JPH01289202A - Voltage-dependent nonlinear resistance element and manufacture thereof - Google Patents
Voltage-dependent nonlinear resistance element and manufacture thereofInfo
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- JPH01289202A JPH01289202A JP63119510A JP11951088A JPH01289202A JP H01289202 A JPH01289202 A JP H01289202A JP 63119510 A JP63119510 A JP 63119510A JP 11951088 A JP11951088 A JP 11951088A JP H01289202 A JPH01289202 A JP H01289202A
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- 230000001419 dependent effect Effects 0.000 title claims description 6
- 238000004519 manufacturing process Methods 0.000 title description 5
- 239000012298 atmosphere Substances 0.000 claims abstract description 13
- 239000002994 raw material Substances 0.000 claims abstract description 5
- 239000000843 powder Substances 0.000 claims abstract description 3
- 150000003839 salts Chemical class 0.000 claims description 13
- 239000002245 particle Substances 0.000 claims description 7
- 239000012299 nitrogen atmosphere Substances 0.000 claims description 5
- 150000004649 carbonic acid derivatives Chemical class 0.000 claims description 4
- 150000001875 compounds Chemical class 0.000 claims description 2
- 238000010438 heat treatment Methods 0.000 claims description 2
- 239000011812 mixed powder Substances 0.000 claims description 2
- 238000000465 moulding Methods 0.000 claims description 2
- 239000004065 semiconductor Substances 0.000 abstract description 16
- 238000005245 sintering Methods 0.000 abstract description 13
- UPWOEMHINGJHOB-UHFFFAOYSA-N oxo(oxocobaltiooxy)cobalt Chemical compound O=[Co]O[Co]=O UPWOEMHINGJHOB-UHFFFAOYSA-N 0.000 abstract description 10
- 238000000034 method Methods 0.000 abstract description 8
- 229910002370 SrTiO3 Inorganic materials 0.000 abstract description 6
- CETPSERCERDGAM-UHFFFAOYSA-N ceric oxide Chemical compound O=[Ce]=O CETPSERCERDGAM-UHFFFAOYSA-N 0.000 abstract description 6
- 229910000422 cerium(IV) oxide Inorganic materials 0.000 abstract description 6
- 230000005611 electricity Effects 0.000 abstract description 6
- 239000011656 manganese carbonate Substances 0.000 abstract description 6
- 235000006748 manganese carbonate Nutrition 0.000 abstract description 6
- 229910000016 manganese(II) carbonate Inorganic materials 0.000 abstract description 6
- 230000003068 static effect Effects 0.000 abstract description 6
- RUDFQVOCFDJEEF-UHFFFAOYSA-N yttrium(III) oxide Inorganic materials [O-2].[O-2].[O-2].[Y+3].[Y+3] RUDFQVOCFDJEEF-UHFFFAOYSA-N 0.000 abstract description 6
- QPLDLSVMHZLSFG-UHFFFAOYSA-N Copper oxide Chemical compound [Cu]=O QPLDLSVMHZLSFG-UHFFFAOYSA-N 0.000 abstract description 5
- 230000007547 defect Effects 0.000 abstract description 3
- MRELNEQAGSRDBK-UHFFFAOYSA-N lanthanum oxide Inorganic materials [O-2].[O-2].[O-2].[La+3].[La+3] MRELNEQAGSRDBK-UHFFFAOYSA-N 0.000 abstract description 2
- KTUFCUMIWABKDW-UHFFFAOYSA-N oxo(oxolanthaniooxy)lanthanum Chemical compound O=[La]O[La]=O KTUFCUMIWABKDW-UHFFFAOYSA-N 0.000 abstract description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 abstract 4
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 abstract 2
- 229910052681 coesite Inorganic materials 0.000 abstract 2
- 229910052906 cristobalite Inorganic materials 0.000 abstract 2
- 239000000377 silicon dioxide Substances 0.000 abstract 2
- 235000012239 silicon dioxide Nutrition 0.000 abstract 2
- 229910052682 stishovite Inorganic materials 0.000 abstract 2
- 229910052905 tridymite Inorganic materials 0.000 abstract 2
- 239000007788 liquid Substances 0.000 abstract 1
- 229910052757 nitrogen Inorganic materials 0.000 abstract 1
- 238000010304 firing Methods 0.000 description 16
- 230000000694 effects Effects 0.000 description 12
- 230000015572 biosynthetic process Effects 0.000 description 7
- 238000010405 reoxidation reaction Methods 0.000 description 6
- 239000007791 liquid phase Substances 0.000 description 5
- 239000000203 mixture Substances 0.000 description 5
- 239000003990 capacitor Substances 0.000 description 4
- 230000007423 decrease Effects 0.000 description 4
- 238000010586 diagram Methods 0.000 description 4
- 238000009766 low-temperature sintering Methods 0.000 description 4
- 239000000654 additive Substances 0.000 description 3
- 230000002159 abnormal effect Effects 0.000 description 2
- 230000000996 additive effect Effects 0.000 description 2
- 125000004429 atom Chemical group 0.000 description 2
- 238000000889 atomisation Methods 0.000 description 2
- 239000011230 binding agent Substances 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 238000005469 granulation Methods 0.000 description 2
- 230000003179 granulation Effects 0.000 description 2
- 150000004679 hydroxides Chemical class 0.000 description 2
- 150000002500 ions Chemical class 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 230000001737 promoting effect Effects 0.000 description 2
- 239000004372 Polyvinyl alcohol Substances 0.000 description 1
- 229910002367 SrTiO Inorganic materials 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 230000001747 exhibiting effect Effects 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 125000001153 fluoro group Chemical group F* 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 229920002451 polyvinyl alcohol Polymers 0.000 description 1
- 238000007670 refining Methods 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 230000004043 responsiveness Effects 0.000 description 1
- 239000002689 soil Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Landscapes
- Compositions Of Oxide Ceramics (AREA)
- Thermistors And Varistors (AREA)
Abstract
Description
【発明の詳細な説明】
産業上の利用分野
本発明は、電子機器、電気機器で発生する異常高電圧、
ノイズ、パルス、静電気から半導体装置回路を保護する
ところの5rTiO,を主成分とする電圧依存性非直線
抵抗体素子及びその製造方法に関するものである。DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to abnormal high voltages generated in electronic equipment and electrical equipment,
The present invention relates to a voltage-dependent nonlinear resistor element mainly composed of 5rTiO, which protects semiconductor device circuits from noise, pulses, and static electricity, and a method for manufacturing the same.
従来の技術
従来、各種電子機器、電気機器で発生する異常高電圧、
ノイズ、パルス、静電気除去のためにバリスタ特性ヲ有
するSiCバリスタやZnO系バリスタが使用されてき
た。このようなバリスタの電圧−電流特性は近似的に次
式のように表すことができる。Conventional technology Conventionally, abnormal high voltages generated in various electronic devices and electrical devices,
SiC varistors and ZnO-based varistors having varistor characteristics have been used to remove noise, pulses, and static electricity. The voltage-current characteristics of such a varistor can be approximately expressed as in the following equation.
I:(V/C)″
ここで、工は電流、Vは電圧、Cはバリスタ固有の定数
であり、αは電圧非直線指数である。I: (V/C)'' Here, Δ is the current, V is the voltage, C is a constant specific to the varistor, and α is the voltage nonlinear index.
SiCバリスタの電圧非直線指数αは2〜7程度、Zn
O系バリスタではαが60にも及ぶものがある。このよ
うなバリスタは、比較的高い電圧の吸収には優れた性能
を有しているが、誘電率が低く、固有の静電容量が小さ
いためバリスタ電圧以下の低い電圧や周波数の高いもの
の吸収に対してはほとんど効果を示さない。また、誘電
損失tanδが6〜10%と大きい。The voltage non-linearity index α of SiC varistor is about 2 to 7, Zn
Some O-type varistors have α 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 low voltages below the varistor voltage or high frequencies. It has almost no effect on Further, the dielectric loss tan δ is as large as 6 to 10%.
一方、低電圧のノイズなどの除去には、見掛けの誘電率
εが5×10程度で、誘電損失tanδが1%前後の半
導体コンデンサが利用されている。On the other hand, semiconductor capacitors with an apparent dielectric constant ε of about 5×10 and a dielectric loss tan δ of about 1% are used to remove low-voltage noise.
しかし、このような半導体コンデンサは、サージなどに
よシある限度以上の電圧は、電流が印加されると破壊し
たり、コンデンサとしての機能を果たさなくなる。そこ
で近年、 5rTiO3i主成分とし、バリスタ特性と
、コンデンサ特性の両方の機能含有するものが開発され
てきている。However, such semiconductor capacitors will be destroyed or will no longer function as a capacitor if a voltage exceeding a certain limit is applied due to a surge or the like. Therefore, in recent years, materials have been developed that contain 5rTiO3i as the main component and have both varistor and capacitor characteristics.
発明が解決しようとする課題
5rTi05に主成分とする容量性バリスタは、バリス
タ電圧が高い、電圧非直線指数αが小さい、見掛は誘電
率εが小さい、容量温度特性が良くないと言う問題を有
しており、全ての特性を同時に満足するものは未だに得
られていない。さらに、焼結温度、再酸化温度が高いこ
とから、エネルギー量の消費が多いと言う問題を有して
いる。従って、5rTiO31主成分とする容量性バリ
スタにおいて、バリスタ電圧が低い、電圧非直線指数α
が大きい、見掛は誘電率εが大きい、容量温度特性が良
いと言う条件を同時に満たし、さらに焼成温度や再酸化
温度が低温で行える必要がある。Problem to be Solved by the Invention 5rCapacitive varistors mainly composed of Ti05 have the following problems: high varistor voltage, small voltage nonlinearity index α, apparently small dielectric constant ε, and poor capacitance-temperature characteristics. However, a product that satisfies all of the characteristics simultaneously has not yet been obtained. Furthermore, since the sintering temperature and reoxidation temperature are high, there is a problem in that a large amount of energy is consumed. Therefore, in a capacitive varistor mainly composed of 5rTiO31, the varistor voltage is low, and the voltage nonlinearity index α
It is necessary to simultaneously satisfy the following conditions: a large dielectric constant, a large apparent dielectric constant ε, and good capacitance-temperature characteristics, and furthermore, the firing temperature and reoxidation temperature must be low.
本発明は、このような点に鑑みてなされたもので、低電
圧のノイズなどの除去が可能なTrTiO5を主成分と
する電圧依存性非直線抵抗体素子及びその製造方法を提
供することを目的とするものである。The present invention has been made in view of the above points, and an object of the present invention is to provide a voltage-dependent nonlinear resistor element mainly composed of TrTiO5, which can remove low voltage noise, and a method for manufacturing the same. That is.
課題を解決するための手段
上記のような問題点を解決するために本発明は、Srと
Tiの比が1,001≦Sr/Ti≦1.05となるよ
うに過剰のSrを含有し、さらにLiと1を合計でo、
oo’y 〜o 、soo wt%含有したSrTiO
3に、CeO2,Y2O3,LIL20. Oうち少な
くとも一種類以上i0.1〜5.0 mo1%と、5i
n2. Cub。Means for Solving the Problems In order to solve the above-mentioned problems, the present invention contains an excess of Sr so that the ratio of Sr and Ti is 1,001≦Sr/Ti≦1.05, Furthermore, the total of Li and 1 is o,
SrTiO containing oo'y ~o, soo wt%
3, CeO2, Y2O3, LIL20. At least one of them: i0.1-5.0 mo1%, and 5i
n2. Cub.
CO205C02O59のうち少なくとも一種類以上を
0.1〜2.0nOL%含ませてなる電圧依存性非直線
抵抗体素子を提供するものであり、またその内部に含ま
れる水溶性塩が0.050wt%以下(但し、0wt%
は含まず)とした電圧依存性非直線抵抗体素子を提供す
るものである。また、本発明は、平均粒径が0.5μ曹
以下の5rTiO5粉末を原料として1.001≦Sr
/Ti≦1.05となるようにSr化合物を添加し、さ
らにLiFを0.7〜7.0mo1%と1 Cub2.
Y2O3,La20.のうち少なくとも一種類以上f
0.1〜5.0 mo1%と、8i、 Cu、 Go。The present invention provides a voltage-dependent nonlinear resistor element containing 0.1 to 2.0 nOL% of at least one type of CO205C02O59, and the water-soluble salt contained therein is 0.050 wt% or less. (However, 0wt%
(not including). Further, the present invention uses 5rTiO5 powder with an average particle size of 0.5μ or less as a raw material and 1.001≦Sr
/Ti≦1.05, and 1 Cub2.
Y2O3, La20. At least one type of f
0.1-5.0 mo1%, 8i, Cu, Go.
Mnのうち少なくとも一種類以上の元素を酸化物、炭酸
化物などの各種の形のいずれかの形にして0.1〜2.
C11o1%添加した混合粉末を成形し、還元雰囲気中
や窒素雰囲気中で1000〜14oO℃の温度で焼成し
、その後、500〜9oo℃で焼付は可能な導電性ペー
ストを用い、上記焼成後の素子にSOO〜900”Cで
焼付けて電極を形成するか、または上記焼成後の素子を
空気中で500〜1000’Cの熱処理を行った後に5
00〜900℃で焼付けて電極を形成し、内部に含まれ
る水溶性塩がo、osowt%以下(但し、owt%は
含まず)とした電圧依存性非直線抵抗体素子の製造方法
を提供するものである。At least one element of Mn is in the form of any of various forms such as oxides and carbonates, and the amount is 0.1 to 2.
The mixed powder containing 1% C11O is molded and fired at a temperature of 1000 to 14oC in a reducing atmosphere or nitrogen atmosphere, and then a conductive paste that can be baked at a temperature of 500 to 90oC is used to mold the fired element. to form electrodes by baking at SOO~900'C, or heat-treating the fired element in air at 500~1000'C and then baking at SOO~900'C.
To provide a method for manufacturing a voltage-dependent nonlinear resistor element, in which an electrode is formed by baking at 00 to 900°C, and the water-soluble salt contained therein is less than or equal to 0,000% (however, not including 000%). It is something.
作用
一般に5rTiO3e半導体化させるには、強制還元す
るか、もしくは半導体化促進剤を添加し還元雰囲気焼成
するかである。しかし、これだけでは半導体化促進剤の
種類によって半導体化が進まない場合がある。そこで、
5rTiO,を化学量論よりSr過剰、またはTi過剰
にすると、格子欠陥が増加し半導体化が促進される。さ
らに、Srを他の元素、例えばCe 、Y、Laで置換
すると、原子化制御により半導体化が促進される。Function Generally, in order to convert 5rTiO3e into a semiconductor, forced reduction is performed, or a semiconductor conversion accelerator is added and firing is performed in a reducing atmosphere. However, with this alone, semiconductor formation may not proceed depending on the type of semiconductor formation accelerator. Therefore,
When 5rTiO is made to have an excess of Sr or an excess of Ti compared to the stoichiometry, lattice defects increase and semiconductor formation is promoted. Furthermore, when Sr is replaced with other elements such as Ce, Y, and La, semiconductor formation is promoted through atomization control.
次に、5in2. OuO、Co2O3,MnC0,f
添加すると、これらが粒界に偏析し、粒界を高抵抗化さ
せ、バリスタ特性を発現させる。Next, 5in2. OuO, Co2O3, MnC0,f
When added, they segregate at grain boundaries, making the grain boundaries high in resistance and exhibiting varistor properties.
またさらに、この時、本発明のようにLiFを添加し、
還元雰囲気や窒素雰囲気中で焼成すると、680℃付近
で5r0−Tio□−LiF系の液相を形成し、液相焼
結により焼結が促進される。また、この液相を介してS
rTiO3が溶解析出し粒成長が起こる。これにより低
温焼結が可能な焼結体素子を得ることができ、焼結のた
めのエネルギー量を削減することができることとなる。Furthermore, at this time, LiF is added as in the present invention,
When fired in a reducing atmosphere or nitrogen atmosphere, a 5r0-Tio□-LiF-based liquid phase is formed at around 680°C, and sintering is promoted by liquid phase sintering. In addition, S through this liquid phase
rTiO3 dissolves and grain growth occurs. As a result, it is possible to obtain a sintered body element that can be sintered at a low temperature, and the amount of energy for sintering can be reduced.
しかし、ここでTi過剰であるとLi2Tie3を形成
するため、SrTiO3の焼結性が抑制される。従って
、Sr過剰が望まれる。しかし、Sr過剰もある限度を
超すと、粒成長が抑制され焼結性が低下することや、焼
結体素子に水浴性塩を過剰に含むため、信頼性や寿命特
性に影響を与える。However, if Ti is excessive here, Li2Tie3 is formed, which suppresses the sinterability of SrTiO3. Therefore, excess Sr is desired. However, if the Sr excess exceeds a certain limit, grain growth is suppressed and sinterability is reduced, and the sintered element contains an excessive amount of water-bathable salt, which affects reliability and life characteristics.
また、5rTiO,に対するLiFの添加量は焼成温度
と密接に関係しており、低温焼結のためには、ある程度
以上のLiFを添加しなければならない。Furthermore, the amount of LiF added to 5rTiO is closely related to the sintering temperature, and for low-temperature sintering, a certain amount or more of LiF must be added.
そして、この場合、添加したLiFが焼成中に飛散し、
これによって焼成用のサヤ、炉壁、発熱体などが侵され
たり、信頼性や寿命特性を著しく低下させるという実用
上の問題点を有している。しかし、本発明者らは研究の
結果、後述するように5rTiO,の原料粒径を微細化
して0.5μm以下の原料を用いることにより、LiF
の添加量を低減しても低温焼結が可能であることを見出
した。従って、これらのことから焼成時のL工Fの飛散
、残存量の抑制、及び焼結体素子の信頼性や寿命特性を
向上させることが可能である。In this case, the added LiF scatters during firing,
This poses a practical problem in that the firing pod, furnace wall, heating element, etc. are attacked, and reliability and life characteristics are significantly reduced. However, as a result of our research, the present inventors found that by refining the raw material particle size of 5rTiO and using a raw material of 0.5 μm or less, as described later, LiF
It has been found that low-temperature sintering is possible even if the amount of addition is reduced. Therefore, from these reasons, it is possible to suppress the scattering and residual amount of L-work F during firing, and to improve the reliability and life characteristics of the sintered body element.
次に、雰囲気焼成の温度を1000〜1400°Cに規
定したのは、同じく後述するように1000℃未満では
焼結体素子に含まれるム土と2の残存量が0.500w
t%よりも多いため、信頼性や電気特性に影響を与える
ことと、焼結密度が低いためである。また、1000℃
を超えると多孔質となシ、焼成密度が低下するためであ
る。Next, the temperature of the atmosphere firing was specified to be 1000 to 1400°C.As will be explained later, below 1000°C, the residual amount of Mu soil and 2 contained in the sintered element is 0.500w.
This is because the amount is higher than t%, which affects reliability and electrical characteristics, and because the sintered density is low. Also, 1000℃
This is because if it exceeds this, it becomes porous and the firing density decreases.
従って、Sr過剰の5rTiO、にCeO2,Y2O5
゜L!L203のうち少なくとも一種類以上と、5in
2゜OuO、Co2O3,MnCO3のうち少なくとも
一種類以上ft添加して得られた焼結体と、Sr過剰の
SrTiO3にCeO2,Y2O3,La2O3のうち
少なくとも一種類以上と、5in2. CuO、Co2
0. 。Therefore, in 5rTiO with excess Sr, CeO2, Y2O5
゜L! At least one type of L203 and 5in
A sintered body obtained by adding 2°ft of at least one type of OuO, Co2O3, and MnCO3, and at least one type of CeO2, Y2O3, and La2O3 to SrTiO3 with excess Sr, and 5 in2. CuO, Co2
0. .
Mnco3のうち少なくとも一種類以上及びLfFを添
加し最終的に得られる焼結体とでは、微細構造、電気特
性が著しく異なり、互いに全く別の組成物であると考え
られる。The sintered body finally obtained by adding at least one type of Mnco3 and LfF has a significantly different microstructure and electrical properties, and is considered to be a completely different composition from each other.
実施例
以下に本発明について、実施例を挙げて具体的に説明す
る。EXAMPLES The present invention will be specifically described below with reference to Examples.
(実施例1)
まず、5rTiO,(平均粒径0.5 μm ) 、5
rCO5゜第1成分のCoo□r Y2O5+ La2
O5を第2成分のSiO□及びLiF″f、下記第1表
に示す組成比になるように秤量し、混合した。これを乾
燥後、O,Swt%ポリビニルアルコール溶液のバイン
ターヲ添加し、1時間混合し造粒した。造粒後、1 t
on/ct4の圧力で12φx 1.0 (m*)の円
板状に成形し、次に空気中で4oo℃、1時間脱バイン
ダーを行った。その後、N2:H2=1o:1の還元雰
囲気中で1000〜1400’C12時間焼成した。(Example 1) First, 5rTiO, (average particle size 0.5 μm), 5
rCO5゜First component Coo□r Y2O5+ La2
O5 and the second component SiO□ and LiF''f were weighed and mixed so that the composition ratio was as shown in Table 1 below. After drying, a binder of O, Swt% polyvinyl alcohol solution was added, and the mixture was heated for 1 hour. Mixed and granulated. After granulation, 1 t
It was molded into a disk shape of 12φx 1.0 (m*) at a pressure of on/ct4, and then the binder was removed in air at 4oo°C for 1 hour. Thereafter, it was fired for 12 hours at 1000 to 1400'C in a reducing atmosphere of N2:H2=1o:1.
このようにして得られた第1図、第2図に示す焼結体1
の両面に、外周を残すようにしてムgなどの導を性ペー
ストラスクリーン印刷し、6oO〜900”C110〜
6o分の条件で焼き付け、焼結体素子の再酸化を行うと
同時に電極2,3を形成した。The sintered body 1 shown in FIGS. 1 and 2 obtained in this way
Screen print a conductive material such as mug on both sides of the paper, leaving the outer periphery.
The electrodes 2 and 3 were formed at the same time as the sintered element was reoxidized by baking at 6°C.
このようにして得られた還元雰囲気中で1300℃、2
時間焼成した素子(電極はムgペーストを800℃、1
5分の条件で焼付けて形成)の電気特性、さらに素子内
部に含まれるLiと2の残存量、同じく素子内部に含ま
れるLi、F、Sr原子を含む水溶性塩の含有量及び信
頼性試験の結果を下記第2表に示す。ここで、素子内部
に含まれる水溶性塩の含有量は、次の方法により解析し
た。まず、焼結した素子を粉砕し、それに水を加え10
分間煮沸し、ろ過後、Li、Srはフレーム原子吸光、
yはイオン電極法により調べた。さらに、信頼性試験の
評価法としては、焼結した素子を温度90℃、湿度90
〜96チの耐湿負荷雰囲気中に500時間放置し、素子
を室温中に48時間放置した後、試験前と後での容量変
化率を比較した。In the reducing atmosphere thus obtained, 1300°C, 2
Elements fired for hours (electrodes are made of mug paste at 800℃ for 1 hour)
Electrical properties of (formed by baking under conditions of 5 minutes), remaining amount of Li and 2 contained inside the element, content of water-soluble salts containing Li, F, and Sr atoms also contained inside the element, and reliability test The results are shown in Table 2 below. Here, the content of water-soluble salt contained inside the element was analyzed by the following method. First, the sintered element is crushed and water is added to it for 10 minutes.
After boiling for a minute and filtering, Li and Sr were analyzed by flame atomic absorption.
y was investigated by the ion electrode method. Furthermore, as an evaluation method for reliability tests, the sintered elements were tested at a temperature of 90°C and a humidity of 90°C.
After leaving the device in a humidity-resistant load atmosphere of ~96 inches for 500 hours and leaving it at room temperature for 48 hours, the rate of change in capacity before and after the test was compared.
(以下余白)
まず、上記第1.第2表について解説すると、試料黒1
〜9.16.17.22〜24.31〜33.36,3
7.44〜62は比較例であり、本発明の請求範囲外で
ある。これらの焼結体素子では、密度が3..5〜4.
97i /ctd (理論密度の67〜94%)と低い
ため、バリスタとしての特性に適していないもの、また
は容量変化率が大きく、信頼性や電気特性に影響し、バ
リスタとしての特性に適していないものである。これに
対し、その他の本発明にかかる試料!10〜15.18
〜21.25〜30,34,35.38〜43では、焼
結体の密度が5.og/cM以上(理論密度の96係以
上)と高く、バリスタとしての特性に適しているもので
ある。さらに、容量変化率が小さく、信頼性や電気特性
に影響せず、バリスタとしての特性に適しているもので
ある。(Left below) First, let's start with the above 1. To explain Table 2, sample black 1
~9.16.17.22~24.31~33.36,3
7.44 to 62 are comparative examples and are outside the scope of the claims of the present invention. These sintered elements have a density of 3. .. 5-4.
97i/ctd (67 to 94% of theoretical density), which makes it unsuitable for varistor characteristics, or the capacitance change rate is large, affecting reliability and electrical characteristics, making it unsuitable for varistor characteristics. It is something. In contrast, other samples according to the present invention! 10-15.18
~21.25~30, 34, 35.38~43, the density of the sintered body is 5. It has a high value of og/cM or more (96th coefficient of theoretical density or more), and is suitable for characteristics as a varistor. Furthermore, the capacitance change rate is small, does not affect reliability or electrical characteristics, and is suitable for characteristics as a varistor.
ここで、第3図は5rTiO,の平均粒径を変え、その
他の組成比、焼成温度などの条件は全て上記試料A10
と同一にした場合において、3rTiO。Here, in Figure 3, the average particle size of 5rTiO was changed, and all other conditions such as composition ratio and firing temperature were the same as above sample A10.
3rTiO.
の平均粒径と焼結体素子の焼結密度との関係を示す図で
あり、SrTiO3の平均粒径が0.6μm以下の場合
には、LiFの添加量が0.7 mo1%と少なくとも
低温焼結が可能であることを示している。FIG. 2 is a diagram showing the relationship between the average grain size of SrTiO3 and the sintered density of the sintered body element, and when the average grain size of SrTiO3 is 0.6 μm or less, the amount of LiF added is 0.7 mo1%, which is at least low temperature. This shows that sintering is possible.
しかし、5rTiO5の平均粒径が0.5μmを超える
と、低温焼結では焼結体素子の焼結密度が低く、バリス
タとしての特性に適していないものである。However, if the average particle size of 5rTiO5 exceeds 0.5 μm, the sintered element will have a low sintered density in low-temperature sintering, making it unsuitable for properties as a varistor.
また、Li、!:Fの残存量を規定したのは、LlとF
はSr Ti Osと反応し、SrO−TiO2−I、
iF系の液相を形成する。そして、液相焼結により焼結
性を促進させる効果があるが、Liと2の残存量が0.
007 wt%未満では、焼結体の密度が向上せず、L
iFの添加効果が得られないためである。Also, Li! :The remaining amount of F was determined by Ll and F.
reacts with SrTiOs to form SrO-TiO2-I,
Forms an iF-based liquid phase. Liquid phase sintering has the effect of promoting sinterability, but the remaining amounts of Li and 2 are 0.
If it is less than 007 wt%, the density of the sintered body will not improve and L
This is because the effect of adding iF cannot be obtained.
一方、残存量がo、soo wtsを超えると素子が多
孔質となり、焼結密度が低下することと、素子内部にL
i 、 F原子を含む水溶性塩の含有量が増加し、信頼
性や電気特性に影響するためである。On the other hand, if the residual amount exceeds o, soo wts, the element becomes porous, the sintered density decreases, and L
This is because the content of water-soluble salts containing i and F atoms increases, which affects reliability and electrical characteristics.
また、言い換えれば製造過程において、添加するLiF
の添加量もこのLiと2の残存量から自ずと規制される
ものである。すなわち、LiFの添加量は0.7〜7.
□mo1%となる。In other words, in the manufacturing process, LiF added
The amount of addition of Li and 2 is naturally regulated based on the remaining amounts of Li and 2. That is, the amount of LiF added is 0.7 to 7.
□mo1%.
次に、5rTi O、tD Sr / Ti比を1.0
01〜1.05に規定したのは、Sr/Ti比が1.0
01未満では試料屋1〜8に示すように焼結体密度が向
上しないためである。これは焼結過程でLiFと5rT
iOsが反応し、Li□Tie5 を形成し、5rTi
Osの焼結性を抑制するためと考えられる。Then 5rTiO, tD Sr/Ti ratio 1.0
01 to 1.05 is specified when the Sr/Ti ratio is 1.0.
This is because if it is less than 01, the density of the sintered body does not improve as shown in Samples 1 to 8. This is caused by LiF and 5rT during the sintering process.
iOs reacts to form Li□Tie5 and 5rTi
It is thought that this is to suppress the sinterability of Os.
一方、Sr/Ti比が1.05i超えると、試料煮44
〜62に示すように焼結体素子の密度が向上しない。こ
れは、Srの含有量が増え過ぎたために粒成長が抑制さ
れ、焼結性が低下するためである。またこの場合、素子
内部にSr原子を含む水溶性塩の含有量が増加し、信頼
性や電気特性に影響する。On the other hand, when the Sr/Ti ratio exceeds 1.05i,
As shown in 62 to 62, the density of the sintered element does not improve. This is because the Sr content increases too much, which suppresses grain growth and reduces sinterability. Furthermore, in this case, the content of water-soluble salts containing Sr atoms inside the element increases, which affects reliability and electrical characteristics.
また、第1成分ノ0eO2,Y2O3,La20.o添
加量を規定したのは、CeO2,Y2O3,La20゜
は、5rTi05中のSrと置換し、原子化制御によシ
半導体化を促進させる効果を示すが、少なくとも一種類
以上が0.1 mo1%未満では、試料屋22゜23.
24に示すように添加効果が得られず、半導体化が抑制
され、誘電率εが劣化し、またバリスタ電圧が高いため
、高容量、低バリスタ電圧の特徴を示さないためである
。一方、s、omo1%を超えると、試料431 .3
2.33に示すように半導体化が抑制されることと、焼
結性が低下するためである。In addition, the first component 0eO2, Y2O3, La20. The amount of O added was specified because CeO2, Y2O3, and La20° replace Sr in 5rTi05 and have the effect of promoting semiconductor formation through atomization control, but at least one of them is 0.1 mo1 If it is less than %, sample shop 22°23.
This is because, as shown in No. 24, the addition effect is not obtained, the semiconductor formation is suppressed, the dielectric constant ε is deteriorated, and the varistor voltage is high, so the characteristics of high capacitance and low varistor voltage are not exhibited. On the other hand, when s, omo exceeds 1%, sample 431. 3
This is because, as shown in 2.33, semiconducting is suppressed and sinterability is reduced.
さらに、素子内部に含まれる水溶性塩の含有量to、0
50wt%以下と規定したのは、0.050wt%を超
えると第4図に示すように耐湿負荷雰囲気中での容量変
化率が上昇し、信頼性や電気特性に影響を与えるためで
ある。Furthermore, the content of water-soluble salts contained inside the element is to, 0.
The reason why it is specified to be 50 wt% or less is because if it exceeds 0.050 wt%, the rate of change in capacity in a humidity-resistant load atmosphere increases as shown in FIG. 4, which affects reliability and electrical characteristics.
次に、焼成温度を1000〜14oO℃に規定したのは
、第6図に示すように1000℃未満では焼結体素子に
含まれるLi、!:Fの残存量がo、soowt%より
も多くなるため、信頼性や電気特性に影響を与えること
と、焼結密度が低いためである。また、1400’Cを
超えると多孔質となり、焼結密度が低下するためである
。この第6図は試料ム36をベースとして焼成温度とL
l。Next, the reason why the firing temperature was set at 1000 to 140°C is because, as shown in FIG. This is because the residual amount of F is greater than o, sowt%, which affects reliability and electrical characteristics, and also because the sintered density is low. Moreover, if the temperature exceeds 1400'C, the material becomes porous and the sintered density decreases. This figure 6 shows the firing temperature and L based on sample 36.
l.
Fの残存量との関係を見たものである。This shows the relationship with the remaining amount of F.
(実施例2)
次に、Sr/Ti比、LiF 、 CeO2、Y2O5
゜La20.の添加量を固定し、第2成分の5i02
。(Example 2) Next, the Sr/Ti ratio, LiF, CeO2, Y2O5
゜La20. 5i02 of the second component is fixed.
.
CuO、Co2O3,MnCO3の組成を下記第3表に
示すように変えてその他は上記実施例1と同様の方法で
混合、造粒、成形、電極焼付けを行い、下記第4表に示
すように各種特性を測定した。The compositions of CuO, Co2O3, and MnCO3 were changed as shown in Table 3 below, and mixing, granulation, molding, and electrode baking were performed in the same manner as in Example 1 above. Characteristics were measured.
(以下余白)
まず、上記第3、第4表について解説すると、試料A1
〜4,16〜18は比較例であり、本発明の請求範囲外
である。これに対し、その他の本発明にかかる試料/1
65〜14は5i02 、 OuO。(Left below) First, to explain Tables 3 and 4 above, sample A1
-4, 16-18 are comparative examples and are outside the scope of the claims of the present invention. In contrast, other samples according to the present invention/1
65-14 is 5i02, OuO.
Co20. 、 MnC0,の添加効果が得られるもの
である。ここで、第2成分の5i02 、 (uo
、 Co20. 。Co20. , MnC0, can be added. Here, the second component 5i02, (uo
, Co20. .
MnCO3の添加量を規定したのは、これらの添加剤を
添加すると、これらが粒界に偏析し、粒界を高抵抗化さ
せ、バリスタ特性を発現させる効果を示すが、0.1
mo1%未満では、試料ム1〜4に示すようにバリスタ
特性を改善する効果がないためである。一方、2.0m
o1%を超えると試料屋16〜18に示すように粒界に
この添加剤が極端に偏析し、バリスタ電圧が上昇すると
共に誘電率が低下するためである。The reason for specifying the amount of MnCO3 added is that when these additives are added, they segregate at the grain boundaries, increase the resistance of the grain boundaries, and exhibit the effect of developing varistor characteristics.
This is because if the mo amount is less than 1%, there is no effect of improving the varistor characteristics as shown in samples 1 to 4. On the other hand, 2.0m
This is because when the amount exceeds 1%, the additive is extremely segregated at the grain boundaries as shown in samples 16 to 18, and the varistor voltage increases and the dielectric constant decreases.
なお、本発明の実施例では、一部の組み合わせについて
示したが他の組み合わせでも同様の効果があることを確
認した。さらに、本発明の実施例では、Li 、Fの添
加剤としてLlFを用いたが他のLiとF化合物を添加
し複合反応させたLiFでも同様の効果を得られること
は言うまでもない。In the examples of the present invention, some combinations were shown, but it was confirmed that other combinations had similar effects. Further, in the examples of the present invention, LIF was used as an additive for Li and F, but it goes without saying that similar effects can be obtained with LiF obtained by adding other Li and F compounds and causing a complex reaction.
そして、Sr過剰の5rTi051に作成するに当たり
、5rCO5を添加したが、酸化物や水酸化物などの形
で用いても良く、さらにはSrを含む各種塩類の形で用
いても同様の効果を得られることは言うまでもない。Although 5rCO5 was added to create 5rTi051 with excess Sr, it may also be used in the form of oxides or hydroxides, or even in the form of various salts containing Sr to obtain the same effect. Needless to say, it can be done.
さらにまた、第2成分としての(uo 、 Co20.
。Furthermore, (uo, Co20.
.
MnCO3についても、これら酸化物、炭酸化物以外の
形で使用しても良く、例えば水酸化物や、さらには各種
塩類の形で用いても良いものである。MnCO3 may also be used in forms other than these oxides and carbonates, for example in the form of hydroxides and various salts.
そして、上記の実施例では、焼成を還元雰囲気中で行う
場合について説明したが、これは窒素雰囲気中で焼成を
行うようにしても良いものである。In the above embodiments, the case where the firing is performed in a reducing atmosphere has been described, but the firing may be performed in a nitrogen atmosphere.
しかし、窒素雰囲気中で焼成を行った場合は、半導体化
が若干しにくい面があるため、還元雰囲気中で焼成を行
うよりも若干高温度(1300〜1400℃)側で焼成
する方が特性上は好ましいものである。However, when firing in a nitrogen atmosphere, it is somewhat difficult to convert into a semiconductor, so firing at a slightly higher temperature (1300 to 1400°C) is better for characteristics than firing in a reducing atmosphere. is preferable.
さらに、上記の実施例では、焼結体の両面にムgベース
トなどの500〜900℃で焼付は可能な導電性ペース
トを印刷し、500〜900’Cで焼付け、焼結体素子
の再酸化を行うと同時に電極を形成する場合について説
明したが、これは従来より一般的に行われているように
、焼成後の素子を空気中で500〜1000℃の熱処理
を行い、焼結体素子の再酸化を行った後に、上記導電性
ペース)i500〜900℃で焼付けて電極を形成する
ようにしても良いものである。Furthermore, in the above example, a conductive paste such as mug base that can be baked at 500 to 900°C is printed on both sides of the sintered body, and the paste is baked at 500 to 900'C to reoxidize the sintered body element. We have described the case where electrodes are formed at the same time as the sintered element, but this is a conventional practice in which the fired element is heat-treated in the air at 500 to 1000°C to form the sintered element. After reoxidation, the conductive paste may be baked at a temperature of 500 to 900° C. to form an electrode.
ここで、本発明において、上記実施例に示すように焼結
体素子の再酸化処理と電極形成が同時に行えることとな
った理由は、一つにはLiFの添加によって低温焼結が
可能になったことにより、再酸化が低温で起こり易いた
めである。また、今一つはFイオンの影響により、焼結
体素子の酸素欠陥が多いために、五gペーストなどを印
刷し低温で焼付けても再酸化が起こり易いことによるも
のである。 ・
このようにして得られた素子はバリスタ電圧が比較的低
く、α、誘電率が大きく、信頼性に優れているといった
特性を同時に満足するため、ノイズや静電気の抑制に有
効であり、誘電率が大きいことから、立ち上がりの鋭い
急峻波パルスに対しても優れた応答性を示す。Here, in the present invention, one of the reasons why the reoxidation treatment of the sintered body element and the electrode formation can be performed simultaneously as shown in the above example is that low temperature sintering is possible due to the addition of LiF. This is because reoxidation tends to occur at low temperatures. Another reason is that the sintered element has many oxygen defects due to the influence of F ions, so reoxidation is likely to occur even if a 5g paste or the like is printed and baked at a low temperature. - The device obtained in this way simultaneously satisfies the characteristics of a relatively low varistor voltage, a large α, a large dielectric constant, and excellent reliability, so it is effective in suppressing noise and static electricity, and has a low dielectric constant. Because of its large value, it exhibits excellent responsiveness even to steep wave pulses with a sharp rise.
発明の効果
以上に示したように本発明によれば、バリスタ電圧が比
較的低く、α、誘電率が大きく、tanδが小さく、信
頼性に優れているといった特性を同時に満足することが
できる。Effects of the Invention As described above, according to the present invention, it is possible to simultaneously satisfy the following characteristics: relatively low varistor voltage, large α and dielectric constant, small tan δ, and excellent reliability.
従来のZnO系バリスタに比べ、バリスタ電圧が比較的
低く、α、誘電率が大きいため、ノイズや静電気といっ
た立ち上がりの鋭い急峻波パルスに対して極めて有効で
ある。Compared to conventional ZnO-based varistors, the varistor voltage is relatively low and α and dielectric constant are large, so it is extremely effective against steep wave pulses with a sharp rise such as noise and static electricity.
従って、本発明によればノイズ、静電気から半導体及び
回路を保護することのできる素子を得ることができ、そ
の実用上の効果は極めて大きいものである。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.
また、従来の5rTiO5系バリスタの焼結温度が10
00℃以上であったのに比べ、本発明では1000〜1
4oo℃の比較的低温で焼結が可能となり焼結過程のエ
ネルギー量の削減が期待されるものである。In addition, the sintering temperature of the conventional 5rTiO5 varistor is 10
Compared to 00℃ or higher, in the present invention, the temperature was 1000 to 1
Sintering can be performed at a relatively low temperature of 40° C., and it is expected that the amount of energy used in the sintering process will be reduced.
第1図は本発明による素子を示す上面図、第2図は同断
面図、第3図は本発明を説明するためのSr Ti O
、の平均粒径と焼結密度との関係を示す図、第4図は同
じく水溶性塩の含有量と容量変化率との関係を示す図、
第5図は同じく焼成温度とLi、Fの残存量との関係を
示す図である。
1・・・・・・焼結体、2 、3 魚−・電極。
代理人の氏名 弁理士 中 尾 敏 男 ほか1名第1
図
第2I2172
第3図
→子力烹U茎t)t)n)FIG. 1 is a top view showing an element according to the present invention, FIG. 2 is a cross-sectional view of the same, and FIG. 3 is a Sr Ti O element for explaining the present invention.
Figure 4 is a diagram showing the relationship between the average particle size and sintered density of , and Figure 4 is a diagram showing the relationship between the content of water-soluble salt and the rate of change in capacity.
FIG. 5 is a diagram showing the relationship between the firing temperature and the remaining amounts of Li and F. 1...Sintered body, 2, 3 Fish--electrode. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 I2172 Figure 3 → Zilifu U stemt)t)n)
Claims (3)
05となるように過剰のSrを含有し、さらにLiとF
を合計で0.007〜0.500wt%含有したSrT
iO_3に、CeO_2,Y_2O_3,La_2O_
3のうち少なくとも一種類以上を0.1〜5.0mol
%と、Si,Cu,Co,Mnのうち少なくとも一種類
以上の元素を酸化物,炭酸化物などの各種の形のいずれ
かの形にして0.1〜2.0mol%含ませてなる電圧
依存性非直線抵抗体素子。(1) The ratio of Sr and Ti is 1.001≦Sr/Ti≦1.
Contains excess Sr so that it becomes 05, and further contains Li and F.
SrT containing 0.007 to 0.500 wt% in total
iO_3, CeO_2, Y_2O_3, La_2O_
0.1 to 5.0 mol of at least one of 3.
% and 0.1 to 2.0 mol% of at least one element among Si, Cu, Co, and Mn in any of various forms such as oxides and carbonates. nonlinear resistor element.
まれる水溶性塩が0.050wt%以下(但し、0wt
%は含まず)であることを特徴とする電圧依存性非直線
抵抗体素子。(2) The water-soluble salt contained in the voltage-dependent nonlinear resistor element according to claim 1 is 0.050 wt% or less (however, 0 wt%
%)).
末を原料として1.001≦Sr/Ti≦1.05とな
るようにSr化合物を添加し、さらにLiFを0.7〜
7.0mol%と、CeO_2,Y_2O_3,La_
2O_3のうち少なくとも一種類以上を0.1〜5.0
mol%と、Si,Cu,Co,Mnのうち少なくとも
一種類以上の元素を酸化物,炭酸化物などの各種の形の
いずれかの形にして0.1〜2.0mol%添加した混
合粉末を成形し、還元雰囲気中や窒素雰囲気中で100
0〜1400℃の温度で焼成し、その後、500〜90
0℃で焼付け可能な導電性ペーストを用い、上記焼成後
の素子に500〜900℃で焼付けて電極を形成するか
、または上記焼成後の素子を空気中で500〜1000
℃の熱処理を行った後に500〜900℃で焼付けて電
極を形成し、内部に含まれる水溶性塩が0.050wt
%以下(但し、0wt%は含まず)であることを特徴と
する電圧依存性非直線抵抗体素子の製造方法。(3) Using SrTiO_3 powder with an average particle size of 0.5 μm or less as a raw material, add an Sr compound so that 1.001≦Sr/Ti≦1.05, and further add 0.7 to 0.7 μm of LiF.
7.0 mol% and CeO_2, Y_2O_3, La_
0.1 to 5.0 of at least one type of 2O_3
A mixed powder containing 0.1 to 2.0 mol% of at least one element among Si, Cu, Co, and Mn in the form of any of various forms such as oxides and carbonates. Molding, 100% in reducing atmosphere or nitrogen atmosphere
Calcinate at a temperature of 0-1400℃, then 500-90℃
Using a conductive paste that can be baked at 0°C, the fired element is baked at 500 to 900°C to form an electrode, or the fired element is baked at 500 to 1000°C in air.
℃ heat treatment and then baking at 500 to 900℃ to form an electrode, and the water-soluble salt contained inside is 0.050wt.
% (however, 0 wt% is not included).
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP63119510A JPH01289202A (en) | 1988-05-17 | 1988-05-17 | Voltage-dependent nonlinear resistance element and manufacture thereof |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP63119510A JPH01289202A (en) | 1988-05-17 | 1988-05-17 | Voltage-dependent nonlinear resistance element and manufacture thereof |
Publications (1)
Publication Number | Publication Date |
---|---|
JPH01289202A true JPH01289202A (en) | 1989-11-21 |
Family
ID=14763050
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP63119510A Pending JPH01289202A (en) | 1988-05-17 | 1988-05-17 | Voltage-dependent nonlinear resistance element and manufacture thereof |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH01289202A (en) |
-
1988
- 1988-05-17 JP JP63119510A patent/JPH01289202A/en active Pending
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