JPH0646524B2 - Ferroelectric thin film - Google Patents
Ferroelectric thin filmInfo
- Publication number
- JPH0646524B2 JPH0646524B2 JP29385785A JP29385785A JPH0646524B2 JP H0646524 B2 JPH0646524 B2 JP H0646524B2 JP 29385785 A JP29385785 A JP 29385785A JP 29385785 A JP29385785 A JP 29385785A JP H0646524 B2 JPH0646524 B2 JP H0646524B2
- Authority
- JP
- Japan
- Prior art keywords
- thin film
- ferroelectric
- plane
- ferroelectric thin
- present
- 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 - Lifetime
Links
- 239000010409 thin film Substances 0.000 title claims description 41
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 claims description 10
- 239000002184 metal Substances 0.000 claims description 9
- 229910052751 metal Inorganic materials 0.000 claims description 9
- 230000010287 polarization Effects 0.000 claims description 8
- 229910052594 sapphire Inorganic materials 0.000 claims description 8
- 239000010980 sapphire Substances 0.000 claims description 8
- 239000010936 titanium Substances 0.000 claims description 5
- 239000010931 gold Substances 0.000 claims description 3
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims description 2
- QCWXUUIWCKQGHC-UHFFFAOYSA-N Zirconium Chemical compound [Zr] QCWXUUIWCKQGHC-UHFFFAOYSA-N 0.000 claims description 2
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 claims description 2
- 229910052737 gold Inorganic materials 0.000 claims description 2
- 229910052746 lanthanum Inorganic materials 0.000 claims description 2
- FZLIPJUXYLNCLC-UHFFFAOYSA-N lanthanum atom Chemical compound [La] FZLIPJUXYLNCLC-UHFFFAOYSA-N 0.000 claims description 2
- 229910052697 platinum Inorganic materials 0.000 claims description 2
- 229910052719 titanium Inorganic materials 0.000 claims description 2
- 229910052726 zirconium Inorganic materials 0.000 claims description 2
- 239000000463 material Substances 0.000 description 13
- 239000000758 substrate Substances 0.000 description 10
- 239000010408 film Substances 0.000 description 8
- 239000013078 crystal Substances 0.000 description 5
- 238000004544 sputter deposition Methods 0.000 description 4
- 229910052782 aluminium Inorganic materials 0.000 description 3
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 3
- 239000007789 gas Substances 0.000 description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- 229910052760 oxygen Inorganic materials 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 229910052786 argon Inorganic materials 0.000 description 1
- 239000012300 argon atmosphere Substances 0.000 description 1
- 239000012298 atmosphere Substances 0.000 description 1
- 229910010293 ceramic material Inorganic materials 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 239000004020 conductor Substances 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
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000005684 electric field Effects 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 239000012528 membrane Substances 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 230000005693 optoelectronics Effects 0.000 description 1
- 230000005616 pyroelectricity Effects 0.000 description 1
- 238000010897 surface acoustic wave method Methods 0.000 description 1
- 238000001947 vapour-phase growth Methods 0.000 description 1
Landscapes
- Inorganic Insulating Materials (AREA)
- Crystals, And After-Treatments Of Crystals (AREA)
Description
【発明の詳細な説明】 産業上の利用分野 本発明は、各種機能素子の基盤材料として期待される強
誘電的特性を有する薄膜に関するものである。TECHNICAL FIELD The present invention relates to a thin film having ferroelectric properties expected as a base material for various functional devices.
従来の技術 強誘電体は種々の特性を有すことから、素子の高性能化
・小型化・集積化等を目ざした薄膜作製の試みが行なわ
れてきた。薄膜作製は、例えばスパッタ法，気相成長
法，塗布法等を用いることにより結晶化膜を作ることが
出来る。これらの強誘電性薄膜の実用的な使用のために
は分極軸がそろっている必要があるが、そのために導電
性基板あるいは導電性材料をコートした絶縁基板上に多
結晶強誘電性薄膜を成膜しさらにその上に電極を付け、
前記強誘電性薄膜を膜厚方向に分極処理する方法がとら
れていた。〔例えばT.Fukami et al.（ジャパン ジャ
ーナル アプライド フィジックス；Jpn.j.Appl.Phy
s.）２４(１９８５)６３２〕 発明が解決しようとする問題点 しかしこのように多結晶薄膜を分極処理しても、本質的
に結晶の方位はランダムであるので、その材料の特性を
最大限に生かすことは出来ていない。そこで特性にすぐ
れた強誘電性薄膜を得るためには、分極軸がそろうよう
にエピタキシャル成長させる必要がある。しかしこのよ
うなエピタキシャル成長は、基板と強誘電体材料が非常
に限定される上に分極軸が有効な方向に向いている必要
がある。また強誘電性エピタキシャル膜は、基板上に直
接成膜されるので電極で挾んだ積層構造に難があり、実
用的な使用が出来なかった。2. Description of the Related Art Since ferroelectrics have various characteristics, attempts have been made to produce thin films aiming at high performance, miniaturization, and integration of devices. The thin film can be formed by using, for example, a sputtering method, a vapor phase growth method, a coating method or the like to form a crystallized film. For practical use of these ferroelectric thin films, it is necessary that the polarization axes be aligned. For this reason, a polycrystalline ferroelectric thin film is formed on a conductive substrate or an insulating substrate coated with a conductive material. Membrane and attach electrodes on it,
A method has been adopted in which the ferroelectric thin film is polarized in the film thickness direction. [For example, T. Fukami et al. (Japan Journal Applied Physics; Jpn.j.Appl.Phy
s.) 24 (1985) 632] Problems to be Solved by the Invention However, even if the polycrystalline thin film is polarized in this way, the orientation of the crystal is essentially random, and the characteristics of the material are maximized. I have not been able to make the most of it. Therefore, in order to obtain a ferroelectric thin film having excellent characteristics, it is necessary to grow epitaxially so that the polarization axes are aligned. However, such epitaxial growth requires that the substrate and the ferroelectric material are very limited and the polarization axis is oriented in an effective direction. Further, since the ferroelectric epitaxial film is formed directly on the substrate, the laminated structure sandwiched by the electrodes is difficult and cannot be practically used.
問題点を解決するための手段 本発明の強誘電性薄膜は、サファイアＣ面とその上にエ
ピタキシャル成長した立方晶金属(111)面薄膜と、さら
にその上にエピタキシャル成長したペロブスカイト型強
誘電体の(111)面薄膜で構成され、薄膜上に形成された
電極と立方晶金属薄膜で膜厚方向に分極処理して得られ
るものである。Means for Solving the Problems The ferroelectric thin film of the present invention comprises a sapphire C plane, a cubic metal (111) plane thin film epitaxially grown thereon, and a perovskite ferroelectric (111) plane epitaxially grown thereon. ) Plane thin film, and is obtained by polarization treatment in the film thickness direction with an electrode formed on the thin film and a cubic metal thin film.
作用 本発明は上記構成により、材料の特性を最大限に生かし
た実用的な強誘電性薄膜を実現したものである。強誘電
体の中でもペロブスカイト型構造を有するものは、圧電
・焦電等の各種特性に優れるため、多結晶セラミックス
材料としての応用が栄んに行われている。従ってこの材
料のエピタキシャル薄膜は、良好な特性を有するものと
して期待される。ペロブスカイト型強誘電体の結晶系は
立方晶からわずかに歪んだ正方晶，斜方晶，三方晶等の
形をとる。一方サファイアは前記ペロブスカイト型強誘
電体とはまるで異った結晶構造であるが、Ｃ面(0001)を
見た場合その酸素配置はペロブスカイト型の(111)面と
似ており、特にサファイアＣ面が持つ３回対称軸は、立
方晶系の(111)面が持つものと同等のものである。本発
明者等は、サファイアＣ面上に立方晶系の金属の(111)
面をエピタキシャル成長させた後、ペロブスカイト型強
誘電体材料の成膜を行えば良好に(111)面がエピタキシ
ャル成長するという発見に基づき本発明を行った。これ
によりエピタキシャル薄膜を金属電極で挾んだ積層構造
が可能となった。それに加えて本発明が優れているの
は、本来立方晶から少し歪んだ結晶構造を持つ強誘電体
が、基板の３回対称軸を反映してエピタキシャル成長す
るため、歪が膜厚方向にのみ誘起されるということであ
る。従って分極方向は膜厚方向に向きやすくなってお
り、前記金属電極と強誘電体薄膜上に形成された電極と
で分極処理を施すと、本来の材料が持つ特性以上の良好
な特性の強誘電性薄膜が実現出来た。Action The present invention realizes a practical ferroelectric thin film that maximizes the characteristics of the material with the above configuration. Among the ferroelectrics, those having a perovskite structure are excellent in various characteristics such as piezoelectricity and pyroelectricity, and are therefore extensively applied as polycrystalline ceramic materials. Therefore, epitaxial thin films of this material are expected to have good properties. The crystal system of perovskite-type ferroelectrics is tetragonal, orthorhombic, or trigonal, which is slightly distorted from cubic. On the other hand, sapphire has a completely different crystal structure from the perovskite-type ferroelectric substance, but when looking at the C-plane (0001), its oxygen arrangement is similar to that of the perovskite-type (111) plane, and especially the sapphire C-plane. The 3-fold axis of symmetry of is the same as that of the cubic (111) plane. The present inventors have found that a cubic metal (111)
The present invention was carried out based on the discovery that if the perovskite type ferroelectric material is deposited after the epitaxial growth of the plane, the (111) plane is favorably epitaxially grown. This enabled a laminated structure in which the epitaxial thin film was sandwiched by metal electrodes. In addition, the present invention is superior in that a ferroelectric substance having a crystal structure that is originally slightly distorted from a cubic crystal epitaxially grows by reflecting the 3-fold symmetry axis of the substrate, so that strain is induced only in the film thickness direction. Is to be done. Therefore, the polarization direction tends to be oriented in the film thickness direction. When the polarization treatment is performed between the metal electrode and the electrode formed on the ferroelectric thin film, the ferroelectric property having better characteristics than the original material has. Thin film was realized.
また本発明において、立方晶系の金属材料として、白金
または金を用いると、サファイア基板上に良好に(111)
面が成長し、さらにその上にペロブスカイト型強誘電体
の(111)面もエピタキシャル成長が非常に良質の結晶性
で再現性良く確認された。Further, in the present invention, when platinum or gold is used as the cubic metal material, it is possible to favorably (111) on the sapphire substrate.
It has been confirmed that the epitaxial growth of the (111) plane of the perovskite-type ferroelectrics is very good and the crystallinity is very good.
またこの種の強誘電体材料としては、少なくとも鉛，ラ
ンタニウムのうち１種およびジルコニウム，チタニウム
のうち１種を含む酸化物であるＰＬＺＴ系材料が、種々
の良好な特性を有し、また再現性よく(111)面がエピタ
キシャル成長することを本発明者等は確認した。As this type of ferroelectric material, a PLZT-based material, which is an oxide containing at least one of lead and lanthanum and one of zirconium and titanium, has various good characteristics and has good reproducibility. The present inventors have confirmed that the (111) plane is often epitaxially grown.
実施例 本発明の内容のより深い理解のために、以下具体的な実
施例により本発明を説明する。ＰＬＺＴ化合物のうちPb
0.92La0.08(Zr0.65Ti0.35)0.98O3で表わされる組成のも
のは、非常に大きな電気光学効果を有し薄膜化により光
集積デバイスへの応用が期待される。さらにこの薄膜に
おいて圧電特性も確認されれば、音響光学効果も合わせ
持った材料として、さらに魅力的なデバイスの可能性を
切り開くものとなる。EXAMPLES The present invention will be described below with reference to specific examples for a deeper understanding of the content of the present invention. Pb among PLZT compounds
The composition represented by 0.92 La 0.08 (Zr 0.65 Ti 0.35 ) 0.98 O 3 has a very large electro-optical effect and is expected to be applied to an optical integrated device by thinning the film. Furthermore, if piezoelectric properties are confirmed in this thin film, it will open up the possibility of an even more attractive device as a material that also has an acousto-optic effect.
この材料を用いて本発明による強誘電性薄膜の作製を行
った。図に構成を示す。まずサファイアＣ面基板１１上
に、アルゴン雰囲気でガス圧5Pa，基板温度３５０℃，
入力電力５０Ｗの条件のもとでスパッタリングによるPt
の成膜を行った。２０分スパッタを行うと1500AのPtの
(111)面エピタキシャル薄膜１２が得られた。次にPb
0.92La0.08(Zr0.65Ti0.35)0.98O3を粉末をターゲットに
用いて、酸素とアルゴン（１：１）の雰囲気ガスのもと
で、ガス圧0.5Pa，基板温度６００℃，入力電力２００
Ｗの条件でスパッタを行い前記Pt／サファイア上に成膜
を行った。１時間のスパッタリングにより4000Aの(111)
面エピタキシャル薄膜１３が作製出来た。薄膜１３上に
形成されたアルミ電極１４とPt金属薄膜１２間に5KV／m
mの直流電界を加えて２００℃から徐冷して、分極処理
を行った。アルミ電極１４の微細エッチングを行って電
極間隔２μｍ，対数４０本の櫛型対向電極をつくり、弾
性表面波を励振させた。電気機械結合係数K2２％とい
うこの種の材料の薄膜では得られていない大きな値が得
られ、良好な圧電性が確認された。すなわち本発明の構
成により、従来にない良好な強誘電性薄膜が実現出来
た。A ferroelectric thin film according to the present invention was manufactured using this material. The structure is shown in the figure. First, on a sapphire C-plane substrate 11, a gas pressure of 5 Pa, a substrate temperature of 350 ° C. in an argon atmosphere,
Pt by sputtering under the condition of input power 50W
Was formed. When sputtered for 20 minutes, Pt of 1500A
A (111) plane epitaxial thin film 12 was obtained. Then Pb
0.92 La 0.08 (Zr 0.65 Ti 0.35 ) 0.98 O 3 was used as a target, and under an atmosphere gas of oxygen and argon (1: 1), a gas pressure of 0.5 Pa, a substrate temperature of 600 ° C., and an input power of 200
Sputtering was performed under the condition of W to form a film on the Pt / sapphire. 4000A (111) by sputtering for 1 hour
The plane epitaxial thin film 13 could be produced. 5KV / m between aluminum electrode 14 and Pt metal thin film 12 formed on thin film 13
A direct current electric field of m was added and the mixture was gradually cooled from 200 ° C. for polarization treatment. The aluminum electrode 14 was finely etched to form a comb-shaped counter electrode having an electrode interval of 2 μm and a logarithm of 40, and a surface acoustic wave was excited. A large value of the electromechanical coupling coefficient K 2 2%, which was not obtained in the thin film of this kind of material, was obtained, and good piezoelectricity was confirmed. That is, with the structure of the present invention, a good ferroelectric thin film which has never been obtained can be realized.
発明の効果 以上のように本発明の強誘電性薄膜は、その材料の特性
を充分に引き出した良好な特性を示し、かつ実用的な電
極で挾んだ積層構造を有する薄膜の構成を提供するもの
であり、本発明の工業的価値は高い。EFFECTS OF THE INVENTION As described above, the ferroelectric thin film of the present invention provides a structure of a thin film which exhibits good characteristics by sufficiently drawing out the characteristics of the material and has a laminated structure sandwiched by practical electrodes. However, the industrial value of the present invention is high.
図は本発明の一実施例における強誘電性薄膜の構成図で
ある。 １１……サファイアＣ面基板、１２……Ptの(111)面エ
ピタキシャル薄膜、１３……Pb0.92La0.08(Zr0.65Ti
0.35)0.98O3(111)面エピタキシャル薄膜、１４……アル
ミ電極。FIG. 1 is a block diagram of a ferroelectric thin film in one embodiment of the present invention. 11 ... Sapphire C-plane substrate, 12 ... Pt (111) plane epitaxial thin film, 13 ... Pb 0.92 La 0.08 (Zr 0.65 Ti
0.35 ) 0.98 O 3 (111) plane epitaxial thin film, 14 …… Aluminum electrode.
Claims (3)
と、その上にエピタキシャル成長した立方晶金属(111)
面薄膜と、さらにその上にエピタキシャル成長したペロ
ブスカイト型強誘電体の(111)面薄膜で構成され、前記
立方晶金属薄膜と、前記強誘電体薄膜上に形成された任
意の電極により、膜厚方向に分極処理して得られること
を特徴とする強誘電性薄膜。1. A sapphire C plane (α-A 2 O 3 (0001) plane)
And cubic metal (111) epitaxially grown on it
Plane thin film and a (111) plane thin film of a perovskite type ferroelectric further epitaxially grown on the plane thin film, and by the cubic metal thin film and any electrode formed on the ferroelectric thin film, A ferroelectric thin film obtained by subjecting a thin film to polarization treatment.
あることを特徴とする特許請求の範囲第１項記載の強誘
電性薄膜。2. The ferroelectric thin film according to claim 1, wherein the cubic metal is platinum (Pt) or gold (Au).
鉛，ランタニウムのうち１種およびジルコニウム，チタ
ニウムのうち１種を含む酸化物であることを特徴とする
特許請求の範囲第１項記載の強誘電性薄膜。3. The ferroelectric according to claim 1, wherein the perovskite type ferroelectric is an oxide containing at least one kind of lead and lanthanum and one kind of zirconium and titanium. Thin film.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP29385785A JPH0646524B2 (en) | 1985-12-26 | 1985-12-26 | Ferroelectric thin film |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP29385785A JPH0646524B2 (en) | 1985-12-26 | 1985-12-26 | Ferroelectric thin film |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS62154407A JPS62154407A (en) | 1987-07-09 |
| JPH0646524B2 true JPH0646524B2 (en) | 1994-06-15 |
Family
ID=17800052
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP29385785A Expired - Lifetime JPH0646524B2 (en) | 1985-12-26 | 1985-12-26 | Ferroelectric thin film |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0646524B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2005078169A1 (en) * | 2004-02-18 | 2005-08-25 | Dai Nippon Printing Co., Ltd. | Corundum crystal formed item |
-
1985
- 1985-12-26 JP JP29385785A patent/JPH0646524B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPS62154407A (en) | 1987-07-09 |
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