JPH0737422A - Composition for forming titanic acid ferroelectric film and its forming method - Google Patents
Composition for forming titanic acid ferroelectric film and its forming methodInfo
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- JPH0737422A JPH0737422A JP5181482A JP18148293A JPH0737422A JP H0737422 A JPH0737422 A JP H0737422A JP 5181482 A JP5181482 A JP 5181482A JP 18148293 A JP18148293 A JP 18148293A JP H0737422 A JPH0737422 A JP H0737422A
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Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は誘電膜、圧電膜、焦電膜
として利用されるチタン酸系強誘電体膜の形成用組成物
と形成法とに関する。より詳しくは、ゾル−ゲル法によ
るチタン酸系強誘電体膜形成の改善に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composition and method for forming a titanate-based ferroelectric film used as a dielectric film, a piezoelectric film or a pyroelectric film. More specifically, it relates to improvement of formation of a titanic acid-based ferroelectric film by a sol-gel method.
【０００２】[0002]
【従来の技術】一般式：Ａx Tiy Ｏz (式中、Ａ成分は
Ba、Sr、Ca、MgおよびPbから選ばれた１もしくは２以上
の金属であるか、またはBiであり、Ａ成分がBiである時
はｘ＝４、ｙ＝３、ｚ＝12であり、Ａ成分がBi以外の金
属である時はｘ＝ｙ＝１，ｚ＝３である) で示される、
ペロブスカイト型結晶構造をとるチタン酸系複合酸化物
が強誘電性を示し、この酸化物の薄膜が誘電膜、圧電
膜、焦電膜などとして利用可能なことは知られている。2. Description of the Related Art General formula: A x Ti y O z (where A component is
One or more metals selected from Ba, Sr, Ca, Mg and Pb, or Bi, and when the A component is Bi, x = 4, y = 3, z = 12, When the component A is a metal other than Bi, x = y = 1, z = 3),
It is known that a titanic acid-based composite oxide having a perovskite type crystal structure exhibits ferroelectricity, and a thin film of this oxide can be used as a dielectric film, a piezoelectric film, a pyroelectric film, or the like.
【０００３】このような膜の形成法として従来より知ら
れているのは、スパッタリング法、ＣＶＤ法、ゾル−ゲ
ル法などである。このうち、スパッタリング法とＣＶＤ
法は、装置が高価で、生産性も低いので、量産には不向
きである上、組成変動が起こり、従って、強誘電体特性
も変動し易いという欠点がある。Conventionally known methods for forming such a film are a sputtering method, a CVD method, a sol-gel method and the like. Of these, sputtering and CVD
The method is not suitable for mass production because the apparatus is expensive and the productivity is low, and there is a drawback that the composition changes, and therefore the ferroelectric characteristics also change easily.
【０００４】これに対し、ゾル−ゲル法は、塗布と加熱
(焼成) という簡便な操作により、高価な装置を使用せ
ずに強誘電体膜を形成することができ、量産に適してい
る。より均質な膜を得るためのゾル−ゲル法の改善とし
て、アルコキシドなどの有機金属化合物を原料とする方
法、即ち、成分金属のアルコキシドの混合物を含有する
有機溶媒溶液を基板に塗布し、焼成する方法が提案され
ている。On the other hand, the sol-gel method uses coating and heating.
By a simple operation of (firing), a ferroelectric film can be formed without using an expensive device, which is suitable for mass production. As an improvement of the sol-gel method for obtaining a more homogeneous film, a method using an organic metal compound such as an alkoxide as a raw material, that is, an organic solvent solution containing a mixture of alkoxides of component metals is applied to a substrate and baked. A method has been proposed.
【０００５】しかし、この方法でも、金属アルコキシド
が大気中の水分により急速に加水分解されてしまうた
め、完全に均質な膜を形成することは困難である。これ
に関して、加水分解を抑制するために金属アルコキシド
の安定化剤を添加することが知られているが、なお満足
できる結果が得られていない。特に、焼成時にアルコキ
シドから酸化物への転化が不完全で、微細な小粒子から
なる緻密化が不完全な膜が生成し、より揮発性の金属成
分の損失による組成変動や、強誘電特性に低下が起こる
原因となっていた。However, even with this method, it is difficult to form a completely homogeneous film because the metal alkoxide is rapidly hydrolyzed by water in the atmosphere. In this regard, it is known to add stabilizers for metal alkoxides to suppress hydrolysis, but still unsatisfactory results have not been obtained. In particular, the conversion of alkoxides to oxides is incomplete during firing, resulting in a film that is composed of fine small particles and is incompletely densified, resulting in composition fluctuations due to loss of more volatile metal components, and ferroelectric properties. It was the cause of the decrease.
【０００６】[0006]
【発明が解決しようとする課題】本発明の目的は、有機
金属化合物を原料とするゾル−ゲル法によるチタン酸系
強誘電体膜の形成において、上記の問題点が解消された
改良された膜形成用組成物と膜形成法を提供することで
ある。SUMMARY OF THE INVENTION An object of the present invention is to provide an improved film in which the above problems have been solved in the formation of a titanic acid type ferroelectric film by a sol-gel method using an organometallic compound as a raw material. It is to provide a forming composition and a film forming method.
【０００７】[0007]
【課題を解決するための手段】上記目的は、有機金属化
合物を有機溶媒中に溶解した、ゾル−ゲル法用のチタン
酸系強誘電体膜形成用組成物中に、酸化剤と安定剤とを
併用添加することによって達成できることが判明した。The above object is to provide an oxidizing agent and a stabilizer in a titanate-based ferroelectric film-forming composition for a sol-gel method in which an organometallic compound is dissolved in an organic solvent. It was found that this can be achieved by adding together.
【０００８】ここに、本発明の要旨は、有機金属化合物
を原料とするゾル−ゲル法により、一般式： Ａx Tiy
Ｏz (式中、Ａ成分はBa、Sr、Ca、MgおよびPbから選ば
れた１もしくは２以上の金属であるか、またはBiであ
り、Ａ成分がBiである時はｘ＝４、ｙ＝３、ｚ＝12であ
り、Ａ成分がBi以外の金属である時はｘ＝ｙ＝１，ｚ＝
３である) で示される複合酸化物からなるチタン酸系強
誘電体膜の形成用組成物であって、各成分金属の原料有
機化合物を目的とする複合酸化物の組成に相当する割合
で有機溶媒中に含有し、さらに安定化剤と酸化剤とを含
有することを特徴とする、チタン酸系強誘電体膜形成用
組成物にある。Here, the gist of the present invention is to obtain a compound of the general formula: A x Ti y by a sol-gel method using an organometallic compound as a raw material.
O z (in the formula, the A component is one or more metals selected from Ba, Sr, Ca, Mg and Pb, or is Bi, and when the A component is Bi, x = 4, y = 3, z = 12, and when the component A is a metal other than Bi, x = y = 1, z =
The composition for forming a titanic acid-based ferroelectric film, which comprises a complex oxide represented by the formula (3), wherein the organic compound is used in a proportion corresponding to the composition of the complex oxide for the raw material organic compound of each component metal. A titanic acid-based ferroelectric film-forming composition which is contained in a solvent and further contains a stabilizer and an oxidizing agent.
【０００９】本発明によれば、上記膜形成用組成物を基
板上に塗布し、加熱することからなるチタン酸系強誘電
体膜の形成法も提供される。According to the present invention, there is also provided a method for forming a titanic acid-based ferroelectric film, which comprises coating the above film-forming composition on a substrate and heating.
【００１０】本発明において原料として使用する有機金
属化合物は、ゾル−ゲル法において従来より使用されて
いる任意の化合物でよい。このような化合物は、一般に
金属原子（即ち、Ba、Sr、Ca、Mg、Pb、Biのいずれか）
が酸素原子を介して有機基と結合した化合物であり、例
えば各金属の有機酸塩、アルコキシド等が例示される。
有機酸塩の具体例には、酢酸塩、プロピオン酸塩、イソ
プロピオン酸塩、酪酸塩、イソ酪酸塩などの低級カルボ
ン酸塩がある。オキシ酢酸塩などのオキシカルボン酸塩
も使用できる。アルコキシドとしては、エトキシド、プ
ロポキシド、イソプロポキシド、ブトキシドなどの低級
アルコキシドが好ましい。原料として好ましい有機金属
化合物は金属アルコキシドであり、成分金属の少なくと
も１つについてはアルコキシドを原料とすることが好ま
しい。各成分金属について、１種もしくは２種以上の有
機化合物を使用することができる。The organometallic compound used as a raw material in the present invention may be any compound conventionally used in the sol-gel method. Such compounds are generally metal atoms (ie, Ba, Sr, Ca, Mg, Pb, Bi).
Is a compound bonded to an organic group through an oxygen atom, and examples thereof include organic acid salts of each metal and alkoxides.
Specific examples of organic acid salts include lower carboxylates such as acetate, propionate, isopropionate, butyrate, isobutyrate. Oxycarboxylates such as oxyacetate can also be used. As the alkoxide, lower alkoxides such as ethoxide, propoxide, isopropoxide and butoxide are preferable. A preferable organic metal compound as a raw material is a metal alkoxide, and it is preferable to use an alkoxide as a raw material for at least one of the component metals. For each component metal, one type or two or more types of organic compounds can be used.
【００１１】有機溶媒としては、原料の有機金属化合物
を溶解できるものを使用する。使用可能な有機溶媒の例
には、エタノール、プロパノール、イソプロパノール、
ブタノール、ヘキサノール、メトキシエタノールなどの
アルコール類、酢酸、プロピオン酸などの脂肪族低級カ
ルボン酸類、ジグリム、トリグリム、テトラグリムなど
の多低エーテル類などがある。２種以上の有機溶媒から
なる混合溶媒も使用できる。混合溶媒の場合には、溶媒
の全体が上記溶媒からなる必要はなく、粘度調整などの
目的で上記以外の有機溶媒 (例、炭化水素系溶媒) を併
用することができる。As the organic solvent, one that can dissolve the organometallic compound as a raw material is used. Examples of organic solvents that can be used are ethanol, propanol, isopropanol,
Examples include alcohols such as butanol, hexanol, and methoxyethanol, lower aliphatic carboxylic acids such as acetic acid and propionic acid, and multi-low ethers such as diglyme, triglyme, and tetraglyme. A mixed solvent composed of two or more organic solvents can also be used. In the case of a mixed solvent, it is not necessary that the entire solvent be composed of the above solvent, and an organic solvent other than the above (for example, a hydrocarbon solvent) can be used in combination for the purpose of adjusting viscosity.
【００１２】酸化剤としては、硝酸、過塩素酸、有機ペ
ルオキシド類およびヒドロペルオキシド類等も使用可能
であるが、経済性と効果の両面からみて好ましい酸化剤
は過酸化水素である。Although nitric acid, perchloric acid, organic peroxides, hydroperoxides and the like can be used as the oxidizing agent, hydrogen peroxide is a preferable oxidizing agent from the viewpoint of economy and effect.
【００１３】安定化剤としては、β−ジケトン類、ケト
ン酸類、ケトエステル類、オキシ酸類、高級カルボン酸
類、多低および環状エーテル類、アミン類などの１種ま
たは２種以上の化合物を使用できる。As the stabilizer, one or more compounds such as β-diketones, ketonic acids, ketoesters, oxyacids, higher carboxylic acids, poly- and cyclic ethers, and amines can be used.
【００１４】[0014]
【作用】本発明のチタン酸系強誘電体膜形成用組成物
は、成分金属の原料有機化合物と酸化剤と安定化剤とを
有機溶媒中に含有する混合液である。原料の有機金属化
合物は、アルコキシドの場合には基板上に塗布されると
大気中の水分による加水分解をまず受け、さらに加熱さ
れると縮重合と熱分解によって、有機分が気化し、金属
酸化物に転化される。有機酸の場合には、直接熱分解に
より有機分が気化し、金属酸化物に転化される。こうし
て、２種以上の成分金属の複合酸化物からなる膜が形成
される。The titanic acid-based ferroelectric film-forming composition of the present invention is a mixed solution containing a raw material organic compound of a component metal, an oxidizing agent and a stabilizer in an organic solvent. In the case of an alkoxide, the raw material organometallic compound is first hydrolyzed by water in the atmosphere when it is applied on the substrate, and when it is further heated, the organic content is vaporized by polycondensation and thermal decomposition, resulting in metal oxidation. Converted into things. In the case of an organic acid, the organic component is vaporized by direct thermal decomposition and converted into a metal oxide. Thus, a film made of a composite oxide of two or more component metals is formed.
【００１５】安定化剤は、混合液中における原料有機金
属化合物の加水分解を抑制するために添加する。それに
より、混合液が安定化し、その保存性が高まると同時
に、成膜時に加水分解の進行速度を抑え、膜の均質性が
高まる。The stabilizer is added to suppress the hydrolysis of the raw material organometallic compound in the mixed solution. As a result, the mixed solution is stabilized and its storability is improved, and at the same time, the progress rate of hydrolysis is suppressed during film formation, and the homogeneity of the film is improved.
【００１６】本発明により、安定化剤に加えて酸化剤を
添加することで、混合液中における原料の金属アルコキ
シドの加水分解をより効果的に抑制することができ、し
かも基板に塗布した後は、有機金属化合物から金属酸化
物により完全に転化できることから、有機分の残留が少
なく、均質かつ緻密で、強誘電特性に優れた強誘電体膜
をより低温での加熱により形成することができる。According to the present invention, by adding an oxidizing agent in addition to the stabilizer, it is possible to more effectively suppress the hydrolysis of the metal alkoxide of the raw material in the mixed solution, and moreover, after applying it to the substrate, Since a metal oxide can be completely converted from an organometallic compound, a ferroelectric film having a small amount of organic components remaining, being homogeneous and dense, and having excellent ferroelectric properties can be formed by heating at a lower temperature.
【００１７】本発明における酸化剤の作用について完全
には解明されていないが、現時点では次のように推測さ
れる。即ち、混合液中に安定化剤とともに酸化剤が共存
すると、まず金属の過酸化物が生成することによって金
属−酸素−金属結合が形成され、成分金属のゆるやかな
重合により、アルコキシド型有機金属化合物の加水分解
と重縮合が部分的に抑制され、混合液が安定化する。一
方、塗布後の加熱（焼成）時には、酸化剤から酸素が供
給され、酸素が多くなるため、加水分解と重縮合による
酸化物への転化が助長され、より低温での加熱によっ
て、有機分の残留の少ないより均質で緻密な膜が生成す
る。Although the action of the oxidizing agent in the present invention has not been completely clarified, it is presumed as follows at the present time. That is, when an oxidant coexists with a stabilizer in the mixed solution, a metal-oxygen-metal bond is formed by first generating a metal peroxide, and the alkoxide-type organometallic compound is formed by the gradual polymerization of the component metals. Hydrolysis and polycondensation are partially suppressed and the mixed solution is stabilized. On the other hand, at the time of heating (baking) after coating, oxygen is supplied from the oxidizing agent, and the amount of oxygen is increased, which promotes conversion into oxides due to hydrolysis and polycondensation, and heating at a lower temperature reduces the organic content. A more homogeneous and dense film with less residue is produced.
【００１８】安定化剤と酸化剤の添加量は、上記の効果
を得るのに十分な量であればよく、実験により決定すれ
ばよいが、目安としては、安定化剤と酸化剤のいずれに
ついても、混合液中の金属合計量１モルに対して 0.5〜
３モルの範囲内である。The amount of the stabilizer and the oxidizing agent added may be an amount sufficient to obtain the above-mentioned effects, and may be determined by an experiment. As a standard, either the stabilizer or the oxidizing agent may be added. Is 0.5 to 1 mol of the total amount of metals in the mixed solution.
It is within the range of 3 mol.
【００１９】酸化剤の量が多すぎると、酸化反応により
生ずる水の量が多くなり、混合液の保存性に問題を生じ
る。一方、酸化剤が少なすぎると、混合液中に上記効果
の達成に十分な量の過酸化物が生成しなくなる。If the amount of the oxidant is too large, the amount of water generated by the oxidation reaction will increase, which causes a problem in the storability of the mixed solution. On the other hand, if the amount of the oxidizing agent is too small, a sufficient amount of peroxide will not be produced in the mixed solution to achieve the above effect.
【００２０】安定化剤が少なすぎると、混合液の安定性
が悪く、保存性が低下する。一方、安定化剤が多過ぎる
と、熱分解温度が上昇し、生成膜の残存炭素量の増大と
言った問題や、混合液中における溶解度の変化による原
料有機金属化合物の結晶析出といった問題を生じる。When the amount of the stabilizer is too small, the stability of the mixed solution is poor and the storage stability is deteriorated. On the other hand, when the amount of the stabilizer is too large, the thermal decomposition temperature rises, which causes problems such as an increase in the amount of residual carbon in the formed film and crystal precipitation of the raw material organometallic compound due to change in solubility in the mixed solution. .
【００２１】本発明のチタン酸系強誘電体膜形成用組成
物は、有機溶媒中に各成分金属の原料有機化合物を必要
により加熱・攪拌下に溶解させ、得られた溶液に安定化
剤と酸化剤を加えることにより調製できる。各成分金属
の原料有機化合物の配合割合は、成膜しようとする目的
の複合酸化物の組成に相当する割合とする。The titanic acid-based ferroelectric film-forming composition of the present invention comprises a raw material organic compound of each component metal dissolved in an organic solvent with heating and stirring as necessary, and a stabilizer is added to the resulting solution. It can be prepared by adding an oxidizing agent. The mixing ratio of the raw material organic compound of each component metal is set to a ratio corresponding to the composition of the target composite oxide to be formed into a film.
【００２２】原料の有機金属化合物の一部または全部を
その場で生成させることもできる。例えば、アルカリ土
類金属であるBa、Sr、Ca、Mgの各アルコキシドは、各金
属を有機溶媒のアルコール中に溶解させることにより、
また金属カルボン酸塩は、金属炭酸塩などの金属塩を有
機溶媒の低級脂肪族カルボン酸中に溶解させることによ
って、それぞれその場で生成させることができる。この
場合も、必要であれば加熱を行う。A part or all of the raw material organometallic compound can be generated in situ. For example, alkaline earth metals Ba, Sr, Ca, each alkoxide of Mg, by dissolving each metal in the alcohol of the organic solvent,
Further, the metal carboxylate can be generated in situ by dissolving a metal salt such as a metal carbonate in a lower aliphatic carboxylic acid as an organic solvent. Also in this case, heating is performed if necessary.
【００２３】必要であれば、さらに有機溶媒を追加し
て、塗布に適した粘度に調整する。また、使用前に、加
水分解の促進のために、水や無機酸 (例、塩酸) を少量
添加してもよい。If necessary, an organic solvent is further added to adjust the viscosity suitable for coating. Before use, a small amount of water or an inorganic acid (eg hydrochloric acid) may be added to accelerate hydrolysis.
【００２４】この組成物を基板上に塗布し、次いで加熱
すると、一般式：Ａx Tiy Ｏz で示される目的とする複
合酸化物組成を持ったチタン酸系強誘電体膜が得られ
る。基板は用途に応じて選択される。塗布は、ロールコ
ート、スピンコートなどの塗工法以外に、噴霧塗布、浸
漬塗布などの手段も可能である。加熱温度および加熱時
間は複合酸化物への転化と結晶化が達成されるように選
択する。加熱温度は一般に 400〜900 ℃の範囲内である
が、低温加熱後に高温加熱を行う二段もしくは多段加熱
方式を採用することもできる。その場合には、最終の加
熱温度が上記範囲内であればよい。When this composition is applied onto a substrate and then heated, a titanic acid-based ferroelectric film having a desired complex oxide composition represented by the general formula: A x Ti y O z is obtained. The substrate is selected according to the application. For coating, other than the coating method such as roll coating and spin coating, means such as spray coating and dip coating can be used. The heating temperature and heating time are selected so that the conversion into the composite oxide and the crystallization are achieved. The heating temperature is generally in the range of 400 to 900 ° C, but a two-stage or multi-stage heating system in which low temperature heating is followed by high temperature heating can also be adopted. In that case, the final heating temperature may be within the above range.
【００２５】この塗布と加熱は、必要に応じて、所定膜
厚の強誘電体膜が得られるまで繰り返してもよい。その
場合には、各塗布後の加熱温度は上記より低くし、最終
的に得られた膜を上記範囲内の温度で加熱して結晶化さ
せることもできる。本発明の方法で形成されるチタン酸
系強誘電体膜の厚みには特に制限はないが、一般には0.
01〜５μｍの範囲内である。This coating and heating may be repeated if necessary until a ferroelectric film having a predetermined film thickness is obtained. In that case, the heating temperature after each coating may be lower than the above temperature, and the finally obtained film may be heated at a temperature within the above range for crystallization. The thickness of the titanic acid-based ferroelectric film formed by the method of the present invention is not particularly limited, but generally 0.
It is in the range of 01 to 5 μm.
【００２６】[0026]
【実施例】以下、本発明を実施例によって説明するが、
本発明はこれらの実施例に限定されるものではない。な
お、実施例および比較例中、％は特に指定しない限り重
量％である。EXAMPLES The present invention will be described below with reference to examples.
The invention is not limited to these examples. In Examples and Comparative Examples,% means% by weight unless otherwise specified.
【００２７】[0027]
【実施例１】金属バリウム20ｇをイソプロピルアルコー
ル 150ｇに溶解し、得られた溶液にチタンテトライソプ
ロポキシド42.3ｇを加え、さらに安定化剤としてアセチ
ルアセトン43ｇを加えた。この混合液を３時間還流加熱
した後、過酸化水素15ｇを加えてさらに充分に攪拌還流
し、水４ｇとトルエンとで全量を339.64ｇとし、合計金
属濃度が酸化物換算で10％のBaTiO3膜形成用組成物を調
製した。Example 1 20 g of metal barium was dissolved in 150 g of isopropyl alcohol, 42.3 g of titanium tetraisopropoxide was added to the resulting solution, and 43 g of acetylacetone was added as a stabilizer. After this mixture heated at reflux for 3 hours, more fully stirred under reflux of hydrogen peroxide 15 g, the total volume of water 4g of toluene and 339.64G, the total metal concentration is BaTiO 10% in terms of oxide 3 A film forming composition was prepared.
【００２８】この溶液をスピンコート法で白金基板上に
塗布し、空気中で400 ℃に10分間加熱した。この塗布と
加熱操作を５回繰り返した後、空気中で700 ℃に１時間
加熱して成膜した。得られた厚み0.3 μｍの膜をＸ線回
折で測定したところ、ペロブスカイト型結晶となってい
ることを確認した。この膜上に白金電極を形成し、基板
の白金電極との間に電圧を印加して、膜の電気的特性を
測定したところ、次の通りであった。This solution was applied on a platinum substrate by spin coating and heated in air at 400 ° C. for 10 minutes. The coating and heating operations were repeated 5 times, and then heated in air at 700 ° C. for 1 hour to form a film. When the obtained film having a thickness of 0.3 μm was measured by X-ray diffraction, it was confirmed that it was a perovskite type crystal. A platinum electrode was formed on this film, a voltage was applied between the film and the platinum electrode on the substrate, and the electrical characteristics of the film were measured. The results were as follows.
【００２９】 ここで、歩留りとは、膜の上下の白金電極間で導通が生
じていない正常な膜部分、具体的には初期耐圧が0.5 Ｖ
以上の膜部分の面積率を意味する。膜が均質かつ緻密で
ないと、上下の電極板の間に直接導通が起こる割合が増
えるため、歩留りが低くなり、絶縁膜として有効に機能
しなくなる。[0029] Here, the yield means a normal film portion in which no conduction occurs between the platinum electrodes above and below the film, specifically, the initial breakdown voltage is 0.5 V.
The above-mentioned area ratio of the film portion is meant. If the film is not homogeneous and dense, the rate of direct conduction between the upper and lower electrode plates increases, resulting in a low yield and ineffective functioning as an insulating film.
【００３０】[0030]
【実施例２】金属ストロンチウム15ｇをイソプロピルア
ルコール 150ｇに溶解し、得られた溶液にチタンテトラ
イソプロポキシド48.6ｇを加え、さらに安定化剤として
アセチルアセトン50ｇを加えた。この混合液を３時間還
流加熱した後、過酸化水素17ｇを加えてさらに充分に攪
拌還流し、水４ｇとトルエンとで全量を314.14ｇとし、
合計金属濃度が酸化物換算で10％のSrTiO3膜形成用組成
物を調製した。Example 2 15 g of strontium metal was dissolved in 150 g of isopropyl alcohol, 48.6 g of titanium tetraisopropoxide was added to the resulting solution, and 50 g of acetylacetone was added as a stabilizer. After heating the mixture under reflux for 3 hours, 17 g of hydrogen peroxide was added and the mixture was further stirred and refluxed until the total amount was 314.14 g with 4 g of water and toluene.
A SrTiO 3 film forming composition having a total metal concentration of 10% in terms of oxide was prepared.
【００３１】この溶液を使用して実施例１と同様に成膜
した。得られた厚み0.3 μｍの膜はＸ線回折によりペロ
ブスカイト型結晶となっていることが確認された。この
膜上に白金電極を形成し、電気的特性を測定したところ
次の通りであった。 A film was formed using this solution in the same manner as in Example 1. It was confirmed by X-ray diffraction that the obtained film having a thickness of 0.3 μm was a perovskite type crystal. A platinum electrode was formed on this film and the electrical characteristics were measured. The results were as follows.
【００３２】[0032]
【実施例３】金属バリウム10ｇと金属ストロンチウム6.
38ｇをイソプロピルアルコール 150ｇに溶解し、得られ
た溶液にチタンテトライソプロポキシド 41.39ｇを加
え、さらに安定化剤としてアセチルアセトン 47.43ｇを
加えた。この混合液を３時間還流加熱した後、過酸化水
素 16.1317ｇを加えてさらに充分に攪拌還流し、水４ｇ
とイソプロピルアルコールとで全量を303.42ｇとして、
合計金属濃度が酸化物換算で10％のBa0.5Sr0.5TiO3膜形
成用組成物を調製した。[Example 3] Metal barium 10 g and metal strontium 6.
38 g was dissolved in 150 g of isopropyl alcohol, 41.39 g of titanium tetraisopropoxide was added to the resulting solution, and 47.43 g of acetylacetone was added as a stabilizer. After heating this mixture under reflux for 3 hours, 16.1317 g of hydrogen peroxide was added, and the mixture was further stirred and refluxed to give 4 g of water.
And isopropyl alcohol to a total amount of 303.42g,
A Ba 0.5 Sr 0.5 TiO 3 film forming composition having a total metal concentration of 10% in terms of oxide was prepared.
【００３３】この溶液を使用して実施例１と同様に成膜
した。得られた厚み0.3 μｍの膜はＸ線回折によりペロ
ブスカイト型結晶となっていることが確認された。この
膜上に白金電極を形成し、電気的特性を測定したところ
次の通りであった。 A film was formed using this solution in the same manner as in Example 1. It was confirmed by X-ray diffraction that the obtained film having a thickness of 0.3 μm was a perovskite type crystal. A platinum electrode was formed on this film and the electrical characteristics were measured. The results were as follows.
【００３４】[0034]
【実施例４】金属カルシウム７ｇを２−メトキシエタノ
ール 100ｇに溶解し、得られた溶液にチタンテトライソ
プロポキシド 49.64ｇを加え、さらに安定化剤としてア
セチルアセトン 34.97ｇを加えた。この混合液を３時間
還流加熱した後、過酸化水素15ｇを加えてさらに充分に
攪拌還流し、水６ｇと２−メトキシエタノールとを加え
て全量を237.46ｇとし、合計金属濃度が酸化物換算で10
％のCaTiO3膜形成用組成物を調製した。Example 4 7 g of metallic calcium was dissolved in 100 g of 2-methoxyethanol, 49.64 g of titanium tetraisopropoxide was added to the resulting solution, and 34.97 g of acetylacetone as a stabilizer was further added. After heating the mixture under reflux for 3 hours, 15 g of hydrogen peroxide was added and the mixture was further stirred and refluxed, and 6 g of water and 2-methoxyethanol were added to bring the total amount to 237.46 g. Ten
% CaTiO 3 film forming composition was prepared.
【００３５】この溶液を使用して実施例１と同様に成膜
した。得られた厚み0.3 μｍの膜はＸ線回折によりペロ
ブスカイト型結晶となっていることが確認された。この
膜上に白金電極を形成し、電気的特性を測定したところ
次の通りであった。 A film was formed using this solution in the same manner as in Example 1. It was confirmed by X-ray diffraction that the obtained film having a thickness of 0.3 μm was a perovskite type crystal. A platinum electrode was formed on this film and the electrical characteristics were measured. The results were as follows.
【００３６】[0036]
【実施例５】金属ストロンチウム６ｇを２−メトキシエ
タノール 100ｇに溶解し、得られた溶液に鉛ジイソプロ
ポキシド9.54ｇとチタンイソプロポキシド 27.29ｇとを
加え、さらに安定化剤としてアセチルアセトン 19.58ｇ
を加えた。この混合液を３時間還加熱した後、過酸化水
素6.65ｇを加えてさらに充分に攪拌還流し、水６ｇと２
−メトキシエタノールとで全量を214.48ｇとして、合計
金属濃度が酸化物換算で10％のSr0.5Pb0.5TiO3膜形成用
組成物を調製した。Example 5 6 g of metal strontium was dissolved in 100 g of 2-methoxyethanol, 9.54 g of lead diisopropoxide and 27.29 g of titanium isopropoxide were added to the resulting solution, and 19.58 g of acetylacetone as a stabilizer.
Was added. After heating the mixture for 3 hours by heating, 6.65 g of hydrogen peroxide was added, and the mixture was further stirred and refluxed to give 6 g of water and 2 g of water.
A total amount of 214.48 g was added with methoxyethanol to prepare a Sr 0.5 Pb 0.5 TiO 3 film forming composition having a total metal concentration of 10% in terms of oxide.
【００３７】この溶液を使用して実施例１と同様に成膜
した。得られた厚み0.3 μｍの膜はＸ線回折によりペロ
ブスカイト型結晶となっていることが確認された。この
膜上に白金電極を形成し、電気的特性を測定したところ
次の通りであった。 A film was formed using this solution in the same manner as in Example 1. It was confirmed by X-ray diffraction that the obtained film having a thickness of 0.3 μm was a perovskite type crystal. A platinum electrode was formed on this film and the electrical characteristics were measured. The results were as follows.
【００３８】[0038]
【実施例６】オキシ酢酸ビスマス10ｇを酢酸 181.6ｇに
溶解して均一溶液とした。この溶液にチタンテトライソ
プロポキシド7.51ｇとアセチルアセトン5.29ｇを加え、
この混合液を２時間還流加熱した後、過酸化水素1.80ｇ
を加えて充分に攪拌還流し、合計金属濃度が酸化物換算
で５％のBi4Ti3O12 膜形成用組成物を調製した。Example 6 10 g of bismuth oxyacetate was dissolved in 181.6 g of acetic acid to prepare a uniform solution. To this solution, 7.51 g of titanium tetraisopropoxide and 5.29 g of acetylacetone were added,
After heating the mixture under reflux for 2 hours, 1.80 g of hydrogen peroxide
Was added and the mixture was stirred and refluxed sufficiently to prepare a Bi 4 Ti 3 O 12 film-forming composition having a total metal concentration of 5% in terms of oxide.
【００３９】この溶液を使用して実施例１と同様に成膜
した。得られた厚み0.3 μｍの膜はＸ線回折によりペロ
ブスカイト型結晶となっていることが確認された。この
膜上に白金電極を形成し、電気的特性を測定したところ
次の通りであった。 以上の実施例において調製した溶液は、いずれも３カ月
放置しても、溶液状態を保持していた。A film was formed using this solution in the same manner as in Example 1. It was confirmed by X-ray diffraction that the obtained film having a thickness of 0.3 μm was a perovskite type crystal. A platinum electrode was formed on this film and the electrical characteristics were measured. The results were as follows. The solutions prepared in the above examples all maintained the solution state even after being left for 3 months.
【００４０】[0040]
【比較例１】過酸化水素を加えないこと以外は全て実施
例１と同様に処理して、合計金属濃度が酸化物換算で10
％のBaTiO3膜形成用組成物を調製した。この溶液を実施
例１と同様に成膜し、得られた厚み0.3 μｍの膜をＸ線
回折で測定したところ、ペロブスカイト型結晶となって
いることが確認された。この膜上に白金電極を形成し、
電気的特性を測定したところ次の通りであった。[Comparative Example 1] The same treatment as in Example 1 was carried out except that hydrogen peroxide was not added, and the total metal concentration was 10 in terms of oxide.
% BaTiO 3 film forming composition was prepared. When this solution was formed into a film in the same manner as in Example 1 and the obtained film having a thickness of 0.3 μm was measured by X-ray diffraction, it was confirmed that it was a perovskite type crystal. Forming a platinum electrode on this film,
The electrical characteristics were measured and were as follows.
【００４１】 なお、調製した溶液は、１週間後に沈殿が生じ、長期保
存することができなかった。[0041] The prepared solution could not be stored for a long period of time because precipitation occurred after 1 week.
【００４２】[0042]
【比較例２】過酸化水素を加えないこと以外は全て実施
例２と同様に処理して、合計金属濃度が酸化物換算で10
％のSrTiO3膜形成用組成物を調製した。この溶液を実施
例１と同様に成膜し、得られた厚み0.3 μｍの膜をＸ線
回折で測定したところ、ペロブスカイト型結晶となって
いることが確認された。この膜上に白金電極を形成し、
電気的特性を測定したところ次の通りであった。[Comparative Example 2] The same treatment as in Example 2 was carried out except that hydrogen peroxide was not added, and the total metal concentration was 10 in terms of oxide.
% SrTiO 3 film forming composition was prepared. When this solution was formed into a film in the same manner as in Example 1 and the obtained film having a thickness of 0.3 μm was measured by X-ray diffraction, it was confirmed that it was a perovskite type crystal. Forming a platinum electrode on this film,
The electrical characteristics were measured and were as follows.
【００４３】 なお、調製した溶液は、１週間後に沈殿が生じ、長期保
存することができなかった。[0043] The prepared solution could not be stored for a long period of time because precipitation occurred after 1 week.
【００４４】以上の結果からわかるように、実施例では
塗布液中に安定化剤と共に酸化剤を加えることにより、
１例は99％、残りは100 ％という非常に高い歩留りを示
す膜が得られた。これは、形成された膜が緻密で均質で
あることを意味している。一方、酸化剤を添加しなかっ
た比較例においては、膜の緻密・均一性がよくないた
め、歩留りが１／３以下に大きく低下し、絶縁性能が著
しく劣っていた。なお、比較例の膜の誘電特性 (誘電
率、誘電損失) が、対応する実施例に比べて大きく低下
していないのは、比較例の膜の正常な部分で誘電特性を
測定しているためである。従って、絶縁膜としての優劣
は主に歩留りによって評価される。As can be seen from the above results, in the examples, by adding the oxidizing agent together with the stabilizer in the coating solution,
A film having a very high yield of 99% in one case and 100% in the rest was obtained. This means that the formed film is dense and homogeneous. On the other hand, in the comparative example in which the oxidizing agent was not added, the film was not dense and uniform, so that the yield was greatly reduced to 1/3 or less, and the insulation performance was remarkably poor. The reason why the dielectric properties (dielectric constant, dielectric loss) of the film of the comparative example did not drop significantly compared to the corresponding examples is that the dielectric properties were measured in the normal part of the film of the comparative example. Is. Therefore, the superiority or inferiority of the insulating film is mainly evaluated by the yield.
【００４５】[0045]
【発明の効果】本発明によれば、有機金属化合物を原料
とするゾル−ゲル法によるチタン酸系強誘電体膜形成用
組成物の貯蔵安定性が向上し、しかも成膜時には、有機
分の残留を減少させて、原料有機金属化合物を実質的に
完全に複合金属酸化物に転化させることによって、均質
かつ緻密で、誘電特性、特に歩留りに優れたチタン酸系
強誘電体膜を得ることができる。その結果、この膜を利
用した誘電膜、圧電膜、焦電膜の品質が一段と改善され
る。EFFECTS OF THE INVENTION According to the present invention, the storage stability of a titanic acid-based ferroelectric film forming composition prepared by a sol-gel method using an organometallic compound as a raw material is improved, and moreover, an organic component is not formed during film formation. It is possible to obtain a titanic acid-based ferroelectric film which is homogeneous and dense and which has excellent dielectric properties, in particular, a yield, by reducing the residue and converting the raw material organometallic compound substantially completely into a composite metal oxide. it can. As a result, the quality of the dielectric film, piezoelectric film, and pyroelectric film using this film is further improved.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 善 英喜 埼玉県大宮市北袋町１丁目297番地 三菱 マテリアル株式会社中央研究所内 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hideki Zen 1-297 Kitabukuro-cho, Omiya City, Saitama Prefecture Central Research Laboratory, Mitsubishi Materials Corporation
Claims (2)
法により、一般式： Ａx Tiy Ｏz (式中、Ａ成分はBa、Sr、Ca、MgおよびPbから選ばれた
１もしくは２以上の金属であるか、またはBiであり、Ａ
成分がBiである時はｘ＝４、ｙ＝３、ｚ＝12であり、Ａ
成分がBi以外の金属である時はｘ＝ｙ＝１，ｚ＝３であ
る) で示される複合酸化物からなるチタン酸系強誘電体
膜を形成するための組成物であって、各成分金属の原料
有機化合物を目的とする複合酸化物の組成に相当する割
合で有機溶媒中に含有し、さらに安定化剤と酸化剤とを
含有することを特徴とする、チタン酸系強誘電体膜形成
用組成物。1. A sol-gel method using an organometallic compound as a raw material according to the general formula: A x Ti y O z (wherein the component A is 1 or 2 selected from Ba, Sr, Ca, Mg and Pb). Any of the above metals or Bi, A
When the component is Bi, x = 4, y = 3, z = 12, and A
When the component is a metal other than Bi, x = y = 1, z = 3.) A composition for forming a titanate-based ferroelectric film composed of a complex oxide represented by A titanic acid-based ferroelectric film, comprising a metal raw material organic compound contained in an organic solvent in a ratio corresponding to the composition of a target composite oxide, and further containing a stabilizer and an oxidizing agent. Forming composition.
し、加熱することからなるチタン酸系強誘電体膜の形成
法。2. A method for forming a titanate-based ferroelectric film, which comprises applying the composition according to claim 1 onto a substrate and heating the substrate.
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|---|---|---|---|
| JP05181482A JP3102210B2 (en) | 1993-07-22 | 1993-07-22 | Composition and method for forming titanate ferroelectric film |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP05181482A JP3102210B2 (en) | 1993-07-22 | 1993-07-22 | Composition and method for forming titanate ferroelectric film |
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| Publication Number | Publication Date |
|---|---|
| JPH0737422A true JPH0737422A (en) | 1995-02-07 |
| JP3102210B2 JP3102210B2 (en) | 2000-10-23 |
Family
ID=16101534
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|---|---|---|---|
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| JP4711744B2 (en) * | 2005-05-27 | 2011-06-29 | 京セラ株式会社 | Method for producing barium titanate powder and barium titanate powder |
| US7540913B2 (en) | 2005-10-04 | 2009-06-02 | Samsung Electro-Mechanics Co., Ltd. | Coating solution for forming high dielectric constant thin film and method for forming dielectric thin film using the same |
| US7887879B2 (en) | 2005-10-04 | 2011-02-15 | Samsung Electro-Mechanics Co., Ltd. | Coating solution for forming high dielectric constant thin film and method for forming dielectric thin film using the same |
| US7927517B2 (en) | 2005-10-04 | 2011-04-19 | Samsung Electro-Mechanics Co., Ltd. | Coating solution for forming high dielectric constant thin film and method for forming dielectric thin film using the same |
| JP2012072043A (en) * | 2010-09-30 | 2012-04-12 | Mitsubishi Materials Corp | Composition for forming dielectric thin film, method for forming dielectric thin film and dielectric thin film formed by the method |
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| JP3102210B2 (en) | 2000-10-23 |
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