JPH0462982A - Method of forming electrode to superconductor - Google Patents
Method of forming electrode to superconductorInfo
- Publication number
- JPH0462982A JPH0462982A JP2174742A JP17474290A JPH0462982A JP H0462982 A JPH0462982 A JP H0462982A JP 2174742 A JP2174742 A JP 2174742A JP 17474290 A JP17474290 A JP 17474290A JP H0462982 A JPH0462982 A JP H0462982A
- Authority
- JP
- Japan
- Prior art keywords
- thin film
- metal oxide
- superconducting thin
- oxide superconducting
- film
- 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
- 239000002887 superconductor Substances 0.000 title claims abstract description 45
- 238000000034 method Methods 0.000 title claims description 45
- 239000010409 thin film Substances 0.000 claims abstract description 89
- 229910044991 metal oxide Inorganic materials 0.000 claims abstract description 82
- 150000004706 metal oxides Chemical class 0.000 claims abstract description 82
- 239000010408 film Substances 0.000 claims abstract description 34
- 229910052751 metal Inorganic materials 0.000 claims abstract description 29
- 239000002184 metal Substances 0.000 claims abstract description 28
- 230000003647 oxidation Effects 0.000 claims description 24
- 238000007254 oxidation reaction Methods 0.000 claims description 24
- 238000010884 ion-beam technique Methods 0.000 claims description 14
- 239000011261 inert gas Substances 0.000 claims description 8
- 230000001678 irradiating effect Effects 0.000 claims description 8
- 239000000463 material Substances 0.000 claims description 7
- 239000002131 composite material Substances 0.000 claims description 4
- 150000001875 compounds Chemical class 0.000 claims description 4
- 229910052737 gold Inorganic materials 0.000 claims description 3
- 229910052746 lanthanum Inorganic materials 0.000 claims description 3
- 229910052697 platinum Inorganic materials 0.000 claims description 3
- 229910052709 silver Inorganic materials 0.000 claims description 3
- 230000001133 acceleration Effects 0.000 claims description 2
- 229910052802 copper Inorganic materials 0.000 claims description 2
- 229910052727 yttrium Inorganic materials 0.000 claims description 2
- 239000010949 copper Substances 0.000 claims 3
- 229910002480 Cu-O Inorganic materials 0.000 claims 2
- 229910014454 Ca-Cu Inorganic materials 0.000 claims 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims 1
- 239000000203 mixture Substances 0.000 claims 1
- 229910052760 oxygen Inorganic materials 0.000 abstract description 31
- 239000001301 oxygen Substances 0.000 abstract description 31
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 abstract description 18
- -1 Oxygen ions Chemical class 0.000 abstract description 14
- 239000000758 substrate Substances 0.000 abstract description 13
- 238000010438 heat treatment Methods 0.000 abstract description 8
- 238000000151 deposition Methods 0.000 abstract description 3
- 150000002500 ions Chemical class 0.000 abstract 2
- 230000001590 oxidative effect Effects 0.000 abstract 1
- 239000010410 layer Substances 0.000 description 19
- 238000005530 etching Methods 0.000 description 17
- 238000004544 sputter deposition Methods 0.000 description 10
- 230000000694 effects Effects 0.000 description 7
- 230000015572 biosynthetic process Effects 0.000 description 6
- 239000013078 crystal Substances 0.000 description 6
- 230000006378 damage Effects 0.000 description 5
- 239000007789 gas Substances 0.000 description 5
- 238000000137 annealing Methods 0.000 description 4
- 230000007423 decrease Effects 0.000 description 4
- 238000010586 diagram Methods 0.000 description 4
- 230000007704 transition Effects 0.000 description 4
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 3
- 238000005229 chemical vapour deposition Methods 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- QSHDDOUJBYECFT-UHFFFAOYSA-N mercury Chemical compound [Hg] QSHDDOUJBYECFT-UHFFFAOYSA-N 0.000 description 3
- 229910052753 mercury Inorganic materials 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- 230000006866 deterioration Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 2
- 239000010931 gold Substances 0.000 description 2
- 238000001755 magnetron sputter deposition Methods 0.000 description 2
- 230000007935 neutral effect Effects 0.000 description 2
- 125000004430 oxygen atom Chemical group O* 0.000 description 2
- 238000005240 physical vapour deposition Methods 0.000 description 2
- 238000001771 vacuum deposition Methods 0.000 description 2
- 238000007740 vapor deposition Methods 0.000 description 2
- 229910000750 Niobium-germanium Inorganic materials 0.000 description 1
- CBENFWSGALASAD-UHFFFAOYSA-N Ozone Chemical compound [O-][O+]=O CBENFWSGALASAD-UHFFFAOYSA-N 0.000 description 1
- 229910008773 WMo Inorganic materials 0.000 description 1
- 238000002441 X-ray diffraction Methods 0.000 description 1
- CFJRGWXELQQLSA-UHFFFAOYSA-N azanylidyneniobium Chemical compound [Nb]#N CFJRGWXELQQLSA-UHFFFAOYSA-N 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000002950 deficient Effects 0.000 description 1
- 230000005670 electromagnetic radiation Effects 0.000 description 1
- 238000005566 electron beam evaporation Methods 0.000 description 1
- 230000008030 elimination Effects 0.000 description 1
- 238000003379 elimination reaction Methods 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- RTRWPDUMRZBWHZ-UHFFFAOYSA-N germanium niobium Chemical compound [Ge].[Nb] RTRWPDUMRZBWHZ-UHFFFAOYSA-N 0.000 description 1
- 238000002513 implantation Methods 0.000 description 1
- 230000005596 ionic collisions Effects 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 238000000053 physical method Methods 0.000 description 1
- 230000002285 radioactive effect Effects 0.000 description 1
- 229910052703 rhodium Inorganic materials 0.000 description 1
- 239000002344 surface layer Substances 0.000 description 1
- 230000008685 targeting Effects 0.000 description 1
- 238000007738 vacuum evaporation Methods 0.000 description 1
- 229910052720 vanadium Inorganic materials 0.000 description 1
- 229910052726 zirconium Inorganic materials 0.000 description 1
Landscapes
- Superconductor Devices And Manufacturing Methods Thereof (AREA)
Abstract
Description
【発明の詳細な説明】
産業上の利用分野
本発明は 金属酸化物超伝導薄膜を用いた超伝導体への
電極形成方法に関する。DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method of forming electrodes on a superconductor using a metal oxide superconducting thin film.
従来の技術
従来 超伝導体としてはＡ１５型２元系化合物として窒
化ニオブ（ＮｂＮ）やニオブ３ゲルマニウム（Ｎｂ３
Ｇｅ）などが知られてい九 またこれらの材料を用いた
超伝導素子も種々提案されている。しかしこれらの材料
の超伝導転移温度Ｔｃはたかだか２４にであった
またペロブスカイト系化合物の超伝導体としてｉｔ、
Ｂａ−Ｐｂ−Ｂ１−０系（特開昭６０−１７３８８
５号公報）が知られており、この系の材料を用いた超伝
導素子も数多く研究されている。Conventional technology Conventional superconductors include A15 type binary compounds such as niobium nitride (NbN) and niobium germanium (Nb3).
In addition, various superconducting elements using these materials have been proposed. However, the superconducting transition temperature Tc of these materials was 24 at most.
Ba-Pb-B1-0 system (JP-A-60-17388
No. 5) is known, and many superconducting devices using materials of this type have been studied.
しかし この材料のＴｃは１３に程度と低く実用化は困
難であっ九
ところ力＜、Ｔｃが３Ｏ−４０Ｋを示すＢａ−Ｌａ−Ｃ
ｕ−０系の高温超伝導体が提案された［Ｊ。However, the Tc of this material is as low as 13, making it difficult to put it into practical use.
A u-0 series high temperature superconductor was proposed [J.
Ｇ、Ｂｅｄｎｏｒｚ ａｎｄ Ｋ、Ａ、Ｍｕｌｌｅｒ
、ツァイＩ・シュリフト フェア フィジーク（Ｚｅｉ
ｔｓｃｈｒｉｆｔ ｆｕｒ ｐｈｙｓｉｋ Ｂ）−Ｃｏ
ｎｄｅｎｓｅｄ Ｍａｔｔｅｒ ６４． １８９−１
９３ （１９８６）］。さらに ］Ｙ−Ｂａ−Ｃｕ−０
では９０Ｋを超えるＴｃが報告されており［Ｍ、に、
Ｗｕ等、フィジカル レビュー レターズ（Ｐｈｙｓｉ
ｃａｌ Ｒｅｖｉｅｗ Ｌｅｔｔｅｒｓ） Ｖｏｌ
、５８．Ｎｏ、９，９０８−９１０ （１９８７）］、
液体窒素の沸点（７７Ｋ）よりも高くなったことで実用
化が有望となってきたＹ Ｂ ａ Ｃｕ Ｏ系に
代表される金属酸化物超伝導体（よ 例えばスパッタリ
ング法等の薄膜形成手法を用いると薄膜状の高温超伝導
体として形成できる。この超伝導薄膜を利用して機能素
子を作製する際に（友 超伝導体への電極形成は様々な
所に使われる可能性があり、また 作製した機能素子に
外部から駆動電流の供給や信号の入出力などを行なう場
合には良好な電極が必ず必要となる。したがって、超伝
導体と電極間の良好なオーミックコンタクトを作る技術
が不可欠である。G., Bednorz and K., Muller.
, Zei I. Schrift Fair Physique (Zei
tschrift fur physik B)-Co
densed Matter 64. 189-1
93 (1986)]. Furthermore ]Y-Ba-Cu-0
Tc exceeding 90K has been reported in [M,
Wu et al., Physical Review Letters (Physi
cal Review Letters) Vol.
, 58. No. 9, 908-910 (1987)],
Metal oxide superconductors, such as the YBaCuO system, which has become promising for practical application because it has become higher than the boiling point of liquid nitrogen (77K) (e.g., using thin film formation methods such as sputtering) It can be formed as a thin film-like high-temperature superconductor.When using this superconducting thin film to create functional devices, forming electrodes on superconductors may be used in various places, and Good electrodes are always required when externally supplying driving current or inputting/outputting signals to functional elements that have been developed.Therefore, technology to create good ohmic contact between superconductors and electrodes is essential. .
しかしながら、金属酸化物超伝導体は化学的に極めて不
安定であるために 様々な素子作製プロセスを重ねたり
、空気中に放置しているだけでＬその表面付近に非超伝
導的な層が形成されることが知られている。この非超伝
導層が形成される原因は金属酸化物超伝導薄膜表面から
の酸素の離脱や表面で化学的な変化を起こし結晶構造が
破壊されていることなどによるものと考えられる。この
ような非超伝導層が形成された表面に直接金属膜を形成
すると、接触抵抗が非常に大きくなってしま っ。However, since metal oxide superconductors are extremely unstable chemically, a non-superconducting layer is formed near their surface by repeating various device fabrication processes or by simply leaving them in the air. It is known that The reason for the formation of this non-superconducting layer is thought to be due to the detachment of oxygen from the surface of the metal oxide superconducting thin film or the destruction of the crystal structure due to chemical changes at the surface. If a metal film was formed directly on a surface with such a non-superconducting layer, the contact resistance would become extremely large.
そこで超伝導体へ電極を形成するために金属酸化物超伝
導薄膜の表面に直接金属膜を形成するのではなく、金属
膜形成前に酸素アニールなどの高温の熱処理を行なって
表面の超伝導特性を回復させてから金属膜を形成する方
法も用いられてきたさらに 金属酸化物超伝導薄膜表面
に形成されてしまった非超伝導層がかなり厚い場合東
表面付近で化学反応が起こり、アニール処理による結晶
性の回復や酸素の供給だけでは非超伝導層の超伝導性を
回復させることが不可能な場合、なんらかの物理的な方
法でこの非超伝導層を取り除かなくてはならない。Therefore, in order to form electrodes on superconductors, instead of forming a metal film directly on the surface of a metal oxide superconducting thin film, we perform high-temperature heat treatment such as oxygen annealing before forming the metal film to improve the superconducting properties of the surface. A method has also been used to recover the metal oxide and then form a metal film.
If a chemical reaction occurs near the surface and it is impossible to restore the superconductivity of the non-superconducting layer by restoring crystallinity through annealing or by supplying oxygen, some physical method can be used to restore the superconductivity of the non-superconducting layer. must be removed.
不活性ガスによるイオンビームエツチングはエツチング
の過程が純粋に機械的なものであることから、金属酸化
物超伝導体のように化学的に不安定な材料に対するエツ
チング手法としては好都合であることを本発明者らは発
見している。そこで、この不活性ガスによるイオンビー
ムエツチングによってこの非超伝導層を取り除き、その
後に超伝導体への電極形成を行えば非常に厚い非超伝導
層が形成されている場合にも有効である。This paper shows that ion beam etching using an inert gas is an advantageous etching method for chemically unstable materials such as metal oxide superconductors because the etching process is purely mechanical. The inventors have discovered. Therefore, removing this non-superconducting layer by ion beam etching using an inert gas and then forming electrodes on the superconductor is effective even when a very thick non-superconducting layer is formed.
発明が解決しようとする課題
しかしながら上記従来の構成で（よ 以下に述べる種々
の課題を有している。Problems to be Solved by the Invention However, the conventional configuration described above has various problems as described below.
金属酸化物超伝導体の表面付近では 非超伝導的な特性
の劣化した層が形成されやすいことから、金属酸化物超
伝導薄膜表面に直接金属膜を形成するのでは超伝導体と
金属膜間に良好なコンタクトを形成することがきわめて
難しくＸ。Since a non-superconducting layer with degraded properties is likely to form near the surface of a metal oxide superconductor, forming a metal film directly on the surface of a metal oxide superconducting thin film will result in a loss of space between the superconductor and the metal film. It is extremely difficult to form a good contact with the
そこで金属酸化物超伝導薄膜表面の超伝導特性を改善す
ることを目的として金属酸化物超伝導薄膜表面の結晶性
を向上させたり酸素を膜内に供給するために高温（少な
くとも７００℃以上）のアニール処理を利用した場合に
（よ 金属酸化物超伝導体が結晶成長を起こして表面の
平坦度が極端に悪化するため良好な電極形成が困難とな
り、ひいては金属酸化物超伝導薄膜と他の材料との複合
素子の実現をも困難にする。Therefore, in order to improve the superconducting characteristics of the surface of a metal oxide superconducting thin film, the crystallinity of the surface of the metal oxide superconducting thin film was improved, and high temperature (at least 700°C or higher) was When annealing is used, the metal oxide superconductor undergoes crystal growth and the surface flatness becomes extremely poor, making it difficult to form a good electrode. It also makes it difficult to realize a composite device with
また表面の非超伝導層を取り除くため艮 金属酸化物超
伝導薄膜表面をエツチングしてから金属膜を形成して超
伝導体へ電極を形成する場合で（戴置も損傷の少ないエ
ッヂング方法として不活性ガスによるイオンビームエツ
チングを利用することが望ましい。この場合でもある程
度まで接触抵抗を低下させることはできる力丈 超伝導
体への良好な電極形成が困難であることもわかっ九 本
発明者ら（よ イオンビームエツチングの影響について
詳しく検討した結果、イオンの衝突によって非超伝導層
は取り除かれる力丈 金属酸化物超伝導薄膜表面付近の
酸素イオンが離脱し 結晶性が劣化した部分が存在する
ことを新たに発見しム この劣化した部分が超伝導体と
金属膜間の接触抵抗の上昇を招き、良好な電極が形成で
きない原因であることを見出した 酸素イオンの離脱に
関して（よ加工後酸化処理を行うことである程度回復す
る力丈しかし超伝導体への良好な電極形成には程遠い。In addition, in order to remove the non-superconducting layer on the surface, the surface of the metal oxide superconducting thin film is etched, and then a metal film is formed to form an electrode on the superconductor. It is desirable to use ion beam etching using an active gas.Even in this case, the contact resistance can be reduced to a certain extent. As a result of a detailed study of the effects of ion beam etching, we found that the non-superconducting layer was removed by ion collisions, and that there were areas where oxygen ions near the surface of the metal oxide superconducting thin film were removed and the crystallinity deteriorated. We have newly discovered that this degraded part causes an increase in the contact resistance between the superconductor and the metal film, and is the reason why a good electrode cannot be formed. Although the strength can be recovered to some extent by doing this, it is still far from forming a good electrode on a superconductor.
本発明は上記従来の課題を解決するもので、高温の熱処
理を用いることなく金属酸化物超伝導薄膜表面の超伝導
特性を改善でき、超伝導体への良好な電極形成を可能と
する超伝導体への電極形成方法を提供することを目的と
するものである。The present invention solves the above-mentioned conventional problems, and improves the superconducting properties of the surface of a metal oxide superconducting thin film without using high-temperature heat treatment. The purpose of this invention is to provide a method for forming electrodes on the body.
課題を解決するための手段
この目的を達成するために本発明の超伝導体への電極形
成方法ｃ＆ 第１には金属酸化物超伝導薄膜の表面に
紫外線以下の波長の電磁波を照射するとともへ 電磁波
の照射中または照射後に酸化処理を施し その後に金属
酸化物超伝導薄膜の表面に金属膜を形成する構成を有し
ており、第２には金属酸化物超伝導薄膜の表面に不活性
ガスのイオンビームを照射した後、紫外線以下の波長の
電磁波を照射するとともに 電磁波の照射中または照射
後に酸化処理を施し その後に金属酸化物超伝導薄膜の
表面に金属膜を形成する構成を有している。Means for Solving the Problems In order to achieve this object, the method of forming electrodes on a superconductor of the present invention c & First, the surface of a metal oxide superconducting thin film is irradiated with electromagnetic waves having a wavelength of less than ultraviolet rays. It has a configuration in which oxidation treatment is performed during or after irradiation with electromagnetic waves, and then a metal film is formed on the surface of the metal oxide superconducting thin film.Secondly, an inert gas is applied to the surface of the metal oxide superconducting thin film. After being irradiated with an ion beam, electromagnetic waves with wavelengths below ultraviolet rays are irradiated, and an oxidation treatment is performed during or after the irradiation of the electromagnetic waves, and then a metal film is formed on the surface of the metal oxide superconducting thin film. There is.
作用
この構成によって、非常に簡単なプロセスで金属酸化物
超伝導薄膜表面の超伝導特性を改善しきわめて接触抵抗
の小さい超伝導体への良好な電極形成を可能とする。Function: With this configuration, it is possible to improve the superconducting properties of the surface of a metal oxide superconducting thin film through a very simple process, and to form a good electrode on a superconductor with extremely low contact resistance.
また 様々なプロセスによって金属酸化物超伝導薄膜表
面に厚い非超伝導層が形成された場合でも、この層を取
り除き、きわめて接触抵抗の小さい超伝導体への良好な
電極形成を可能とする。Furthermore, even if a thick non-superconducting layer is formed on the surface of a metal oxide superconducting thin film through various processes, this layer can be removed, making it possible to form a good electrode on a superconductor with extremely low contact resistance.
この構成によって、金属酸化物超伝導薄膜表面の超伝導
性回復のために従来よく利用されてきた高温の熱処理等
を必要としないた敦 金属酸化物超伝導薄膜の結晶成長
などの影響による表面平坦度や形状に変化が生じない。This structure eliminates the need for high-temperature heat treatment, which has traditionally been used to restore superconductivity on the surface of metal oxide superconducting thin films. No change in degree or shape occurs.
実施例
以下本発明の実施例について、図面を参照しながら説明
する。EXAMPLES Hereinafter, examples of the present invention will be described with reference to the drawings.
実施例１
第１図（ａ）〜（ｃ）は本発明の一実施例における超伝
導体への電極形成方法を示す工程断面図である。Embodiment 1 FIGS. 1(a) to 1(c) are process cross-sectional views showing a method of forming electrodes on a superconductor in an embodiment of the present invention.
まず第１図（ａ）に示すように 基板１上に金属酸化物
超伝導薄膜２を例えばスパッタリング法で形成する。必
要に応じて酸素雰囲気中で熱処理する力＼ あるいは酸
素イオンまたは励起状態の中性酸素原子を打ち込んで超
伝導性を得る。通常、金属酸化物超伝導薄膜を空気中に
放置するとその表面付近の超伝導特性が劣化する。
そこで、同図（ｂ）のように紫外線または紫外線よ
りも波長の短い電磁波３を金属酸化物超伝導薄膜２の表
面に均一に照射した後、例え（戯 酸素プラズマに曝す
ことによって酸化処理を行なう。最後？Ｑ 同図（ｃ
）のように 金属酸化物超伝導薄膜表面２上に例えば真
空蒸着によって金属膜４を形成する。First, as shown in FIG. 1(a), a metal oxide superconducting thin film 2 is formed on a substrate 1 by, for example, a sputtering method. If necessary, superconductivity can be achieved by heat treatment in an oxygen atmosphere or by implanting oxygen ions or excited neutral oxygen atoms. Normally, when a metal oxide superconducting thin film is left in the air, the superconducting properties near its surface deteriorate.
Therefore, after uniformly irradiating the surface of the metal oxide superconducting thin film 2 with ultraviolet rays or electromagnetic waves 3 with a shorter wavelength than ultraviolet rays, as shown in FIG. .The last?Q Same figure (c
) A metal film 4 is formed on the metal oxide superconducting thin film surface 2 by, for example, vacuum deposition.
金属酸化物超伝導薄膜をＸ線またはＴ線など紫外線より
も波長の短い電磁波で照射処理することにより、金属酸
化物超伝導体中の酸素イオンが部離脱し還元される力交
その後酸化処理をすることによって酸素イオンが効率
よく取り込まれ 照射前に比べてより秩序良く酸素イオ
ンが配列する。By irradiating the metal oxide superconducting thin film with electromagnetic waves having a shorter wavelength than ultraviolet rays, such as X-rays or T-rays, oxygen ions in the metal oxide superconductor are partially released and reduced. By doing so, oxygen ions are taken in efficiently and the oxygen ions are arranged in a more orderly manner than before irradiation.
さらに これらの電磁波の照射により金属酸化物超伝導
薄膜の結晶性が向上することを確認し九そのた敢 電磁
波の照射中または照射後に酸化処理を施した場合は こ
のような電磁波照射と酸化処理を行なわない場合や酸化
処理のみを行なった場合に比べて、その超伝導特性が向
上することも併せて発見した
第２図は電磁波照射による結晶性向」二の効果を示すＸ
線回折図である。同図は金属酸化物超伝導薄膜としであ
る程度Ｃ軸配向したＥｒ−Ｂａ−Ｃｕ−０薄膜に対して
Ｘ線を照射する前（曲線２１）、照射後（曲線２２）お
よび照射後酸化処理をしたとき（曲線２３）のＸ線回折
強度を示している。処理するにつれて（１０３）ピーク
の相対的強度が減少している。この（１０３）ピークは
多結晶状態の時に最も強く観測されるものて （１０３
）ピークの相対的強度から間接的に膜の結晶性が評価で
きる。実際に第２図に示した例で＋ｉ （１０３）ピ
ーク強度の（００５）ピーク強度に刻する比率が照射前
０．４４（曲線２１）であったもの力（照射後０．３１
（曲線２２）に減少している。これは結晶性の劣った多
結晶部分が減少し結晶性の優れたＣ軸配向状態に変化し
たことを示している。したがって、この結果はＸ線照射
が金属酸化物超伝導薄膜の結晶性を向上させたことを示
すものである。このような効果（よ Ｘ線だけでなく紫
外線あるいは紫外線よりも波長の短い電磁波によって観
測されることを確認している。Furthermore, we confirmed that irradiation with these electromagnetic waves improves the crystallinity of metal oxide superconducting thin films. It was also discovered that the superconducting properties were improved compared to when no oxidation treatment or only oxidation treatment was performed. Figure 2 shows the effect of crystal orientation due to electromagnetic radiation.
It is a line diffraction diagram. The figure shows the results of oxidation treatment before (curve 21), after (curve 22), and after irradiation of X-rays on an Er-Ba-Cu-0 thin film that is a metal oxide superconducting thin film and has some degree of C-axis orientation. It shows the X-ray diffraction intensity when (curve 23). The relative intensity of the (103) peak decreases with processing. This (103) peak is observed most strongly in the polycrystalline state (103)
) The crystallinity of the film can be indirectly evaluated from the relative intensity of the peaks. Actually, in the example shown in Figure 2, the ratio of the +i (103) peak intensity to the (005) peak intensity was 0.44 (curve 21) before irradiation;
(curve 22). This indicates that the polycrystalline portion with poor crystallinity decreased and changed to a C-axis orientation state with excellent crystallinity. Therefore, this result indicates that X-ray irradiation improved the crystallinity of the metal oxide superconducting thin film. It has been confirmed that this effect is observed not only with X-rays but also with ultraviolet light or electromagnetic waves with wavelengths shorter than ultraviolet light.
紫外線以下の波長の電磁波として（よ 通常のＷＭｏ、
Ｒｈ、 Ｃｕ、 Ｆｅ、 Ｃｏ、 Ｃｒ、
ＡＩ、 Ｍｇ、ＺｒなどをターゲットとするＸ線
管から放出されるＸｌｌ Ｈ，Ｈｅ、 Ｎｅなどの
ガス放電による紫外撤 水銀ランプからの輻射光あるい
は放射性元素のＴ崩壊によって放射されるγ線などがあ
り、同様の効果を発揮する。この電磁波を超伝導薄膜に
照射することにより照射処理が行われるカミ 薄膜超伝
導体にこれら電磁波を照射することによって薄膜が還元
されて結晶中の酸素イオンを一旦離脱させ、その後の酸
化処理で効率よく酸素を取り込むことによって超伝導に
対する最適な酸素含有状態を作り出すとともに第２図で
示したように金属酸化物超伝導薄膜の結晶状態も向上さ
せる効果がある。As electromagnetic waves with wavelengths below ultraviolet rays (normal WMo,
Rh, Cu, Fe, Co, Cr,
Xll emitted from an X-ray tube targeting AI, Mg, Zr, etc. Ultraviolet removal by gas discharge of H, He, Ne, etc. Radiant light from a mercury lamp or gamma rays emitted by T decay of radioactive elements, etc. Yes, and has the same effect. Irradiation treatment is carried out by irradiating the superconducting thin film with these electromagnetic waves. By irradiating the thin film superconductor with these electromagnetic waves, the thin film is reduced and oxygen ions in the crystal are temporarily released, and the subsequent oxidation treatment increases efficiency. By incorporating sufficient oxygen, an optimum oxygen-containing state for superconductivity is created, and as shown in FIG. 2, the crystalline state of the metal oxide superconducting thin film is also improved.
具体的にζｉ （１００）面ＭｇＯ単結晶を基板ｌと
して用ｕｋ 焼結したＹ Ｂ ａ２ｃ １１４．６０
ＸターゲツトをＡｒと０２の混合ガス雰囲気中で高周波
プレチーマグネトロンスパッタ法によりスパッタリング
蒸着して基板１上に結晶性のＹＢａ２ＣｕｓＯ×薄膜か
らなる金属酸化物超伝導薄膜２を付着させた
この場合、ガス圧力は０ 、５ Ｐ ａ、 スパッタ
リング電力１５０ Ｗ、 スパッタリング時間５０分
、膜厚０．５μｍ、基板温度７００℃であった このよ
うにして得られた簿膜は超伝導性を示し その転移温度
は９０にであっ島
この金属酸化物超伝導薄膜２に対して、 １５０Ｗの低
圧水銀ランプを用いて紫外線を約３時間照射した後、高
周波電力４００Ｗによって励起された約１０Ｐａの酸素
プラズマ中に１５分間曝して酸化処理を行った この後
金属酸化物超伝導薄膜２の表面？Ｑ 電極用の金属膜
４として約０． １μｍ厚の金の膜を蒸着し九
この方法によって作製した超伝導体の電極の接触抵抗は
処理を行わずに作製した場合に比べて小さくなることを
確認し池 特に金属酸化物超伝導薄膜２の照射前の表面
状態がよくない場合（よ 照射および酸化処理により表
面状態が改善され数桁程度接触抵抗が減少する場合もあ
ることもわかり、本発明の超伝導体への電極形成方法の
有効性が確言忍できた
実施例２
第３図（ａ）〜（ｄ）は本発明の第２の実施例を示す工
程断面図である。Specifically, a ζi (100) plane MgO single crystal was used as the substrate l, uk sintered Y B a2c 114.60
A metal oxide superconducting thin film 2 consisting of a crystalline YBa2CusOx thin film was deposited on the substrate 1 by sputtering the X target by high frequency pre-chip magnetron sputtering in a mixed gas atmosphere of Ar and O2. The pressure was 0.5 Pa, the sputtering power was 150 W, the sputtering time was 50 minutes, the film thickness was 0.5 μm, and the substrate temperature was 700°C. The film thus obtained exhibited superconductivity, and its transition temperature was After irradiating the metal oxide superconducting thin film 2 with ultraviolet rays for about 3 hours using a 150 W low-pressure mercury lamp, it was placed in an oxygen plasma of about 10 Pa excited by high-frequency power of 400 W for 15 minutes. After this, the surface of metal oxide superconducting thin film 2 was subjected to oxidation treatment. Q Approximately 0.0 as metal film 4 for electrode. It was confirmed that the contact resistance of superconductor electrodes fabricated by depositing a 1 μm thick gold film using this method was smaller than that of electrodes fabricated without any treatment.In particular, metal oxide superconducting thin films 2 It was also found that when the surface condition before irradiation is not good (i.e., irradiation and oxidation treatment improve the surface condition and reduce the contact resistance by several orders of magnitude, the method of forming electrodes on superconductors of the present invention is effective. Embodiment 2 in which the reliability was clearly observed FIGS. 3(a) to 3(d) are process cross-sectional views showing a second embodiment of the present invention.
まず第３図（ａ）に示すように基板ｌ上に金属酸化物超
伝導薄膜２を例えばスパッタリング法で形成する。必要
に応じて酸素雰囲気中で熱処理する力＼ あるいは酸素
イオンまたは励起状態の中性酸素原子を打ち込んで超伝
導性を得る。通常、金属酸化物超伝導薄膜２を空気中に
放置したり、また様々な素子作製プロセス等を経ると、
同図（ｂ）のように金属酸化物超伝導薄膜２の表面に比
較的厚い非超伝導層５が形成される。そこで、薄膜２の
表面に不活性ガスのイオンビームを照射し 表面に形成
されている非超伝導層５を取り除く。次？−同図（Ｃ）
のように紫外線あるいは紫外線よりも波長の短い電磁波
３を金属酸化物超伝導薄膜２の表面に均一に照射した後
、例えば 酸素プラズマに曝すことによって酸化処理を
行なう。最後に 同図（ｄ）のようへ 金属酸化物超伝
導薄膜表面２上に例えば真空蒸着によって金属膜４を形
成する。First, as shown in FIG. 3(a), a metal oxide superconducting thin film 2 is formed on a substrate 1 by, for example, a sputtering method. If necessary, superconductivity can be achieved by heat treatment in an oxygen atmosphere or by implanting oxygen ions or excited neutral oxygen atoms. Usually, when the metal oxide superconducting thin film 2 is left in the air or goes through various device manufacturing processes,
As shown in FIG. 2B, a relatively thick non-superconducting layer 5 is formed on the surface of the metal oxide superconducting thin film 2. Therefore, the surface of the thin film 2 is irradiated with an ion beam of an inert gas to remove the non-superconducting layer 5 formed on the surface. Next? -Same figure (C)
After uniformly irradiating the surface of the metal oxide superconducting thin film 2 with ultraviolet rays or electromagnetic waves 3 having a shorter wavelength than ultraviolet rays, oxidation treatment is performed by exposing the thin film 2 to, for example, oxygen plasma. Finally, as shown in FIG. 4(d), a metal film 4 is formed on the metal oxide superconducting thin film surface 2 by, for example, vacuum evaporation.
不活性ガスを用いたイオンビームエツチングは金属酸化
物超伝導薄膜２に対して化学的な損傷は与え槓 また結
晶性の劣化や酸素の離脱などの損傷がエツチングされた
表面部分の極めて限られた層にのみ生じることを本発明
者らは見出している。Ion beam etching using an inert gas does not cause any chemical damage to the metal oxide superconducting thin film 2, but damage such as deterioration of crystallinity and elimination of oxygen is extremely limited to the etched surface area. The present inventors have discovered that this phenomenon occurs only in layers.
エツチングの後、金属酸化物超伝導薄膜を紫外線やＸ線
またはＴ線など紫外線よりも波長の短い電磁波で照射処
理することにより、金属酸化物超伝導体中の酸素イオン
が一部離脱し還元される力（その後酸化処理をすること
によって酸素イオンが効率よく取り込まれ 照射前に比
べてより秩序良く酸素イオンが配列する。さら鳳 これ
らの電磁波の照射により金属酸化物超伝導薄膜の結晶性
が向上することを確認した そのた人 エツチングされ
た表面付近の超伝導特性は電磁波照射と酸化処理を行な
わない場合や酸化処理のみを行なった場合に比べて、そ
の超伝導特性が向上することも併せて発見し九
具体的に＋：Ｌ（１００）面ＭｇＯ単結晶を基板ｌとし
て用（＼ 焼結したＹ Ｂ ａ ａＣｕ ４．６Ｑ ｘ
ターゲットをＡｒと０２の混合ガス雰囲気中で高周波プ
レチーマグネトロンスパッタ法によりスパッタリング蒸
着して、基板１上に結晶性のＹＢａ２Ｃｕ３Ｏｘ薄膜か
らなる金属酸化物超伝導体薄膜２を付着させた
この場合、ガス圧力は０ 、５ Ｐ ａ、 スパッタ
リング電力１５０Ｗ、 スパッタリング時間６０分、
膜厚０．６μへ 基板温度７００℃であっ九 このよう
にして得られた薄膜は超伝導性を示し その転移温度は
９０にであっ丸
この金属酸化物超伝導薄膜２に対して、Ａｒガスを用い
たイオンビームエツチングを用いて金属酸化物超伝導薄
膜２の表面に存在する非超伝導層５をエツチングにより
除去し九 エツチング条件（よ イオン加速電圧５５０
Ｖ、Ａｒ圧力０．０１Ｐａ、エツチング時間約５分で、
このエツチングによって約０． １μｍはど金属酸化物
超伝導薄膜２の表面が削られているものと考えられ 非
超伝導層５を除去するには十分の量であると考えられる
。次に１５０Ｗの低圧水銀ランプを用いて紫外線を約３
時間照射したのち、高周波電力４００Ｗによって励起さ
れた約１０Ｐａの酸素プラズマ中に１５分間曝し 酸化
処理を行なった この後、金属酸化物超伝導薄膜２の表
面く 電極用の金属膜４として、約０．１μｍ厚の金の
膜を蒸着し池第４図は金属酸化物超伝導薄膜２と金属膜
４の間の接触抵抗の温度変化を示す特性図である。第４
図中の曲線３１は金属酸化物超伝導薄膜２の表面をエツ
チングした上にそのまま金属膜４を蒸着もＱ 曲線３２
はエツチングおよび酸化処理だけを行なった後に金属膜
４を蒸着したもヘ 曲線３３はエラチン久 紫外線照射
および酸化処理を行なった後に金属膜４を蒸着したもの
である。第４図に示すように 酸化処理だけ行なった場
合よりも紫外線照射と酸化処理を併用したときの方が接
触抵抗が大きく減少し また抵抗の温度変化の仕方がよ
り金属的（温度の減少とともに抵抗値も減少する）にな
っている。このことより、金属酸化物超伝導薄膜２の表
面の超伝導性が改善されて超伝導体へ良好な電極が形成
されていることがわかり、本発明の超伝導体への電極形
成方法の有効性が確認できム
なおエツチングに用いた不活性ガスとして、本実施例に
示すＡｒガス以外に他の不活性ガス、例え１１ Ｈｅ
、 Ｘｅ、 Ｎｅ等でも同様の効果が得られること
を確言忍している。After etching, the metal oxide superconducting thin film is irradiated with electromagnetic waves with wavelengths shorter than ultraviolet rays, such as ultraviolet rays, X-rays, or T-rays, so that some of the oxygen ions in the metal oxide superconductor are released and reduced. (The subsequent oxidation treatment allows oxygen ions to be taken in efficiently, and the oxygen ions are arranged in a more orderly manner than before irradiation.Saraho: Irradiation with these electromagnetic waves improves the crystallinity of metal oxide superconducting thin films. The person also confirmed that the superconducting properties near the etched surface are improved compared to when electromagnetic wave irradiation and oxidation treatment are not performed, or when only oxidation treatment is performed. Specifically, I discovered that +: L (100) plane MgO single crystal was used as the substrate (＼ Sintered Y Ba aCu 4.6Q x
A metal oxide superconductor thin film 2 consisting of a crystalline YBa2Cu3Ox thin film was deposited on the substrate 1 by sputtering a target in a mixed gas atmosphere of Ar and 02 by high-frequency pre-chip magnetron sputtering. Pressure was 0.5 Pa, sputtering power 150 W, sputtering time 60 minutes,
The thin film obtained in this way exhibits superconductivity and its transition temperature is 90°C. The non-superconducting layer 5 present on the surface of the metal oxide superconducting thin film 2 is removed by etching using ion beam etching using ion beam etching.
V, Ar pressure 0.01 Pa, etching time approximately 5 minutes,
This etching results in approximately 0. It is thought that the surface of the metal oxide superconducting thin film 2 is scraped by 1 μm, which is considered to be a sufficient amount to remove the non-superconducting layer 5. Next, use a 150W low-pressure mercury lamp to emit ultraviolet rays at approximately 3
After being irradiated for a period of time, it was exposed to oxygen plasma of about 10 Pa excited by a high frequency power of 400 W for 15 minutes to undergo oxidation treatment. Figure 4 is a characteristic diagram showing the temperature change in contact resistance between the metal oxide superconducting thin film 2 and the metal film 4. Fourth
Curve 31 in the figure shows that the surface of the metal oxide superconducting thin film 2 is etched and then the metal film 4 is directly deposited.Curve 32
Curve 33 shows the case in which the metal film 4 was deposited after only etching and oxidation treatment. Curve 33 shows the case in which the metal film 4 was deposited after ultraviolet irradiation and oxidation treatment. As shown in Figure 4, the contact resistance decreases more when ultraviolet irradiation and oxidation treatment are used together than when only oxidation treatment is performed, and the way the resistance changes with temperature is more metallic (as the temperature decreases, the resistance value also decreases). This shows that the superconductivity of the surface of the metal oxide superconducting thin film 2 is improved and a good electrode is formed on the superconductor, and the method of forming an electrode on a superconductor of the present invention is effective. In addition to the Ar gas shown in this example, other inert gases such as He
We are confident that similar effects can be obtained with , Xe, Ne, etc.
またエツチングの際のイオンビームの加速電圧を１ｋＶ
以下にすると、エツチングの損傷が金属酸化物超伝導薄
膜のきわめて浅い表面付近に限られることを確認した
したがって、 この範囲の加速電圧のイオンビームを照
射することが特に有効であることも確言忍し九
次Ｅ、 実施例１および実施例２に共通することにつ
いて述べる。In addition, the acceleration voltage of the ion beam during etching was set to 1kV.
It was confirmed that the etching damage was limited to the extremely shallow surface area of the metal oxide superconducting thin film when
Therefore, it can be clearly stated that irradiation with an ion beam having an accelerating voltage in this range is particularly effective, and what is common to the ninth E, Example 1, and Example 2 will be described.
実施例で（よ 照射する電磁波として紫外線を例に取っ
て説明したカミ 紫外線に限らず、Ｘ線またはγ線でも
同様の効果があることを確認している。Although the explanation was given using ultraviolet rays as an example of electromagnetic waves to be irradiated in the example, it has been confirmed that not only ultraviolet rays but also X-rays or γ-rays have similar effects.
また酸化処理の方法として（よ 実施例で述べた酸素プ
ラズマ中に曝す手法に限るわけではなく、酸素イオンを
打ち込んだり、オゾンなど活性酸素中に曝したり、また
は低温（３００〜４００℃）酸素アニールなど行なって
も同様に有効である。In addition, oxidation treatment methods (not limited to the method of exposure to oxygen plasma described in the example) include implantation of oxygen ions, exposure to active oxygen such as ozone, or low-temperature (300 to 400°C) oxygen annealing. It is equally effective to do the following.
さらに、 紫外線あるいは紫外線よりも波長の短い電
磁波照射と酸化処理を同時に行なえば金属酸化物超伝導
薄膜中により効率よく酸素が取り込まれ 超伝導特性も
向上することを本発明者らは確認している。Furthermore, the present inventors have confirmed that if irradiation with ultraviolet rays or electromagnetic waves with a shorter wavelength than ultraviolet rays is performed simultaneously with oxidation treatment, oxygen can be taken into the metal oxide superconducting thin film more efficiently and the superconducting properties can be improved. .
電極用金属膜４についても、実施例で述べた金の蒸着膜
以外にもＰｔ、Ａｇ、ＡＩなと二 通常の電極用に利用
される金属元素を同様に利用しても同じく有効である。Regarding the electrode metal film 4, in addition to the vapor-deposited gold film described in the embodiment, it is equally effective to use metal elements such as Pt, Ag, and AI that are commonly used for electrodes.
ただし金属酸化物超伝導薄膜２中に酸素が多く含まれて
いることから、イオン化傾向の小さい酸化されにくい金
属膜ｉＡｕ、Ｐｔ、Ａｇの利用が特に有効であることを
確認している。また 金属膜４の形成方法についても、
実施例で述べた真空蒸着法に限るわけではなく、スパッ
タリング法なとミ 通常の薄膜形成方法を利用すること
ができる。However, since the metal oxide superconducting thin film 2 contains a large amount of oxygen, it has been confirmed that the use of metal films iAu, Pt, and Ag, which have a small ionization tendency and are difficult to oxidize, is particularly effective. Also, regarding the method of forming the metal film 4,
The method is not limited to the vacuum evaporation method described in the embodiments, and any conventional thin film forming method such as sputtering can be used.
また 金属酸化物超伝導薄膜２の形成に（よ ＹＢａ−
Ｃｕ−０の他にＡ−Ｂ−Ｃｕ−０、Ｂ１５ｒ−Ｃａ −
Ｃｕ−０、またはＴｌ−Ｂａ−ＣａＣｕ−０複合化合物
を例えば電子ビーム蒸着、 レーザビーム蒸着等の物理
的気相成長法で基板１上に付着させてもよい。これら金
属酸化物超伝導体は組成式がまだ明確には決定されてい
ない力＜、ＡＢ−Ｃｕ−０に関しては酸素欠損ペロブス
カイト（Ａ、Ｂ）ｓＣｕｓｏｖ−×といわれており、こ
の種の材料に関して本発明者ら＋Ｌ ＡはＹ、Ｌａ、
およびＬａ系列元素（原子番号５７、５９〜６０．６２
〜７１）の内少なくともＩ＠ ＢはＢａ、Ｓ一加−
ｒなどＩＩａ族元素の内少なくとも１＠ か□つ作製さ
れた薄膜の元素比率力（
０，５≦（Ａ＋Ｂ）／Ｃｕ≦２．５
の範囲にあれば 臨界温度に多少の差があっても超伝導
現象が見出されることを確認し九まｆ＝ Ｂ１−３ｒ
−Ｃａ−Ｃｕ−０、Ｔｌ−ＢａＣａ−Ｃｕ−０超伝導体
は臨界温度が１００Ｋを超えるものができ、実用上極め
て有用である力（含まれる元素数が多いため優れた超伝
導膜形成は比較的困難であった 本発明者ら（戴 作製
条件などを厳密に制御すれば これら材料についても先
のＡ−Ｂ−Ｃｕ−０超伝導体と同様の方法で再現性よく
薄膜化できることを確認し九 金属酸化物超伝導薄膜の
形成法は物理的気相成長法に限定されたものではなく、
化学的気相成長法例えば常圧あるいは減圧化学的気相成
長法、プラズマ化学的気相成長法、光化学的気相成長法
も成分元素の比を合致させれ（Ｌ 有効であることを本
発明者らは確認した
本発明者らは金属酸化物超伝導薄膜を基板の表面に付着
させる場合、基板の最適の温度範囲が存在することを確
認し九 最適温度範囲は１００〜１０００℃である。な
抵 １００℃以下では基板表面への金属酸化物超伝導薄
膜の付着性が悪くなる。ま？、、、１０００℃以上では
金属酸化物超伝導薄膜中の各成分元素の化学量論比から
のずれが大きくなる。さらに 金属酸化物超伝導薄膜を
付着させるときの基板の温度はとりわけ５００〜９００
℃の範囲がこの種の蒸着装置の機組 金属酸化物超伝導
薄膜の特性の再現性からみて最適であることを本発明者
らは確認し九
発明の効果
以上のように本発明は金属酸化物超伝導薄膜の表面に紫
外線以下の波長の電磁波を照射するとともに その電磁
波の照射中または照射後に酸化処理を施し その後に金
属酸化物超伝導薄膜の表面に金属膜を形成することによ
り優れた超伝導体への電極形成方法を実現できるもので
ある。In addition, for the formation of metal oxide superconducting thin film 2 (YBa-
In addition to Cu-0, A-B-Cu-0, B15r-Ca −
Cu-0 or a Tl-Ba-CaCu-0 composite compound may be deposited on the substrate 1 by a physical vapor deposition method such as electron beam evaporation or laser beam evaporation. These metal oxide superconductors are known as oxygen-deficient perovskites (A, B) sCusov-× for AB-Cu-0, whose compositional formula has not yet been clearly determined; The inventors+LA is Y, La,
and La series elements (atomic numbers 57, 59-60.62
~71), at least I@B is at least one of group IIa elements such as Ba, S, and r. It was confirmed that superconductivity phenomenon can be found even if there is a slight difference in critical temperature if it is in the range of 5.
-Ca-Cu-0, Tl-BaCa-Cu-0 superconductors can have critical temperatures exceeding 100K, and are extremely useful in practice (due to the large number of elements contained, excellent superconducting film formation is possible. Although it was relatively difficult, the present inventors (Dai) confirmed that it is possible to make thin films of these materials with good reproducibility by strictly controlling the manufacturing conditions etc. using the same method as the A-B-Cu-0 superconductor described above. 9. The method of forming metal oxide superconducting thin films is not limited to physical vapor deposition;
Chemical vapor deposition methods such as normal pressure or reduced pressure chemical vapor deposition method, plasma chemical vapor deposition method, and photochemical vapor deposition method can also be performed by matching the ratio of component elements (L). The inventors have confirmed that there is an optimum temperature range for the substrate when a metal oxide superconducting thin film is deposited on the surface of the substrate.9 The optimum temperature range is 100-1000C. At temperatures below 100°C, the adhesion of the metal oxide superconducting thin film to the substrate surface deteriorates. At temperatures above 1000°C, the stoichiometric ratio of each component element in the metal oxide superconducting thin film deteriorates. The deviation becomes large.Furthermore, the temperature of the substrate when depositing the metal oxide superconducting thin film is particularly between 500 and 900℃.
The present inventors have confirmed that the range of temperature is optimal for this type of vapor deposition apparatus in terms of the reproducibility of the characteristics of metal oxide superconducting thin films. Excellent superconductivity is achieved by irradiating the surface of a superconducting thin film with electromagnetic waves of wavelengths below ultraviolet rays, performing oxidation treatment during or after irradiation with the electromagnetic waves, and then forming a metal film on the surface of the metal oxide superconducting thin film. This makes it possible to realize a method for forming electrodes on the body.
金属酸化物超伝導薄膜は化学的に不安定で、特にその表
面付近では超伝導特性が劣化する場合がよくある力（紫
外線以下の波長の電磁波の照射と酸化処理により回復さ
せることができる。このように電磁波の照射による金属
酸化物超伝導薄膜の処理は薄膜を高温に加熱する必要が
なく、制御性もよく、かつ処理が簡単である。したがっ
て、本発明における形成方法を利用することによってき
わめて接触抵抗の小さい良好な特性を有する電極を容易
に形成することができる。Metal oxide superconducting thin films are chemically unstable, and their superconducting properties often deteriorate, especially near their surfaces (which can be restored by irradiation with electromagnetic waves at wavelengths below ultraviolet rays and oxidation treatment). As described above, the treatment of metal oxide superconducting thin films by electromagnetic wave irradiation does not require heating the thin film to high temperatures, has good controllability, and is easy to process.Therefore, by using the formation method of the present invention, Electrodes having good characteristics with low contact resistance can be easily formed.
また金属酸化物超伝導薄膜表面付近に比較的厚い非超伝
導層が形成されてしまった場合、超伝導体に良好な電極
を形成するためにはなんらかの方法で非超伝導層を削り
取らなければならない。不活性ガスを用いたイオンビー
ムエツチングで（よ金属酸化物超伝導薄膜に対して化学
的損傷は与えずミ エツチングされた部分の表面層近傍
に酸素イオンの離脱と結晶性の劣化を招く程度である。Furthermore, if a relatively thick non-superconducting layer forms near the surface of a metal oxide superconducting thin film, the non-superconducting layer must be scraped off by some method in order to form a good electrode on the superconductor. . Ion beam etching using an inert gas does not cause any chemical damage to the metal oxide superconducting thin film, but only causes the release of oxygen ions and deterioration of crystallinity near the etched surface layer. be.
そして、これらの影響（戴 続いて行う紫外線以下の波
長の電磁波の照射および酸化処理により回復させること
ができる。したがって、本発明における形成方法を利用
することによって、表面状態がき一羽−
わめて悪い金属酸化物超伝導薄膜に対してでも接触抵抗
の小さい良好な特性を有する電極を容易に形成すること
ができる。These effects can be reversed by subsequent irradiation with electromagnetic waves of wavelengths below ultraviolet rays and oxidation treatment. Therefore, by using the formation method of the present invention, the surface condition can be improved significantly. Even with poor metal oxide superconducting thin films, electrodes with low contact resistance and good characteristics can be easily formed.
またＳ Ｑ Ｕ Ｉ Ｄ （Ｓｕｐｅｒｃｏｎｄｕｃｔ
ｉｎｇ Ｑｕａｎｔｕｍ Ｉｎｔｅｒｆｅｒｅｎｃｅ
Ｄｅｖｉｃｅ）やジョセフソン素子等の超伝導デバイス
またはその他の超伝導を利用した各種電子デバイスへの
駆動電流の供給や信号の人出力のために（よ 金属酸化
物超伝導薄膜上に接触抵抗の小さい電極を高温の熱処理
を伴わずに形成する本発明の形成方法が必要不可欠であ
る。また 特にこの種の金属酸化物超伝導体の転移温度
が室温になる可能性もあり、本発明の実用の範囲は極め
て広く、その工業的価値は高しもAlso, S Q U I D (Superconduct
ing Quantum Interference
For the supply of driving current to superconducting devices such as devices), Josephson devices, and various other electronic devices using superconductivity, and for outputting signals, the contact resistance is low on the metal oxide superconducting thin film The method of the present invention, which forms electrodes without high-temperature heat treatment, is indispensable.In particular, the transition temperature of this type of metal oxide superconductor may be room temperature, which makes it difficult to implement the present invention in practical use. Its scope is extremely wide and its industrial value is high.
第１図（ａ）〜（ｃ）は本発明の一実施例における超伝
導体への電極形成方法を示す工程断面１第２図は電磁波
照射による結晶性向上の効果を示すＸ線回折医 第３図
（ａ）〜（ｄ）は本発明の第２の実施例を示す工程断面
医 第４図は金属酸化物超伝導薄膜と金属膜の間の接触
抵抗の温度変−冴
化を示す特性図である。
２・・・金属酸化物超伝導薄膜 ３・・・紫外線以下の
波長の電磁波、 ４・・・金属乱
代理人の氏名 弁理士 粟野重孝 はか１名１でFigures 1 (a) to (c) are process cross-sections showing a method for forming electrodes on a superconductor in one embodiment of the present invention. 3(a) to (d) are process cross-sectional diagrams showing the second embodiment of the present invention. FIG. 4 is a characteristic showing the temperature variation and enhancement of the contact resistance between the metal oxide superconducting thin film and the metal film. It is a diagram. 2...Metal oxide superconducting thin film 3...Electromagnetic waves with wavelengths below ultraviolet rays 4...Name of metal disorder agent Patent attorney Shigetaka Awano 1 person 1 person
Claims (1)
の電磁波を照射するとともに、前記電磁波の照射中また
は照射後に酸化処理を施し、その後に前記金属酸化物超
伝導薄膜の表面に金属膜を形成する超伝導体への電極形
成方法。 （２）金属酸化物超伝導薄膜の表面に不活性ガスのイオ
ンビームを照射した後、前記超伝導薄膜の表面に紫外線
以下の波長の電磁波を照射するとともに、前記電磁波の
照射中または照射後に酸化処理を施し、その後に前記金
属酸化物超伝導薄膜の表面に金属膜を形成する超伝導体
への電極形成方法。 （３）金属酸化物超伝導薄膜が銅元素を含む材料からな
る請求項１または請求項２記載の超伝導体への電極形成
方法。 （４）金属酸化物超伝導薄膜がＡ−Ｂ−Ｃｕ−Ｏ複合化
合物からなる請求項１または請求項２記載の超伝導体へ
の電極形成方法。 ここに、ＡはＹ、ＬａおよびＬａ系列元素（原子番号５
７、５９〜６０、６２〜７１）の内少なくとも１種、Ｂ
はＢａ、ＳｒなどIIａ族元素の内少なくとも１種、かつ
Ａ、Ｂ元素とＣｕ元素の組成比は ０．５≦（Ａ＋Ｂ）／Ｃｕ≦２．５である。 （５）金属酸化物超伝導薄膜がＢｉ−Ｓｒ−Ｃａ−Ｃｕ
−ＯまたはＴｌ−Ｂａ−Ｃａ−Ｃｕ−Ｏ複合化合物から
なる請求項１または請求項２記載の超伝導体への電極形
成方法。 （６）金属膜がＡｕ、ＡｇまたはＰｔである請求項１ま
たは請求項２記載の超伝導体への電極形成方法。 （７）イオンビームの加速電圧が１ｋＶ以下である請求
項２記載の超伝導体への電極形成方法。[Scope of Claims] (1) The surface of the metal oxide superconducting thin film is irradiated with electromagnetic waves having a wavelength below ultraviolet rays, and an oxidation treatment is performed during or after the irradiation of the electromagnetic waves, and then the metal oxide superconducting thin film is A method for forming electrodes on superconductors that forms a metal film on the surface of a thin film. (2) After irradiating the surface of the metal oxide superconducting thin film with an ion beam of an inert gas, the surface of the superconducting thin film is irradiated with electromagnetic waves of wavelengths below ultraviolet rays, and oxidation occurs during or after the irradiation with the electromagnetic waves. A method for forming an electrode on a superconductor, which comprises performing a treatment and then forming a metal film on the surface of the metal oxide superconducting thin film. (3) A method for forming an electrode on a superconductor according to claim 1 or 2, wherein the metal oxide superconducting thin film is made of a material containing copper element. (4) A method for forming an electrode on a superconductor according to claim 1 or 2, wherein the metal oxide superconducting thin film is made of an AB-Cu-O composite compound. Here, A is Y, La and La series elements (atomic number 5
7, 59-60, 62-71), B
is at least one of group IIa elements such as Ba and Sr, and the composition ratio of the A, B elements and the Cu element is 0.5≦(A+B)/Cu≦2.5. (5) Metal oxide superconducting thin film is Bi-Sr-Ca-Cu
3. The method for forming an electrode on a superconductor according to claim 1 or 2, comprising -O or a Tl-Ba-Ca-Cu-O composite compound. (6) The method for forming an electrode on a superconductor according to claim 1 or 2, wherein the metal film is Au, Ag or Pt. (7) The method for forming electrodes on a superconductor according to claim 2, wherein the acceleration voltage of the ion beam is 1 kV or less.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2174742A JP2822623B2 (en) | 1990-07-02 | 1990-07-02 | Method of forming electrodes on superconductor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2174742A JP2822623B2 (en) | 1990-07-02 | 1990-07-02 | Method of forming electrodes on superconductor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0462982A true JPH0462982A (en) | 1992-02-27 |
| JP2822623B2 JP2822623B2 (en) | 1998-11-11 |
Family
ID=15983885
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2174742A Expired - Fee Related JP2822623B2 (en) | 1990-07-02 | 1990-07-02 | Method of forming electrodes on superconductor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2822623B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007255073A (en) * | 2006-03-23 | 2007-10-04 | Inaba Denki Sangyo Co Ltd | Filler support fitting |
-
1990
- 1990-07-02 JP JP2174742A patent/JP2822623B2/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007255073A (en) * | 2006-03-23 | 2007-10-04 | Inaba Denki Sangyo Co Ltd | Filler support fitting |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2822623B2 (en) | 1998-11-11 |
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