JPH04265206A - Method for manufacturing high temperature oxide superconductor thin film and device therefor - Google Patents
Method for manufacturing high temperature oxide superconductor thin film and device thereforInfo
- Publication number
- JPH04265206A JPH04265206A JP3045865A JP4586591A JPH04265206A JP H04265206 A JPH04265206 A JP H04265206A JP 3045865 A JP3045865 A JP 3045865A JP 4586591 A JP4586591 A JP 4586591A JP H04265206 A JPH04265206 A JP H04265206A
- Authority
- JP
- Japan
- Prior art keywords
- thin film
- oxygen
- oxide superconductor
- temperature
- 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.)
- Granted
Links
- 239000010409 thin film Substances 0.000 title claims abstract description 74
- 239000002887 superconductor Substances 0.000 title claims abstract description 51
- 238000000034 method Methods 0.000 title claims abstract description 15
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 13
- 239000001301 oxygen Substances 0.000 claims abstract description 135
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 135
- 239000000758 substrate Substances 0.000 claims abstract description 50
- 238000001816 cooling Methods 0.000 claims abstract description 28
- 239000010408 film Substances 0.000 claims abstract description 19
- 230000001678 irradiating effect Effects 0.000 claims abstract description 7
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 65
- 230000015572 biosynthetic process Effects 0.000 claims description 11
- 230000004907 flux Effects 0.000 claims description 5
- 239000007789 gas Substances 0.000 claims description 2
- 238000006243 chemical reaction Methods 0.000 abstract description 3
- 238000001704 evaporation Methods 0.000 description 22
- 230000008020 evaporation Effects 0.000 description 18
- 238000010438 heat treatment Methods 0.000 description 15
- 238000000151 deposition Methods 0.000 description 14
- 238000007740 vapor deposition Methods 0.000 description 14
- 229910052751 metal Inorganic materials 0.000 description 13
- 238000000427 thin-film deposition Methods 0.000 description 12
- 230000008021 deposition Effects 0.000 description 11
- 239000002184 metal Substances 0.000 description 10
- 238000005516 engineering process Methods 0.000 description 7
- 238000007254 oxidation reaction Methods 0.000 description 7
- 229910052727 yttrium Inorganic materials 0.000 description 7
- 229910052788 barium Inorganic materials 0.000 description 6
- 238000010549 co-Evaporation Methods 0.000 description 6
- 229910052802 copper Inorganic materials 0.000 description 6
- 230000003647 oxidation Effects 0.000 description 6
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 5
- 229910001882 dioxygen Inorganic materials 0.000 description 5
- 230000007423 decrease Effects 0.000 description 4
- 150000002739 metals Chemical class 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- 230000001590 oxidative effect Effects 0.000 description 4
- 238000010586 diagram Methods 0.000 description 3
- 238000004544 sputter deposition Methods 0.000 description 3
- 230000002159 abnormal effect Effects 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 2
- 230000014759 maintenance of location Effects 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 239000010453 quartz Substances 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 239000007921 spray Substances 0.000 description 2
- 229910003098 YBa2Cu3O7−x Inorganic materials 0.000 description 1
- 229910052797 bismuth Inorganic materials 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000010894 electron beam technology Methods 0.000 description 1
- 239000011810 insulating material Substances 0.000 description 1
- 229910052747 lanthanoid Inorganic materials 0.000 description 1
- 150000002602 lanthanoids Chemical class 0.000 description 1
- 229910052745 lead Inorganic materials 0.000 description 1
- 229910052758 niobium Inorganic materials 0.000 description 1
- -1 quartz or BN Chemical compound 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
- 238000001771 vacuum deposition Methods 0.000 description 1
- 238000007738 vacuum evaporation Methods 0.000 description 1
- VWQVUPCCIRVNHF-UHFFFAOYSA-N yttrium atom Chemical compound [Y] VWQVUPCCIRVNHF-UHFFFAOYSA-N 0.000 description 1
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
Landscapes
- Inorganic Compounds Of Heavy Metals (AREA)
- Superconductors And Manufacturing Methods Therefor (AREA)
- Oxygen, Ozone, And Oxides In General (AREA)
- Superconductor Devices And Manufacturing Methods Thereof (AREA)
Abstract
Description
【０００１】0001
【産業上の利用分野】本発明は、良好な超伝導特性を持
つ高温酸化物超伝導体薄膜の製造方法及び製造装置に関
するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for producing a high-temperature oxide superconductor thin film having good superconducting properties.
【０００２】0002
【従来の技術】１９８６年に３０〜４０ＫとＮｂ、Ｐｂ
等の従来の金属系超伝導体に比べ著しく高い超伝導転移
温度Ｔｃを持つＬａ１−ｘＭｘＣｕＯｙ（Ｍ：Ｓｒ、Ｂ
ａ）が発見 された。これを契機に転移温度Ｔｃ〜９０
ＫのＬｎＢａＣｕＯｙ系（Ｌｎはイッ トリウム、ある
いはランタノイド元素）、同じく〜１１０ＫのＢｉＳｒ
ＣａＣｕＯｙ系、同じく〜１２０ＫのＴｌＢａＣａＣｕ
Ｏｙ系の発見が相次いで行われた。いずれの場合も酸化
物を基本としており、より高いＴｃを持つ超伝導体も発
見される可能性もある。これ等の超伝導材料は、高温超
伝導体、高Ｔｃ超伝導体、高温酸化物超伝導体などと呼
ばれている。この高温酸化物超伝導体を電子デバイス、
超伝導配線等のエレクトロニクス応用に展開するために
は、良好な超伝導特性を持つ薄膜の形成技術が必要とな
る。[Prior art] In 1986, 30-40K, Nb, Pb
La1-xMxCuOy (M: Sr, B
a) was discovered. Taking this as an opportunity, the transition temperature Tc~90
LnBaCuOy system of K (Ln is yttrium or lanthanoid element), BiSr of ~110K
CaCuOy system, also ~120K TlBaCaCu
The Oy system was discovered one after another. In either case, they are based on oxides, and there is a possibility that superconductors with higher Tc will also be discovered. These superconducting materials are called high temperature superconductors, high Tc superconductors, high temperature oxide superconductors, and the like. This high-temperature oxide superconductor can be used in electronic devices,
In order to develop this technology into electronics applications such as superconducting wiring, a technology for forming thin films with good superconducting properties is required.
【０００３】これ等の高温酸化物超伝導体薄膜の形成技
術として、反応性共蒸着法、スパッタ法、レーザ蒸着法
、ＣＶＤ法など、半導体薄膜形成を目的に開発された多
くの真空蒸着法を基本にした方法が試みられている。
いずれの場合も、酸化物薄膜を形成する必要があるため
酸化雰囲気中での薄膜形成がベースである。As techniques for forming these high-temperature oxide superconductor thin films, there are many vacuum evaporation methods developed for the purpose of forming semiconductor thin films, such as reactive co-evaporation, sputtering, laser evaporation, and CVD. Basic methods are being tried. In either case, since it is necessary to form an oxide thin film, thin film formation in an oxidizing atmosphere is the basis.
【０００４】これ等従来の高温酸化物超伝導体薄膜形成
法の共通する最も大きな欠点は、薄膜形成中、あるいは
冷却過程において高い酸素圧力（薄膜作製時では約５×
１０−２Ｔｏｒｒ以上、冷却時で約１００Ｔｏｒｒ以上
）での蒸着、冷却を行なわないと超伝導特性を持つ薄膜
を形成できないことである。このため、Ｋセル、ＥＢガ
ン、基板加熱ヒータ等の真空部品等が高圧力の酸素によ
りダメージを受ける、あるいは蒸着レートが不安定にな
る等の欠点を持つ。The biggest drawback common to these conventional high-temperature oxide superconductor thin film formation methods is the high oxygen pressure (approximately 5×
A thin film having superconducting properties cannot be formed unless vapor deposition and cooling are performed at a temperature of 10 -2 Torr or higher (approximately 100 Torr or higher during cooling). For this reason, there are drawbacks such as damage to vacuum components such as the K cell, EB gun, substrate heater, etc. due to the high pressure oxygen, or the evaporation rate becomes unstable.
【０００５】以下に、反応性共蒸着法の場合を例に、こ
の欠点を具体的に示す。[0005] This drawback will be specifically illustrated below using the case of the reactive co-evaporation method as an example.
【０００６】図６に、反応性共蒸着装置の概略を示す。
ここでは、高温酸化物超伝導体として、ＹＢａ２Ｃｕ３
Ｏ７−ｘの薄膜を形成する場合を考える（他の高温酸化
物超伝導 体の場合も金属元素の種類、数が異なるだけ
で、基本的には同様の原理を元に薄膜作製が行なわれて
いる。）。FIG. 6 schematically shows a reactive codeposition apparatus. Here, YBa2Cu3 is used as a high-temperature oxide superconductor.
Consider the case of forming a thin film of O7-x (thin films of other high-temperature oxide superconductors are basically fabricated based on the same principle, only the type and number of metal elements are different). ).
【０００７】各金属元素Ｙ，Ｂａ、ＣｕはＫセル、ＥＢ
ガン、抵抗加熱源等の蒸着源を用いて、同時に独立に蒸
発させる。図６では、ＹはＥＢガン２、ＢａはＥＢガン
１、Ｃｕは抵抗加熱源３で蒸発させる。ＥＢガン１，２
は加速した電子ビームを蒸着材料に当て加熱蒸発させ、
抵抗加熱源３の場合は、抵抗ヒータ４に電流を流すこと
により加熱蒸発させる。基板６は基板加熱ヒータ５によ
り加熱される。超伝導体薄膜の形成には、基板温度は約
６００℃以上の温度が必要である。装置のチャンバ内に
は酸素ガス（酸素分子）が導入される。その際、チャン
バ内の酸素圧力を低減するためにチャンバ内は真空ポン
プにより排気される。[0007] Each metal element Y, Ba, Cu is K cell, EB
Simultaneously and independently evaporate using a evaporation source such as a gun or a resistance heating source. In FIG. 6, Y is evaporated by the EB gun 2, Ba is evaporated by the EB gun 1, and Cu is evaporated by the resistance heating source 3. EB gun 1, 2
applies an accelerated electron beam to the evaporation material and evaporates it by heating it.
In the case of the resistance heating source 3, current is passed through the resistance heater 4 to heat and evaporate it. The substrate 6 is heated by the substrate heater 5. Formation of a superconductor thin film requires a substrate temperature of approximately 600° C. or higher. Oxygen gas (oxygen molecules) is introduced into the chamber of the device. At this time, the inside of the chamber is evacuated by a vacuum pump in order to reduce the oxygen pressure inside the chamber.
【０００８】蒸発した金属元素と酸素は反応しながら基
板６上に堆積し、酸化物薄膜が形成される。良好な超伝
導特性を持つ酸化物薄膜を得るためには、１）薄膜中の
金属元素の組成比Ｙ：Ｂａ：Ｃｕが１：２：３になるよ
うに調整されること、２）十分な酸化が行なえる条件に
あることが重要である。１）は蒸発源の蒸発レートをコ
ントロールすることにより行なわれる。２）はチャンバ
内の酸化圧力を増加させることにより実現される。The evaporated metal element and oxygen react with each other and deposit on the substrate 6, forming an oxide thin film. In order to obtain an oxide thin film with good superconducting properties, 1) the composition ratio of metal elements Y:Ba:Cu in the thin film must be adjusted to 1:2:3, and 2) sufficient It is important that the conditions are such that oxidation can take place. 1) is performed by controlling the evaporation rate of the evaporation source. 2) is achieved by increasing the oxidation pressure within the chamber.
【０００９】金属元素と酸素との反応を完全に行なうこ
とにより良好な超伝導特性を持つ薄膜を得るためには、
酸素分子で酸素を供給する場合（従来の方法の場合）、
基板近傍の酸素圧力は１０−１Ｔｏｒｒ以上が必要であ
ると言われている。[0009] In order to obtain a thin film with good superconducting properties by completely reacting the metal element with oxygen,
When supplying oxygen with oxygen molecules (conventional method),
It is said that the oxygen pressure near the substrate needs to be 10<-1 >Torr or more.
【００１０】しかし、チャンバ内がこのような高い酸素
圧力になると以下のような弊害が発生する。それは、抵
抗加熱用のヒータ、基板加熱用のヒータ、及びＥＢガン
の電子発生用ヒータが酸素と反応して断線してしまうこ
とである。（蒸発源がＫセルの場合も同じであり、加熱
ヒータが切れてしまう。）。However, when the inside of the chamber reaches such a high oxygen pressure, the following problems occur. This is because the heater for resistance heating, the heater for heating the substrate, and the heater for generating electrons of the EB gun react with oxygen and break. (The same is true when the evaporation source is a K cell, and the heater will turn off.)
【００１１】他の弊害としては、ＥＢガンが異常放電し
蒸発レートのコントロールが不可能になることである。
蒸発レートのコントロールが不可能になると薄膜の組成
比のずれが起き、超伝導特性を得られない。Another problem is that the EB gun may discharge abnormally, making it impossible to control the evaporation rate. If it becomes impossible to control the evaporation rate, the composition ratio of the thin film will shift, making it impossible to obtain superconducting properties.
【００１２】基板６近傍の酸素圧力のみを増加させ基板
から離れた場所（例えば蒸発源付近）の酸素圧力（バッ
クグラウンド酸素圧力）を減少させるために、ノルズ７
で酸素ガスを基板に吹き付けることも試みられている。
しかし、この場合でも、基板近傍と十分離れた場所間に
おける酸素圧力差はせいぜい半分程度、つまり５×１０
−２Ｔｏｒｒ程度にしかできず、上記弊害を本質的に解
決できるものではない。さらに、基板吹き付けでは基板
内での酸素圧力を均一にすることは難しく、広い面積で
超伝導体薄膜を得ることができないという欠点も生じる
。In order to increase only the oxygen pressure near the substrate 6 and reduce the oxygen pressure (background oxygen pressure) at a location away from the substrate (for example, near the evaporation source), the
Attempts have also been made to spray oxygen gas onto the substrate. However, even in this case, the oxygen pressure difference between the vicinity of the substrate and a sufficiently distant location is at most half, that is, 5 × 10
This can only be done at about -2 Torr, and cannot essentially solve the above-mentioned problems. Furthermore, substrate spraying has the disadvantage that it is difficult to make the oxygen pressure uniform within the substrate, and it is not possible to obtain a superconductor thin film over a wide area.
【００１３】以上に述べた様に、従来の方法では、薄膜
蒸着時に酸素圧力が高いということに起因した多くの欠
点を持つ。As described above, the conventional method has many drawbacks due to the high oxygen pressure during thin film deposition.
【００１４】また、室温で良好な超伝導特性を得るため
には、成膜後、〜１００Ｔｏｒｒ以上の酸素圧力中で、
成膜温度から室温まで数時間かけて冷却する必要がある
。基板ヒータと蒸発源とをともに停止した後であっても
それらは瞬時には冷えないため、〜１００Ｔｏｒｒとい
う成膜時の酸素圧力に比べ３桁以上高い圧力の酸素ガス
に高温状態で触れる。従って、成膜中以上にヒータの断
線等の真空部品に対するダメージが大きい。In addition, in order to obtain good superconducting properties at room temperature, after film formation, it is necessary to
It is necessary to cool the film from the film formation temperature to room temperature over several hours. Even after both the substrate heater and the evaporation source are stopped, they do not cool down instantaneously, so they come into contact with oxygen gas at a high temperature of ~100 Torr, which is three orders of magnitude higher than the oxygen pressure during film formation. Therefore, damage to the vacuum components, such as heater disconnection, is greater than during film formation.
【００１５】以上述べたように、従来の高温酸化物超伝
導体薄膜形成法では、良好な超伝導特性を持つ薄膜を実
現するためには、薄膜蒸着時、及び冷却時にチャンバ内
のバックグラウンド酸素圧力を高くせざるを得ず、その
ため真空部品に対するダメージ等の入内な弊害を生じる
という欠点を持っていた。As described above, in the conventional high-temperature oxide superconductor thin film formation method, in order to realize a thin film with good superconducting properties, it is necessary to eliminate background oxygen in the chamber during thin film deposition and cooling. The pressure has to be increased, which has the disadvantage of causing internal harm such as damage to vacuum parts.
【００１６】[0016]
【発明が解決しようとする課題】本発明の目的は、真空
部品等に対してダメージの少ない、かつ優れた超伝導特
性を出現させる高温酸化物伝導体薄膜の製造方法及び製
造装置を提供することにある。SUMMARY OF THE INVENTION An object of the present invention is to provide a method and apparatus for producing a high-temperature oxide conductor thin film that causes less damage to vacuum components and exhibits excellent superconducting properties. It is in.
【００１７】[0017]
【課題を解決するための手段】
上記課題を解決するための本発明
の第１の要旨は、薄膜形成時に、基板近傍に酸素ラジカ
ルを照射することを特徴とする高温酸化物超伝導体薄膜
の製造方法に存在する。[Means to solve the problem]
A first aspect of the present invention for solving the above problems resides in a method for producing a high-temperature oxide superconductor thin film, which is characterized by irradiating oxygen radicals near a substrate during thin film formation.
【００１８】また、上記課題を解決するための本発明の
第２の要旨は、薄膜形成後の冷却時に、基板近傍に酸素
ラジカルを照射することを特徴とする高温酸化物超伝導
体薄膜の製造方法に存在する。A second aspect of the present invention to solve the above problems is to manufacture a high-temperature oxide superconductor thin film, which is characterized by irradiating oxygen radicals near the substrate during cooling after forming the thin film. Exist in method.
【００１９】さらに、上記課題を解決するための本発明
の第３の要旨は、内部に基板を保持するための手段を有
する酸化物超伝導体の反応性成膜装置に、酸素ラジカル
を発生させる手段を、酸素ラジカルが該基板近傍に照射
されるように配置して設けたことを特徴とする高温酸化
物超伝導体薄膜の製造装置に存在する。Furthermore, a third aspect of the present invention for solving the above problems is to generate oxygen radicals in a reactive film forming apparatus for an oxide superconductor having means for holding a substrate inside. An apparatus for producing a high-temperature oxide superconductor thin film is provided, characterized in that means are arranged so that oxygen radicals are irradiated near the substrate.
【００２０】[0020]
【作用】酸素ラジカルは酸素分子に比べ化学的に活性で
あるため、蒸着後、及び冷却時に必要な酸素圧力を桁違
いに低減できる。そのため、蒸着源、ヒータ等の真空部
品に対するダメージが大きく低減できる。[Operation] Since oxygen radicals are chemically more active than oxygen molecules, the oxygen pressure required after vapor deposition and during cooling can be reduced by an order of magnitude. Therefore, damage to vacuum components such as the evaporation source and heater can be greatly reduced.
【００２１】[0021]
【実施例】（第１実施例）図１に、本発明の高温酸化物
超伝導体薄膜の製造装置の一例を示す。本例では、反応
性成膜装置の一例として反応性共蒸着装置を示し、これ
基づいて成膜の原理を説明する。なお、スパッタ法、レ
ーザ蒸着法等の他の製造装置の場合も、動作原理は同様
である。Embodiments (First Embodiment) FIG. 1 shows an example of an apparatus for producing a high-temperature oxide superconductor thin film according to the present invention. In this example, a reactive co-evaporation apparatus is shown as an example of a reactive film forming apparatus, and the principle of film forming will be explained based on this. Note that the operating principle is the same for other manufacturing apparatuses such as sputtering and laser evaporation.
【００２２】図１に示す装置は、従来の技術で述べた反
応性共蒸着装置と同様、真空蒸着装置を基本としている
。８は高温酸化物超伝導体を構成する金属元素（例えば
、ＹＢａ２Ｃｕ３Ｏ７−ｘ系高温酸化物超伝導体の場合
は、Ｙ、Ｂａ、Ｃｕの３つの元素、ＢｉＳｒＣａＣｕＯ
ｙ系高温酸化物超伝導体の場合は、Ｂｉ、Ｓｒ、Ｃａ、
Ｃｕの４つの元素）を蒸発させるための蒸着源である。
Ｋセル、ＥＢガン、抵抗加熱源などが用いられるがどれ
を用いても同様である。The apparatus shown in FIG. 1 is based on a vacuum evaporation apparatus, similar to the reactive co-evaporation apparatus described in the prior art section. 8 is a metal element constituting a high-temperature oxide superconductor (for example, in the case of a YBa2Cu3O7-x-based high-temperature oxide superconductor, the three elements Y, Ba, and Cu, BiSrCaCuO
In the case of y-based high temperature oxide superconductors, Bi, Sr, Ca,
This is an evaporation source for evaporating four elements (Cu). A K cell, an EB gun, a resistance heating source, etc. are used, but the same applies regardless of which one is used.
【００２３】６はその上に超伝導体薄膜を堆積させるた
めの基板である。５は基板を加熱するためのヒータであ
る。９は酸素ラジカルＯ＊を発生させる ための酸素ラ
ジカル源であり、酸素ラジカルＯ＊は基板近傍に照射さ
れる。従って、各金属元素、及び酸素ラジカルとの反応
により、基板６上に酸化物薄膜が形成できる。6 is a substrate on which a superconductor thin film is deposited. 5 is a heater for heating the substrate. 9 is an oxygen radical source for generating oxygen radicals O*, and the oxygen radicals O* are irradiated near the substrate. Therefore, an oxide thin film can be formed on the substrate 6 by the reaction with each metal element and oxygen radicals.
【００２４】従来の技術では金属元素の酸化は酸化分子
により行なったが、本発明では酸素分子より化学的に活
性であるため酸化力が格段に優れた酸素ラジカルを用い
る。これが、本発明の最も重要な特徴である。酸素ラジ
カルは活性で酸化力が強いので、酸素圧力が低くても十
分な酸化反応が実現できる。後の実施例で具体的に述べ
るが、バックグランド酸素圧力が約１０−５Ｔｏｒｒ（
従来の高温酸化物超伝導体作製技術に必要な酸素バック
グランド圧力に比べて、薄膜蒸着時で１／２００００、
冷却時で１／１０００００００の低酸素圧力）でも、良
好な超伝導特性を持つ薄膜を実現できる。また、酸素ラ
ジカルは金属との反応により消滅するために、酸素ラジ
カルの存在は基板６近傍に限られ、蒸発源がある場所ま
では広がらない。[0024] In the conventional technology, oxidation of metal elements was carried out using oxidizing molecules, but in the present invention, oxygen radicals, which are chemically more active than oxygen molecules and therefore have much superior oxidizing power, are used. This is the most important feature of the invention. Oxygen radicals are active and have strong oxidizing power, so a sufficient oxidation reaction can be achieved even at low oxygen pressure. As will be specifically described in later examples, the background oxygen pressure is approximately 10-5 Torr (
Compared to the oxygen background pressure required for conventional high-temperature oxide superconductor fabrication technology, thin film deposition reduces the oxygen background pressure by 1/20,000.
A thin film with good superconducting properties can be achieved even at a low oxygen pressure of 1/10000000 during cooling. Furthermore, since oxygen radicals are annihilated by reaction with metal, their presence is limited to the vicinity of the substrate 6 and does not spread to the location where the evaporation source is located.
【００２５】以上の結果、例えば、抵抗加熱用のヒータ
、基板加熱用のヒータ、及びＥＢガンの電子発生用ヒー
タ等の真空部品のダメージが大幅に抑えられる。また、
酸素圧力が低いのでＥＢガンの異常放電を引き起こさず
、組成比をコントロールすることができる。As a result of the above, damage to vacuum components such as resistance heating heaters, substrate heating heaters, and electron generation heaters of EB guns can be significantly suppressed. Also,
Since the oxygen pressure is low, the composition ratio can be controlled without causing abnormal discharge in the EB gun.
【００２６】（第２実施例）図２に、第２実施例として
、酸素ラジカル源の概要を示す。(Second Embodiment) FIG. 2 shows an outline of an oxygen radical source as a second embodiment.
【００２７】石英、ＢＮ等の酸素との反応を起こし難い
絶縁体材料からなる放電管１０の内部に酸素ガスを導入
し、ＲＦコイル１１に高周波を印加し放電を起こす。す
ると、放電管内の酸素ガスは高エネルギー状態（プラズ
マ状態）になる。この高エネルギーガスを複数の微細穴
１２があいた石英製のアパーチャ１３を通すと酸素ラジ
カルを発生できる。プラズマをラジカルにするために必
要とされる微細穴の直径は、放電管１０内の圧力、成膜
室内の圧力をどのように設定するかによっても左右され
るが、一般的には、０．１ｍｍ〜３ｍｍが好ましい。Oxygen gas is introduced into the discharge tube 10 made of an insulating material that does not easily react with oxygen, such as quartz or BN, and a high frequency is applied to the RF coil 11 to generate a discharge. Then, the oxygen gas within the discharge tube enters a high energy state (plasma state). Oxygen radicals can be generated by passing this high-energy gas through an aperture 13 made of quartz with a plurality of micro holes 12. The diameter of the fine hole required to make the plasma into radicals depends on how the pressure inside the discharge tube 10 and the pressure inside the film forming chamber are set, but generally it is 0. 1 mm to 3 mm is preferable.
【００２８】典型的な設計の酸素ラジカル源の性能を次
に示す。酸素流量＝０．６６ＣＣＭ、バックグラウンド
酸素圧力＝１×１０−５Ｔｏｒｒ、放電管内でのＲＦ電
力密度＝１１Ｗ／ｃｍ２（入力電力２５０Ｗ）での、基
板上（酸素ラジカル源のアパーチャ部から約 ７ｃｍ離
れた箇所）での酸素ラジカルフラックス流量＝５×１０
１３（個／ｓ・ｃｍ２）の値が実現できている。酸素流
量、ＲＦ電力を増加させると、酸素ラジカルフ ラック
ス流量も増加させることができる。The performance of a typical oxygen radical source design is shown below. Oxygen flow rate = 0.66 CCM, background oxygen pressure = 1 x 10-5 Torr, RF power density in the discharge tube = 11 W/cm2 (input power 250 W), on the substrate (approximately 7 cm away from the aperture of the oxygen radical source) Oxygen radical flux flow rate = 5×10
A value of 13 (pieces/s·cm2) has been achieved. Increasing the oxygen flow rate and RF power can also increase the oxygen radical flux flow rate.
【００２９】（第３実施例）第３実施例として、第１実
施例で述べた高温酸化物超伝導体薄膜反応性共蒸着装置
、及び第２実施例で示した酸素ラジカル源を用いた高温
酸化物超伝導体薄膜形成の具体例を示す。(Third Example) As a third example, high-temperature oxide superconductor thin film reactive co-evaporation apparatus described in the first example and the oxygen radical source shown in the second example were used. A specific example of forming an oxide superconductor thin film will be shown.
【００３０】酸素ラジカル源から発生した酸素ラジカル
を基板６に照射する。酸素ラジカルを照射した状態でＫ
セルにより金属Ｙ、Ｂａ、Ｃｕを同時に蒸発させ基板６
上に薄膜を形成した。The substrate 6 is irradiated with oxygen radicals generated from an oxygen radical source. K under irradiation with oxygen radicals
The metals Y, Ba, and Cu are simultaneously evaporated by the cell and the substrate 6
A thin film was formed on top.
【００３１】代表的な蒸着条件を以下に示す。酸素流量
＝０．６６ＣＣＭ、バックグラウンド酸素圧力＝１×１
０−５Ｔｏｒｒ、放電管内でのＲＦ電力密度＝１１Ｗ／
ｃｍ２（入力電力２５０Ｗ）、基板温度＝７００℃ 、
蒸着レートＲ＝１Å／ｓである。薄膜蒸着後、上記と同
じ酸素ラジカル照射条件（酸素流量＝０．６６ＣＣＭ、
バックグラウンド酸素圧力＝１×１０−５Ｔｏｒｒ、放
電管内でのＲＦ電力密度＝１１Ｗ／ｃｍ２（入力電力２
５０Ｗ））下で、 冷却速度Ｃ＝３００℃／ｈで成膜温
度（＝７００℃）から室温まで冷却した。Typical vapor deposition conditions are shown below. Oxygen flow rate = 0.66CCM, background oxygen pressure = 1 x 1
0-5 Torr, RF power density inside the discharge tube = 11W/
cm2 (input power 250W), substrate temperature = 700℃,
The deposition rate R=1 Å/s. After thin film deposition, the same oxygen radical irradiation conditions as above (oxygen flow rate = 0.66 CCM,
Background oxygen pressure = 1 x 10-5 Torr, RF power density in the discharge tube = 11 W/cm2 (input power 2
The film was cooled from the film forming temperature (=700°C) to room temperature at a cooling rate C=300°C/h under 50W).
【００３２】この様にして作製した薄膜の抵抗の温度変
化を図３に示す。９０Ｋから抵抗が減少し始め、８７Ｋ
で零抵抗になり、良好な超伝導特性を持つ。なお、抵抗
が減少し始める臨界温度はオンセット臨界温度と呼ばれ
、零抵抗となる臨界温度は零抵抗臨界温度と呼ばれてい
る。また、酸化物超伝導体の酸化量、及び超伝導特性の
性能を表すパラメターであるｃ軸の長さ（１１．６８Å
であると酸化が十分で、かつ超伝導特性が良い。酸化不
足で超伝導特性が劣化すると長くなる。）は、１１．６
８Åとバルクの完全な超伝導体ＹＢａ２Ｃｕ３０ｙの値
と等しく、酸素の取り込みは十分に行われた良好な超伝
導体薄膜であると判る。FIG. 3 shows the temperature change in the resistance of the thin film produced in this manner. Resistance starts to decrease from 90K and reaches 87K.
It has zero resistance and good superconducting properties. The critical temperature at which the resistance begins to decrease is called the onset critical temperature, and the critical temperature at which the resistance becomes zero is called the zero-resistance critical temperature. In addition, the oxidation amount of the oxide superconductor and the c-axis length (11.68 Å
If so, oxidation is sufficient and superconducting properties are good. It becomes longer if the superconducting properties deteriorate due to insufficient oxidation. ) is 11.6
The value is 8 Å, which is equal to the value of the bulk perfect superconductor YBa2Cu30y, which indicates that the film is a good superconductor thin film with sufficient oxygen uptake.
【００３３】ここで、従来の高温酸化物超伝導体薄膜作
製技術と大きく異なるのは、従来の技術では薄膜蒸着時
の酸素バックグラウンド圧力として基板に酸素を吹き付
けた場合でも５×１０−２Ｔｏｒｒ以上、冷却時の酸素
バックグラウンド圧力として１００Ｔｏｒｒ以上ないと
超伝導特性を持つ薄膜が得られなかったのが、本発明に
よると薄膜蒸着時、及び冷却時共に１×１０−５Ｔｏｒ
ｒの酸素バックグラウンド圧力で良好な超伝導特性を持
つ薄膜を形成できるということである。[0033] Here, the major difference from conventional high-temperature oxide superconductor thin film fabrication technology is that in conventional technology, even when oxygen is blown onto the substrate as an oxygen background pressure during thin film deposition, it is 5 × 10-2 Torr or more. , a thin film with superconductivity could not be obtained unless the oxygen background pressure during cooling was 100 Torr or more, but according to the present invention, the oxygen background pressure during both thin film deposition and cooling is 1 x 10-5 Torr.
This means that a thin film with good superconducting properties can be formed at an oxygen background pressure of r.
【００３４】つまり、従来の技術で必要な酸素バックグ
ラウンド圧力に比べて、薄膜蒸着時で１／２００００、
冷却時で１／１０００００００の低い酸素バックグラウ
ンド圧力での良好な超伝導特性を持つ高温酸化物超伝導
体薄膜を形成することができる。[0034] That is, compared to the oxygen background pressure required in the conventional technology, the oxygen background pressure during thin film deposition is 1/20,000,
It is possible to form high-temperature oxide superconductor thin films with good superconducting properties at oxygen background pressures as low as 1/100000000 when cooled.
【００３５】従って、ＥＢガンの異常放電を防止し酸化
物超伝導体の構成元素の組成比を正確にコントロールで
きると共に、抵抗加熱のヒータ、基板加熱のヒータ等の
真空部品のダメージを画期的に低減できる。Therefore, abnormal discharge of the EB gun can be prevented and the composition ratio of the constituent elements of the oxide superconductor can be accurately controlled, and damage to vacuum components such as resistance heating heaters and substrate heating heaters can be dramatically reduced. can be reduced to
【００３６】（第４実施例）第４実施例では、第３実施
例において、良好な超伝導特性を持つ薄膜を得るための
薄膜成膜条件を示す。(Fourth Example) In the fourth example, conditions for forming a thin film for obtaining a thin film having good superconducting properties in the third example will be described.
【００３７】酸素ラジカルを照射した状態でＫセルによ
り金属Ｙ、Ｂａ、Ｃｕを同時に蒸発させ基板６上に薄膜
を形成した。A thin film was formed on the substrate 6 by simultaneously evaporating metals Y, Ba, and Cu using a K cell under irradiation with oxygen radicals.
【００３８】以下の２つの蒸着条件により薄膜を形成し
た。Thin films were formed under the following two deposition conditions.
【００３９】１）の条件は、第３実施例と全く同じで、
酸素流量＝０．６６ＣＣＭ、バックグラウンド酸素圧力
＝１×１０−５Ｔｏｒｒ、放電管内でのＲＦ電力密度＝
１１Ｗ／ｃｍ２（入力電力２５０Ｗ）、基板温度＝７０
０℃、蒸着レートＲ＝１Å／ｓである。The conditions of 1) are exactly the same as in the third embodiment,
Oxygen flow rate = 0.66 CCM, background oxygen pressure = 1 x 10-5 Torr, RF power density in the discharge tube =
11W/cm2 (input power 250W), substrate temperature = 70
The temperature was 0° C., and the deposition rate R was 1 Å/s.
【００４０】２）の条件は、酸素流量のみを減少させた
（バックグラウンド酸素圧力も流量に比例し減少する。
）場合で、酸素流量＝０．２７ＣＣＭ、バックグラウン
ド酸素圧力＝４．１×１０−６Ｔｏｒｒ、放電管内での
ＲＦ電力密度＝１１Ｗ／ｃｍ２（入力電力２５０Ｗ）、
基板温度＝７００℃、蒸着レートＲ＝１Å／ｓである。Condition 2) is the case where only the oxygen flow rate is decreased (the background oxygen pressure also decreases in proportion to the flow rate), oxygen flow rate = 0.27 CCM, background oxygen pressure = 4.1 × 10 -6 Torr, RF power density inside the discharge tube = 11 W/cm2 (input power 250 W),
The substrate temperature was 700° C., and the deposition rate R was 1 Å/s.
【００４１】１）と２）の酸素ラジカル条件の違いは、
酸素ラジカルの流量が、１）では５×１０１３ （個／
ｓ・ｃｍ２）であるのに対して、 ２）では２×１０１
３（個／ｓ・ｃｍ２）と減少したことである。薄膜蒸着
後、両者共に 良好な超伝導特性を持つ薄膜が得られた
第３実施例と同じ冷却条件、つまり、酸素流量＝０．６
６ＣＣＭ、バックグラウンド酸素圧力＝１×１０−５Ｔ
ｏｒｒ、放電管内でのＲＦ電力密度＝１１Ｗ／ｃｍ２（
入力電力２５０Ｗ）の酸素ラジカ ル照射下で、冷却速
度Ｃ＝３００℃／ｈで成膜温度（＝７００℃）から室温
まで冷却した。The difference in oxygen radical conditions between 1) and 2) is as follows:
In 1), the flow rate of oxygen radicals is 5×1013 (numbers/
s・cm2), whereas in 2) it is 2×101
This is a decrease of 3 (pieces/s·cm2). After thin film deposition, the cooling conditions were the same as in the third example, in which both thin films with good superconducting properties were obtained, that is, oxygen flow rate = 0.6.
6CCM, background oxygen pressure = 1 x 10-5T
orr, RF power density in the discharge tube = 11W/cm2 (
Under oxygen radical irradiation with an input power of 250 W), the film was cooled from the film forming temperature (=700° C.) to room temperature at a cooling rate C=300° C./h.
【００４２】１）の薄膜蒸着条件（つまり第３実施例と
同じ。）で作製した薄膜は、第３実施例で示した様に、
オンセット臨界温度＝９０Ｋ、零抵抗臨界温度＝８７Ｋ
、ｃ軸長＝１１．６８Å（バルクの完全な超伝導体ＹＢ
ａ２Ｃｕ３０ｙの値と 等しい。）と良好な超伝導特性
を持っている。As shown in the third example, the thin film produced under the thin film deposition conditions of 1) (that is, the same as in the third example) was
Onset critical temperature = 90K, zero resistance critical temperature = 87K
, c-axis length = 11.68 Å (bulk perfect superconductor YB
Equal to the value of a2Cu30y. ) and has good superconducting properties.
【００４３】しかし、２）の蒸着条件で作製した薄膜は
、オンセット臨界温度は９０Ｋであるが、零抵抗臨界温
度が５０Ｋと低下し、かつｃ軸長も１１．７５Åと長く
なり（これは酸素の取り込みが十分でない証拠である。
）、その超伝導特性は劣化している。従って、蒸着レー
トＲ＝１Å／ｓで蒸着する場合に良好な超伝導特性を得
るための酸素ラジカル流量の臨界値は２×１０１３（個
／ｓ・ｃｍ２）と５×１０１３（個／ｓ・ｃｍ２）の間
にあると考えられる。ここでは、安全サイドに見積もっ
て、良好な超伝導特性を得た実績があるということで、
臨界値を５×１０１３（個／ｓ・ｃｍ２）とする。つま
り、蒸着レートＲ＝１Å／ｓ で蒸着する場合に良好な
超伝導特性を得るためには、この臨界値（５×１０１３
（個／ｓ・ｃｍ２））以上の酸素ラジカル流量を基板に
供給する必要がある。However, although the onset critical temperature of the thin film produced under the evaporation conditions 2) is 90 K, the zero resistance critical temperature is lower to 50 K, and the c-axis length is longer to 11.75 Å (this is (This is evidence that oxygen uptake is not sufficient.), and its superconducting properties have deteriorated. Therefore, the critical value of the oxygen radical flow rate to obtain good superconducting properties when depositing at a deposition rate R = 1 Å/s is 2 x 1013 (numbers/s cm2) and 5 x 1013 (numbers/s cm2). ). Here, we estimate on the safe side and say that we have a track record of obtaining good superconducting properties.
The critical value is set to 5×1013 (pieces/s·cm2). In other words, in order to obtain good superconductivity when depositing at a deposition rate of R=1 Å/s, this critical value (5×10
It is necessary to supply the substrate with a flow rate of oxygen radicals of (numbers/s·cm2) or more.
【００４４】一方 、蒸着レートが増加すると、当然必
要な単位時間、単位面積当りの酸素ラジカル流量、つま
り酸素ラジカル流量も蒸着レートに比例して増加させる
必要がある。従って、蒸着レートＲ（Å／ｓ）の場合の
臨界酸素ラジカル流量値は、５×１０１３×Ｒ（個／ｓ
・ｃｍ２）となる。従って、蒸着レートＲ（Å／ｓ）で
蒸着する場合に 良好な超伝導特性を得るためには、こ
の臨界値（５×１０１３×Ｒ（個／ｓ・ｃｍ２ ））以
上の酸素ラジカル流量を基板に供給する必要がある。On the other hand, as the vapor deposition rate increases, the required flow rate of oxygen radicals per unit time and unit area, that is, the flow rate of oxygen radicals, must also increase in proportion to the vapor deposition rate. Therefore, the critical oxygen radical flow rate value in case of vapor deposition rate R (Å/s) is 5×1013×R(numbers/s
・cm2). Therefore, in order to obtain good superconducting properties when depositing at a deposition rate of R (Å/s), the flow rate of oxygen radicals on the substrate must be greater than this critical value (5 x 1013 x R (numbers/s cm2)). It is necessary to supply
【００４５】（第５実施例）第５実施例では、第３実施
例において良好な超伝導特性を持つ薄膜を得るための冷
却条件を示す。(Fifth Example) In a fifth example, cooling conditions for obtaining a thin film having good superconducting properties in the third example are shown.
【００４６】酸素ラジカルを照射した状態でＫセルによ
り金属Ｙ、Ｂａ、Ｃｕを同時に蒸発させ基板６上に薄膜
を形成した。A thin film was formed on the substrate 6 by simultaneously evaporating metals Y, Ba, and Cu using a K cell while irradiating oxygen radicals.
【００４７】蒸着条件は、第３実施例を全く同じで、酸
素流量＝０．６６ＣＣＭ、バックグラウンド圧力＝１×
１０−５Ｔｏｒｒ、放電管内でのＲＦ電力密度＝１１Ｗ
／ｃｍ２（入力電力２５０ Ｗ）、基板温度＝７００℃
、蒸着レートＲ＝１Å／ｓである。酸素ラジカル流量は
、５×１０１３（個／ｓ・ｃｍ２）である。The vapor deposition conditions were exactly the same as in the third embodiment, oxygen flow rate = 0.66 CCM, background pressure = 1×
10-5 Torr, RF power density inside the discharge tube = 11W
/cm2 (input power 250 W), substrate temperature = 700°C
, the deposition rate R=1 Å/s. The oxygen radical flow rate was 5×10 13 (numbers/s·cm 2 ).
【００４８】薄膜蒸着後、蒸着時と同じ酸素ラジカル
照射条件下、つまり、酸素ラジカル流量＝０．６６ＣＣ
Ｍ、バックグラウンド酸素圧力＝１×１０−５Ｔｏｒｒ
、放電管内でのＲＦ電力密度＝１１Ｗ／ｃｍ２（入 力
電力２５０Ｗ）で（従って、酸素ラジカルの流量は５×
１０１３（個／ｓ・ｃｍ２ ））、冷却速度Ｃ（℃／ｈ
）をパラメータとして成膜温度（＝７００℃）から室温
で冷却した。After thin film deposition, the same oxygen radicals as during deposition
Under irradiation conditions, that is, oxygen radical flow rate = 0.66 CC
M, background oxygen pressure = 1 x 10-5 Torr
, RF power density in the discharge tube = 11 W/cm2 (input power 250 W) (therefore, the flow rate of oxygen radicals is 5×
1013 (pieces/s cm2)), cooling rate C (°C/h
) was used as a parameter to cool the film forming temperature (=700° C.) to room temperature.
【００４９】図４はオンセット臨界温度、零抵抗臨界温
度、ｃ軸長の冷却速度Ｃ（℃／ｈ）に対する依存性を示
すグラフである。冷却速度Ｃ（℃／ｈ）が約３００（℃
／ｈ）以下で、オンセット臨界温度９０Ｋ、零抵抗臨界
温度＝８７Ｋ、ｃ軸長＝１１．６８Å（バルクの完全な
超伝導体ＹＢａ２Ｃｕ３Ｏｙの値と等しい。）と良好な
超伝導特性を 持つ薄膜を得ることができる。つまり、
酸素ラジカル流量が５×１０１３個／ｓ・ｃｍ２の場合
は、約３００（℃／ｈ）以下の速度で冷却すれば良好な
超伝導特性 を持つ薄膜を形成できる。FIG. 4 is a graph showing the dependence of onset critical temperature, zero resistance critical temperature, and c-axis length on cooling rate C (° C./h). The cooling rate C (°C/h) is approximately 300 (°C
/h), the onset critical temperature is 90 K, the zero resistance critical temperature is 87 K, and the c-axis length is 11.68 Å (equivalent to the value of the bulk perfect superconductor YBa2Cu3Oy), making it a thin film with good superconducting properties. can be obtained. In other words,
When the oxygen radical flow rate is 5 x 1013/s/cm2, a thin film with good superconductivity can be formed by cooling at a rate of about 300°C/h or less.
【００５０】また、良好な超伝導特性を得るための冷却
速度を上げるためには、単位時間、単位面積当りに供給
される酸素ラジカル量、つまり酸素ラジカル流量を冷却
速度に比例して増加させる必要がある。従って、冷却速
度Ｃ（℃／ｈ）の場合に必要な酸素ラジカル流量値は、
５×１０１３（個／ｓ・ｃｍ２ ）／３００（℃／ｈ）
×Ｃ（℃／ｈ）、つまり約１．７×１０１１×Ｃ（個／
ｓ・ｃｍ２）となる。従って、冷却温度Ｃ（℃／ｈ）の
場合に良好な超伝導特性を得る ためには、この臨界値
（約１．７×１０１１×Ｃ（個／ｓ・ｃｍ２））以上の
酸素 ラジカル流量を基板に供給する必要がある。Furthermore, in order to increase the cooling rate to obtain good superconducting properties, it is necessary to increase the amount of oxygen radicals supplied per unit time and unit area, that is, the flow rate of oxygen radicals, in proportion to the cooling rate. There is. Therefore, when the cooling rate is C (°C/h), the required oxygen radical flow rate is:
5×1013 (pieces/s・cm2)/300 (℃/h)
×C (°C/h), that is, approximately 1.7 × 1011 × C (pieces/h)
s・cm2). Therefore, in order to obtain good superconducting properties at a cooling temperature of C (°C/h), the flow rate of oxygen radicals must be greater than this critical value (approximately 1.7 × 1011 × C (numbers/s cm2)). It is necessary to supply it to the board.
【００５１】（第６実施例）第６実施例では、第３実施
例において、第５実施例と同様良好な超伝導特性を持つ
薄膜を得るための冷却条件を示す。(Sixth Example) In the sixth example, cooling conditions for obtaining a thin film having good superconducting properties in the third example are shown, similar to the fifth example.
【００５２】酸素ラジカルを照射した状態でＫセルによ
り金属Ｙ、Ｂａ、Ｃｕを同時に蒸発させ基板６上に薄膜
を形成した。A thin film was formed on the substrate 6 by simultaneously evaporating metals Y, Ba, and Cu using a K cell while irradiating oxygen radicals.
【００５３】蒸着条件は、第３実施例と全く同じで、酸
素流量＝０．６６ＣＣＭ、バックグラウンド酸素圧力＝
１×１０−５Ｔｏｒｒ、放電管内でのＲＦ電力密度＝１
１Ｗ／ｃｍ２（入力電力２５０Ｗ）、基板温度７００℃
、蒸着レートＲ＝１Å／ｓである 。酸素ラジカルの流
量は、５×１０１３（個／ｓ・ｃｍ２）である。The vapor deposition conditions are exactly the same as in the third example, oxygen flow rate = 0.66 CCM, background oxygen pressure =
1 x 10-5 Torr, RF power density inside the discharge tube = 1
1W/cm2 (input power 250W), substrate temperature 700℃
, the deposition rate R=1 Å/s. The flow rate of oxygen radicals is 5×10 13 (numbers/s·cm 2 ).
【００５４】薄膜蒸着後、蒸着 時と同じ酸素ラジカル
照射条件下、つまり、酸素流量＝０．６６ＣＣＭ、バッ
クグラウンド圧力＝１×１０−５Ｔｏｒｒ、放電管内で
のＲＦ電力密度＝１１Ｗ／ｃｍ２（入力電力２５０Ｗ）
で（従って、酸素ラジカルの流量は５×１０１３（個／
ｓ・ｃｍ２））、成膜温度（＝７００℃）から４００℃
〜５００℃の一定の温度まで 急冷した後、その温度で
保持時間ｔ（ｍｉｎ．）保持し、再び室温まで急冷した
。After thin film deposition, under the same oxygen radical irradiation conditions as during deposition, that is, oxygen flow rate = 0.66 CCM, background pressure = 1 x 10-5 Torr, RF power density in the discharge tube = 11 W/cm2 (input power 250W)
(Therefore, the flow rate of oxygen radicals is 5×1013 (numbers/
s・cm2)), film forming temperature (=700℃) to 400℃
After being rapidly cooled to a constant temperature of ~500°C, it was maintained at that temperature for a holding time t (min.), and then rapidly cooled to room temperature again.
【００５５】図５に、オンセット臨界温度、ｃ軸長の、
４００℃〜５００℃の一定温度（ここでは４５０℃に設
定。）での保持時間ｔ（ｍｉｎ．）依存性を示すグラフ
である。保持時間ｔ（ｍｉｎ．）が約２０（ｍｉｎ．）
以上で、オンセット臨界温度９０Ｋ、零抵抗臨界温度＝
８７Ｋ、ｃ軸長＝１１．６８Å（バルクの完全な超伝導
体ＹＢａ２Ｃｕ３Ｏｙの値と等しい。）と良好な超伝導
特性を持つ薄膜を得ることができる。FIG. 5 shows the onset critical temperature, c-axis length,
It is a graph showing the dependence on holding time t (min.) at a constant temperature of 400°C to 500°C (set at 450°C here). Holding time t (min.) is approximately 20 (min.)
Above, onset critical temperature 90K, zero resistance critical temperature =
A thin film having good superconducting properties at 87 K and c-axis length of 11.68 Å (equivalent to the value of the bulk perfect superconductor YBa2Cu3Oy) can be obtained.
【００５６】つまり 、酸素ラジカル流量が５×１０１
３（個／ｓ・ｃｍ２）の場合は、４００℃〜５００℃
の一定温度（ここでは４５０℃に設定）で２０（ｍｉｎ
．）以上保持すれば良好な超伝導特性を持つ薄膜を形成
できる。[0056] That is, the oxygen radical flow rate is 5×101
3 (pieces/s cm2), 400℃ to 500℃
20 (min.
．． ) or more, a thin film with good superconducting properties can be formed.
【００５７】また、良好な超伝導特性を得るための保持
時間を短縮するためには、単位時間、単位面積当りに供
給される酸素ラジカル量、つまり酸素ラジカル流量を保
持時間に逆比例して増加させる必要がある。Furthermore, in order to shorten the holding time to obtain good superconducting properties, the amount of oxygen radicals supplied per unit time and unit area, that is, the oxygen radical flow rate, is increased in inverse proportion to the holding time. It is necessary to do so.
【００５８】従って、保持時間ｔ（ｍｉｎ．）の場合に
必要な酸素ラジカル流量値は、５×１０１３（個／ｓ・
ｃｍ２）×２０（ｍｉｎ．）／ｔ（ｍｉｎ．）、つまり
約１×１ ０１５／ｔ（個／ｓ・ｃｍ２）となる。従っ
て、保持時間ｔ（ｍｉｎ．）の場合に 良好な超伝導性
特性を得るためには、この臨界値（約１×１０１５／ｔ
（個／ｓ・ｃｍ２））以上の流量の酸素ラジカルを基板
に供給する必要がある。[0058] Therefore, when the retention time is t (min.), the required oxygen radical flow rate is 5 x 1013 (numbers/s.
cm2)×20 (min.)/t (min.), that is, approximately 1×1015/t (pieces/s·cm2). Therefore, in order to obtain good superconducting properties when the retention time is t (min.), this critical value (approximately 1×1015/t
It is necessary to supply oxygen radicals to the substrate at a flow rate of (numbers/s·cm2) or more.
【００５９】以上、反応性共蒸着法、及びＹＢａＣｕＯ
ｙ系酸化物超伝導体薄膜を例として説明したが、その他
の高温酸化物超伝導体薄膜、及び高温酸化物超伝導体薄
膜作製法、例えばスパッタ法、レーザ蒸着法でも、酸素
ラジカルが酸素分子に比べて活性である特性を反映した
効果を同様に実現できる。As described above, the reactive co-evaporation method and YBaCuO
The explanation has been given using a y-based oxide superconductor thin film as an example, but in other high-temperature oxide superconductor thin films and methods for producing high-temperature oxide superconductor thin films, such as sputtering and laser evaporation, oxygen radicals are It is possible to similarly achieve an effect that reflects the property of being more active than that of .
【００６０】[0060]
【発明の効果】以上説明したように、本発明は、薄膜蒸
着中、及びその冷却過程において、基板近傍に酸素分子
に比べ化学的には活性な酸素ラジカルを照射することを
特徴とする。良好な超伝導体薄膜を得るために必要な蒸
着時、及び冷却時のバックグラウンド酸素圧力を桁違い
に低減できる。そのため、蒸着源、ヒータ等の真空部品
に対するイメージを大きく低減できる。また、酸素ラジ
カル照射条件等の薄膜形成条件を定量的に示したため、
良好な超伝導特性を持つ薄膜を容易に実現できる。As explained above, the present invention is characterized in that oxygen radicals, which are chemically more active than oxygen molecules, are irradiated near the substrate during thin film deposition and during the cooling process. The background oxygen pressure during vapor deposition and cooling required to obtain a good superconductor thin film can be reduced by an order of magnitude. Therefore, the image of vacuum components such as the evaporation source and heater can be greatly reduced. In addition, we quantitatively demonstrated thin film formation conditions such as oxygen radical irradiation conditions.
Thin films with good superconducting properties can be easily realized.
【図１】 本発明の第１実施例に係る反応性共蒸着装
置例の概略図。FIG. 1 is a schematic diagram of an example of a reactive codeposition apparatus according to a first embodiment of the present invention.
【図２】 本発明の第２実施例に係る酸素ラジカル源
の概略図。FIG. 2 is a schematic diagram of an oxygen radical source according to a second embodiment of the present invention.
【図３】 本発明の第３実施例により形成した高温酸
化物超伝導体薄膜の抵抗の温度変化を示すグラフ図FIG. 3 is a graph showing the temperature change in resistance of a high-temperature oxide superconductor thin film formed according to the third embodiment of the present invention.
【図
４】 本発明の第５実施例におけるオンセット臨界温
度、零抵抗臨界温度、ｃ軸長の冷却温度Ｃ（℃／ｈ）依
存性を示すグラフFIG. 4 Graph showing dependence of onset critical temperature, zero resistance critical temperature, and c-axis length on cooling temperature C (°C/h) in the fifth embodiment of the present invention.
【図５】 本発明の第６実施例におけるオンセット臨
界温度、零抵抗臨界温度、ｃ軸長の、４００℃〜５００
℃の一定温度（ここでは４５０℃に設定。）での保持時
間ｔ（ｍｉｎ．）依存性を示すグラフFIG. 5: Onset critical temperature, zero resistance critical temperature, and c-axis length of 400°C to 500°C in the sixth embodiment of the present invention.
Graph showing dependence on holding time t (min.) at a constant temperature of °C (here set at 450 °C)
【図６】 従来例に係る反応性共蒸着装置の概略図。FIG. 6 is a schematic diagram of a reactive codeposition apparatus according to a conventional example.
１……蒸着源ＥＢガン（Ｂａ用）、２……蒸着源ＥＢガ
ン（Ｙ用）、３……蒸着源抵抗加熱、４……抵抗加熱蒸
着源用ヒータ、５……基板加熱ヒータ、６……基板、７
……酸素吹き付け用ノズル、８……蒸着源、９……酸素
ラジカル源、１０……放電管、１１……ＲＦコイル、１
２……微細穴、１３……アパーチャ。1... Vapor deposition source EB gun (for Ba), 2... Vapor deposition source EB gun (for Y), 3... Vapor deposition source resistance heating, 4... Resistance heating vapor deposition source heater, 5... Substrate heating heater, 6 ...board, 7
... Oxygen spray nozzle, 8 ... Vapor deposition source, 9 ... Oxygen radical source, 10 ... Discharge tube, 11 ... RF coil, 1
2...Minute hole, 13...Aperture.
Claims (8)
ルを照射することを特徴とする高温酸化物超伝導体薄膜
の製造方法。1. A method for producing a high-temperature oxide superconductor thin film, which comprises irradiating the vicinity of a substrate with oxygen radicals when forming the thin film.
素ラジカルを照射することを特徴とする高温酸化物超伝
導体薄膜の製造方法。2. A method for producing a high-temperature oxide superconductor thin film, which comprises irradiating the vicinity of the substrate with oxygen radicals during cooling after forming the thin film.
）とすると、供給する酸素ラジカルのフラックス流量を
約５×１０１３×Ｒ（個／ｓ・ｃｍ２）以上とす るこ
とを特徴とする請求項１記載の高温酸化物超伝導体薄膜
の製造方法。3. The film formation rate on the substrate is set to R (Å/s
), the method for producing a high-temperature oxide superconductor thin film according to claim 1, characterized in that the flux flow rate of oxygen radicals to be supplied is approximately 5 x 1013 x R (numbers/s cm2) or more.
給する酸素ラジカルのフラックス流量を約１．７×１０
１１×Ｃ（個／ｓ・ｃｍ２）以上とすることを特 徴と
する請求項２記載の高温酸化物超伝導体薄膜の製造方法
。4. If the cooling rate is C (°C/h), the flux flow rate of oxygen radicals to be supplied is approximately 1.7×10
3. The method for producing a high-temperature oxide superconductor thin film according to claim 2, characterized in that the temperature is 11×C (pieces/s·cm2) or more.
〜５００℃の温度に保持時間ｔ（ｍｉｎ．）の間保持し
、その間に供給する酸素ラジカルのフラックス流量を約
１×１０１５ ／ｔ（個／ｓ・ｃｍ２）以上とすること
を特徴とする請求項２または４記載の高温酸化物超伝導
体薄膜の製造方法。5. During cooling, the substrate is heated to 400°C.
A claim characterized in that the temperature is maintained at a temperature of ~500°C for a holding time t (min.), and the flux flow rate of oxygen radicals supplied during that time is approximately 1 x 1015 /t (numbers/s cm2) or more. 5. A method for producing a high-temperature oxide superconductor thin film according to item 2 or 4.
を発生させ、そのプラズマを微細穴を通すことにより酸
素ラジカルを生成することを特徴とする請求項１ないし
請求項５のいずれか１項記載の高温酸化物超伝導体薄膜
の製造方法。6. The high-temperature method according to claim 1, wherein plasma gas is generated by high-frequency discharge of oxygen, and oxygen radicals are generated by passing the plasma through fine holes. Method for producing oxide superconductor thin film.
する酸化物超伝導体の反応性成膜装置に、酸素ラジカル
を発生させる手段を、酸素ラジカルが該基板近傍に照射
されるように配置して設けたことを特徴とする高温酸化
物超伝導体薄膜の製造装置。7. A reactive film forming apparatus for an oxide superconductor having means for holding a substrate therein, and a means for generating oxygen radicals arranged so that the oxygen radicals are irradiated near the substrate. An apparatus for producing a high-temperature oxide superconductor thin film, characterized in that it is provided as a high-temperature oxide superconductor thin film.
、酸素をプラズマ化させるための放電管の出口に、酸素
のプラズマが通過した際に酸素ラジカルを発生せしめ得
る大きさの径の微細穴を有するアパチャーを設けること
により構成されていることを特徴とする請求項７記載の
高温酸化物超伝導体薄膜の製造装置。8. The means for generating oxygen radicals has a fine hole at the outlet of the discharge tube for turning oxygen into plasma, the diameter of which is large enough to generate oxygen radicals when the oxygen plasma passes through. 8. The apparatus for producing a high-temperature oxide superconductor thin film according to claim 7, characterized in that it is constructed by providing an aperture.
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| JP3045865A JP2848977B2 (en) | 1991-02-18 | 1991-02-18 | Method and apparatus for producing high-temperature oxide superconductor thin film |
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| Application Number | Priority Date | Filing Date | Title |
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| JP3045865A JP2848977B2 (en) | 1991-02-18 | 1991-02-18 | Method and apparatus for producing high-temperature oxide superconductor thin film |
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|---|---|
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| JP2848977B2 JP2848977B2 (en) | 1999-01-20 |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2013245388A (en) * | 2012-05-28 | 2013-12-09 | Nippon Telegr & Teleph Corp <Ntt> | Manufacturing method of superconductor |
| JP2020194870A (en) * | 2019-05-28 | 2020-12-03 | 国立大学法人東海国立大学機構 | Manufacturing method of superconducting device and superconducting device |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0350104A (en) * | 1989-07-18 | 1991-03-04 | Fujitsu Ltd | Method and device for producing oxide superconductor thin film |
| JPH0393608A (en) * | 1989-09-05 | 1991-04-18 | Chiyoudendou Hatsuden Kanren Kiki Zairyo Gijutsu Kenkyu Kumiai | Production of thin film of oxide superconductor |
| JPH04132604A (en) * | 1990-09-25 | 1992-05-06 | Rikagaku Kenkyusho | Production of oxide superconductor thin film |
-
1991
- 1991-02-18 JP JP3045865A patent/JP2848977B2/en not_active Expired - Fee Related
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0350104A (en) * | 1989-07-18 | 1991-03-04 | Fujitsu Ltd | Method and device for producing oxide superconductor thin film |
| JPH0393608A (en) * | 1989-09-05 | 1991-04-18 | Chiyoudendou Hatsuden Kanren Kiki Zairyo Gijutsu Kenkyu Kumiai | Production of thin film of oxide superconductor |
| JPH04132604A (en) * | 1990-09-25 | 1992-05-06 | Rikagaku Kenkyusho | Production of oxide superconductor thin film |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2013245388A (en) * | 2012-05-28 | 2013-12-09 | Nippon Telegr & Teleph Corp <Ntt> | Manufacturing method of superconductor |
| JP2020194870A (en) * | 2019-05-28 | 2020-12-03 | 国立大学法人東海国立大学機構 | Manufacturing method of superconducting device and superconducting device |
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| Publication number | Publication date |
|---|---|
| JP2848977B2 (en) | 1999-01-20 |
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