JPH0195418A - Formation of superconducting thin film - Google Patents
Formation of superconducting thin filmInfo
- Publication number
- JPH0195418A JPH0195418A JP62253191A JP25319187A JPH0195418A JP H0195418 A JPH0195418 A JP H0195418A JP 62253191 A JP62253191 A JP 62253191A JP 25319187 A JP25319187 A JP 25319187A JP H0195418 A JPH0195418 A JP H0195418A
- Authority
- JP
- Japan
- Prior art keywords
- thin film
- producing
- superconducting thin
- film according
- superconductor
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 239000010409 thin film Substances 0.000 title claims abstract description 68
- 230000015572 biosynthetic process Effects 0.000 title claims description 6
- 229910052731 fluorine Inorganic materials 0.000 claims abstract description 30
- 239000011737 fluorine Substances 0.000 claims abstract description 23
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 21
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 21
- 239000001301 oxygen Substances 0.000 claims abstract description 21
- 239000002253 acid Substances 0.000 claims abstract description 14
- KRHYYFGTRYWZRS-UHFFFAOYSA-M Fluoride anion Chemical compound [F-] KRHYYFGTRYWZRS-UHFFFAOYSA-M 0.000 claims abstract description 11
- 239000010408 film Substances 0.000 claims abstract description 11
- 230000003647 oxidation Effects 0.000 claims abstract description 11
- 238000007254 oxidation reaction Methods 0.000 claims abstract description 11
- 230000000737 periodic effect Effects 0.000 claims abstract description 11
- 239000007789 gas Substances 0.000 claims abstract description 9
- 238000005240 physical vapour deposition Methods 0.000 claims abstract description 9
- 239000000203 mixture Substances 0.000 claims abstract description 4
- PXGOKWXKJXAPGV-UHFFFAOYSA-N Fluorine Chemical compound FF PXGOKWXKJXAPGV-UHFFFAOYSA-N 0.000 claims abstract 7
- 239000002131 composite material Substances 0.000 claims description 48
- 239000013078 crystal Substances 0.000 claims description 28
- 238000004519 manufacturing process Methods 0.000 claims description 27
- 239000002887 superconductor Substances 0.000 claims description 20
- 239000000758 substrate Substances 0.000 claims description 19
- 229910052746 lanthanum Inorganic materials 0.000 claims description 7
- 238000004544 sputter deposition Methods 0.000 claims description 4
- 238000010438 heat treatment Methods 0.000 claims description 3
- 238000007733 ion plating Methods 0.000 claims description 2
- 238000007738 vacuum evaporation Methods 0.000 claims description 2
- 229910052727 yttrium Inorganic materials 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
- 229910052719 titanium Inorganic materials 0.000 claims 4
- 229910052725 zinc Inorganic materials 0.000 claims 4
- 238000001451 molecular beam epitaxy Methods 0.000 claims 1
- 238000000034 method Methods 0.000 abstract description 10
- 239000000463 material Substances 0.000 abstract description 9
- YCKRFDGAMUMZLT-UHFFFAOYSA-N Fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 description 15
- 150000002222 fluorine compounds Chemical class 0.000 description 4
- 238000000151 deposition Methods 0.000 description 3
- 230000008021 deposition Effects 0.000 description 3
- 238000001704 evaporation Methods 0.000 description 3
- 230000008020 evaporation Effects 0.000 description 3
- 230000005668 Josephson effect Effects 0.000 description 2
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 2
- 125000004429 atom Chemical group 0.000 description 2
- 239000000919 ceramic Substances 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000005291 magnetic effect Effects 0.000 description 2
- 238000001755 magnetron sputter deposition Methods 0.000 description 2
- 229910021521 yttrium barium copper oxide Inorganic materials 0.000 description 2
- 229910052684 Cerium Inorganic materials 0.000 description 1
- 229910052688 Gadolinium Inorganic materials 0.000 description 1
- 229910052689 Holmium Inorganic materials 0.000 description 1
- 229910052765 Lutetium Inorganic materials 0.000 description 1
- 229910002367 SrTiO Inorganic materials 0.000 description 1
- 229910052769 Ytterbium Inorganic materials 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000005292 diamagnetic effect Effects 0.000 description 1
- 125000001153 fluoro group Chemical group F* 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 229910052747 lanthanoid Inorganic materials 0.000 description 1
- 150000002602 lanthanoids Chemical class 0.000 description 1
- 229910052758 niobium Inorganic materials 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
- 230000007704 transition Effects 0.000 description 1
- 238000007740 vapor deposition Methods 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
- Crystals, And After-Treatments Of Crystals (AREA)
- Physical Vapour Deposition (AREA)
- Superconductor Devices And Manufacturing Methods Thereof (AREA)
- Superconductors And Manufacturing Methods Therefor (AREA)
Abstract
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作製方法に関する。より詳細には
、高い超電導臨界温度および臨界電流を有し、優れた超
電導特性を持つ超電導薄膜の作製方法に関する。DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for producing superconducting thin films. More specifically, the present invention relates to a method for producing a superconducting thin film having high superconducting critical temperature and critical current, and having excellent superconducting properties.
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。BACKGROUND OF THE INVENTION Superconductivity, which is said to be a phase transition of electrons, is a phenomenon in which the electrical resistance of a conductor becomes zero under certain conditions and exhibits complete diamagnetic properties.
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 types of superconducting elements are known in the field of electronics. A typical example is an element that utilizes the Josephson effect, in which a quantum effect appears macroscopically due to an applied current when superconducting materials are weakly bonded together.
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。Tunnel junction type Josephson devices are expected to be extremely high-speed switching devices with low power consumption because the energy gap of superconducting materials is small. Also,
Since the Josephson effect on electromagnetic waves and magnetic fields appears as a precise quantum phenomenon, it is expected that Josephson devices will be used as ultrasensitive sensors for magnetic fields, microwaves, radiation, etc. Furthermore, as the degree of integration of electronic circuits increases, power consumption per unit area reaches the limit of cooling capacity. Therefore, there is a need for the development of superconducting elements 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Ｎｂ、Ｇｅ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） ａｃｕｏ４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５０にという従来に比
べて飛躍的に高いＴ。が観測され、７０に以上の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 for Nb and Ge for a long period of time, but last year, in the future, [La, Ba
Sintered materials of oxides such as 2Cuo4 or (La, Sr) acuo4 have been discovered as superconducting materials with high Tc, and the possibility of realizing non-low temperature superconductivity has greatly increased. These materials have a T of 30 to 50, which is dramatically higher than that of conventional materials. has been observed, and Tc of 70 or higher has also been observed.
また、ＹＢＣＯと称されるＹ（Ｂａ２Ｃｕ３０７−Ｘで
表される複合酸化物は、１００に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、Ｔ
ｃは低く、また、オンセ・ソ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。In addition, it has been announced that a composite oxide represented by Y (Ba2Cu307-X) called YBCO is a 100-class superconductor.The superconducting properties of these composite oxide superconductors include Oxygen vacancies in the crystal play a major role.In other words, if the oxygen vacancies in the crystal are not appropriate, the T
c is low, and the difference between the temperature at which the resistance becomes completely zero is also large.
また、上記の複合酸化物の酸素の一部をフッ素で置き換
えた複合酸フッ化物は、さらに高いＴｃを示すことが明
らかになりつつある。Furthermore, it is becoming clear that a composite acid fluoride in which part of the oxygen in the above composite oxide is replaced with fluorine exhibits an even higher Tc.
発明が解決しようとする問題点
従来、上記複合酸フッ化物超電導体薄膜を作製する際に
は、焼結等で生成した酸フッ化物を蒸着源として物理蒸
着を行っていた。Problems to be Solved by the Invention Conventionally, when producing the above composite oxyfluoride superconductor thin film, physical vapor deposition was performed using oxyfluoride produced by sintering or the like as a deposition source.
しかしながら、上記の複合酸フッ化物焼結体を作製する
のは、かなり困難であり、また、複合酸フッ化物焼結体
を蒸着源としても、得られる薄膜に含まれるフッ素の量
は、十分ではなかった。However, it is quite difficult to produce the above composite acid fluoride sintered body, and even if the composite acid fluoride sintered body is used as a deposition source, the amount of fluorine contained in the resulting thin film is insufficient. There wasn't.
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緒特性
を安定的に有し、均一な組成および組織の複合酸フッ化
物超電導材料の薄膜を作製する方法を提供することにあ
る。Therefore, an object of the present invention is to solve the above-mentioned problems of the prior art, and to create a composite oxyfluoride superconducting material that stably has excellent superconducting properties including a high critical temperature Tc, and has a uniform composition and structure. An object of the present invention is to provide a method for producing a thin film of.
問題点を解決するための手段
本発明に従うと、周期律表１ＩＩａ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［［ａ族元素から
選択された少なくとも１種の元素βおよび周期律表Ｉｂ
、［ｂ、］Ｉ［ｂ、ＩＶａ、■ａ族元素から選択された
少なくとも１種の元素γを含有する複合酸フッ化物超電
導体薄膜を作製する方法において、物理蒸着により上記
元素α、βおよびＴを含有する薄膜を生成し、該薄膜を
酸素およびフッ素の混合ガスプラズマに曝すプラズマ酸
化処理を行って複合酸フッ化物超電導体薄膜を作製する
ことを特徴とする超電導薄膜の作製方法が提供される。Means for Solving the Problems According to the present invention, at least one element α selected from the elements of group 1IIa of the periodic table, at least one element β selected from the elements of group A of the periodic table, and period Table Ib
, [b,] I[b, IVa, ■ In a method for producing a composite oxyfluoride superconductor thin film containing at least one element γ selected from group a elements, the above elements α, β and A method for producing a superconducting thin film is provided, which comprises producing a thin film containing T, and performing a plasma oxidation treatment of exposing the thin film to a mixed gas plasma of oxygen and fluorine to produce a composite oxyfluoride superconducting thin film. Ru.
本発明の方法で作製される複合酸フッ化物超電導薄膜は
、下記一般式：
％式％）
（但し、αは周期律表Ｉ［ａ族に含まれる元素であり、
βは周期律表１ｉａ族に含まれる元素であり、γは周期
律表Ｉ ｂ、 ｎｂ、 ＩＩ［ｂ、 ｒＶａ右よび■ａ
族から選択される少なくとも一つの元素であり、Ｘ５Ｖ
ｓＺはそれぞれ０．１≦Ｘ≦０．９．０．４≦ｙ≦３゜
０．１≦２≦５を満たす数である）
で示される複合酸フッ化物で構成されることが好ましい
。これらの複合酸フッ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フッ化物を主体としたものと考え
られる。The composite oxyfluoride superconducting thin film produced by the method of the present invention has the following general formula:
β is an element included in group 1ia of the periodic table, and γ is an element included in group 1ia of the periodic table.
at least one element selected from the group X5V
sZ is a number satisfying 0.1≦X≦0.9, 0.4≦y≦3°, 0.1≦2≦5, respectively). These composite acid fluorides are thought to be mainly composed of perovskite-type or pseudo-perovskite-type acid fluorides.
上記周期律表［ａ族元素αとしては、Ｂａ５Ｓｒ。The periodic table [a group element α is Ba5Sr.
Ｃａ５Ｍｇ５Ｂｅ等が好ましく、例えば、Ｂａ５Ｓｒを
挙げることができ、この元素αの１０〜８０％をＭｇ５
Ｃａ。Ca5Mg5Be etc. are preferable, for example, Ba5Sr can be mentioned, and 10 to 80% of this element α is Mg5
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１１ｉａ族元素βはとし
ては、Ｙ、 Ｌａ５Ｓｃ、 Ｃｅ、 Ｇｄ、 Ｈｏ、８
ｒ、 Ｔｍ。It can also be replaced with one or two elements selected from Sr. Further, the elements β of group 11ia of the periodic table include Y, La5Sc, Ce, Gd, Ho, 8
r, Tm.
Ｙｂ、 Ｌｕ等が好ましく、例えばＹ、Ｌａとすること
ができ、この元素βのうち、１０〜８０％をＳｃまたは
Ｌａ以外の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Ｔは一般
にＣｕであるが、その一部を周期律表Ｉｂ。Yb, Lu, etc. are preferable, and for example, Y and La can be used, and 10 to 80% of this element β can be replaced with one or two elements selected from lanthanide elements other than Sc or La. You can also do it. The element T is generally Cu, and some of it is listed in Periodic Table Ib.
ＩＩ ｂ、 Ｉ［ｂ、 ｒＶａおよび■ａ族から選択さ
れる他の元素、例えば、Ｔｉ５Ｖ等で置換することもで
きる。It is also possible to substitute other elements selected from the IIb, I[b, rVa and ■a groups, for example, Ti5V.
本発明の態様に従うと、上記の複合酸フッ化物超電導薄
膜を形成する基板としては、ＭｇＯ単結晶、ＳｒＴｉＯ
３単結晶または２ｒＯ□単結晶が好ましく、特に、Ｍｇ
Ｏ単結晶または５ｒＴｉＯｓ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 an aspect of the present invention, the substrate on which the composite oxyfluoride superconducting thin film is formed is MgO single crystal, SrTiO
3 single crystal or 2rO□ single crystal is preferred, especially Mg
The film formation surface of the O single crystal or 5rTiOs single crystal substrate is
It is preferable to use a (001) plane or a (011) plane.
作用
本発明の超電導薄膜の作製方法は、スパッタリング、Ｍ
ＢＥ、イオンプレーティング、真空蒸着等の物理蒸着で
作製した複合酸化物薄膜を、酸素およびフッ素の混合ガ
スプラズマに曝すプラズマ酸化処理を行い、複合酸フッ
化物超電導薄膜を得るところにその主要な特徴がある。Function The method for producing the superconducting thin film of the present invention includes sputtering, M
Its main feature is that a composite oxide thin film produced by physical vapor deposition such as BE, ion plating, or vacuum evaporation is subjected to plasma oxidation treatment by exposing it to a mixed gas plasma of oxygen and fluorine to obtain a composite oxyfluoride superconducting thin film. There is.
すなわち、ＹＢＣＯと称されるＹ ｒ ＢａｚＣｕ３０
１−ｘで代表される複合酸化物超電導体の酸素の一部を
フッ素で置換した複合酸フッ化物は、上記の複合酸化物
超電導体よりさらに優れた超電導特性を有する。しかし
ながら、従来の方法では、上記の複合酸フッ化物超電導
薄膜を組成を厳密に制御しながら作製することが困難で
あった。そのため、従来得られた複合酸フッ化物超電導
薄膜は、薄膜ごとにその特性が大幅に異なり、安定しな
かった。That is, Y r BazCu30 called YBCO
A composite oxyfluoride obtained by substituting a part of the oxygen of a composite oxide superconductor represented by 1-x with fluorine has superconducting properties superior to those of the above-mentioned composite oxide superconductor. However, with conventional methods, it has been difficult to fabricate the above composite oxyfluoride superconducting thin film while strictly controlling the composition. Therefore, the properties of the conventionally obtained composite oxyfluoride superconducting thin films differed greatly depending on the thin film and were not stable.
これは、蒸着源となる複合酸フッ化物の作製が困難であ
ること、また、蒸着源の複合酸フッ化物が作製できても
、酸化物とフッ化物の蒸着特性が大幅に異なるため、薄
膜中のフッ素量を制御することができなかった。また、
蒸着雰囲気をフッ素含有雰囲気とすることも゛、装置が
高価になること等から不利である。This is because it is difficult to prepare a composite acid fluoride as an evaporation source, and even if a composite oxyfluoride can be made as an evaporation source, the deposition characteristics of oxides and fluorides are significantly different. It was not possible to control the amount of fluorine. Also,
Using a fluorine-containing atmosphere as the vapor deposition atmosphere is also disadvantageous because the equipment becomes expensive.
従って、本発明の方法では、予め物理蒸着で複合酸化物
薄膜を作製し、該薄膜を酸素、フッ素混合ガスプラズマ
でプラズマ酸化処理することにより、複合酸化物結晶中
の酸素の一部をフッ素で置き換えた複合酸フッ化物を生
成するとともに、結晶の酸素欠陥を調整する。Therefore, in the method of the present invention, a composite oxide thin film is prepared in advance by physical vapor deposition, and a part of the oxygen in the composite oxide crystal is converted into fluorine by plasma oxidation treatment of the thin film with oxygen and fluorine mixed gas plasma. A substituted complex acid fluoride is generated, and oxygen defects in the crystal are adjusted.
本発明の複合酸フッ化物超電導薄膜を形成する複合酸７
フ化物としては、Ｙ、Ｂａ２Ｃｕ、 （ｏ、 Ｆ ）
７−Ｘ％Ｌａ＋ＢａｚＣｕｓ （ｏ、 Ｆ〕ｆｆ−Ｘ５
Ｌａ＋Ｂａ２Ｃｕｓ ［０，Ｆｉｌ ｆｆ−Ｘ、また
はＨＯｔＢａ２Ｃｕ３（０，Ｆ 〕〕７−ｘ（ただしＸ
は０くｘ＜ｌを満たす数である。）が好ましい。Composite acid 7 forming composite acid fluoride superconducting thin film of the present invention
Fluorides include Y, Ba2Cu, (o, F)
7-X%La+BazCus (o, F]ff-X5
La+Ba2Cus [0, Fil ff-X, or HOtBa2Cu3(0,F]]7-x (however, X
is a number that satisfies 0x<l. ) is preferred.
本発明の物理蒸着は、スパッタリング特にマグネトロン
スパッタリングが好ましい。これは、蒸着雰囲気、スパ
ッタリング電力、ターゲットの種類、ターゲットと基板
の位置等のパラメータの選折幅が広いため、各種の特性
を有する薄膜を作製することができるからである。In the physical vapor deposition of the present invention, sputtering, particularly magnetron sputtering, is preferable. This is because there is a wide selection range of parameters such as evaporation atmosphere, sputtering power, type of target, and position of the target and substrate, so thin films with various characteristics can be produced.
また、本発明のプラズマ酸化は、圧力０．１〜５Ｔｏｒ
ｒでＦ２／（Ｆ２＋Ｏ２）の比が、１〜５０原子％であ
ること、特に５〜３０原子％であることが好ましい。In addition, the plasma oxidation of the present invention is performed at a pressure of 0.1 to 5 Torr.
It is preferable that the ratio of F2/(F2+O2) in r is 1 to 50 at%, particularly 5 to 30 at%.
この理由は、圧力が０．ＩＴｏｒｒ未満および５ Ｔｏ
ｒｒを越えるとプラズマの強さが十分ではなく、また、
Ｆ２／（Ｆ２”０２）の比が、１原子％未満では薄膜中
のフッ素が十分とならず、５０原子％を越えると逆に薄
膜中のフッ素が過剰となり、いずれの場合も薄膜の超電
導特性は悪化するからである。さらに、上記Ｆ２／（Ｆ
２＋Ｏ２）の比が５〜３０原子％の範囲では緒特性の優
れた超電導薄膜が得られ易いため、５〜３０原子％の範
囲が特に好ましい。The reason for this is that the pressure is 0. less than ITorr and 5 Torr
If rr is exceeded, the plasma strength is not sufficient, and
If the ratio of F2/(F2''02) is less than 1 atomic %, there will not be enough fluorine in the thin film, and if it exceeds 50 atomic %, the fluorine in the thin film will be excessive, and in either case, the superconducting properties of the thin film will be affected. This is because F2/(F
When the ratio of 2+O2) is in the range of 5 to 30 atom %, a superconducting thin film with excellent properties can be easily obtained, so the range of 5 to 30 atom % is particularly preferable.
本発明の態様に従うと、上記の複合酸フッ化物超電導薄
膜を形成する基板としては、ＭｇＯ単結晶、ＳｒＴ＋Ｃ
）＋単結晶またはＺｒＯ２単結晶基板が好ましい。According to an aspect of the present invention, the substrate on which the composite oxyfluoride superconducting thin film is formed is MgO single crystal, SrT+C
) + single crystal or ZrO2 single crystal substrate is preferred.
特に、λＩｇＯ単結晶基板または５ｒＴｉＯａ単結晶基
板の（ＯＯＮ面または（０１１）面を成膜面として用い
ることが好ましい。In particular, it is preferable to use the (OON plane or (011) plane) of the λIgO single crystal substrate or the 5rTiOa single crystal substrate as the film forming surface.
本発明の複合酸フッ化物超電導体は、その電気抵抗に結
晶異方性を有する。すなわち、結晶のＣ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フッ化物超電導薄
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。The composite acid fluoride superconductor of the present invention has crystal anisotropy in its electrical resistance. That is, current tends to flow in a direction parallel to the plane determined by the c-axis and b-axis of the crystal. The composite oxyfluoride superconducting thin film formed on the film formation surface of the above substrate has a particularly large critical current density Jc because the C axis of its crystal is perpendicular or at an angle close to perpendicular to the substrate film formation surface. Become.
従って、ＭｇＯ単結晶基板または５ｒＴｔＯａ単結晶基
板の（００１）面を成膜面として用いることが好ましい
。また、（０１１）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、ＭｇＯ１ＳｒＴｉＯｓは、熱膨張率が上記の複合酸
フッ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
れもない。Therefore, it is preferable to use the (001) plane of the MgO single crystal substrate or the 5rTtOa single crystal substrate as the film forming surface. In addition, the C axis is made parallel to the substrate using the (011) plane,
It is also possible to specify and use a direction perpendicular to the C-axis. Furthermore, since MgO1SrTiOs has a coefficient of thermal expansion close to that of the above-mentioned composite oxyfluoride superconductor, unnecessary stress is not applied to the thin film during heating and cooling processes, and there is no risk of damaging 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、以下の開示に何隻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 explained below using examples, but it goes without saying that the technical scope of the present invention is not limited to the following disclosure.
本発明の方法により、マグネトロンスパッタリングで超
電導薄膜を作製した。原料酸化物として、Ｈｏ：Ｂａ：
Ｃｕのモル比が１：２：４であるＨｏ −Ｂａ −Ｃｕ
−０セラミツクを用いた。上記のセラミックをφ１００
＋ｎ＋ｎの円板に成形し、ターゲットとした。基板は、
ＭｇＯ単結晶基板とし、（１００）面を成膜面として用
いた。A superconducting thin film was fabricated by magnetron sputtering according to the method of the present invention. As raw material oxides, Ho:Ba:
Ho-Ba-Cu in which the molar ratio of Cu is 1:2:4
-0 ceramic was used. The above ceramic is φ100
+n+n disk was formed and used as a target. The board is
A MgO single crystal substrate was used, and the (100) plane was used as the film formation surface.
成膜条件を以下に示す。The film forming conditions are shown below.
基板温度 ６７０℃
圧 力 ０．０１〜０． ＩＴｏｒｒＲＦ電
力 １００〜２００ Ｗ
成膜時間は６０分で、得られた薄膜の膜厚は約０．８μ
ｍであった。Substrate temperature 670℃ Pressure 0.01~0. ITorrRF electric
Power: 100-200 W Film-forming time was 60 minutes, and the thickness of the obtained thin film was approximately 0.8μ.
It was m.
次いで、上記のように作製した複合酸化物薄膜を酸素、
フッ素混合ガスプラズマと酸素のみのプラズマのそれぞ
れのプラズマでプラズマ酸化処理した。プラズマ酸化条
件を以下に示す。尚、雲囲気以外の他の条件は共通であ
る。Next, the composite oxide thin film prepared as described above was exposed to oxygen,
Plasma oxidation treatment was performed using both fluorine mixed gas plasma and oxygen-only plasma. The plasma oxidation conditions are shown below. Note that the other conditions other than the cloud enclosure are the same.
酸素流量 １０〜２０ＳＣＣＭ フッ素流量 ２ ＳＣＣＭ 圧 力 ０．５〜ＩＴｏｒｒ ＲＦ電 力 ４０Ｗ 処理時間は、いずれも４時間である。Oxygen flow rate 10~20SCCM Fluorine flow rate 2 SCCM Pressure Force 0.5~ITorr RF power 40W The processing time was 4 hours in both cases.
得られたそれぞれの超電導薄膜の主な超電導特性を以下
に示す。The main superconducting properties of each superconducting thin film obtained are shown below.
本発明 従来例
臨界電流密度 ２ ＸＩＯ’ Ｉ ＸＩＯ’
Ｊｃ （Ａ／ｃ＋＋ｆ） ７７に
上記のように本発明の方法により作製された超電導薄膜
は、従来のものより良好な超電導特性を示す。これは、
酸素サイトの一部に、電気陰性度が高いフッ素が入った
ことによるものと考えられる。Present invention Prior art critical current density 2 XIO' I XIO'
Jc (A/c++f) 77 The superconducting thin film produced by the method of the present invention as described above exhibits better superconducting properties than conventional ones. this is,
This is thought to be due to the introduction of fluorine, which has a high electronegativity, into some of the oxygen sites.
発明の効果
以上詳述のように、本発明の方法によって得られた超電
導薄膜は、従来の方法で作製されたものに較べ、高いＴ
ｃ５Ｊｃを示す。Effects of the Invention As detailed above, the superconducting thin film obtained by the method of the present invention has a higher T than that produced by the conventional method.
c5Jc is shown.
これは、本発明の方法に特徴的な処理方法に従って、ペ
ロプスカイト型結晶構造を持つ酸化物の酸素サイトの一
部を電気陰性度が高いフッ素と晋き換えることにより初
めて実現したものである。This was achieved for the first time by replacing some of the oxygen sites of an oxide with a perovskite crystal structure with fluorine, which has a high electronegativity, according to a treatment method characteristic of the method of the present invention.
また、本発明の方法に従えば、従来よりも置き換えるフ
ッ素の量を厳密に制御できるため、より安定に高性能な
超電導薄膜を供給することが可能となる。Further, according to the method of the present invention, the amount of fluorine to be replaced can be controlled more strictly than in the past, so it becomes possible to more stably supply a high-performance superconducting thin film.
特許出願人 住友電気工業株式会社Patent applicant: Sumitomo Electric Industries, Ltd.
Claims (20)
種の元素α、周期律表IIIａ族元素から選択された少な
くとも１種の元素βおよび周期律表 I ｂ、IIｂ、IIIｂ
、IVａ、VIIIａ族元素から選択された少なくとも１種の
元素γを含有する複合酸フッ化物超電導体薄膜を作製す
る方法において、物理蒸着により上記元素α、βおよび
γを含有する薄膜を生成し、該薄膜を酸素およびフッ素
の混合ガスプラズマに曝すプラズマ酸化処理を行って複
合酸フッ化物超電導体薄膜を作製することを特徴とする
超電導薄膜の作製方法。(1) At least one selected from group IIa elements of the periodic table
element α, at least one element β selected from group IIIa elements of the periodic table, and elements I b, IIb, IIIb of the periodic table
, IVa, and VIIIa group elements, a method for producing a composite oxyfluoride superconductor thin film containing at least one element γ selected from group IVa and VIIIa elements, comprising: producing a thin film containing the above elements α, β, and γ by physical vapor deposition; A method for producing a superconducting thin film, which comprises producing a composite oxyfluoride superconductor thin film by subjecting the thin film to a plasma oxidation treatment in which the thin film is exposed to a mixed gas plasma of oxygen and fluorine.
ｚ（但し、α、β、γは、上記定義の元素であり、ｘは
α＋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（α＿１＿−＿ｘβ＿ｘ）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項に記載の超電導薄膜の作製方法。(2) The above composite acid fluoride superconductor has the general formula: (α_1_−_xβ_x)γ_y[O,F]_
z (However, α, β, γ are the elements defined above, x is the atomic ratio of β to α + β, 0.1≦x≦0.9, and y and z are (α_1_−_xβ_x) Claim 1 is characterized in that the oxide is an oxide having a composition represented by The method for producing the superconducting thin film described above.
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
または第２項に記載の超電導薄膜の作製方法。(3) The method for producing a superconducting thin film according to claim 1 or 2, wherein the composite acid fluoride superconductor is a perovskite-type oxide.
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項に記載の超電導薄膜の作製方法。(4) The composite oxyfluoride superconductor contains Ba, Y, and at least one element selected from the group consisting of Al, Fe, Co, Ni, Zn, Cu, Ag, and Ti. Claims 1 to 3 of the claims
A method for producing a superconducting thin film according to any one of the above.
び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項に記載の超電導薄膜の作製方法。(5) The composite oxyfluoride superconductor contains Ba, La, and at least one element selected from the group consisting of Al, Fe, Co, Ni, Zn, Cu, Ag, and Ti. A method for producing a superconducting thin film according to any one of claims 1 to 3.
び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項に記載の超電導薄膜の作製方法。(6) The composite oxyfluoride superconductor contains Sr, La, and at least one element selected from the group consisting of Al, Fe, Co, Ni, Zn, Cu, Ag, and Ti. A method for producing a superconducting thin film according to any one of claims 1 to 3.
び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項に記載の超電導薄膜の作製方法。(7) The composite oxyfluoride superconductor contains Ba, Ho, and at least one element selected from the group consisting of Al, Fe, Co, Ni, Zn, Cu, Ag, and Ti. A method for producing a superconducting thin film according to any one of claims 1 to 3.
しｘは０＜ｘ＜１を満たす数である） で表される複合酸フッ化物であることを特徴とする特許
請求の範囲第４項に記載の超電導薄膜の作製方法。(8) The composite oxyfluoride superconductor is characterized by being a composite oxyfluoride represented by Y_1Ba_2Cu_3[O,F]_7_-_x (where x is a number satisfying 0<x<1). A method for producing a superconducting thin film according to claim 4.
だしｘは０＜ｘ＜１を満たす数である） で表される複合酸フッ化物であることを特徴とする特許
請求の範囲第５項に記載の超電導薄膜の作製方法。(9) The composite oxyfluoride superconductor is characterized by being a composite oxyfluoride represented by La_1Ba_2Cu_3[O,F]_7_-_x (where x is a number satisfying 0<x<1). A method for producing a superconducting thin film according to claim 5.
だしｘは０＜ｘ＜１を満たす数である） で表される複合酸フッ化物であることを特徴とする特許
請求の範囲第６項に記載の超電導薄膜の作製方法。(10) The composite oxyfluoride superconductor is characterized by being a composite oxyfluoride represented by La_1Sr_2Cu_3[O,F]_7_-_x (where x is a number satisfying 0<x<1). A method for producing a superconducting thin film according to claim 6.
だしｘは０＜ｘ＜１を満たす数である） で表される複合酸フッ化物であることを特徴とする特許
請求の範囲第７項に記載の超電導薄膜の作製方法。(11) The composite oxyfluoride superconductor is characterized by being a composite oxyfluoride represented by Ho_1Ba_2Cu_3[O,F]_7_-_x (where x is a number satisfying 0<x<1). A method for producing a superconducting thin film according to claim 7.
タキシー（ＭＢＥ）、イオンプレーティングおよび真空
蒸着のいずれかであることを特徴とする特許請求の範囲
第１項乃至第１１項のいずれか１項に記載の超電導薄膜
の作製方法。(12) According to any one of claims 1 to 11, wherein the physical vapor deposition is one of sputtering, molecular beam epitaxy (MBE), ion plating, and vacuum evaporation. The method for producing the superconducting thin film described above.
ら行うことを特徴とする特許請求の範囲第１項乃至第１
２項のいずれか１項に記載の超電導薄膜の作製方法。(13) Claims 1 to 1, characterized in that the film formation by physical vapor deposition is performed while heating the substrate.
The method for producing a superconducting thin film according to any one of Item 2.
ることを特徴とする特許請求の範囲第１３項に記載の超
電導薄膜の作製方法。(14) The method for producing a superconducting thin film according to claim 13, wherein the heating temperature of the substrate is 150 to 800°C.
間隔と近い面間隔を有する酸化物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項に記載の超電導薄膜の作製方法。(15) According to any one of claims 1 to 14, wherein the substrate is an oxide single crystal having a lattice spacing close to that of the composite oxyfluoride crystal. The method for producing the superconducting thin film described above.
３単結晶またはＺｒＯ＿２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１５項のいずれか１項
に記載の超電導薄膜の作製方法。(16) As the substrate, MgO single crystal, SrTiO_
The method for producing a superconducting thin film according to any one of claims 1 to 15, characterized in that a ZrO_2 single crystal or a ZrO_2 single crystal is used.
基板の成膜面を、｛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１６項に記載の超
電導薄膜の作製方法。(17) The method for producing a superconducting thin film according to claim 16, wherein the film-forming surface of the MgO single crystal or SrTiO_3 single crystal substrate is a {001} plane or a {011} plane.
素の割合Ｆ＿２／（Ｆ＿２＋Ｏ＿２）が、１乃至５０原
子％の範囲であることを特徴とする特許請求の範囲第１
項乃至第１７項のいずれか１項に記載の超電導薄膜の作
製方法。(18) Claim 1, characterized in that the proportion of oxygen and fluorine in the mixed gas of oxygen and fluorine, F_2/(F_2+O_2), is in the range of 1 to 50 atomic %.
The method for producing a superconducting thin film according to any one of Items 1 to 17.
素の割合Ｆ＿２／（Ｆ＿２＋Ｏ＿２）が、５乃至３０原
子％の範囲であることを特徴とする特許請求の範囲第１
８項に記載の超電導薄膜の作製方法。(19) Claim 1, characterized in that the proportion of oxygen and fluorine in the mixed gas of oxygen and fluorine, F_2/(F_2+O_2), is in the range of 5 to 30 atomic %.
The method for producing a superconducting thin film according to item 8.
ｏｒｒの範囲であることを特徴とする特許請求の範囲第
１項乃至第１９項のいずれか１項に記載の超電導薄膜の
作製方法。(20) The pressure during the plasma oxidation is 0.1 to 5T.
20. The method for producing a superconducting thin film according to any one of claims 1 to 19, wherein the superconducting thin film is in the range of orr.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62253191A JPH0195418A (en) | 1987-10-07 | 1987-10-07 | Formation of superconducting thin film |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62253191A JPH0195418A (en) | 1987-10-07 | 1987-10-07 | Formation of superconducting thin film |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0195418A true JPH0195418A (en) | 1989-04-13 |
Family
ID=17247815
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP62253191A Pending JPH0195418A (en) | 1987-10-07 | 1987-10-07 | Formation of superconducting thin film |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0195418A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5475521A (en) * | 1992-05-09 | 1995-12-12 | Alcatel Sel Aktiengesellschaft | Optical communication system with monitoring device for avoiding giant pluses |
-
1987
- 1987-10-07 JP JP62253191A patent/JPH0195418A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5475521A (en) * | 1992-05-09 | 1995-12-12 | Alcatel Sel Aktiengesellschaft | Optical communication system with monitoring device for avoiding giant pluses |
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