JPH0648895A - Production of oxide ferroelectric thin film and oxide ferroelectric material - Google Patents
Production of oxide ferroelectric thin film and oxide ferroelectric materialInfo
- Publication number
- JPH0648895A JPH0648895A JP4200061A JP20006192A JPH0648895A JP H0648895 A JPH0648895 A JP H0648895A JP 4200061 A JP4200061 A JP 4200061A JP 20006192 A JP20006192 A JP 20006192A JP H0648895 A JPH0648895 A JP H0648895A
- Authority
- JP
- Japan
- Prior art keywords
- thin film
- oxide
- oxide ferroelectric
- buffer layer
- substrate
- 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.)
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- Crystals, And After-Treatments Of Crystals (AREA)
- Inorganic Insulating Materials (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、酸化物強誘電薄膜の製
造方法および基板上に酸化物強誘電薄膜を形成してなる
酸化物強誘電材料に関するものである。さらに詳しく
は、本発明は、光導波路素子、圧電素子、電気光学素
子、赤外線検出素子等に用いられる酸化物強誘電薄膜の
製造方法および酸化物強誘電材料に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an oxide ferroelectric thin film and an oxide ferroelectric material formed by forming an oxide ferroelectric thin film on a substrate. More specifically, the present invention relates to a method for manufacturing an oxide ferroelectric thin film used for an optical waveguide element, a piezoelectric element, an electro-optical element, an infrared detecting element, and the like, and an oxide ferroelectric material.
【０００２】[0002]
【従来の技術】エレクトロニクス、オプトエレクトロニ
クス技術の急速な発展にともない、これらの技術の基盤
としての電子材料の機能性の向上が望まれている。この
ような状況において、各種材料の微細結晶構造、精密制
御などの検討が精力的に進められており、酸化物強誘電
材料についても、機能性向上のための工夫がなされてい
る。2. Description of the Related Art With the rapid development of electronics and optoelectronic technologies, it is desired to improve the functionality of electronic materials as the basis of these technologies. Under such circumstances, studies on the fine crystal structure of various materials, precise control, and the like have been energetically advanced, and oxide ferroelectric materials have also been devised to improve their functionality.
【０００３】酸化物強誘電材料のエレクトロニクス分野
への応用のためには、薄膜化は不可欠である。特に、シ
リコン単結晶基板上に酸化物強誘電材料をエピタキシャ
ル成長させることが期待されている。しかしながら、酸
化物強誘電材料をシリコン単結晶基板表面上に直接成形
しようとすると、酸化物強誘電材料内にシリコンが拡散
したり、酸化物強誘電材料の構成原子がシリコン中に拡
散するなどして良質の酸化物強誘電薄膜を得ることがで
きなかった。Thin film formation is indispensable for application of oxide ferroelectric materials to the electronics field. In particular, it is expected that an oxide ferroelectric material will be epitaxially grown on a silicon single crystal substrate. However, when an oxide ferroelectric material is directly formed on the surface of a silicon single crystal substrate, silicon diffuses into the oxide ferroelectric material or constituent atoms of the oxide ferroelectric material diffuse into the silicon. Therefore, a good quality oxide ferroelectric thin film could not be obtained.
【０００４】そこで、白金等の金属材料や熱処理してで
きる二酸化珪素膜をシリコン単結晶表面上に緩衝層とし
て形成し、原子拡散の障壁とする方法が考えられるが、
いずれの場合も障壁としての機能が充分でなく、良質の
酸化物強誘電薄膜は得られていない。さらに、酸化物強
誘電材料をエピタキシャル成長させるという点からみて
も、これらの材料からなる緩衝層を用いることは最適な
方法であるとは言いがたいのが実情である。Therefore, a method is conceivable in which a metal material such as platinum or a silicon dioxide film formed by heat treatment is formed as a buffer layer on the surface of a silicon single crystal to serve as a barrier for atomic diffusion.
In either case, the function as a barrier is not sufficient, and a good oxide ferroelectric thin film has not been obtained. Further, from the viewpoint of epitaxially growing an oxide ferroelectric material, it is difficult to say that using a buffer layer made of these materials is the optimum method.
【０００５】[0005]
【発明が解決しようとする課題】上述したように、従来
の酸化物強誘電材料においては、シリコン単結晶基板上
の緩衝層の原子拡散抑制の能力が実用的レベルにないと
いう問題点があった。本発明の目的は、シリコン単結晶
基板上に良質の酸化物強誘電材料を得るのに適した製造
方法を提供することにある。As described above, the conventional oxide ferroelectric materials have a problem that the buffer layer on the silicon single crystal substrate does not have a practical level of suppressing the atomic diffusion. . An object of the present invention is to provide a manufacturing method suitable for obtaining a good quality oxide ferroelectric material on a silicon single crystal substrate.
【０００６】[0006]
【課題を解決するための手段】上記の課題を解決するた
めに、酸化物強誘電薄膜をシリコン単結晶基板上に相互
の反応なしに形成するには、著しく高い原子拡散抑制の
能力を持つと同時に酸化物強誘電材料をエピタキシャル
成長させるのに適した格子定数を持った緩衝層を用いる
と良い。In order to solve the above problems, in order to form an oxide ferroelectric thin film on a silicon single crystal substrate without mutual reaction, it is necessary to have a remarkably high atomic diffusion suppressing ability. At the same time, it is preferable to use a buffer layer having a lattice constant suitable for epitaxially growing the oxide ferroelectric material.
【０００７】本発明者らは、酸化亜鉛が自然に〔０００
１〕方向に配向して成長し、また、格子定数が酸化物強
誘電材料の格子定数に近いこと、さらに透明下部電極に
なりうることに着目し、図１に示すように、これを酸化
物強誘電材料を成膜するための緩衝層とし、本発明を成
すに至った。よって、本発明は、基板上に、緩衝層とし
て〔０００１〕配向した酸化亜鉛薄膜を形成後、該緩衝
層表面上に酸化物強誘電薄膜を〔１１１〕配向させて成
長させたことを特徴とする酸化物強誘電薄膜の製造方法
を提供するものである。The present inventors have found that zinc oxide is naturally [000
1] direction and grow, the lattice constant is close to the lattice constant of the oxide ferroelectric material, and it can be a transparent lower electrode. As shown in FIG. The present invention has been completed as a buffer layer for forming a ferroelectric material film. Therefore, the present invention is characterized in that after forming a [0001] -oriented zinc oxide thin film as a buffer layer on a substrate, an oxide ferroelectric thin film is [111] -oriented and grown on the surface of the buffer layer. A method for manufacturing an oxide ferroelectric thin film is provided.
【０００８】また、本発明は、基板と、〔０００１〕方
向に配向した酸化亜鉛薄膜と、〔１１１〕方向に配向し
た酸化物強誘電薄膜とからなる酸化物強誘電材料を提供
するものである。The present invention also provides an oxide ferroelectric material comprising a substrate, a zinc oxide thin film oriented in the [0001] direction, and an oxide ferroelectric thin film oriented in the [111] direction. .
【０００９】[0009]
【作用】本発明に用いられる基板は、半導体、金属、誘
電体などからなる結晶あるいはアモルファス基板のいず
れでもよい。緩衝層である酸化亜鉛は、六方晶系の結晶
構造を持っており、薄膜を成膜する際、基板の表面構造
にかかわらず〔０００１〕方向に配向して成長すること
が知られている。図２に示すように、〔０００１〕方向
に配向した酸化亜鉛の（０００１）面の２次元構造は六
回対称性を有しており、その一辺であるａ軸が 0.325ｎ
ｍの格子定数をもつ。一方、多くの酸化物強誘電材料の
（１１１）面の結晶構造は、酸化亜鉛と同様の構造を持
つか極めて近い構造を持ち、その一辺は約 0.6ｎｍであ
る。即ち、酸化亜鉛の（０００１）面のａ軸の２倍であ
る0.65ｎｍを繰り返し単位と考えれば、酸化物強誘電薄
膜の（１１１）面の繰り返し単位 0.6ｎｍとの格子不整
合は10％程度である。従って、酸化亜鉛（０００１）面
へ酸化物強誘電材料をエピタキシャル成長させることが
可能となる。The substrate used in the present invention may be a crystalline or amorphous substrate made of semiconductor, metal, dielectric or the like. Zinc oxide, which is a buffer layer, has a hexagonal crystal structure, and it is known that when a thin film is formed, it grows while being oriented in the [0001] direction regardless of the surface structure of the substrate. As shown in FIG. 2, the two-dimensional structure of the (0001) plane of zinc oxide oriented in the [0001] direction has six-fold symmetry, and one side of the a-axis is 0.325n.
It has a lattice constant of m. On the other hand, the crystal structure of the (111) plane of many oxide ferroelectric materials has a structure similar to or very close to that of zinc oxide, and one side thereof is about 0.6 nm. That is, if 0.65 nm, which is twice the a-axis of the (0001) plane of zinc oxide, is considered as the repeating unit, the lattice mismatch with the repeating unit of 0.6 nm on the (111) plane of the oxide ferroelectric thin film is about 10%. Is. Therefore, it becomes possible to epitaxially grow the oxide ferroelectric material on the zinc oxide (0001) plane.
【００１０】また、酸化物強誘電材料を直接シリコン単
結晶基板、あるいは表面が酸化された（酸化膜が形成さ
れた）シリコン単結晶基板、あるいは白金等の金属薄膜
を形成したシリコン単結晶基板上に形成すると、酸化物
強誘電材料の構成原子である鉛などが緩衝層中に拡散し
てシリコン基板まで達してしまうことが多い。この場合
には、酸化物強誘電材料の組成が変化し、強誘電性のな
いパイロクロア結晶相が生成する。Further, the oxide ferroelectric material is directly on a silicon single crystal substrate, a silicon single crystal substrate whose surface is oxidized (on which an oxide film is formed), or a silicon single crystal substrate on which a metal thin film such as platinum is formed. When it is formed, the lead atoms, which are the constituent atoms of the oxide ferroelectric material, often diffuse into the buffer layer and reach the silicon substrate. In this case, the composition of the oxide ferroelectric material changes, and a pyrochlore crystal phase having no ferroelectric property is generated.
【００１１】これに対して、シリコン単結晶基板（酸化
膜が形成されたもの、金属薄膜が形成されたものの場合
には、その表面）と酸化物強誘電薄膜との間に緩衝層と
して酸化亜鉛薄膜を形成した場合には、拡散による酸化
物強誘電材料の組成変化は起こらず、適切な処理温度に
より強誘電性をもつペロブスカイト結晶相が生成する。
形成された酸化物薄膜がほぼ 100％ペロブスカイト結晶
構造を持つことにより初めて強誘電材料としての特性を
充分に引き出すことができる。On the other hand, zinc oxide is used as a buffer layer between a silicon single crystal substrate (the surface of which is formed with an oxide film or a metal thin film, and its surface) and the oxide ferroelectric thin film. When a thin film is formed, the composition change of the oxide ferroelectric material due to diffusion does not occur, and a perovskite crystal phase having ferroelectricity is generated at an appropriate processing temperature.
Only when the formed oxide thin film has almost 100% perovskite crystal structure, the characteristics as a ferroelectric material can be fully obtained.
【００１２】本発明において基板上に緩衝層である酸化
亜鉛を成膜する方法は、スパッタリング法、真空蒸着
法、ＭＯ−ＣＶＤ法、レーザーアブソレーション法、ゾ
ルゲル法等のいかなる方法を用いても良い。以下、実施
例に本発明を具体的に説明するが、本発明はこれに限ら
れるものではない。In the present invention, any method such as a sputtering method, a vacuum vapor deposition method, a MO-CVD method, a laser ablation method, a sol-gel method or the like may be used as a method for forming a zinc oxide film as a buffer layer on a substrate. . Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited thereto.
【００１３】[0013]
【実施例】真空槽中、圧力10-3Torr（アルゴン90％、酸
素10％）下において、酸化亜鉛をターゲットとするスパ
ッタリング法でシリコン単結晶基板上に基板温度 500℃
で〔０００１〕方向に配向させた酸化亜鉛緩衝層を厚さ
１μｍ成長させた。その酸化亜鉛緩衝層上に、同様に圧
力10-3Torr（アルゴン90％、酸素10％）下において、ジ
ルコニウム酸チタン酸鉛（ＰＺＴ）焼結体をターゲット
とするスパッタリング法により基板温度 500℃で、厚さ
0.5μｍのＰＺＴ薄膜をエピタキシャル成長させた。Ｘ
線回折法により、得られたＰＺＴ薄膜が〔１１１〕方向
に配向していることを確認した。[Example] In a vacuum chamber, under a pressure of 10 -3 Torr (90% argon, 10% oxygen), a substrate temperature of 500 ° C. was formed on a silicon single crystal substrate by a sputtering method using zinc oxide as a target.
Then, a zinc oxide buffer layer oriented in the [0001] direction was grown to a thickness of 1 μm. On the zinc oxide buffer layer, similarly, under a pressure of 10 -3 Torr (90% argon, 10% oxygen), a substrate temperature of 500 ° C was obtained by a sputtering method using a lead zirconate titanate (PZT) sintered body as a target. ,thickness
A 0.5 μm PZT thin film was epitaxially grown. X
It was confirmed by a line diffraction method that the obtained PZT thin film was oriented in the [111] direction.
【００１４】[0014]
【発明の効果】以上のように、本発明によれば、シリコ
ン基板に直接、酸化物強誘電薄膜を形成できるのみでな
く、表面に酸化珪素膜を持つシリコン基板、ガリウム砒
素基板などにも配向膜（酸化物強誘電薄膜）を形成でき
る。さらに、本発明においては、緩衝層である酸化亜鉛
薄膜が透明電極となるため、光導波路などの光学的応用
においても光の吸収による光学損失に影響を与えること
なく応用することができる。As described above, according to the present invention, not only can an oxide ferroelectric thin film be formed directly on a silicon substrate, but it can also be oriented on a silicon substrate having a silicon oxide film on its surface, a gallium arsenide substrate, or the like. A film (oxide ferroelectric thin film) can be formed. Further, in the present invention, since the zinc oxide thin film as the buffer layer serves as a transparent electrode, it can be applied to optical applications such as optical waveguides without affecting the optical loss due to absorption of light.
【図１】 本発明に係る酸化物強誘電薄膜の断面図であ
る。FIG. 1 is a cross-sectional view of an oxide ferroelectric thin film according to the present invention.
【図２】 酸化亜鉛（０００１）面と酸化物強誘電薄膜
（１１１）面結晶構造および格子定数の整合性を説明し
た図である。FIG. 2 is a diagram for explaining conformity between a zinc oxide (0001) plane and an oxide ferroelectric thin film (111) plane crystal structure and a lattice constant.
１ 基板 ２ 〔０００１〕方向に配向した酸化亜鉛緩衝層 ３ 〔１１１〕方向に配向した酸化物強誘電薄膜 ４ 酸化物強誘電薄膜（１１１）の格子 ５ 酸化亜鉛（０００１）の格子 1 substrate 2 zinc oxide buffer layer oriented in [0001] direction 3 oxide ferroelectric thin film oriented in [111] direction 4 lattice of oxide ferroelectric thin film (111) 5 lattice of zinc oxide (0001)
Claims (4)
に配向した酸化亜鉛薄膜を形成後、該緩衝層表面上に酸
化物強誘電薄膜を〔１１１〕方向に配向させて成長させ
たことを特徴とする酸化物強誘電薄膜の製造方法。1. A zinc oxide thin film oriented in the [0001] direction is formed as a buffer layer on a substrate, and an oxide ferroelectric thin film is grown on the surface of the buffer layer in the [111] direction. And a method for producing an oxide ferroelectric thin film.
〔０００１〕方向に配向した酸化亜鉛薄膜を形成後、該
緩衝層表面上にペロブスカイト型鉛系複合酸化物薄膜を
〔１１１〕方向に配向させて成長させたことを特徴とす
るペロブスカイト型鉛系複合酸化物強誘電薄膜の製造方
法。2. A zinc oxide thin film oriented in the [0001] direction is formed as a buffer layer on a silicon single crystal substrate, and a perovskite type lead-based complex oxide thin film is oriented in the [111] direction on the surface of the buffer layer. A method of manufacturing a perovskite-type lead-based complex oxide ferroelectric thin film, which is characterized in that it is grown.
亜鉛薄膜と、〔１１１〕方向に配向した酸化物強誘電薄
膜とからなる酸化物強誘電材料。3. An oxide ferroelectric material comprising a substrate, a zinc oxide thin film oriented in the [0001] direction, and an oxide ferroelectric thin film oriented in the [111] direction.
に配向した酸化亜鉛薄膜と、〔１１１〕方向に配向した
ペロブスカイト型鉛系複合酸化物強誘電薄膜とからなる
ペロブスカイト型鉛系複合酸化物強誘電材料。4. A perovskite-type lead-based complex oxide comprising a silicon single crystal substrate, a zinc oxide thin film oriented in the [0001] direction, and a perovskite-type lead-based complex oxide ferroelectric film oriented in the [111] direction. Ferroelectric material.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4200061A JPH0648895A (en) | 1992-07-28 | 1992-07-28 | Production of oxide ferroelectric thin film and oxide ferroelectric material |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4200061A JPH0648895A (en) | 1992-07-28 | 1992-07-28 | Production of oxide ferroelectric thin film and oxide ferroelectric material |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0648895A true JPH0648895A (en) | 1994-02-22 |
Family
ID=16418193
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP4200061A Pending JPH0648895A (en) | 1992-07-28 | 1992-07-28 | Production of oxide ferroelectric thin film and oxide ferroelectric material |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0648895A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2000051175A1 (en) * | 1999-02-26 | 2000-08-31 | Symetrix Corporation | Method for fabricating ferroelectric field effect transistor |
| US7215162B2 (en) | 2002-09-25 | 2007-05-08 | Denso Corporation | Start signal outputting circuit |
-
1992
- 1992-07-28 JP JP4200061A patent/JPH0648895A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2000051175A1 (en) * | 1999-02-26 | 2000-08-31 | Symetrix Corporation | Method for fabricating ferroelectric field effect transistor |
| US6255121B1 (en) | 1999-02-26 | 2001-07-03 | Symetrix Corporation | Method for fabricating ferroelectric field effect transistor having an interface insulator layer formed by a liquid precursor |
| US6469334B2 (en) | 1999-02-26 | 2002-10-22 | Symetrix Corporation | Ferroelectric field effect transistor |
| US7215162B2 (en) | 2002-09-25 | 2007-05-08 | Denso Corporation | Start signal outputting circuit |
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