz, and the surge withstand capacity is determined by the change in vlmA (voltage when 1 mA of current is passed) after applying a pulsed current. The evaluation is based on the maximum pulse current value within ±10 inches.

(Hereinafter, blank spaces) Note that although only some of the additives were shown in this example, it was confirmed that a similar effect could be achieved with a combination of other additives.

In addition, the main components (CaxSr, -x), TiO3, (Ba
aSr+-a)6Tie5. (MgcSr, -0)d
Tie3's X, y,? The ranges of L, b, c, and d were defined because x, a, and c have no effect if they are less than 0.001;
This is because when it exceeds 0.4, grain growth and semiconductor formation are suppressed, resulting in deterioration of characteristics.

7, t), d is 1. This is because oO does not generate lattice defects and does not promote semiconductor formation, and when it is smaller than 0.96, Ti becomes too excessive and Ti crystals are formed, the structure becomes non-uniform and the customization deteriorates.

Mata, Y 20, , YF 5. Nb 20s
, Ta 20s + L! The amount of L 205 added was 0. ○0 No effect is shown below 1 mol, 2, ○
If it exceeds OOmol%, the grain boundaries will not have a sufficiently high resistance,
a becomes smaller, tan δ becomes larger, and the surge resistance becomes lower.

The amount of Ga2O3, CuO, and human g20 added is 0.001n.
No effect is shown below o/%, 5.000 m0Il
If the value exceeds the 0.5%, the segregation of additives to the grain boundaries will increase, the varistor voltage will increase, and the dielectric constant will decrease significantly. Also, Ba
O has the effect of promoting oxygen diffusion to grain boundaries, and is effective for uniform oxygen diffusion on the surface and inside of the sintered body. If the amount added is less than 0.001 m01%, it will not show any effect,
If it exceeds s, o o o moA%, the diffusion of oxygen into the grain boundaries will be promoted, the width of the high resistance layer will increase, the varistor voltage will increase, the dielectric constant will decrease, and the surge resistance will become weak.

Also, B ONiO, Mob, , Beo, Fe
2O,, Li2O.

23+ 0r20. , PbO, CaO, Tie□, P,,
O,,,5b205. If the amount of Al2O3゜v205 added is less than 0.001 mol%, no effect will be shown.6. ○
When 95≦d<1.00 molq6, the segregation of additives to grain boundaries increases, the varistor voltage increases, the dielectric constant decreases significantly, and the surge resistance decreases.

Effects of the Invention As described above, according to the present invention, characteristics such as a low varistor voltage, a large α and dielectric constant surge resistance, and a small tan δ can be simultaneously satisfied. Therefore, compared to conventional ZnO-based varistors, the varistor voltage is lower and the dielectric constant is larger, making it extremely effective against pulses with steep rises such as noise and static electricity.

Therefore, according to the present invention, an element capable of protecting semiconductors and circuits from noise and static electricity can be obtained, and its practical effects are extremely large.

[Brief explanation of drawings]

FIG. 1 is a top view showing an element according to the present invention, and FIG. 2 is a sectional view thereof. 1... Sintered body, 2, 3... Electrode.

Claims (2)

[Claims] (1) (Ca_xSr_1_-_x)_yTiO_3(
0.001≦x≦0.4) (0.95≦y<1.00)
(Ba_aSr_1_-_a)_bTiO_3(0.0
01≦a≦0.4) (0.95≦b<1.00) (Mg
_cSr_1_-_c)_dTiO_3(0.001≦
c≦0.4) (0.95≦d<1.00) at least one type from 88.000 to 99.997 mol%
, Y_2O_3, YF_3, Nb_2O_5, Ta_2
0.001 to 2.000 mol% of at least one type of O_5, La_2O_3, Co_2O_3, C
0.0 of at least one type of uO, Ag_2O
01-5.000 mol%, BaO 0.001-5.000 mol%.
A voltage-dependent nonlinear resistor ceramic composition containing 000 mol%. (2) (Ca_xSr_1_-_x)_yTiO_3(
0.001≦x≦0.4) (0.95≦y<1.00)
(Ba_aSr_1_-_a)_bTiO_3(0.0
01≦a≦0.4) (0.96≦b<1.00) (Mg
_cSr_1_-_c)_dTiO_3(0.001≦
c≦0.4) (0.96≦d≦1.00) at least one type from 83.000 to 99.996 mol%
, Y_2O_3, YF_3, Nb_2O_5, Ta_2
0.001 to 2.000 mol% of at least one type of O_5, La_2O_3, Co_2O_3, C
0.0 of at least one type of uO, Ag_2O
01-5.000 mol%, BaO 0.001-5.000 mol%.
000mol%, B_2O_3, NiO, MoO_3,
BeO, Fe_2O_3, Li_2O, Cr_2O_3
, PbO, CaO, TiO_2, P_2O_5, Sb_
A voltage-dependent nonlinear resistor ceramic composition containing 0.001 to 5.000 mol% of at least one of 2O_3, Al_2O_3, and V_2O_5.