JPH0446081A - Formation of oxide superconducting thin film - Google Patents
Formation of oxide superconducting thin filmInfo
- Publication number
- JPH0446081A JPH0446081A JP2154207A JP15420790A JPH0446081A JP H0446081 A JPH0446081 A JP H0446081A JP 2154207 A JP2154207 A JP 2154207A JP 15420790 A JP15420790 A JP 15420790A JP H0446081 A JPH0446081 A JP H0446081A
- Authority
- JP
- Japan
- Prior art keywords
- thin film
- substrate
- laser
- oxide superconducting
- chamber
- 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.)
- Pending
Links
- 239000010409 thin film Substances 0.000 title claims abstract description 31
- 230000015572 biosynthetic process Effects 0.000 title claims description 13
- 239000000758 substrate Substances 0.000 claims abstract description 28
- 239000010408 film Substances 0.000 claims abstract description 17
- 238000007740 vapor deposition Methods 0.000 claims abstract description 11
- 239000002887 superconductor Substances 0.000 claims description 13
- 238000004519 manufacturing process Methods 0.000 claims description 8
- 238000001704 evaporation Methods 0.000 claims 2
- 230000008020 evaporation Effects 0.000 claims 1
- 238000000034 method Methods 0.000 abstract description 16
- 239000002994 raw material Substances 0.000 abstract description 2
- 239000013078 crystal Substances 0.000 description 6
- 238000002441 X-ray diffraction Methods 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 238000004544 sputter deposition Methods 0.000 description 2
- 229910014454 Ca-Cu Inorganic materials 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 238000000151 deposition Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
Landscapes
- Physical Vapour Deposition (AREA)
- Superconductor Devices And Manufacturing Methods Thereof (AREA)
- Inorganic Compounds Of Heavy Metals (AREA)
Abstract
Description
【発明の詳細な説明】
産業上の利用分野
本発駅は、酸化物超電導薄膜の作製方法に関する。より
詳細には、レーザ蒸着法を用いてａ軸配向またはｂ軸配
向、すなわち結晶のａ軸またはｂ軸が基板面に垂直な酸
化物超電導薄膜を作製する方法に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing oxide superconducting thin films. More specifically, the present invention relates to a method of producing an oxide superconducting thin film with an a-axis orientation or a b-axis orientation, that is, a crystal a-axis or a b-axis perpendicular to a substrate surface, using a laser deposition method.
従来の技術
Ｙ−Ｂａ−Ｃｕ−○系、Ｂｉ −３ｒ −Ｃａ−Ｃｕ
−０系およびＴｌ−Ｂａ−ロａ−Ｃｕ−０系の各酸化物
超電導体は、臨界温度が高く、実用化が有望と考えられ
ている。Conventional technology Y-Ba-Cu-○ system, Bi-3r-Ca-Cu
-0 series and Tl-Ba-roa-Cu-0 series oxide superconductors have high critical temperatures and are considered promising for practical use.
これらの酸化物超電導体を、ジョセフソン素子、超電導
トランジスタ等の電子デバイスに応用するためには、薄
膜化することが必須である。In order to apply these oxide superconductors to electronic devices such as Josephson elements and superconducting transistors, it is essential to make them thin.
一方、酸化物超電導体は、その超電導特性に異方性のあ
ることが知られており、特に、結晶のｃ軸に垂直な方向
の超電導臨界電流密度が大きい。On the other hand, oxide superconductors are known to have anisotropy in their superconducting properties, and particularly have a large superconducting critical current density in the direction perpendicular to the c-axis of the crystal.
従来、薄膜の表面に平行な方向に大きい電流を流すこと
ができる、Ｃ軸配向の酸化物超電導体薄膜を作製する研
究が多く行われてきた。その結果、スパッタリング法、
蒸着法、レーザ蒸着法等の方法で、良質なＣ軸配向の酸
化物超電導体の単結晶薄膜が得られている。Conventionally, much research has been conducted to produce C-axis oriented oxide superconductor thin films that allow a large current to flow in a direction parallel to the surface of the thin film. As a result, the sputtering method,
High quality single crystal thin films of C-axis oriented oxide superconductors have been obtained by methods such as vapor deposition and laser vapor deposition.
発明が解決しようとする課題
上記の酸化物超電導体は、コヒーレンス長にも異方性が
あり、結晶のａ軸方向およびｂＷＢ方向のコヒーレンス
長は、Ｃ軸方向のコヒーレンス長よりも長い（Ｃ軸方向
のコヒーレンス長：数人、ａ軸方向およびｂ軸方向のコ
ヒーレンス長；１０数人）従って、酸化物超電導体をエ
レクトロニクスに応用する、例えばジョセフソン接合を
作製するためには、コヒーレンス長のより長いＣ軸配向
の薄膜が必要とされている。Problems to be Solved by the Invention The above oxide superconductor also has anisotropy in coherence length, and the coherence length in the a-axis direction and bWB direction of the crystal is longer than the coherence length in the C-axis direction (C-axis Coherence length in the direction: several people, coherence length in the a-axis direction and b-axis direction: about 10 people) Therefore, in order to apply oxide superconductors to electronics, for example to create Josephson junctions, it is necessary to Thin films with long C-axis orientation are needed.
Ｃ軸配向またはｂ軸配向の酸化物超電導薄膜を、例えば
スパッタリング法で作製するには、Ｃ軸配向の酸化物超
電導薄膜を作製する場合より、基板温度を数１０℃低く
すればよいことがわかっている。It has been found that in order to fabricate a c-axis or b-axis oriented oxide superconducting thin film using, for example, sputtering, the substrate temperature can be lowered by several tens of degrees Celsius than when fabricating a c-axis oriented oxide superconducting thin film. ing.
ところが、この基板温度は低過ぎて、この基板温度で成
膜すると、薄膜を構成する酸化物超電導体の結晶性が悪
く、また、結晶に酸素が十分に供給されない。従って、
従来の方法で作製されたＣ軸配向またはｂ軸配向の酸化
物超電導薄膜の電気特性は良好ではなかった。However, this substrate temperature is too low, and when a film is formed at this substrate temperature, the crystallinity of the oxide superconductor forming the thin film is poor, and oxygen is not sufficiently supplied to the crystal. Therefore,
C-axis oriented or b-axis oriented oxide superconducting thin films produced by conventional methods have not had good electrical properties.
従って、本発明の目的は、上記従来技術の問題点を解決
して、高品質のＣ軸配向、ｂ軸配向またはａ軸およびｂ
軸の両方の配向性を有する酸化物超電導薄膜の作製方法
を提供することにある。Therefore, it is an object of the present invention to solve the above-mentioned problems of the prior art and provide high-quality C-axis orientation, b-axis orientation, a-axis orientation, and b-axis orientation.
An object of the present invention is to provide a method for producing an oxide superconducting thin film having both axial orientations.
以下、Ｃ軸配向、ｂｒＦＩＢ配向またはａｆ＃およびｂ
軸の両方の配向性を有する薄膜をａ、ｂ軸配向の薄膜と
記す。Hereinafter, C-axis orientation, brFIB orientation or af# and b
A thin film having both axes orientation is referred to as an a- and b-axis oriented thin film.
課題を解決するための手段
本発明に従うと、酸化物超電導体の薄膜を基板上にパル
スレーザによるレーザ蒸着法で作製する方法において、
以下のことをそれぞれ特徴とする方法が提供される。Means for Solving the Problems According to the present invention, in a method for producing a thin film of an oxide superconductor on a substrate by a laser vapor deposition method using a pulsed laser,
A method is provided, each characterized by the following:
■ 成膜時の前記基板温度を６２０℃以下とする。(2) The substrate temperature during film formation is 620°C or less.
■ 成膜中の圧力を２００ｍＴｏｒｒ以下とする。■ The pressure during film formation is 200 mTorr or less.
■ 成膜時の前記基板温度を６２０℃以下とし、成膜中
の圧力を２００ｍＴｏｒｒ以下とする。(2) The temperature of the substrate during film formation is 620° C. or less, and the pressure during film formation is 200 mTorr or less.
作用
本発明の方法では、パルスレーザによるレーザ蒸着法を
使用して、基板上に、ａ、ｂ軸配向の酸化物超電導薄膜
を作製する。本発明の方法では、成膜時の基板温度が６
２０℃以下である。６２０℃を超える基板温度で成膜し
た場合には、Ｃ軸配向の薄膜となる。Operation In the method of the present invention, an oxide superconducting thin film with a- and b-axis orientation is fabricated on a substrate using a laser vapor deposition method using a pulsed laser. In the method of the present invention, the substrate temperature during film formation is 6.
The temperature is below 20°C. If the film is formed at a substrate temperature exceeding 620° C., the film will be C-axis oriented.
本発明の方法では、成膜中の圧力を２００ｍＴｏｒｒ以
下とする。成膜中の圧力が２００ｍＴｏｒｒを超えた場
合には、プラズマの状態が変化し、Ｃ軸配向またはＣ軸
配向とａＸｂ軸配向が混在する薄膜となる。In the method of the present invention, the pressure during film formation is 200 mTorr or less. If the pressure during film formation exceeds 200 mTorr, the state of the plasma changes, resulting in a thin film with C-axis orientation or a mixture of C-axis and aXb-axis orientations.
本発明の方法で使用するレーザは、例えばエキシマレー
ザ、ＣＯ２レーザ等の高畠力が可能なものが好ましい。The laser used in the method of the present invention is preferably one capable of high power, such as an excimer laser or a CO2 laser.
以下、本発明を実施例により、さらに詳しく説明するが
、以下の開示は本発明の単なる実施例に過ぎず、本発明
の技術的範囲をなんら制限するものではない。EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples, but the following disclosure is merely an example of the present invention and does not limit the technical scope of the present invention in any way.
実施例
第１図に本発明の方法を実現するレーザ蒸着装置の一例
を示す。第１図のレーザ蒸着装置では、レーザ装置１０
て発生されたレーザ光がレンズ６によって集光され、チ
ャンバ１のレーザ光入射窓９に入射し、チャンバ１内に
収納されている原料ターゲット５を照射する。レーザ族
＠１０はパルスレーザ光を発振し、ターゲット５を照射
する。チャンバ１は、内部を高真空に排気可能で、ター
ゲット５に対向するように基板ホルダ３に基板２が固定
されている。基板ホルダ３内には、基板２を加熱するヒ
ータ４が備えられている。Embodiment FIG. 1 shows an example of a laser vapor deposition apparatus for realizing the method of the present invention. In the laser vapor deposition apparatus shown in FIG.
The generated laser light is focused by a lens 6, enters a laser light entrance window 9 of the chamber 1, and irradiates the raw material target 5 housed in the chamber 1. The laser group @10 oscillates pulsed laser light and irradiates the target 5. The chamber 1 can be evacuated to a high vacuum, and a substrate 2 is fixed to a substrate holder 3 so as to face a target 5 . A heater 4 for heating the substrate 2 is provided inside the substrate holder 3 .
本発明の方法で、Ｙ１Ｂａ２Ｃｕ３Ｏ７−Ｘ酸化物超電
導薄膜を作製した。主な作製条件を以下に示す。A Y1Ba2Cu3O7-X oxide superconducting thin film was produced by the method of the present invention. The main manufacturing conditions are shown below.
基 板 ５ｒＴＩＣｈ単結晶基板基板温度
６００℃
圧 力 １００ｍＴｏｒｒレーザエネ
ルギ １．２ Ｊ ／ （ｃＩＩ！・ｐｕｌｓｅ
）レーザパルスレート １ρｐｓ
本実施例では、予めチャンバ１内を５ Ｘ １Ｏ−６Ｔ
ｏｒｒまで排気してから、０２を併給して上記の圧力を
保って蒸着を行った。それぞれの酸化物超電導薄膜を草
さ２００ ｎｍまで成長させ、冷却速度４℃／分で室温
まで冷却した。成膜後には、−切の熱処理を行わなかっ
た。Substrate 5rTICh single crystal substrate substrate temperature
600℃ Pressure 100mTorr Laser energy 1.2 J/(cII!・pulse
) Laser pulse rate 1ρps In this example, the inside of the chamber 1 is
After evacuation to orr, 02 was fed together to maintain the above pressure for vapor deposition. Each oxide superconducting thin film was grown to a thickness of 200 nm and cooled to room temperature at a cooling rate of 4° C./min. After film formation, -cutting heat treatment was not performed.
得られた酸化物超電導薄膜をＸ線回折により解析したと
ころ、第２図に示すよう結晶性のよいａ軸配向の薄膜で
あった。また、この酸化物超電導薄膜の超電導特性の測
定を行ったところ、以下の第１表に示す結果が得られた
。When the obtained oxide superconducting thin film was analyzed by X-ray diffraction, it was found to be an a-axis oriented thin film with good crystallinity, as shown in FIG. Furthermore, when the superconducting properties of this oxide superconducting thin film were measured, the results shown in Table 1 below were obtained.
第１表
発明の効果
以上詳述のように、本発明の方法によれば、従来よりも
簡便にａ軸配向の酸化物超電導薄膜が作製可能である。Table 1 Effects of the Invention As detailed above, according to the method of the present invention, an a-axis oriented oxide superconducting thin film can be produced more easily than before.
本発明の方法は、隼に成膜条件の制御を行うだけである
ので、従来の方法と較べてコストが特に上昇することも
ない。Since the method of the present invention simply controls the film forming conditions, there is no particular increase in cost compared to conventional methods.
本発明により、特にエレクトロニクス分野への酸化物超
電導体の応用が促進される。The present invention particularly facilitates the application of oxide superconductors to the electronics field.
第１図は、本発明の方法を実現するレーザ蒸着装置の一
例の概略図であり、
第２図は、本発明の方法により作製された酸化物超電導
薄膜のＸ線回折による分析結果を示すグラフである。
〔主な参照番号〕
１・・・チャンバ、
２・・・基板、
３・・・基板ホルダ、
ヒータ、
ターゲット、
レンズ、
レーザ光入射窓、
レーザ装置FIG. 1 is a schematic diagram of an example of a laser vapor deposition apparatus that implements the method of the present invention, and FIG. 2 is a graph showing the results of X-ray diffraction analysis of the oxide superconducting thin film produced by the method of the present invention. It is. [Main reference numbers] 1...Chamber, 2...Substrate, 3...Substrate holder, heater, target, lens, laser beam entrance window, laser device
Claims (3)
よるレーザ蒸着法で作製する方法において、成膜時の前
記基板温度を６２０℃以下とすることを特徴とする酸化
物超電導薄膜の作製方法。(1) A method for producing an oxide superconductor thin film on a substrate by laser evaporation using a pulsed laser, characterized in that the substrate temperature during film formation is 620°C or less. .
よるレーザ蒸着法で作製する方法において、成膜中の圧
力を２００ｍＴｏｒｒ以下とすることを特徴とする酸化
物超電導薄膜の作製方法。(2) A method for producing an oxide superconductor thin film on a substrate by a laser evaporation method using a pulsed laser, characterized in that the pressure during film formation is 200 mTorr or less.
よるレーザ蒸着法で作製する方法において、成膜時の前
記基板温度を６２０℃以下とし、成膜中の圧力を２００
ｍＴｏｒｒ以下とすることを特徴とする酸化物超電導薄
膜の作製方法。(3) In a method for producing a thin film of an oxide superconductor on a substrate by laser vapor deposition using a pulsed laser, the substrate temperature during film formation is 620°C or less, and the pressure during film formation is 200°C.
A method for producing an oxide superconducting thin film, characterized in that the pressure is less than or equal to mTorr.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2154207A JPH0446081A (en) | 1990-06-13 | 1990-06-13 | Formation of oxide superconducting thin film |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2154207A JPH0446081A (en) | 1990-06-13 | 1990-06-13 | Formation of oxide superconducting thin film |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0446081A true JPH0446081A (en) | 1992-02-17 |
Family
ID=15579186
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2154207A Pending JPH0446081A (en) | 1990-06-13 | 1990-06-13 | Formation of oxide superconducting thin film |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0446081A (en) |
-
1990
- 1990-06-13 JP JP2154207A patent/JPH0446081A/en active Pending
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