JPH025005B2 - - Google Patents
Info
- Publication number
- JPH025005B2 JPH025005B2 JP1386983A JP1386983A JPH025005B2 JP H025005 B2 JPH025005 B2 JP H025005B2 JP 1386983 A JP1386983 A JP 1386983A JP 1386983 A JP1386983 A JP 1386983A JP H025005 B2 JPH025005 B2 JP H025005B2
- Authority
- JP
- Japan
- Prior art keywords
- lead titanate
- thin film
- precursor solution
- lead
- heat
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- NKZSPGSOXYXWQA-UHFFFAOYSA-N dioxido(oxo)titanium;lead(2+) Chemical compound [Pb+2].[O-][Ti]([O-])=O NKZSPGSOXYXWQA-UHFFFAOYSA-N 0.000 claims description 62
- 239000010409 thin film Substances 0.000 claims description 52
- 239000002243 precursor Substances 0.000 claims description 40
- 239000000758 substrate Substances 0.000 claims description 23
- 238000010438 heat treatment Methods 0.000 claims description 14
- 238000004519 manufacturing process Methods 0.000 claims description 12
- YRKCREAYFQTBPV-UHFFFAOYSA-N acetylacetone Chemical group CC(=O)CC(C)=O YRKCREAYFQTBPV-UHFFFAOYSA-N 0.000 claims description 10
- 238000007598 dipping method Methods 0.000 claims description 9
- 238000010304 firing Methods 0.000 claims description 8
- 150000003609 titanium compounds Chemical class 0.000 claims description 8
- 239000011521 glass Substances 0.000 claims description 7
- 239000007795 chemical reaction product Substances 0.000 claims description 6
- 150000002611 lead compounds Chemical class 0.000 claims description 6
- 229910052751 metal Inorganic materials 0.000 claims description 5
- 239000002184 metal Substances 0.000 claims description 5
- 239000000203 mixture Substances 0.000 claims description 5
- 239000000919 ceramic Substances 0.000 claims description 4
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims description 3
- 239000011888 foil Substances 0.000 claims description 2
- 238000000034 method Methods 0.000 description 17
- 239000010408 film Substances 0.000 description 13
- 239000010936 titanium Substances 0.000 description 9
- 239000011248 coating agent Substances 0.000 description 6
- 238000000576 coating method Methods 0.000 description 6
- 150000001875 compounds Chemical class 0.000 description 6
- 239000002994 raw material Substances 0.000 description 6
- -1 titanium alkoxides Chemical class 0.000 description 6
- 238000006460 hydrolysis reaction Methods 0.000 description 5
- 229910010413 TiO 2 Inorganic materials 0.000 description 4
- 239000012298 atmosphere Substances 0.000 description 4
- 230000007062 hydrolysis Effects 0.000 description 4
- FPCJKVGGYOAWIZ-UHFFFAOYSA-N butan-1-ol;titanium Chemical compound [Ti].CCCCO.CCCCO.CCCCO.CCCCO FPCJKVGGYOAWIZ-UHFFFAOYSA-N 0.000 description 3
- 239000003990 capacitor Substances 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 3
- 150000002902 organometallic compounds Chemical class 0.000 description 3
- 239000002904 solvent Substances 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- 229910052719 titanium Inorganic materials 0.000 description 3
- DHMQDGOQFOQNFH-UHFFFAOYSA-N Glycine Chemical compound NCC(O)=O DHMQDGOQFOQNFH-UHFFFAOYSA-N 0.000 description 2
- WGCNASOHLSPBMP-UHFFFAOYSA-N Glycolaldehyde Chemical compound OCC=O WGCNASOHLSPBMP-UHFFFAOYSA-N 0.000 description 2
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 2
- URLKBWYHVLBVBO-UHFFFAOYSA-N Para-Xylene Chemical group CC1=CC=C(C)C=C1 URLKBWYHVLBVBO-UHFFFAOYSA-N 0.000 description 2
- 239000002253 acid Substances 0.000 description 2
- 239000013522 chelant Substances 0.000 description 2
- 239000002131 composite material Substances 0.000 description 2
- 238000002425 crystallisation Methods 0.000 description 2
- 230000008025 crystallization Effects 0.000 description 2
- SWXVUIWOUIDPGS-UHFFFAOYSA-N diacetone alcohol Chemical compound CC(=O)CC(C)(C)O SWXVUIWOUIDPGS-UHFFFAOYSA-N 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 150000002148 esters Chemical class 0.000 description 2
- 238000007654 immersion Methods 0.000 description 2
- JVTAAEKCZFNVCJ-UHFFFAOYSA-N lactic acid Chemical compound CC(O)C(O)=O JVTAAEKCZFNVCJ-UHFFFAOYSA-N 0.000 description 2
- 229940046892 lead acetate Drugs 0.000 description 2
- 229910000464 lead oxide Inorganic materials 0.000 description 2
- VJPLIHZPOJDHLB-UHFFFAOYSA-N lead titanium Chemical compound [Ti].[Pb] VJPLIHZPOJDHLB-UHFFFAOYSA-N 0.000 description 2
- 150000002739 metals Chemical class 0.000 description 2
- YEXPOXQUZXUXJW-UHFFFAOYSA-N oxolead Chemical compound [Pb]=O YEXPOXQUZXUXJW-UHFFFAOYSA-N 0.000 description 2
- 229920000642 polymer Polymers 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 238000005245 sintering Methods 0.000 description 2
- POILWHVDKZOXJZ-ARJAWSKDSA-M (z)-4-oxopent-2-en-2-olate Chemical compound C\C([O-])=C\C(C)=O POILWHVDKZOXJZ-ARJAWSKDSA-M 0.000 description 1
- CVBUKMMMRLOKQR-UHFFFAOYSA-N 1-phenylbutane-1,3-dione Chemical compound CC(=O)CC(=O)C1=CC=CC=C1 CVBUKMMMRLOKQR-UHFFFAOYSA-N 0.000 description 1
- WDJHALXBUFZDSR-UHFFFAOYSA-N Acetoacetic acid Natural products CC(=O)CC(O)=O WDJHALXBUFZDSR-UHFFFAOYSA-N 0.000 description 1
- RFHDCQCOSYMOKG-UHFFFAOYSA-N C(C)[Ti](OCCCC)(OCCCC)CC Chemical compound C(C)[Ti](OCCCC)(OCCCC)CC RFHDCQCOSYMOKG-UHFFFAOYSA-N 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- PXGOKWXKJXAPGV-UHFFFAOYSA-N Fluorine Chemical compound FF PXGOKWXKJXAPGV-UHFFFAOYSA-N 0.000 description 1
- 239000004471 Glycine Substances 0.000 description 1
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 1
- 238000002441 X-ray diffraction Methods 0.000 description 1
- 150000007513 acids Chemical class 0.000 description 1
- 125000003545 alkoxy group Chemical group 0.000 description 1
- 150000001371 alpha-amino acids Chemical class 0.000 description 1
- 235000008206 alpha-amino acids Nutrition 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 229910052787 antimony Inorganic materials 0.000 description 1
- WATWJIUSRGPENY-UHFFFAOYSA-N antimony atom Chemical compound [Sb] WATWJIUSRGPENY-UHFFFAOYSA-N 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 125000000484 butyl group Chemical group [H]C([*])([H])C([H])([H])C([H])([H])C([H])([H])[H] 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- RKTYLMNFRDHKIL-UHFFFAOYSA-N copper;5,10,15,20-tetraphenylporphyrin-22,24-diide Chemical compound [Cu+2].C1=CC(C(=C2C=CC([N-]2)=C(C=2C=CC=CC=2)C=2C=CC(N=2)=C(C=2C=CC=CC=2)C2=CC=C3[N-]2)C=2C=CC=CC=2)=NC1=C3C1=CC=CC=C1 RKTYLMNFRDHKIL-UHFFFAOYSA-N 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- WOWBFOBYOAGEEA-UHFFFAOYSA-N diafenthiuron Chemical compound CC(C)C1=C(NC(=S)NC(C)(C)C)C(C(C)C)=CC(OC=2C=CC=CC=2)=C1 WOWBFOBYOAGEEA-UHFFFAOYSA-N 0.000 description 1
- 125000005594 diketone group Chemical group 0.000 description 1
- 239000002019 doping agent Substances 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- XGZNHFPFJRZBBT-UHFFFAOYSA-N ethanol;titanium Chemical compound [Ti].CCO.CCO.CCO.CCO XGZNHFPFJRZBBT-UHFFFAOYSA-N 0.000 description 1
- 125000001495 ethyl group Chemical group [H]C([H])([H])C([H])([H])* 0.000 description 1
- 229910052731 fluorine Inorganic materials 0.000 description 1
- 239000011737 fluorine Substances 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 238000010574 gas phase reaction Methods 0.000 description 1
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 1
- 229910052737 gold Inorganic materials 0.000 description 1
- 239000010931 gold Substances 0.000 description 1
- 125000001183 hydrocarbyl group Chemical group 0.000 description 1
- 229910003437 indium oxide Inorganic materials 0.000 description 1
- PJXISJQVUVHSOJ-UHFFFAOYSA-N indium(iii) oxide Chemical compound [O-2].[O-2].[O-2].[In+3].[In+3] PJXISJQVUVHSOJ-UHFFFAOYSA-N 0.000 description 1
- 150000002484 inorganic compounds Chemical class 0.000 description 1
- 229910010272 inorganic material Inorganic materials 0.000 description 1
- 235000014655 lactic acid Nutrition 0.000 description 1
- 239000004310 lactic acid Substances 0.000 description 1
- 238000010030 laminating Methods 0.000 description 1
- HTUMBQDCCIXGCV-UHFFFAOYSA-N lead oxide Chemical compound [O-2].[Pb+2] HTUMBQDCCIXGCV-UHFFFAOYSA-N 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 125000002496 methyl group Chemical group [H]C([H])([H])* 0.000 description 1
- 239000000178 monomer Substances 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 150000002894 organic compounds Chemical class 0.000 description 1
- 239000007800 oxidant agent Substances 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 125000001436 propyl group Chemical group [H]C([*])([H])C([H])([H])C([H])([H])[H] 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- 238000004544 sputter deposition Methods 0.000 description 1
- 230000002195 synergetic effect Effects 0.000 description 1
- 238000005979 thermal decomposition reaction Methods 0.000 description 1
- XOLBLPGZBRYERU-UHFFFAOYSA-N tin dioxide Chemical compound O=[Sn]=O XOLBLPGZBRYERU-UHFFFAOYSA-N 0.000 description 1
- 229910001887 tin oxide Inorganic materials 0.000 description 1
- VXUYXOFXAQZZMF-UHFFFAOYSA-N titanium(IV) isopropoxide Chemical compound CC(C)O[Ti](OC(C)C)(OC(C)C)OC(C)C VXUYXOFXAQZZMF-UHFFFAOYSA-N 0.000 description 1
- 238000001771 vacuum deposition Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Landscapes
- Inorganic Compounds Of Heavy Metals (AREA)
- Fixed Capacitors And Capacitor Manufacturing Machines (AREA)
Description
本発明は誘電体薄膜、特に厚さが数100Åない
し数μｍのチタン酸鉛誘電体薄膜およびその製造
方法に関する。
誘電体膜は従来粉粒体状の誘電体組成物を成形
焼結して製造しているが、該方法においては優れ
たコンデンサー膜の条件である厚さ数μｍ以下と
薄く、かつ、高い比誘電率を有する薄膜を製造す
ることは困難であり、また焼結温度が極めて高温
であるため電極として高価な金属を用いなければ
ならない欠点がある。優れたコンデンサー膜に適
した誘電体薄膜の製造方法として、スパツタリン
グ法、真空蒸着法、気相反応法等が検討されてい
るが、これらの方法においてはストイチオメトリ
制御が極めて困難であることにより実用化されて
いない。これらの方法を改良する方法として、有
機金属化合物溶液をガラス基板上に滴下法または
デイツピング法（浸漬引上げ法）により塗布し、
常温空気中で30分間、さらに110℃の恒温槽中で
30分間乾燥して加水分解反応を終了させた後、電
気炉中において強制的に水蒸気を送入しながら
200〜800℃の温度に加熱焼成して誘電体薄膜を製
造する方法が特開昭56−28408号公報に提案され
ている。しかしながら、該方法においては、例示
される有機金属化合物溶液が大気中の水分を吸収
して極めて容易に加水分解されるため不安定であ
り、均質な塗膜を得ることが困難である。また、
加水分解時および加熱焼成時における雰囲気、特
に水蒸気分圧の制御が極めて困難でありクラツク
あるいはピンホール等が発生し易いため、導通を
生じ良好な電気特性、特に誘電特性を有する薄膜
を得ることは困難であり、該公報には電気特性の
具体的な記載はない。
一般に、高い比誘電率を得るためには、誘電体
組成を結晶化させる必要があるが、薄膜の場合、
薄膜組成の結晶化により結晶粒界に起因する導通
が生ずるため高い比誘電率を有する誘電体薄膜は
得られないとするのが通説となつている。
本発明は高い比誘電率を有し、厚さが数100Å
ないし数μｍの均質、かつ透明なチタン酸鉛誘電
体薄膜を提供することをその目的とする。
本発明者等は前記目的を達成すべく鋭意研究し
た結果、鉛−チタン複合有機金属化合物のアセチ
ルアセトン溶液をチタン酸鉛形成前駆体溶液とし
て耐熱性基板上に塗布して加熱焼成し、塗布、加
熱焼成を繰返すことによりチタン酸鉛薄膜を積層
せしめて得た透明なチタン酸鉛薄膜が、比誘電率
（ε）が170にも達することを見出し本発明を完成
した。
本発明はチタン酸鉛薄膜を耐熱性基板上に多層
に積層せしめることを特徴とするチタン酸鉛誘電
体薄膜およびその製造方法である。
本発明のチタン酸鉛誘電体薄膜は耐熱性基板た
とえばガラス板、セラミツク板、錫をドープした
酸化インジウム薄膜、フツ素、アンチモン等をド
ープした酸化錫薄膜、金属類の蒸着膜等の導電性
薄膜で被覆したガラス板またはセラミツク板、ニ
ツケル、チタン、銅、アルミ、金等の金属板また
は金属箔等にチタン酸鉛薄膜を２〜10層の多層に
積層せしめた厚さ数100Åないし数μｍの均質、
かつ透明なチタン酸鉛薄膜であり、比誘電率
（ε）130〜170を有する。
本発明においてチタン酸鉛誘電体薄膜は下記の
方法で製造する。
チタン化合物と鉛化合物との混合物またはチタ
ン化合物と鉛化合物との反応生成物のβ−ジケト
ン溶液をチタン酸鉛形成前駆体溶液とし、該前駆
体溶液を耐熱性基板に塗布してチタン酸鉛前駆体
溶液を形成せしめた後、酸素含有ガス雰囲気中に
おいて450℃以上の温度に加熱焼成し、以降前駆
体溶液の塗布、加熱焼成を繰返すことにより当該
耐熱性基板上にチタン酸鉛薄膜が多層に積層して
形成されチタン酸鉛誘電体薄膜が製造される。
チタン酸鉛形成前駆体溶液の原料に用いるチタ
ン化合物は、β−ジケトンに可溶性のものであれ
ばいずれでも使用できる。具体的には、テトラエ
トキシチタン、テトライソプロポキシチタン、テ
トラブトキシチタン、ジエチルジブトキシチタン
等のチタンアルコキシド類およびその加水分解に
より生成する重合体類、チタンアルコキシドのア
ルコキシ基の一部または全部をキレート化剤たと
えばアセチルアセトン等のβ−ジケトン類、アセ
ト酢酸等のα−またはβ−ケトン酸類、該ケトン
酸のメチル、エチル、プロピル、ブチル等のエス
テル類、乳酸等のα−またはβ−オキシ酸類、該
オキシ酸のエステル類、ジアセトンアルコール等
のα−またはβ−オキシケトン類、グリコールア
ルデヒド等のα−またはβ−オキシアルデヒド
類、グリシン等のα−アミノ酸類、アミノエチル
アルコール等のα−またはβ−アミノアルコール
類等で置換した有機チタン化合物類およびその加
水分解により生成する重合体類が挙げられる。一
方、鉛化合物は、β−ジケトン可溶性であるか、
チタン化合物と反応してβ−ジケトン可溶性物質
を生成するものが使用できる。たとえば酸化鉛等
の無機化合物類、酢酸鉛等の有機酸塩類、アセチ
ルアセトナト鉛等のβ−ジケトンキレート化合物
類等が挙げられる。また、チタン酸鉛形成前駆体
溶液に用いる原料化合物として、本願出願人が特
願昭56−138877号で提案した下記一般式（）
〔Pb・TiO2(OR)x(OCOR′)y〕 ……〔〕
（ここにＲ、R′は、同種または異種の１価の炭
化水素基を表し、ｘおよびｙは、０、１または２
であり、かつｘ＋ｙ＝２である。）
で表わされる構成ユニツトを有する繰返し数が、
１ないし50の単量体または多量体である鉛化合物
とチタン化合物との反応生成物であるチタン−鉛
複合有機化合物が好ましく使用される。チタン酸
鉛形成前駆体溶液は、溶媒として、アセチルアセ
トン、ベンゾイルアセトン等のβ−ジケトン類を
溶媒とし、通常前記原料化合物をチタン酸鉛
（Pb・TiO3）換算濃度５〜20重量％含有する溶
液である。
前記チタン酸鉛形成前駆体溶液を好ましくは40
〜95℃に加温保持した中に、前記耐熱性基板を好
ましくは該前駆体溶液とほぼ同温度に加温して浸
漬し、一定の速度、好ましくは５〜200cm／min
の速度で引上げ当該基板上に該前駆体被膜を形成
せしめ、ついで450℃以上、好ましくは450〜700
℃の温度に電気炉中で加熱焼成することにより、
当該基板上にチタン酸鉛薄膜を形成させる。この
基板を冷却し、再び該前駆体溶液に浸漬、引上げ
て加熱焼成して、チタン酸鉛薄膜上に別のチタン
酸薄膜を形成させる。この操作を繰返すことによ
り、目的とするチタン酸鉛薄膜を多層に積層せし
めたチタン酸鉛誘電体薄膜を製造することができ
る。チタン酸鉛前駆体溶液中の原料化合物の
Pb・TiO3換算濃度が５重量％未満では、一回の
浸漬引上げで形成される該前駆体の塗膜が薄くな
り過ぎ浸漬引上げ、加熱焼成の繰返し数を多くし
なければ所望のチタン酸鉛誘電体薄膜が得られ
ず、また20重量％を越えると一回の浸漬引上げで
形成される該前駆体の塗膜が厚くなり過ぎ加熱焼
成に際してクラツクが発生し易くなるので好まし
くない。また、チタン酸鉛前駆体溶液の温度は、
温度が高い程一回の浸漬引上げで形成される前駆
体被膜が厚くなる。したがつて温度が低過ぎると
浸漬引上げ、加熱焼成の繰返し数を多くしなけれ
ばならず、また高過ぎると溶媒の蒸気圧が上昇し
作業性が悪くなるので40〜95℃の範囲が好まし
い。さらに基板を該前駆体溶液とほぼ等しい温度
に加温して浸漬引上げを行うことにより良好な前
駆体塗膜が得られる。基板の引上げ速度は、目的
とするチタン酸鉛薄膜の厚さ、前駆体溶液の原料
化合物の種類、Pb・TiO3換算濃度、温度等によ
り異なるが通常５〜200cm／minである。前駆体
溶液の耐熱性基板への好ましい塗布法としてデイ
ツピング法を例示したが、スプレー法、スピンナ
ー法等により行うこともできる。チタン酸鉛形成
前駆体を塗布した基板の加熱焼成温度は450℃以
上、好ましくは450〜700℃である。450℃未満で
はチタン酸鉛の結晶化が進まず、高い比誘電率を
得ることは困難であり、また700℃を越えるとチ
タン酸鉛結晶の粗粒化が進み、結晶粒界を通して
の導電が生じ易くなるので好ましくない。浸漬引
上げ加熱焼成の繰返しの回数は、目的とするチタ
ン酸鉛誘電体薄膜の比誘電率、厚み、またチタン
酸鉛形成前駆体溶液の原料化合物の種類、Pb・
TiO3換算濃度、温度、さらに基板の引上げ速度
等により変えることができるが２〜10回、好まし
くは３〜８回である。
本発明のチタン酸鉛誘電体薄膜は、前記した方
法によりチタン酸鉛薄膜を多層に積層せしめたも
のであり、誘電損失が低く、高い比誘電率を有す
る。誘電体薄膜として優れた特性を有する理由に
ついては定かではないが、チタン酸鉛薄膜を多層
に積層せしめたことにより、ピンホール、結晶粒
界を通しての導通が防止されるのか、比較的低温
で焼成することにより結晶粒界がアモルフアスな
チタン酸鉛で充填され導通が防止されるのか、あ
るいはそれらの相乗の効果によるものと想定され
る。さらにチタン酸鉛形成前駆体溶液の溶媒をβ
−ジケトンとしたことにより該前駆体溶液が安定
化され、通常の雰囲気での加水分解による該前駆
体溶液の粘度上昇が防止されるため繰返しの使用
に対し常に安定した該前駆体塗膜が得られること
も相乗的に寄与しているものと想定される。
本発明のチタン酸鉛誘電体薄膜は、誘電損失が
低く高い比誘電率を有し、均質、かつ透明である
ため小型、大容量コンデンサーへの応用、電気光
学効果を利用したエレクトロルミネツセンスデイ
スプレイへの応用が期待できる。また、その製造
に用いるチタン酸鉛形成前駆体溶液は、溶液性で
あるため、化学量論的なTi／Pb比のコントロー
ルが容易であり、さらに誘電体の設計に従つて所
望のドーパント等の異種物質を任意の割合で、か
つ均一に混合することができる。
本発明は、高い比誘電率を有し、均質、かつ透
明な厚さ数100Åないし数μｍのチタン酸鉛誘電
体薄膜およびその製造方法を提供するものであ
り、その産業的意義は極めて大きい。
以下、本発明を実施例によりさらに詳細に説明
する。ただし、本発明の範囲は下記実施例により
何等限定されるものではない。
実施例 １
チタン酸鉛形成前駆体溶液の調製：
テトラブトキシチタン：Ti（OC4H9）4と酢酸
鉛：Pb（CH3COO）2とをTi／Pb比が１となる如
くそれぞれを秤取し、パラキシレン中において
130〜140℃の温度に加熱して反応させた。減圧下
に低沸物を留去し粉末状の反応生成物を得た。本
反応は下記反応式(1)の如く進行したものと推定さ
れる。
Ti（OC4H9）4＋Pb（CH3COO）2→Pb・TiO2（OC4H9
）2＋２・CH3COOC4H9……(1)
得られた反応生成物Pb・TiO2（OC4H9）2を500
℃の温度において加熱分解した。得られた粉末は
Ｘ線回析により正方晶のPb・TiO3であることが
確認された。
反応生成物Pb・TiO2（OC4H9）2粉末をアセチル
アセトンに溶解し、Pb・TiO3換算濃度14重量％
のチタン酸鉛形成前駆体溶液を調製した。
チタン酸鉛誘電体薄膜の製造：
前記調製したチタン酸鉛形成駆体溶液を40〜50
℃の温度に加温保持した中に、錫をドープした酸
化インジウム膜（ITO膜）を被覆した100mm×50
mm×１mmのガラス基板を50℃に加温して浸漬し、
30cm／minの速さで引上げチタン酸鉛前駆体の塗
膜を形成した。ついで500℃の温度に加熱した電
気炉中において30分間保持して加熱焼成した。デ
イツピング−加熱焼成を繰返し透明なチタン酸鉛
薄膜を得た。
デイツピング−加熱焼成の繰返し回数と得られ
たチタン酸鉛薄膜の諸特性を第１表に示す。
The present invention relates to a dielectric thin film, particularly a lead titanate dielectric thin film having a thickness of several hundred angstroms to several micrometers, and a method for manufacturing the same. Dielectric films have conventionally been manufactured by molding and sintering a powder-like dielectric composition, but in this method, a thin film with a thickness of several μm or less and a high ratio can be produced, which are the conditions for an excellent capacitor film. It is difficult to produce a thin film with a dielectric constant, and the sintering temperature is extremely high, so expensive metals must be used as electrodes. Sputtering method, vacuum evaporation method, gas phase reaction method, etc. are being considered as methods for producing dielectric thin films suitable for excellent capacitor films, but these methods are extremely difficult to control stoichiometry. Not put into practical use. As a method to improve these methods, an organometallic compound solution is applied onto a glass substrate by a dropping method or a dipping method.
30 minutes in room temperature air and then in a constant temperature oven at 110℃
After drying for 30 minutes to complete the hydrolysis reaction, it is heated in an electric furnace while forcefully introducing steam.
JP-A-56-28408 proposes a method of manufacturing a dielectric thin film by heating and baking at a temperature of 200 to 800°C. However, in this method, the exemplified organometallic compound solution absorbs moisture in the atmosphere and is extremely easily hydrolyzed, making it unstable and making it difficult to obtain a homogeneous coating film. Also,
It is extremely difficult to control the atmosphere during hydrolysis and heating and baking, especially the partial pressure of water vapor, and cracks or pinholes are likely to occur, so it is difficult to obtain a thin film that is conductive and has good electrical properties, especially dielectric properties. This is difficult, and there is no specific description of electrical characteristics in this publication. Generally, in order to obtain a high dielectric constant, it is necessary to crystallize the dielectric composition, but in the case of thin films,
It is generally accepted that a dielectric thin film having a high dielectric constant cannot be obtained because conduction due to grain boundaries occurs due to crystallization of the thin film composition. The present invention has a high dielectric constant and a thickness of several hundred Å.
The purpose is to provide a homogeneous and transparent lead titanate dielectric thin film with a thickness of several μm to several μm. As a result of intensive research to achieve the above object, the present inventors applied an acetylacetone solution of a lead-titanium composite organometallic compound as a lead titanate formation precursor solution onto a heat-resistant substrate, heated and baked it, applied it, and heated it. The present invention was completed by discovering that a transparent lead titanate thin film obtained by laminating lead titanate thin films through repeated firing has a dielectric constant (ε) of as high as 170. The present invention relates to a lead titanate dielectric thin film and a method for producing the same, characterized in that the lead titanate thin film is laminated in multiple layers on a heat-resistant substrate. The lead titanate dielectric thin film of the present invention can be applied to conductive thin films on heat-resistant substrates such as glass plates, ceramic plates, indium oxide thin films doped with tin, tin oxide thin films doped with fluorine, antimony, etc., vapor-deposited films of metals, etc. Lead titanate thin film is laminated in multiple layers of 2 to 10 layers on a glass plate or ceramic plate coated with nickel, titanium, copper, aluminum, gold, etc. or metal foil, etc., with a thickness of several 100 Å to several μm. homogeneous,
It is a transparent lead titanate thin film and has a dielectric constant (ε) of 130 to 170. In the present invention, the lead titanate dielectric thin film is manufactured by the following method. A β-diketone solution of a mixture of a titanium compound and a lead compound or a reaction product of a titanium compound and a lead compound is used as a lead titanate forming precursor solution, and the precursor solution is applied to a heat-resistant substrate to form a lead titanate precursor. After forming the body solution, it is heated and fired at a temperature of 450°C or higher in an oxygen-containing gas atmosphere, and then the precursor solution is applied and heated and fired repeatedly to form a multilayer lead titanate thin film on the heat-resistant substrate. A lead titanate dielectric thin film is manufactured by stacking the lead titanate dielectric thin film. Any titanium compound used as a raw material for the lead titanate forming precursor solution can be used as long as it is soluble in β-diketone. Specifically, titanium alkoxides such as tetraethoxytitanium, tetraisopropoxytitanium, tetrabutoxytitanium, diethyldibutoxytitanium, etc., and polymers produced by their hydrolysis, chelate some or all of the alkoxy groups of titanium alkoxides. oxidizing agents such as β-diketones such as acetylacetone, α- or β-ketone acids such as acetoacetic acid, esters of said ketonic acids such as methyl, ethyl, propyl, butyl, α- or β-oxyacids such as lactic acid, Esters of the oxyacids, α- or β-oxyketones such as diacetone alcohol, α- or β-oxyaldehydes such as glycolaldehyde, α-amino acids such as glycine, α- or β-such as aminoethyl alcohol, etc. Examples include organic titanium compounds substituted with -amino alcohols and the like, and polymers produced by hydrolysis thereof. On the other hand, lead compounds are β-diketone soluble or
A substance that reacts with a titanium compound to produce a β-diketone soluble substance can be used. Examples include inorganic compounds such as lead oxide, organic acid salts such as lead acetate, and β-diketone chelate compounds such as lead acetylacetonate. In addition, as a raw material compound used in the lead titanate forming precursor solution, the following general formula () [Pb・TiO 2 (OR) x (OCOR′) y ] proposed by the applicant in Japanese Patent Application No. 138877/1982 was used. ...[] (Here, R and R' represent the same or different monovalent hydrocarbon groups, and x and y are 0, 1 or 2
and x+y=2. ) is the number of repetitions with constituent units represented by
A titanium-lead composite organic compound which is a reaction product of a titanium compound and a lead compound which is a monomer or multimer of 1 to 50 is preferably used. The lead titanate forming precursor solution is a solution that uses β-diketones such as acetylacetone and benzoylacetone as a solvent and usually contains the above-mentioned raw material compound at a concentration of 5 to 20% by weight in terms of lead titanate (Pb/TiO 3 ). It is. The lead titanate forming precursor solution is preferably 40%
The heat-resistant substrate is preferably heated to approximately the same temperature as the precursor solution and immersed in a solution heated to ~95°C, and immersed at a constant speed, preferably 5 to 200 cm/min.
The precursor film is formed on the substrate by pulling at a speed of 450°C or higher, preferably 450 to 700°C.
By heating and firing in an electric furnace to a temperature of ℃,
A lead titanate thin film is formed on the substrate. This substrate is cooled, immersed in the precursor solution again, pulled up, and heated and fired to form another titanate thin film on the lead titanate thin film. By repeating this operation, the desired lead titanate dielectric thin film in which lead titanate thin films are laminated in multiple layers can be manufactured. of raw material compounds in lead titanate precursor solution
If the concentration in terms of Pb/TiO 3 is less than 5% by weight, the coating film of the precursor formed by one immersion-pulling process will become too thin, and unless the immersion-pulling process and the heating and baking process are repeated many times, the desired lead titanate can be obtained. A dielectric thin film cannot be obtained, and if it exceeds 20% by weight, the coating film of the precursor formed by one immersion and pulling becomes too thick and cracks are likely to occur during heating and baking, which is not preferable. In addition, the temperature of the lead titanate precursor solution is
The higher the temperature, the thicker the precursor film formed by one immersion and pull-up. Therefore, if the temperature is too low, the number of repetitions of dipping and pulling and heating and baking must be increased, and if the temperature is too high, the vapor pressure of the solvent increases and workability deteriorates, so a range of 40 to 95°C is preferable. Furthermore, a good precursor coating film can be obtained by heating the substrate to approximately the same temperature as the precursor solution and performing dipping and pulling. The pulling speed of the substrate varies depending on the thickness of the target lead titanate thin film, the type of raw material compound of the precursor solution, the concentration in terms of Pb/TiO 3 , the temperature, etc., but is usually 5 to 200 cm/min. Although the dipping method has been exemplified as a preferred method for applying the precursor solution to the heat-resistant substrate, spray methods, spinner methods, etc. may also be used. The heating and firing temperature of the substrate coated with the lead titanate forming precursor is 450°C or higher, preferably 450 to 700°C. At temperatures below 450℃, lead titanate crystallization does not proceed and it is difficult to obtain a high dielectric constant. At temperatures above 700℃, lead titanate crystals become coarser and conductivity through grain boundaries is reduced. This is not preferable because it tends to occur. The number of repetitions of dipping, pulling, heating and firing depends on the dielectric constant and thickness of the target lead titanate dielectric thin film, the type of raw material compound of the lead titanate forming precursor solution, Pb.
The number of times can be changed depending on the TiO 3 equivalent concentration, temperature, substrate pulling speed, etc., but the number of times is 2 to 10 times, preferably 3 to 8 times. The lead titanate dielectric thin film of the present invention is obtained by stacking lead titanate thin films in multiple layers by the method described above, and has a low dielectric loss and a high dielectric constant. It is not clear why it has such excellent properties as a dielectric thin film, but it may be that the multilayered lead titanate thin film prevents electrical conduction through pinholes and grain boundaries, or that it is fired at a relatively low temperature. It is assumed that this causes the grain boundaries to be filled with amorphous lead titanate and prevents conduction, or that it is due to a synergistic effect of these. Furthermore, the solvent of the lead titanate forming precursor solution is β
- The use of diketone stabilizes the precursor solution and prevents the viscosity of the precursor solution from increasing due to hydrolysis in a normal atmosphere, resulting in a coating film of the precursor that is always stable for repeated use. It is assumed that the effects of the above factors also contribute synergistically. The lead titanate dielectric thin film of the present invention has low dielectric loss, high relative permittivity, is homogeneous, and is transparent, so it can be applied to small-sized, large-capacity capacitors, and electroluminescent displays using electro-optic effects. It can be expected to be applied to In addition, since the lead titanate forming precursor solution used for its production is solution-based, it is easy to control the stoichiometric Ti/Pb ratio, and furthermore, the desired dopants, etc. can be added according to the design of the dielectric. Different materials can be mixed uniformly in any proportion. The present invention provides a homogeneous and transparent lead titanate dielectric thin film with a thickness of several 100 Å to several μm having a high dielectric constant, and a method for manufacturing the same, and has extremely great industrial significance. Hereinafter, the present invention will be explained in more detail with reference to Examples. However, the scope of the present invention is not limited in any way by the following examples. Example 1 Preparation of lead titanate forming precursor solution: Tetrabutoxytitanium: Ti(OC 4 H 9 ) 4 and lead acetate: Pb(CH 3 COO) 2 were weighed so that the Ti/Pb ratio was 1. Take it and put it in paraxylene.
The reaction was carried out by heating to a temperature of 130-140°C. Low-boiling substances were distilled off under reduced pressure to obtain a powdery reaction product. It is presumed that this reaction proceeded as shown in reaction formula (1) below. Ti(OC 4 H 9 ) 4 +Pb(CH 3 COO) 2 →Pb・TiO 2 (OC 4 H 9
) 2 + 2・CH 3 COOC 4 H 9 ...(1) The obtained reaction product Pb・TiO 2 (OC 4 H 9 ) 2 is 500
Thermal decomposition was carried out at a temperature of °C. The obtained powder was confirmed to be tetragonal Pb.TiO 3 by X-ray diffraction. The reaction product Pb・TiO 2 (OC 4 H 9 ) 2 powder was dissolved in acetylacetone to give a concentration of 14% by weight in terms of Pb・TiO 3
A lead titanate forming precursor solution was prepared. Production of lead titanate dielectric thin film: 40-50% of the prepared lead titanate forming precursor solution
A 100mm
A glass substrate of mm x 1 mm was heated to 50℃ and immersed.
A coating film of the pulled lead titanate precursor was formed at a speed of 30 cm/min. Then, it was heated and fired in an electric furnace heated to a temperature of 500°C for 30 minutes. Dipping and heating and baking were repeated to obtain a transparent lead titanate thin film. Table 1 shows the number of repetitions of dipping and heating and firing and various properties of the obtained lead titanate thin film.
【表】
実施例 ２
テトラブトキシチタン：Ti（OC4H9）4と酸化
鉛：PbOとをTi／Pb比が１となる如く秤取し、
アセチルアセトン中において120〜130℃の温度に
加熱し、生成してくるブタノールを留去しPb・
TiO3換算濃度18重量％のチタン酸鉛形成前駆体
溶液を調製した。
50℃に加温保持してある前記調製したチタン酸
鉛形成前駆体溶液に実施例１で用いたと同様に
ITO膜を被覆したガラス基板を実施例１と同様に
処理し、チタン酸鉛誘電体薄膜を得た。得られた
チタン酸鉛誘電体薄膜の特性は下記の通りであつ
た。[Table] Example 2 Tetrabutoxytitanium: Ti(OC 4 H 9 ) 4 and lead oxide: PbO were weighed out so that the Ti/Pb ratio was 1,
Pb and
A lead titanate forming precursor solution with a TiO 3 equivalent concentration of 18% by weight was prepared. In the same manner as used in Example 1, the lead titanate forming precursor solution prepared above was heated and maintained at 50°C.
The glass substrate coated with the ITO film was treated in the same manner as in Example 1 to obtain a lead titanate dielectric thin film. The properties of the obtained lead titanate dielectric thin film were as follows.
Claims (1)
せしめてなることを特徴とするチタン酸鉛誘電体
薄膜。 ２ チタン酸鉛薄膜の積層数が２〜10層である特
許請求の範囲第１項記載の誘電体薄膜。 ３ 耐熱性基板が、ガラス板、セラミツク板、導
電性薄膜で被覆したガラス板またはセラミツク板
もしくは金属板または金属箔である特許請求の範
囲第１項記載の誘電体薄膜。 ４ チタン化合物と鉛化合物との混合物、または
チタン化合物と鉛化合物との反応生成物のβ−ジ
ケトン溶液をチタン酸鉛形成前駆体溶液とし、該
前駆体溶液を耐熱性基板上に塗布して加熱焼成
し、ついで前駆体溶液の塗布、加熱焼成を繰返
し、当該耐熱性基板上にチタン酸塩薄膜を多層に
積層せしめることを特徴とするチタン酸鉛誘電体
薄膜の製造方法。 ５ β−ジケトンがアセチルアセトンである特許
請求の範囲第４項記載の製造方法。 ６ チタン酸鉛形成前駆体溶液中のチタン酸鉛
（Pb・TiO3）換算濃度が５〜20重量％である特
許請求の範囲第４項記載の製造方法。 ７ チタン酸鉛形成前駆体溶液の耐熱性基板への
塗布をデイツピング法により行う特許請求の範囲
第４項記載の製造方法。 ８ チタン酸鉛形成前駆体溶液を40〜95℃の温度
に保持し、耐熱性基板のデイツピングを行う特許
請求の範囲第７項記載の製造方法。 ９ 加熱焼成を450℃〜700℃の温度に保持した電
気炉中で行う特許請求の範囲第４項記載の製造方
法。[Claims] 1. A lead titanate dielectric thin film, characterized in that the lead titanate thin film is laminated in multiple layers on a heat-resistant substrate. 2. The dielectric thin film according to claim 1, wherein the number of laminated lead titanate thin films is 2 to 10. 3. The dielectric thin film according to claim 1, wherein the heat-resistant substrate is a glass plate, a ceramic plate, a glass plate or ceramic plate coated with a conductive thin film, a metal plate, or a metal foil. 4 A β-diketone solution of a mixture of a titanium compound and a lead compound or a reaction product of a titanium compound and a lead compound is used as a lead titanate forming precursor solution, and the precursor solution is applied onto a heat-resistant substrate and heated. 1. A method for producing a lead titanate dielectric thin film, which comprises repeating firing, applying a precursor solution, and heating and firing to stack a multilayer titanate thin film on the heat-resistant substrate. 5. The manufacturing method according to claim 4, wherein the β-diketone is acetylacetone. 6. The manufacturing method according to claim 4, wherein the lead titanate (Pb.TiO 3 ) equivalent concentration in the lead titanate forming precursor solution is 5 to 20% by weight. 7. The manufacturing method according to claim 4, wherein the lead titanate forming precursor solution is applied to the heat-resistant substrate by a dipping method. 8. The manufacturing method according to claim 7, wherein the lead titanate forming precursor solution is maintained at a temperature of 40 to 95°C and dipping of the heat-resistant substrate is performed. 9. The manufacturing method according to claim 4, wherein the heating and firing is performed in an electric furnace maintained at a temperature of 450°C to 700°C.
Priority Applications (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1386983A JPS59139617A (en) | 1983-01-31 | 1983-01-31 | Lead titanate dielectric thin film and method of producing same |
| PCT/JP1984/000027 WO1984003003A1 (en) | 1983-01-31 | 1984-01-31 | Thin-film dielectric and process for its production |
| US06/662,295 US4636908A (en) | 1983-01-31 | 1984-01-31 | Thin-film dielectric and process for its production |
| EP19840900646 EP0134249A4 (en) | 1983-01-31 | 1984-01-31 | Process for the production of a thin-film dielectric. |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1386983A JPS59139617A (en) | 1983-01-31 | 1983-01-31 | Lead titanate dielectric thin film and method of producing same |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS59139617A JPS59139617A (en) | 1984-08-10 |
| JPH025005B2 true JPH025005B2 (en) | 1990-01-31 |
Family
ID=11845241
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1386983A Granted JPS59139617A (en) | 1983-01-31 | 1983-01-31 | Lead titanate dielectric thin film and method of producing same |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS59139617A (en) |
-
1983
- 1983-01-31 JP JP1386983A patent/JPS59139617A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS59139617A (en) | 1984-08-10 |
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