JP2501609B2 - Method for producing complex oxide superconducting thin film - Google Patents
Method for producing complex oxide superconducting thin filmInfo
- Publication number
- JP2501609B2 JP2501609B2 JP62332303A JP33230387A JP2501609B2 JP 2501609 B2 JP2501609 B2 JP 2501609B2 JP 62332303 A JP62332303 A JP 62332303A JP 33230387 A JP33230387 A JP 33230387A JP 2501609 B2 JP2501609 B2 JP 2501609B2
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- JP
- Japan
- Prior art keywords
- thin film
- superconducting thin
- composite oxide
- oxide superconducting
- producing
- 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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Links
- 239000010409 thin film Substances 0.000 title claims description 66
- 238000004519 manufacturing process Methods 0.000 title claims description 24
- 239000002131 composite material Substances 0.000 claims description 45
- 239000000758 substrate Substances 0.000 claims description 29
- 239000013078 crystal Substances 0.000 claims description 25
- 239000010408 film Substances 0.000 claims description 19
- 239000002887 superconductor Substances 0.000 claims description 17
- 238000004544 sputter deposition Methods 0.000 claims description 15
- 238000000034 method Methods 0.000 claims description 14
- 230000000737 periodic effect Effects 0.000 claims description 11
- 229910002367 SrTiO Inorganic materials 0.000 claims description 7
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 7
- 239000001301 oxygen Substances 0.000 claims description 7
- 229910052760 oxygen Inorganic materials 0.000 claims description 7
- 229910052746 lanthanum Inorganic materials 0.000 claims description 6
- 229910052719 titanium Inorganic materials 0.000 claims description 5
- 229910052727 yttrium Inorganic materials 0.000 claims description 3
- 239000000126 substance Substances 0.000 claims description 2
- 229910052802 copper Inorganic materials 0.000 claims 4
- 229910052742 iron Inorganic materials 0.000 claims 4
- 229910052759 nickel Inorganic materials 0.000 claims 4
- 229910052709 silver Inorganic materials 0.000 claims 4
- 229910052725 zinc Inorganic materials 0.000 claims 4
- 239000000919 ceramic Substances 0.000 claims 1
- 230000002950 deficient Effects 0.000 claims 1
- 239000011521 glass Substances 0.000 claims 1
- 230000003647 oxidation Effects 0.000 claims 1
- 238000007254 oxidation reaction Methods 0.000 claims 1
- 239000010453 quartz Substances 0.000 claims 1
- 229910052594 sapphire Inorganic materials 0.000 claims 1
- 239000010980 sapphire Substances 0.000 claims 1
- 239000004065 semiconductor Substances 0.000 claims 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims 1
- 229910001220 stainless steel Inorganic materials 0.000 claims 1
- 239000010935 stainless steel Substances 0.000 claims 1
- 238000000137 annealing Methods 0.000 description 10
- 230000015572 biosynthetic process Effects 0.000 description 7
- 238000007796 conventional method Methods 0.000 description 6
- 239000007789 gas Substances 0.000 description 6
- 239000000463 material Substances 0.000 description 6
- 238000010438 heat treatment Methods 0.000 description 5
- 239000000203 mixture Substances 0.000 description 4
- 238000001816 cooling Methods 0.000 description 3
- 230000007547 defect Effects 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 238000005259 measurement Methods 0.000 description 3
- 229910052689 Holmium Inorganic materials 0.000 description 2
- 206010021143 Hypoxia Diseases 0.000 description 2
- 230000005668 Josephson effect Effects 0.000 description 2
- 230000032683 aging Effects 0.000 description 2
- 229910052747 lanthanoid Inorganic materials 0.000 description 2
- 150000002602 lanthanoids Chemical class 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- 229910021521 yttrium barium copper oxide Inorganic materials 0.000 description 2
- 229910052691 Erbium Inorganic materials 0.000 description 1
- 229910052688 Gadolinium Inorganic materials 0.000 description 1
- 229910052765 Lutetium Inorganic materials 0.000 description 1
- 229910052775 Thulium Inorganic materials 0.000 description 1
- 229910052769 Ytterbium Inorganic materials 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 238000000151 deposition Methods 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000018109 developmental process Effects 0.000 description 1
- 230000008030 elimination Effects 0.000 description 1
- 238000003379 elimination reaction Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 239000001307 helium Substances 0.000 description 1
- 229910052734 helium Inorganic materials 0.000 description 1
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- WABPQHHGFIMREM-UHFFFAOYSA-N lead(0) Chemical compound [Pb] WABPQHHGFIMREM-UHFFFAOYSA-N 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000001755 magnetron sputter deposition Methods 0.000 description 1
- 238000005240 physical vapour deposition Methods 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000005245 sintering Methods 0.000 description 1
- 230000035882 stress Effects 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
- 238000007738 vacuum evaporation Methods 0.000 description 1
- 229910052720 vanadium Inorganic materials 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)
- Physical Vapour Deposition (AREA)
- Superconductor Devices And Manufacturing Methods Thereof (AREA)
- Superconductors And Manufacturing Methods Therefor (AREA)
Description
【発明の詳細な説明】 産業上の利用分野 本発明は超電導薄膜の製造方法に関する。より詳細に
は、優れた超電導特性を有し、組成および組織の均一な
超電導薄膜の作製方法に関する。TECHNICAL FIELD The present invention relates to a method for producing a superconducting thin film. More specifically, it relates to a method for producing a superconducting thin film having excellent superconducting properties and having a uniform composition and structure.
従来の技術 電子の相転移であるといわれる超電導現象は、特定の
条件下で導体の電気抵抗が零の状態となり完全な反磁性
を示す現象である。2. Description of the Related Art The superconducting phenomenon, which is said to be a phase transition of electrons, is a phenomenon in which the electric resistance of a conductor becomes zero under certain conditions and shows perfect diamagnetism.
エレクトロニクスの分野では各種の超電導素子が知ら
れている。代表的なものとしては、超電導材料どうしを
弱く接合した場合に、印加電流によって量子効果が巨視
的に現れるジョセフソン効果を利用した素子が挙げられ
る。Various superconducting elements are known in the field of electronics. A typical example is an element utilizing the Josephson effect in which quantum effects appear macroscopically by an applied current when superconducting materials are weakly joined.
トンネル接合型ジョセフソン素子は、超電導材料のエ
ネルギーギャップが小さいことから、極めて高速な低電
力消費のスイッチング素子として期待されている。ま
た、電磁波や磁場に対するジョセフソン効果が正確な量
子現象として現れることから、ジョセフソン素子を磁
場、マイクロ波、放射線等の超高感度センサとして利用
することも期待されている。さらに、電子回路の集積度
が高くなるにつれて単位面積当たりの消費電力が冷却能
力の限界に達する。そこで超高速計算機には超電導素子
の開発が要望されている。Since the energy gap of the superconducting material is small, the tunnel junction type Josephson device is expected as a switching device with extremely high speed and low power consumption. In addition, since the Josephson effect on electromagnetic waves and magnetic fields appears as an accurate quantum phenomenon, it is expected that the Josephson element is used as an ultrasensitive sensor for magnetic fields, microwaves, radiation, and the like. Furthermore, as the degree of integration of electronic circuits increases, the power consumption per unit area reaches the limit of cooling capacity. Therefore, the development of superconducting elements has been demanded for ultra-high-speed computers.
一方、様々な努力にもかかわらず、超電導材料の超電
導臨界温度Tcは長期間に亘ってNb3Geの23Kを越えること
ができなかったが、昨年未来、〔La,Ba〕2CuO4または
〔La,Sr〕2CuO4等の酸化物の焼結材が高いTcをもつ超電
導材料として発見され、非低温超電導を実現する可能性
が大きく高まっている。これらの物質では、30乃至50K
という従来に比べて飛躍的に高いTcが観測され、70K以
上のTcも観測されている。On the other hand, despite various efforts, the superconducting critical temperature Tc of superconducting materials could not exceed 23K of Nb 3 Ge for a long time, but in the future last year, [La, Ba] 2 CuO 4 or La, Sr] 2 CuO 4 and other oxide sintered materials have been discovered as superconducting materials with high Tc, and the possibility of realizing non-low temperature superconductivity is greatly increasing. For these substances, 30-50K
Dramatically higher T c than the conventional is observed, it is also observed over Tc 70K called.
また、YBCOと称されるY1Ba2Cu3O7-xで表される複合酸
化物は、90K級の超電導体であることが発表されてい
る。これら複合酸化物超電導体の超電導特性には、結晶
中の酸素欠陥が大きな役割を果たしている。すなわち、
結晶中の酸素欠陥が適正でないと、Tcは低く、また、オ
ンセット温度と抵抗が完全に０となる温度との差も大き
くなる。Further, it has been announced that a composite oxide represented by Y 1 Ba 2 Cu 3 O 7-x called YBCO is a 90K-class superconductor. Oxygen defects in the crystal play a major role in the superconducting properties of these complex oxide superconductors. That is,
If oxygen deficiency in the crystal is not proper, Tc will be low, and the difference between the onset temperature and the temperature at which the resistance becomes zero will be large.
発明が解決しようとする問題点 従来、例えばYBCO系超電導体薄膜を作製する際には、
YBa2Cu3O7-x焼結体をターゲットとしてスパッタリング
等の物理蒸着で成膜し、酸素含有雰囲気で700〜1000℃
に加熱する熱処理（アニール）を行っていた。Problems to be Solved by the Invention Conventionally, for example, when producing a YBCO-based superconductor thin film,
YBa 2 Cu 3 O 7-x sintered body is used as a target to form a film by physical vapor deposition such as sputtering, and 700 to 1000 ° C in an oxygen-containing atmosphere.
The heat treatment (annealing) of heating to was performed.
上記の熱処理を行わないと、薄膜は超電導性を示さな
いか、また、超電導性を示しても超電導臨界温度、臨界
電流等の諸特性は非常に悪い。これは、超電導体結晶中
の酸素欠陥が上記のアニールにより適正化されるためで
あると考えられている。Without the heat treatment, the thin film does not show superconductivity, or even if it shows superconductivity, various properties such as superconducting critical temperature and critical current are very poor. It is considered that this is because oxygen defects in the superconductor crystal are optimized by the above-described annealing.
従って、上記の複合酸化物超電導薄膜を作製効率は悪
く、また、成膜−アニール間の温度履歴により薄膜の超
電導特性は経時的に悪化したり、また、特性そのものも
ばらつきがあった。Therefore, the production efficiency of the above-mentioned composite oxide superconducting thin film was poor, and the superconducting properties of the thin film deteriorated over time due to the temperature history between film formation and annealing, and the properties themselves also varied.
そこで、本発明の目的は、上記従来技術の問題点を解
決し、高い臨界温度Tcを始めとする優れた超電導諸特性
を安定的に有し、均一な組成および組織の複合酸化物超
電導材料の薄膜を高効率で作製する方法を提供すること
にある。Therefore, the object of the present invention is to solve the problems of the above-mentioned conventional techniques, stably have excellent superconducting properties including a high critical temperature Tc, and a composite oxide superconducting material having a uniform composition and structure. It is to provide a method for producing a thin film with high efficiency.
問題点を解決するための手段 本発明に従うと、周期律表II a族元素から選択された
少なくとも１種の元素α、周期律表III a族元素から選
択された少なくとも１種の元素β、周期律表I b、II
b、III b、IV a、VIII a族元素から選択された少なくと
も１種の元素γを含有する複合酸化物超電導体薄膜を作
製する方法において、ターゲットとして上記元素α、β
およびγの単体を組み合わせたもの、および／または上
記元素α、βおよびγを含む酸化物を用いて基板温度62
0乃至700℃でスパッタリングを行い、酸化物の薄膜を形
成することを特徴とする複合酸化物超電導薄膜の作製方
法が提供される。According to the present invention, at least one element α selected from Group IIa elements of the periodic table II, at least one element β selected from Group IIIa elements of the periodic table, Law table Ib, II
In a method for producing a composite oxide superconductor thin film containing at least one element γ selected from the group consisting of b, III b, IV a and VIII a elements, the above elements α and β are used as targets.
And γ are used in combination, and / or an oxide containing the above elements α, β and γ is used to obtain a substrate temperature of 62
There is provided a method for producing a composite oxide superconducting thin film, which comprises performing sputtering at 0 to 700 ° C. to form an oxide thin film.
本発明の方法で作製される複合酸化物超電導薄膜は、
下記一般式： （α1-xβｘ）γyOz （但し、αは周期律表II a族に含まれる元素であり、β
は周期律表III a族に含まれる元素であり、γは周期律
表I b、II b、III b、IV aおよびVIII a族から選択され
る少なくとも一つの元素であり、ｘ、ｙ、ｚはそれぞれ
0.1≦ｘ≦0.9、0.4≦ｙ≦3.0、１≦ｚ≦５を満たす数で
ある） で示される複合酸化物で構成されることが好ましい。こ
れらの複合酸化物はペロブスカイト型または擬似ペロブ
スカイト型酸化物を主体としたものと考えられる。The composite oxide superconducting thin film produced by the method of the present invention,
The following general formula: (α 1-x β x ) γ y O z (where α is an element included in Group IIa of the periodic table, and β
Is an element included in Group IIIa of the Periodic Table, γ is at least one element selected from Groups Ib, IIb, IIIb, IVa and VIIIa of the Periodic Table, and x, y, z Are each
0.1 ≦ x ≦ 0.9, 0.4 ≦ y ≦ 3.0, and 1 ≦ z ≦ 5)). It is considered that these complex oxides are mainly composed of perovskite type or pseudo perovskite type oxides.
上記周期律表II a族元素αとしては、Ba、Sr、Ca、M
g、Be等が好ましく、例えば、Ba、Srを挙げることがで
き、この元素αの10〜80％をMg、Ca、Srから選択された
１種または２種の元素で置換することもできる。また上
記周期律表III a族元素βはとしては、Ｙの他La、Sc、C
e、Gd、Ho、Er、Tm、Yb、Lu等ランタノイド元素が好ま
しく、例えばＹ、La、Hoとすることができ、この元素β
のうち、10〜80％をScまたはランタノイド元素から選択
された１種または２種の元素で置換することもできる。
前記元素γは一般にCuであるが、その一部を周期律表I
b、II b、III b、IV aおよびVIII a族から選択される他
の元素、例えば、Ti、Ｖ等で置換することもできる。The Group IIa element α of the periodic table includes Ba, Sr, Ca, and M.
g, Be and the like are preferable, and examples thereof include Ba and Sr, and 10 to 80% of the element α can be replaced with one or two elements selected from Mg, Ca and Sr. Further, the group IIIa element β of the periodic table is, in addition to Y, La, Sc, C
Lanthanoid elements such as e, Gd, Ho, Er, Tm, Yb, and Lu are preferable, and can be, for example, Y, La, and Ho.
Of these, 10 to 80% can be replaced with one or two elements selected from Sc or lanthanoid elements.
The element γ is generally Cu, a part of which is shown in the periodic table I
It can also be replaced by other elements selected from the groups b, IIb, IIIb, IVa and VIIIa, for example Ti, V and the like.
本発明の態様に従うと、上記の複合酸化物超電導薄膜
を形成する基板としては、MgO単結晶、SrTiO3単結晶ま
たはZrO2単結晶が好ましく、特に、MgO単結晶またはSrT
iO3単結晶基板の成膜面を、｛001｝面または｛011｝面
とすることが好ましい。According to the embodiment of the present invention, as the substrate for forming the above-mentioned complex oxide superconducting thin film, MgO single crystal, SrTiO 3 single crystal or ZrO 2 single crystal is preferable, and in particular, MgO single crystal or SrT.
The film formation surface of the iO 3 single crystal substrate is preferably a {001} surface or a {011} surface.
作用 本発明の複合酸化物超電導薄膜の作製方法は、基板温
度620〜700℃、好ましくは670℃で、スパッタリング
法、好ましくはマグネトロンスパッタリグ法で成膜する
ことで、成膜後の熱処理（アニール）を不要にしたこと
にその主要な特徴がある。Action The method for producing a composite oxide superconducting thin film of the present invention is a substrate temperature of 620 to 700 ° C., preferably 670 ° C., and a film is formed by a sputtering method, preferably a magnetron sputter rig method. The main feature is the elimination of).
すなわち、上記の複合酸化物超電導体の超電導特性に
は、その結晶中の酸素欠陥が大きく影響している。特
に、薄膜にした場合、成膜しただけでは酸素欠陥が適正
な範囲から外れた結晶となり、超電導特性が悪い。従っ
て、従来は成膜後酸素含有雰囲気中において700〜1000
℃でアニールしていた。That is, the superconducting properties of the composite oxide superconductor are greatly affected by oxygen defects in the crystal. In particular, when the film is formed into a thin film, the oxygen deficiency becomes a crystal out of an appropriate range only by forming the film, and the superconductivity is poor. Therefore, conventionally, after film formation, it is 700 to 1000 in an oxygen-containing atmosphere.
It was annealed at ℃.
しかしながら、従来の方法では、成膜後超時間にわた
るアニール処理が必要であるのみならず、従来の方法の
アニールは、不十分であり、従来の方法で作製された超
電導薄膜は超電導特性にばらつきがあるだけでなく、経
時変化を起こし、超電導特性が大幅に悪化する。However, in the conventional method, not only annealing treatment for a super time after film formation is necessary, but also annealing in the conventional method is insufficient, and the superconducting thin film produced by the conventional method has a variation in superconducting properties. In addition to being present, superconducting properties are significantly deteriorated due to aging.
本発明の方法に従うと、基板温度670℃で成膜するこ
とが好ましい。本発明者等の実験によると、基板温度67
0℃で成膜された上記の複合酸化物超電導薄膜は、アニ
ール処理を行わなくても、従来のアニール処理を行った
複合酸化物超電導薄膜と同様な特性を示す。また、基板
温度670℃で成膜した複合酸化物超電導薄膜は、さらに
アニール処理を行っても、その特性はほとんど向上しな
い。従って、基板温度670℃で成膜することにより上記
の複合酸化物超電導薄膜は、アニール処理が不要にな
る。According to the method of the present invention, it is preferable to form a film at a substrate temperature of 670 ° C. According to the experiments by the present inventors, the substrate temperature is 67
The above-mentioned composite oxide superconducting thin film formed at 0 ° C. exhibits the same characteristics as the conventional annealed composite oxide superconducting thin film without annealing. Further, the properties of the composite oxide superconducting thin film formed at the substrate temperature of 670 ° C. are hardly improved even if the annealing treatment is further performed. Therefore, by forming the film at the substrate temperature of 670 ° C., the above-mentioned composite oxide superconducting thin film does not need annealing treatment.
また、本発明の態様では、スパッタリング雰囲気のO2
分圧が1.0×10-3〜4.0×10-1Torrの範囲内であることが
好ましい。すなわち、本発明の方法ではスパッタリン
グ、好ましくはマグネトロンスパッタリングにより複合
酸化物超電導薄膜を成膜する。スパッタリングガスは一
般には、Ar等の不活性ガスを使用するが、本発明の方法
では複合酸化物超電導薄膜の特性を向上させるため、ス
パッタリングガスに酸素を含有させる。その際、O2分圧
は上記の範囲であることが好ましく、また、スパッタリ
ングガスのO2濃度は10〜50％であることが好ましい。In addition, in an embodiment of the present invention, O 2 in the sputtering atmosphere
The partial pressure is preferably within the range of 1.0 × 10 −3 to 4.0 × 10 −1 Torr. That is, in the method of the present invention, the composite oxide superconducting thin film is formed by sputtering, preferably magnetron sputtering. As the sputtering gas, an inert gas such as Ar is generally used, but in the method of the present invention, oxygen is contained in the sputtering gas in order to improve the characteristics of the composite oxide superconducting thin film. At that time, the O 2 partial pressure is preferably in the above range, and the O 2 concentration of the sputtering gas is preferably 10 to 50%.
さらに本発明の別の態様では、上記スパッタリング時
の高周波電力は、0.4〜3W/cm2であることが好ましい。
この高周波電力の大きさは、成膜速度、薄膜の特性等に
大きく影響するが、各種の条件から上記の範囲が最も好
ましい。Further, in another aspect of the present invention, the high frequency power during the sputtering is preferably 0.4 to 3 W / cm 2 .
The magnitude of the high frequency power has a great influence on the film forming rate, the characteristics of the thin film, etc., but the above range is most preferable from various conditions.
本発明の態様に従うと、上記の複合酸化物超電導薄膜
を形成する基板としては、MgO単結晶、SrTiO3単結晶ま
たはZrO2単結晶基板が好ましい。特に、MgO単結晶基板
またはSrTiO3単結晶基板の｛001｝面または｛011｝面を
成膜面として用いることが好ましい。According to the embodiment of the present invention, a MgO single crystal, SrTiO 3 single crystal or ZrO 2 single crystal substrate is preferable as the substrate for forming the above-mentioned composite oxide superconducting thin film. In particular, it is preferable to use the {001} plane or {011} plane of the MgO single crystal substrate or the SrTiO 3 single crystal substrate as the film formation surface.
本発明の複合酸化物超電導体は、その電気抵抗に結晶
異方性を有する。すなわち、結晶のａ軸およびｂ軸で決
定される面に平行な方向に電流が流れ易い。上記の基板
の上記成膜面上に形成された複合酸化物超電導薄膜は、
その結晶のｃ軸が基板成膜面に対し垂直または垂直に近
い角度となるため、特に臨界電流密度Jcが大きくなる。
従って、MgO単結晶基板またはSrTiO3単結晶基板の｛00
1｝面を成膜面として用いることが好ましい。また、｛0
11｝面を用いてｃ軸を基板と平行にし、ｃ軸と垂直な方
向を特定して用いることもできる。さらに、MgO、SrTiO
3は、熱膨脹率が上記の複合酸化物超電導体と近いた
め、加熱、冷却の過程で薄膜に不必要な応力を加えるこ
とがなく、薄膜を破損する恐れがなく、また、基板中の
元素が薄膜中に拡散するのを防止することができる。The composite oxide superconductor of the present invention has a crystalline anisotropy in its electric resistance. That is, current easily flows in a direction parallel to a plane determined by the a-axis and the b-axis of the crystal. The composite oxide superconducting thin film formed on the film-forming surface of the substrate,
Since the c-axis of the crystal is perpendicular or nearly perpendicular to the film formation surface of the substrate, the critical current density Jc becomes particularly large.
Therefore, the MgO single crystal substrate or the SrTiO 3 single crystal substrate
It is preferable to use the 1} plane as the film formation surface. Also, ｛0
It is also possible to make the c-axis parallel to the substrate by using the 11} plane and specify and use the direction perpendicular to the c-axis. In addition, MgO, SrTiO
No. 3 has a coefficient of thermal expansion close to that of the above complex oxide superconductor, so unnecessary stress is not applied to the thin film during heating and cooling, there is no risk of damage to the thin film, and the elements in the substrate are It can be prevented from diffusing into the thin film.
実施例 以下に本発明を実施例により説明するが、本発明の技
術的範囲はこれらの実施例に何等制限されるものではな
いことは勿論である。Examples The present invention will be described below with reference to examples, but it goes without saying that the technical scope of the present invention is not limited to these examples.
本発明の方法で、複合酸化物超電導体を作製した。原
料ターゲットとして、BaCO3とCuOを混合、加熱して得た
BaCuO2、Y2O3およびCuOを混合し、950℃焼結して得たYB
2Cu3O7焼結体ブロックを用いた。焼結体のY:Ba:Cuの原
子比は、1:2:3.2とした。これは、Cuがスパッタリング
されやすく、薄膜の組成とターゲットの組成が変わって
しまうためである。A composite oxide superconductor was produced by the method of the present invention. It was obtained by mixing and heating BaCO 3 and CuO as a raw material target.
YB obtained by mixing BaCuO 2 , Y 2 O 3 and CuO and sintering at 950 ° C
2 Cu 3 O 7 sintered block was used. The atomic ratio of Y: Ba: Cu in the sintered body was 1: 2: 3.2. This is because Cu is easily sputtered and the composition of the thin film and the composition of the target change.
基板にはMgO単結晶を用い、（001）面を成膜面とし
た。スパッタリングガスとして、チャンバ内に8.0×10
-2TorrのArガスと2.0×10-2TorrのO2ガスを導入、基板
温度670℃でスパッタリングを行った。成膜速度は、約
0.50Å／秒で膜厚が１μｍになるまで成膜した。MgO single crystal was used for the substrate, and the (001) plane was used as a film forming surface. 8.0 × 10 in the chamber as sputtering gas
-2 Torr Ar gas and 2.0 × 10 -2 Torr O 2 gas were introduced, and sputtering was performed at a substrate temperature of 670 ° C. Deposition rate is about
The film was formed at 0.50 ° / sec until the film thickness became 1 μm.
尚、比較のため基板温度730℃で成膜し、その後１気
圧のO2雰囲気下で基板温度900℃で４時間保持するアニ
ール処理を行う従来の方法でも薄膜の作製を行った。For comparison, a thin film was also formed by a conventional method in which a film was formed at a substrate temperature of 730 ° C. and then an annealing treatment was carried out at a substrate temperature of 900 ° C. for 4 hours under an O 2 atmosphere of 1 atm.
次いで、得られた薄膜の抵抗を測定するためサンプル
を作製した。抵抗測定を行うサンプルは、基板上に形成
された薄膜の両端部分に、さらに真空蒸着で一対のAl電
極を形成し、このAl電極にリード線をハンダ付けした。Next, a sample was prepared for measuring the resistance of the obtained thin film. In the sample for performing the resistance measurement, a pair of Al electrodes was further formed on both ends of the thin film formed on the substrate by vacuum evaporation, and a lead wire was soldered to the Al electrode.
臨界温度Tco並びにTciの測定は、クライオスタット中
で液体ヘリウムに浸して一旦8Kまで冷却し、試料が超電
導を示すことを確認した後ヒータによって徐々に昇温
し、試料が超電導を失い始め、電気抵抗を示し始める温
度（Tci）と、試料の超電導が消失して常態と同じ電気
抵抗を示す温度（Tco）とを測定した。なお、Tco、Tci
の測定は、超電導薄膜作製直後と１ヶ月後の２回行い、
経時変化の影響を調べた。測定の結果を第１表に示す。The critical temperatures Tco and Tci were measured by immersing the sample in liquid helium in a cryostat, cooling it to 8K, and then confirming that the sample showed superconductivity. And the temperature (Tco) at which the superconductivity of the sample disappears and shows the same electrical resistance as in the normal state was measured. In addition, Tco, Tci
Measurement is performed twice immediately after the superconducting thin film is produced and one month later.
The effect of aging was investigated. The measurement results are shown in Table 1.
以上の実施例により、本発明の方法に従って作製した
超電導薄膜は、従来の方法で作製した超電導薄膜に比べ
Tco、Tci共に高く、しかもその好特性を長期間に亘って
維持することが立証された。 According to the above examples, the superconducting thin film produced according to the method of the present invention is compared with the superconducting thin film produced by the conventional method.
It was proved that both Tco and Tci were high and that their good properties were maintained over a long period of time.
発明の効果 以上説明したように、本発明により、従来の超電導体
よりもはるかに安定した超電導特性を有する酸化物超電
導薄膜および作製方法が提供される。これは、本発明の
方法に独特な、アニールにより初めて可能になったもの
である。Effects of the Invention As described above, the present invention provides an oxide superconducting thin film having superconducting properties far more stable than conventional superconductors and a method for producing the same. This is made possible only by annealing, which is unique to the method of the present invention.
従って、本発明を、超電導体を薄膜素子として応用す
る分野、例えばジョセフソン素子と呼ばれるマティソー
（Matisoo）のスイッチング素子やアナッカー（Anacke
r）のメモリー素子、さらには超電導量子干渉計（SQUI
D）などに利用すると効果的である。Therefore, the present invention is applied to a field in which a superconductor is applied as a thin film element, for example, a switching element of Matisoo called Josephson element or an anacker (Anacke).
r) memory element, and even superconducting quantum interferometer (SQUI
It is effective when used for D).
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.6 識別記号 庁内整理番号 ＦＩ 技術表示箇所 Ｈ０１Ｌ 39/24 ＺＡＡ Ｈ０１Ｌ 39/24 ＺＡＡＢ (72)発明者 矢津 修示 兵庫県伊丹市昆陽北１丁目１番１号 住 友電気工業株式会社伊丹製作所内 (72)発明者 上代 哲司 兵庫県伊丹市昆陽北１丁目１番１号 住 友電気工業株式会社伊丹製作所内 (56)参考文献 特開 昭64−14820（ＪＰ，Ａ) 特開 昭64−19614（ＪＰ，Ａ) 特開 昭64−35819（ＪＰ，Ａ)─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. 6 Identification number Internal reference number FI Technical display location H01L 39/24 ZAA H01L 39/24 ZAAB (72) Inventor Shuji Yazu 1 Kunyokita, Itami City, Hyogo Prefecture 1-1-1, Sumitomo Electric Industries, Ltd. Itami Works (72) Inventor Tetsuji Ueshiro 1-1-1, Konyokita, Itami City, Hyogo Prefecture Sumitomo Electric Industries, Ltd. Itami Works (56) References 64-14820 (JP, A) JP 64-19614 (JP, A) JP 64-35819 (JP, A)
Claims (17)
とも１種の元素α、周期律表III a族元素から選択され
た少なくとも１種の元素β、周期律表I b、II b、III
b、IV a、VIII a族元素から選択された少なくとも１種
の元素γを含有する複合酸化物超電導体薄膜を作製する
方法において、ターゲットとして上記元素α、βおよび
γの単体を組み合わせたもの、および／または上記元素
α、βおよびγを含む酸化物を用いて基板温度620乃至7
00℃でスパッタリングを行い、酸化物の薄膜を形成する
ことを特徴とする複合酸化物超電導薄膜の作製方法。1. At least one element α selected from Group IIa elements of the Periodic Table, at least one element β selected from Group IIIa elements of the Periodic Table, Periodic Tables Ib, IIb, III
b, a method of producing a composite oxide superconductor thin film containing at least one element γ selected from the group IVa, VIIIa, in which a simple substance of the above elements α, β and γ is combined as a target, And / or using an oxide containing the above-mentioned elements α, β and γ with a substrate temperature of 620 to 7
A method for producing a composite oxide superconducting thin film, which comprises forming an oxide thin film by performing sputtering at 00 ° C.
乃至680℃であることを特徴とする特許請求の範囲第１
項に記載の複合酸化物超電導薄膜の作製方法。2. The substrate temperature during the sputtering is 660.
To 680 ° C. Claim 1
Item 8. A method for producing a composite oxide superconducting thin film according to the item.
＋βに対するβの原子比で、0.1≦ｘ≦0.9であり、ｙお
よびｚは（α1-xβｘ）を１とした場合に0.4≦ｙ≦3.
0、１≦ｚ≦５となる原子比である） で表される組成の酸化物であることを特徴とする特許請
求の範囲第１項または第２項に記載の複合酸化物超電導
薄膜の作製方法。3. The composite oxide superconducting thin film according to the general formula: (α 1 -x β x ) γ y O z (where α, β and γ are the elements defined above, and x is α
The atomic ratio of β to + β is 0.1 ≦ x ≦ 0.9, and y and z are 0.4 ≦ y ≦ 3 when (α 1−x β x ) is 1.
0 is an atomic ratio satisfying 0 ≦ 1 ≦ z ≦ 5), and the composite oxide superconducting thin film according to claim 1 or 2, characterized in that Method.
イト型または酸素欠陥ペロブスカイト型酸化物であるこ
とを特徴とする特許請求の範囲第１項乃至第３項のいず
れか１項に記載の複合酸化物超電導薄膜の作製方法。4. The complex oxide according to claim 1, wherein the complex oxide superconducting thin film is a perovskite type oxide or an oxygen deficient perovskite type oxide. Method for manufacturing superconducting thin film.
を含み、さらにAl、Fe、Co、Ni、Zn、Cu、Ag、Tiによっ
て構成される群から選択される少なくとも１種の元素を
含む複合酸化物超電導体で構成されることを特徴とする
特許請求の範囲第１項乃至第４項のいずれか１項に記載
の複合酸化物超電導薄膜の作製方法。5. The composite oxide superconducting thin film comprises Ba and Y.
And a composite oxide superconductor containing at least one element selected from the group consisting of Al, Fe, Co, Ni, Zn, Cu, Ag, and Ti. The method for producing a complex oxide superconducting thin film according to any one of claims 1 to 4.
る） で表される複合酸化物で構成されることを特徴とする特
許請求の範囲第５項に記載の複合酸化物超電導薄膜の作
製方法。6. The composite oxide superconducting thin film is composed of a composite oxide represented by Y 1 Ba 2 Cu 3 O 7-x (where x is a number satisfying 0 <x <1). The method for producing a complex oxide superconducting thin film according to claim 5, characterized in that
を含み、さらにAl、Fe、Co、Ni、Zn、Cu、Ag、Tiによっ
て構成される群から選択される少なくとも１種の元素を
含む複合酸化物超電導体で構成されることを特徴とする
特許請求の範囲第１項乃至第４項のいずれか１項に記載
の複合酸化物超電導薄膜の作製方法。7. The composite oxide superconducting thin film comprises Ba and La.
And a composite oxide superconductor containing at least one element selected from the group consisting of Al, Fe, Co, Ni, Zn, Cu, Ag, and Ti. The method for producing a complex oxide superconducting thin film according to any one of claims 1 to 4.
る） で表される複合酸化物で構成されることを特徴とする特
許請求の範囲第７項に記載の超電導体層を有する半導体
基板。8. The composite oxide superconducting thin film is composed of a composite oxide represented by La 1 Ba 2 Cu 3 O 7-x (where x is a number satisfying 0 <x <1). A semiconductor substrate having a superconductor layer according to claim 7.
を含み、さらにAl、Fe、Co、Ni、Zn、Cu、Ag、Tiによっ
て構成される群から選択される少なくとも１種の元素を
含む複合酸化物超電導体で構成されることを特徴とする
特許請求の範囲第１項乃至第４項のいずれか１項に記載
の複合酸化物超電導薄膜の作製方法。9. The composite oxide superconducting thin film comprises Sr and La.
And a composite oxide superconductor containing at least one element selected from the group consisting of Al, Fe, Co, Ni, Zn, Cu, Ag, and Ti. The method for producing a complex oxide superconducting thin film according to any one of claims 1 to 4.
る） で表される複合酸化物で構成されることを特徴とする特
許請求の範囲第９項に記載の複合酸化物超電導薄膜の作
製方法。10. The composite oxide superconducting thin film is composed of a composite oxide represented by La 1 Sr 2 Cu 3 O 7-x (where x is a number satisfying 0 <x <1). 10. The method for producing a composite oxide superconducting thin film according to claim 9, wherein
Hoを含み、さらにAl、Fe、Co、Ni、Zn、Cu、Ag、Tiによ
って構成される群から選択される少なくとも１種の元素
を含む複合酸化物超電導体で構成されることを特徴とす
る特許請求の範囲第１項乃至第４項のいずれか１項に記
載の複合酸化物超電導薄膜の作製方法。11. The composite oxide superconducting thin film comprises Ba and
A composite oxide superconductor containing Ho and further containing at least one element selected from the group consisting of Al, Fe, Co, Ni, Zn, Cu, Ag, and Ti. The method for producing a complex oxide superconducting thin film according to any one of claims 1 to 4.
る） で表される複合酸化物で構成されることを特徴とする特
許請求の範囲第11項に記載の複合酸化物超電導薄膜の作
製方法。12. The composite oxide superconducting thin film is composed of a composite oxide represented by Ho 1 Ba 2 Cu 3 O 7-x (where x is a number satisfying 0 <x <1). 12. The method for producing a composite oxide superconducting thin film according to claim 11, characterized in that.
0×10-3乃至4.0×10-1Torrの範囲内であることを特徴と
する特許請求の範囲第１項乃至第12項のいずれか１項に
記載の複合酸化物超電導薄膜の作製方法。13. The O 2 partial pressure of the sputtering atmosphere is 1.
The method for producing a composite oxide superconducting thin film according to any one of claims 1 to 12, wherein the method is within a range of 0 × 10 -3 to 4.0 × 10 -1 Torr.
0.4乃至3W/cm2であることを特徴とする特許請求の範囲
第１項乃至第13項のいずれか１項に記載の複合酸化物超
電導薄膜の作製方法。14. The high frequency power during the sputtering is
14. The method for producing a complex oxide superconducting thin film according to claim 1, wherein the superconducting thin film has a density of 0.4 to 3 W / cm 2 .
結晶またはZrO2単結晶を用いることを特徴とする特許請
求の範囲第１項乃至第14項のいずれか１項に記載の複合
酸化物超電導薄膜の作製方法。15. The composite oxidation according to any one of claims 1 to 14, wherein MgO single crystal, SrTiO 3 single crystal or ZrO 2 single crystal is used as the substrate. Method for manufacturing superconducting thin film.
の成膜面を、｛001｝面または｛011｝面とすることを特
徴とする特許請求の範囲第15項に記載の複合酸化物超電
導薄膜の作製方法。16. The composite oxide according to claim 15, wherein the film forming surface of the MgO single crystal or SrTiO 3 single crystal substrate is a {001} surface or a {011} surface. Manufacturing method of superconducting thin film.
レス鋼、サファイアおよびセラミックスからなる群より
選択された１種であることを特徴とする特許請求の範囲
第１項乃至第14項のいずれか１項に記載の複合酸化物超
電導薄膜の作製方法。17. The method according to claim 1, wherein the substrate is one kind selected from the group consisting of glass, quartz, Si, stainless steel, sapphire and ceramics. 2. The method for producing a composite oxide superconducting thin film according to Item 1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62332303A JP2501609B2 (en) | 1987-12-29 | 1987-12-29 | Method for producing complex oxide superconducting thin film |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62332303A JP2501609B2 (en) | 1987-12-29 | 1987-12-29 | Method for producing complex oxide superconducting thin film |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH01176217A JPH01176217A (en) | 1989-07-12 |
| JP2501609B2 true JP2501609B2 (en) | 1996-05-29 |
Family
ID=18253451
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP62332303A Expired - Fee Related JP2501609B2 (en) | 1987-12-29 | 1987-12-29 | Method for producing complex oxide superconducting thin film |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2501609B2 (en) |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6414820A (en) * | 1987-07-08 | 1989-01-19 | Matsushita Electric Ind Co Ltd | Manufacture of superconductor thin film |
| JPS6419614A (en) * | 1987-07-14 | 1989-01-23 | Matsushita Electric Ind Co Ltd | Thin film type superconductor |
| JPS6435819A (en) * | 1987-07-31 | 1989-02-06 | Matsushita Electric Ind Co Ltd | Manufacture of superconducting membrane |
-
1987
- 1987-12-29 JP JP62332303A patent/JP2501609B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH01176217A (en) | 1989-07-12 |
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