JP2776362B2 - Method of forming oxide superconductor thin film - Google Patents
Method of forming oxide superconductor thin filmInfo
- Publication number
- JP2776362B2 JP2776362B2 JP8052877A JP5287796A JP2776362B2 JP 2776362 B2 JP2776362 B2 JP 2776362B2 JP 8052877 A JP8052877 A JP 8052877A JP 5287796 A JP5287796 A JP 5287796A JP 2776362 B2 JP2776362 B2 JP 2776362B2
- Authority
- JP
- Japan
- Prior art keywords
- thin film
- oxide superconductor
- superconductor thin
- oxide
- forming
- 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
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
- Y02E40/60—Superconducting electric elements or equipment; Power systems integrating superconducting elements or equipment
Description
【発明の詳細な説明】
【０００１】
【発明の属する技術分野】本発明は、酸化物超伝導体の
薄膜の形成法に関するものである。
【０００２】
【従来の技術】Ｌａ−Ｓｒ−ＣｕＯ系、Ｙ−Ｂａ−Ｃｕ
Ｏ系を中心とする酸化物超伝導体は、従来にない高い超
伝導温度を示し、各方面で注目を集めている。
【０００３】また、現在電子素子への応力を目的とし
て、優れた特性を示す超伝導薄膜の形成方法が各方面で
研究されている。上記の酸化物超伝導体の薄膜形成に
は、現在主にスパッタ法とＭＢＥ法が用いられている。
【０００４】尚、関連する従来技術としては特開昭５２
−３９２７４５号公報がある。
【０００５】
【発明が解決しようとする課題】スパッタ法では、酸化
物超伝導体の焼結体をターゲットとし、不活性ガスある
いは酸素と不活性ガスとの混合ガス中でスパッタし、対
向する基板上に薄膜を形成する。しかし、酸化物超伝導
体を形成する各元素のスパッタ率に差があるため、薄膜
の組成の制御が難しく、焼結体のような優れた超伝導特
性を示す薄膜を形成することは難しい。また、この酸化
物超伝導体の超伝導機構は、酸素原子の欠損が重要な役
割をはたしていると言われ、薄膜形成のためには雰囲気
の酸素分圧の制御が極めて重要である。しかしながら、
スパッタ法による薄膜形成では、雰囲気圧力が制限さ
れ、雰囲気の酸素分圧の広範な制御が難しい。ＭＢＥ法
は、組成制御が容易であるが、高価な真空容器を必要と
し、かつ成膜速度が遅く、生産性に問題がある。また、
ＭＢＥ法はスパッタ法と同様に膜形成雰囲気の酸素分圧
の広範な制御が難しい。
【０００６】本発明の目的は、生産性よく良質の酸化物
超伝導薄膜を形成することにある。
【０００７】
【課題を解決するための手段】上記目的は、本超伝導機
構において極めて重要な酸素欠損を制御するために、雰
囲気の酸素分圧を、広範にかつ正確に制御しながら薄膜
を形成することにより、達成される。
【０００８】本願発明は、酸化物で超伝導を示す金属の
粉末焼結体又は合金にレーザを照射して蒸発させたもの
を雰囲気ガスとを作用させて酸化物超伝導の蒸発物と
し、この蒸発物を酸化物超伝導体として基板上に析出さ
せることを特徴とする。
【０００９】上記発明においては酸化物超伝導薄膜を形
成する雰囲気を酸素、あるいは酸素と不活性ガスの混合
ガスとすることが望ましく、また酸化物超伝導体薄膜を
形成する雰囲気の一部、あるいは全部をプラズマ状態と
することが好ましい。
【００１０】レーザ照射は、ターゲットを極部的に瞬時
に蒸発させるために、薄膜のターゲットからの組成変化
が少ない。また、レーザ加熱は雰囲気圧力、及び状態に
制限がなく、雰囲気の酸素分圧が広範に制御でき、超伝
導体薄膜の酸素欠損の制御が容易である。また、プラズ
マ化された雰囲気は、蒸発原子との反応性を高める。
【００１１】
【発明の実施の形態】以下、本発明の一実施例を図面に
より説明する。図において、１は容器、２は酸化物超伝
導体の焼結体（以後ターゲットと記す）３はレーザ発振
器、４はレーザ光、５は超伝導薄膜を形成する基板、６
はプラズマ発生のための高周波電極、７は高周波電源、
８は石英ガラス管、９は石英ガラス支持治具、１０はシ
ヤツタ、１１は膜厚測定器の測定子、１２は膜厚計、１
３は基板加熱ホルダ、１４は圧力計、１５は圧力計の測
定子、１６は真空排気装置、１７はゲートバルブ、１８
はターゲット支持治具、１９はベローズ、２０はＸＹス
テージ、２１はレーザ光導入窓、２２はストップバル
ブ、２３は流量調節バルブ、２４は高純度アルゴン、２
５は高純度酸素、２６はプラズマ領域、２７は基板加熱
用の電源、２８はアースである。
【００１２】薄膜形成手順を次に示す。
【００１３】まず、仮焼ずみ酸化物超伝導体粉末の焼結
体（ターゲット）を支持治具１８に設置し、容器内を十
分に真空排気する。なお本実施例の場合、焼結体は、共
沈法で作成した、Ｙ04Ｂａ06ＣｕＯ3粉末を焼結したも
のを用いた。またレーザは、高出力のＹＡＧレーザ（パ
ルスレーザ、平均最大出力３５０Ｗ）を用いた。
【００１４】真空排気後、容器内に高純度酸素と高純度
アルゴンの混合ガスを封入する。本実施例の場合、雰囲
気全圧力は１×１０~6〜数＋Ｔorrの範囲であり、酸素
濃度は１０〜１００％の範囲である。
【００１５】諸定の圧力までガスを封入後、高周波によ
って容器内に設置した石英ガラス管内をプラズマ化す
る。用いた高周波電源の出力は最大５００Ｗである。容
器内を上記状態にした後、ターゲットにＹＡＧレーザを
照射する。照射条件は、レーザエネルギーがパルス当り
３０Ｊ〜１００Ｊ、パルス幅が１ｍｓ〜１２ｍｓであ
る。
【００１６】基板は、上記石英管の出口に、ターゲット
に対向するように設置した。また、薄膜の接着力を増す
ためと形成した薄膜の超伝導特性を増すために、加熱ホ
ルダによって基板を約８００℃に加熱した。
【００１７】ターゲットに高出力レーザを照射すると、
ターゲットが瞬時に蒸発する。蒸発原子、分子は、石英
管中のプラズマ領域中で反応し、サフアイア基板上にた
い積して、酸化物超伝導体薄膜を形成する。膜厚は基板
の近くに設置した水晶振動型の膜厚計によって測定す
る。諸定の膜厚に達したならば、シヤツタを閉じる。
【００１８】ターゲットの全面を照射できるように、容
器の外から、ベローズを通して、ＸＹテーブルによっ
て、ターゲットを動かせるようにした。
【００１９】本実施例ではＹＡＧレーザを用いたが、タ
ーゲットを瞬時に蒸発できるエネルギがあればよく、特
にレーザの種類に制限はない。またターゲットは、酸化
物ではなく、酸化物超伝導体を形成する金属元素からな
る合金、あるいは、上記金属元素粉末の混合粉の焼結体
でもよい。あるいは、各金属元素からなる複数のターゲ
ットを容器内に設置し、各ターゲットに順次レーザを照
射する、あるいはマルチレーザで一度に照射してもよ
い。この場合、蒸発した金属原子は、プラズマ領域で反
応し、酸化物となって基板上にたい積し、薄膜を形成す
る。
【００２０】
【発明の効果】本発明によれば、ターゲットは金属でも
非金属でもよい。また雰囲気圧力の制限もないから、薄
膜形成時の雰囲気の酸素分圧が広範囲に制御できるた
め、形成した酸化物超伝導体薄膜の酸素欠損が容易に制
御でき、良質の酸化物超伝導薄膜が形成できる。さら
に、成膜速度も速く、生産性に優れる。Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a thin film of an oxide superconductor. [0002] La-Sr-CuO-based, Y-Ba-Cu
Oxide superconductors, mainly O-based materials, exhibit an unprecedentedly high superconducting temperature and have attracted attention in various fields. At present, various methods for forming superconducting thin films exhibiting excellent characteristics have been studied for the purpose of stressing electronic devices. At present, a sputtering method and an MBE method are mainly used for forming a thin film of the oxide superconductor. A related prior art is disclosed in
No. 3,392,745. In the sputtering method, a sintered body of an oxide superconductor is used as a target, and is sputtered in an inert gas or a mixed gas of oxygen and an inert gas. A thin film is formed thereon. However, since there is a difference in the sputtering rate of each element forming the oxide superconductor, it is difficult to control the composition of the thin film, and it is difficult to form a thin film having excellent superconducting properties such as a sintered body. It is said that the deficiency of oxygen atoms plays an important role in the superconducting mechanism of this oxide superconductor, and control of the oxygen partial pressure of the atmosphere is extremely important for forming a thin film. However,
In the formation of a thin film by sputtering, the atmospheric pressure is limited, and it is difficult to control the oxygen partial pressure of the atmosphere over a wide range. The MBE method is easy to control the composition, but requires an expensive vacuum vessel, has a low deposition rate, and has a problem in productivity. Also,
In the MBE method, similarly to the sputtering method, it is difficult to control the oxygen partial pressure in the film formation atmosphere over a wide range. An object of the present invention is to form a high-quality oxide superconducting thin film with good productivity. The object of the present invention is to form a thin film while controlling the oxygen partial pressure of the atmosphere over a wide range and accurately in order to control oxygen deficiency which is extremely important in the present superconducting mechanism. Is achieved by doing so. According to the present invention, an oxide superconducting metal powder sintered body or an alloy is irradiated with a laser to evaporate the powdered sintered body or alloy, and the resulting gas is allowed to act on an atmospheric gas to produce an oxide superconducting evaporate. It is characterized in that the evaporated substance is deposited on the substrate as an oxide superconductor. In the above invention, it is desirable that the atmosphere in which the oxide superconducting thin film is formed is oxygen or a mixed gas of oxygen and an inert gas. It is preferable that the whole be in a plasma state. [0010] In laser irradiation, since the target is partially and instantaneously evaporated, the composition of the thin film from the target is small. Further, the laser heating is not limited to the atmospheric pressure and the state, the oxygen partial pressure of the atmosphere can be controlled in a wide range, and the oxygen deficiency of the superconductor thin film can be easily controlled. Moreover, the atmosphere converted into plasma enhances the reactivity with the evaporated atoms. An embodiment of the present invention will be described below with reference to the drawings. In the figure, 1 is a container, 2 is a sintered body of an oxide superconductor (hereinafter referred to as a target), 3 is a laser oscillator, 4 is a laser beam, 5 is a substrate on which a superconducting thin film is formed, 6
Is a high frequency electrode for plasma generation, 7 is a high frequency power supply,
8 is a quartz glass tube, 9 is a quartz glass support jig, 10 is a shutter, 11 is a measuring element of a film thickness measuring device, 12 is a film thickness meter, 1
3 is a substrate heating holder, 14 is a pressure gauge, 15 is a measuring element of the pressure gauge, 16 is a vacuum exhaust device, 17 is a gate valve, 18
Is a target support jig, 19 is a bellows, 20 is an XY stage, 21 is a laser beam introduction window, 22 is a stop valve, 23 is a flow control valve, 24 is high purity argon, 2
5 is high-purity oxygen, 26 is a plasma region, 27 is a power supply for heating the substrate, and 28 is a ground. The procedure for forming a thin film is as follows. First, a sintered body (target) of a calcined oxide superconductor powder is set on a support jig 18 and the inside of the container is sufficiently evacuated. In the case of this example, a sintered body prepared by sintering Y 04 Ba 06 CuO 3 powder prepared by a coprecipitation method was used. As the laser, a high-output YAG laser (pulse laser, average maximum output 350 W) was used. After evacuation, a mixed gas of high-purity oxygen and high-purity argon is sealed in the container. In the case of this embodiment, the total pressure of the atmosphere is in the range of 1 × 10 to 6 to several + Torr, and the oxygen concentration is in the range of 10 to 100%. After filling the gas to a predetermined pressure, the inside of the quartz glass tube installed in the container is turned into plasma by high frequency. The output of the high-frequency power supply used is up to 500 W. After the inside of the container is in the above state, the target is irradiated with a YAG laser. The irradiation conditions are such that the laser energy is 30 J to 100 J per pulse, and the pulse width is 1 ms to 12 ms. The substrate was set at the outlet of the quartz tube so as to face the target. Further, in order to increase the adhesive force of the thin film and to increase the superconductivity of the formed thin film, the substrate was heated to about 800 ° C. by a heating holder. When the target is irradiated with a high-power laser,
The target evaporates instantly. The evaporated atoms and molecules react in the plasma region in the quartz tube and deposit on the sapphire substrate to form an oxide superconductor thin film. The film thickness is measured by a quartz vibrating type film thickness meter installed near the substrate. When the specified thickness is reached, the shutter is closed. The target can be moved by an XY table through a bellows from outside the container so that the entire surface of the target can be irradiated. In this embodiment, a YAG laser is used. However, any energy can be used as long as the target can be instantaneously evaporated, and the type of laser is not particularly limited. The target may be not an oxide but an alloy made of a metal element forming an oxide superconductor, or a sintered body of a mixed powder of the metal element powder. Alternatively, a plurality of targets made of each metal element may be placed in a container, and each target may be irradiated with laser sequentially, or may be irradiated at once with a multi-laser. In this case, the evaporated metal atoms react in the plasma region, form oxides, deposit on the substrate, and form a thin film. According to the invention, the target may be metallic or non-metallic. In addition, since there is no limitation on the atmospheric pressure, the oxygen partial pressure of the atmosphere during the formation of the thin film can be controlled over a wide range, so that the oxygen deficiency of the formed oxide superconductor thin film can be easily controlled, and a high-quality oxide superconducting thin film can be obtained. Can be formed. Further, the film forming speed is high and the productivity is excellent.
【図面の簡単な説明】
【図１】 本発明の一実施形態である酸化物超伝導体の
成形方法で用いる薄膜形成装置の縦断面図である。
【符号の説明】
２…ターゲット、３…レーザ発振器、４…レーザ光、５
…基板、６…高周波電極、８…石英管、１６…真空排気
装置。BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal sectional view of a thin film forming apparatus used in a method for forming an oxide superconductor according to an embodiment of the present invention. [Description of Signs] 2 ... Target, 3 ... Laser oscillator, 4 ... Laser light, 5
... substrate, 6 ... high frequency electrode, 8 ... quartz tube, 16 ... vacuum evacuation device.
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.6 識別記号 ＦＩ Ｈ０１Ｂ 13/00 ５６５ Ｈ０１Ｂ 13/00 ５６５Ｄ // Ｈ０１Ｂ 12/06 ＺＡＡ 12/06 ＺＡＡ Ｈ０１Ｌ 39/12 ＺＡＡ Ｈ０１Ｌ 39/12 ＺＡＡＣ (72)発明者 荒谷 雄 茨城県土浦市神立町502番地 株式会社 日立製作所 機械研究所内 (72)発明者 日置 進 茨城県土浦市神立町502番地 株式会社 日立製作所 機械研究所内 (58)調査した分野(Int.Cl.6，ＤＢ名) C01G 1/00,3/00 C30B 29/22 C23C 14/08,14/28 H01B 12/06,13/00 H01L 39/12──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. 6 Identification symbol FI H01B 13/00 565 H01B 13/00 565D // H01B 12/06 ZAA 12/06 ZAA H01L 39/12 ZAA H01L 39/12 ZAAC ( 72) Inventor Takeshi Aratani 502 Kandate-cho, Tsuchiura-city, Ibaraki Pref., Hitachi, Ltd.Mechanical Laboratory (72) Inventor Susumu Hioki 502, Kachi-cho, Tsuchiura-City, Ibaraki Pref., Hitachi, Ltd.Mechanical Laboratory, 58 Int.Cl. 6 , DB name) C01G 1 / 00,3 / 00 C30B 29/22 C23C 14 / 08,14 / 28 H01B 12 / 06,13 / 00 H01L 39/12
Claims (1)
レーザを照射して蒸発させたものを雰囲気ガスと作用さ
せて酸化物超伝導の蒸発物とし、この蒸発物を酸化物超
伝導体として基板上に析出させることを特徴とする酸化
物超伝導体薄膜の形成方法。 ２．特許請求の範囲第１項記載において、酸化物超伝導
薄膜を形成する雰囲気を酸素、あるいは酸素と不活性ガ
スの混合ガスとすることを特徴とする酸化物超伝導体薄
膜の形成方法。 ３．特許請求の範囲第１項または第２項記載において、
酸化物超伝導体薄膜を形成する雰囲気の一部、あるいは
全部をプラズマ状態とすることを特徴とする酸化物超伝
導体薄膜の形成方法。(57) [Claims] A powder sintered body or alloy of a metal exhibiting superconductivity as an oxide is irradiated with a laser and evaporated, and the vaporized material is allowed to act on an atmospheric gas to form an oxide superconducting evaporate. A method for forming an oxide superconductor thin film, wherein the oxide superconductor thin film is deposited on a substrate. 2. 2. The method for forming an oxide superconductor thin film according to claim 1, wherein the atmosphere in which the oxide superconductor thin film is formed is oxygen or a mixed gas of oxygen and an inert gas. 3. In claim 1 or claim 2,
A method for forming an oxide superconductor thin film, wherein a part or all of an atmosphere in which an oxide superconductor thin film is formed is in a plasma state.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8052877A JP2776362B2 (en) | 1996-03-11 | 1996-03-11 | Method of forming oxide superconductor thin film |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8052877A JP2776362B2 (en) | 1996-03-11 | 1996-03-11 | Method of forming oxide superconductor thin film |
Related Parent Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP62097372A Division JP2650910B2 (en) | 1987-04-22 | 1987-04-22 | Method of forming oxide superconductor thin film |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH08245298A JPH08245298A (en) | 1996-09-24 |
| JP2776362B2 true JP2776362B2 (en) | 1998-07-16 |
Family
ID=12927120
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP8052877A Expired - Lifetime JP2776362B2 (en) | 1996-03-11 | 1996-03-11 | Method of forming oxide superconductor thin film |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2776362B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4771632B2 (en) | 2001-10-12 | 2011-09-14 | 富士通株式会社 | Method for forming high-temperature superconductor film |
| JP5658891B2 (en) * | 2010-02-24 | 2015-01-28 | 株式会社フジクラ | Manufacturing method of oxide superconducting film |
-
1996
- 1996-03-11 JP JP8052877A patent/JP2776362B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH08245298A (en) | 1996-09-24 |
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