JPH03110879A - Production of josephson junction element - Google Patents
Production of josephson junction elementInfo
- Publication number
- JPH03110879A JPH03110879A JP1249904A JP24990489A JPH03110879A JP H03110879 A JPH03110879 A JP H03110879A JP 1249904 A JP1249904 A JP 1249904A JP 24990489 A JP24990489 A JP 24990489A JP H03110879 A JPH03110879 A JP H03110879A
- Authority
- JP
- Japan
- Prior art keywords
- substrate
- thin film
- film
- oxide
- junction
- 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
- 238000004519 manufacturing process Methods 0.000 title claims description 8
- 239000000758 substrate Substances 0.000 claims abstract description 50
- 239000010409 thin film Substances 0.000 claims abstract description 37
- 239000002887 superconductor Substances 0.000 claims abstract description 34
- 229910052751 metal Inorganic materials 0.000 claims abstract description 17
- 239000002184 metal Substances 0.000 claims abstract description 17
- 238000000034 method Methods 0.000 claims abstract description 17
- 239000013078 crystal Substances 0.000 claims abstract description 4
- 238000001816 cooling Methods 0.000 claims description 5
- 229910052594 sapphire Inorganic materials 0.000 claims description 4
- 239000010980 sapphire Substances 0.000 claims description 4
- 239000010408 film Substances 0.000 abstract description 23
- 239000004020 conductor Substances 0.000 abstract description 13
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 abstract description 8
- 239000007788 liquid Substances 0.000 abstract description 5
- 229910052757 nitrogen Inorganic materials 0.000 abstract description 4
- 238000007740 vapor deposition Methods 0.000 abstract description 4
- 229910052709 silver Inorganic materials 0.000 abstract description 3
- 239000004332 silver Substances 0.000 abstract description 3
- 238000001704 evaporation Methods 0.000 abstract description 2
- 230000008020 evaporation Effects 0.000 abstract description 2
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 abstract description 2
- 229910052737 gold Inorganic materials 0.000 abstract description 2
- 239000010931 gold Substances 0.000 abstract description 2
- 230000009257 reactivity Effects 0.000 abstract description 2
- 230000015572 biosynthetic process Effects 0.000 description 5
- 239000012212 insulator Substances 0.000 description 5
- 239000000463 material Substances 0.000 description 5
- 238000004544 sputter deposition Methods 0.000 description 4
- 238000010586 diagram Methods 0.000 description 3
- 239000007789 gas Substances 0.000 description 3
- 238000010894 electron beam technology Methods 0.000 description 2
- 238000005530 etching Methods 0.000 description 2
- 229910052758 niobium Inorganic materials 0.000 description 2
- 239000010955 niobium Substances 0.000 description 2
- GUCVJGMIXFAOAE-UHFFFAOYSA-N niobium atom Chemical compound [Nb] GUCVJGMIXFAOAE-UHFFFAOYSA-N 0.000 description 2
- 239000004065 semiconductor Substances 0.000 description 2
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 238000010924 continuous production Methods 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000000151 deposition Methods 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000010438 heat treatment 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
- 238000005259 measurement Methods 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 238000000059 patterning Methods 0.000 description 1
- 238000001552 radio frequency sputter deposition Methods 0.000 description 1
- 238000000992 sputter etching Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000007738 vacuum evaporation Methods 0.000 description 1
- 239000002699 waste material Substances 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
- Superconductor Devices And Manufacturing Methods Thereof (AREA)
- Superconductors And Manufacturing Methods Therefor (AREA)
Abstract
Description
【発明の詳細な説明】
「発明の利用分野」
本発明はジョセフソン接合素子（超伝導トンネル接合素
子）の作製方法に関する。DETAILED DESCRIPTION OF THE INVENTION Field of Application of the Invention The present invention relates to a method for manufacturing a Josephson junction device (superconducting tunnel junction device).
「従来技術および問題点」
ジョセフソン接合は、１９６２年Ｂ、Ｄ、Ｊｏｓｅｐｈ
ｓｏｎによって提唱され、以後、金属系の超伝導体を中
心に研究が進められ現在ではニオブ超伝導体を使った超
伝導ＬＳＩが試作されるまでにいたっている。"Prior Art and Problems" Josephson junction was developed in 1962 by B. D. Joseph
Since then, research has focused on metal-based superconductors, and a superconducting LSI using niobium superconductors has now been prototyped.
ジョセフソン接合素子の最大のメリットはその高速性で
、超高速性のスイッチング動作が可能で、それを集積化
した超伝導ＬＳＩを用いれば超高速コンピューターを作
製できる。ある試算によると半導体を用いたコンピュー
ターに比べ、ジョセフソン接合素子を用いた場合は５０
倍も高速なコンピューターが作製できるという。また、
半導体と違って消費電力が著しく小さいということもジ
ョセフソン接合素子の特長である。また、ジョセフソン
接合素子は微小磁場や電磁波・光の超高速センサーとし
ても利用できる。しかし、従来のジョセフソン接合素子
は臨界温度の低い金属系の超伝導材料（例えば、ニオブ
や鉛）を用いていたため、ジョセフソン接合素子を動作
するために、極低温が必要であった。そのため、高価で
資源的にも偏在した液体ヘリウムを使用せざるを得す、
実用化の妨げとなっていた。The greatest advantage of Josephson junction devices is their high speed, which allows them to perform ultra-high-speed switching operations, and by using superconducting LSIs that integrate them, ultra-high-speed computers can be created. According to some estimates, compared to computers using semiconductors, using Josephson junction devices costs 50% less.
It is said that it is possible to create computers that are twice as fast. Also,
Another feature of Josephson junction devices is that, unlike semiconductors, their power consumption is extremely low. Josephson junction devices can also be used as ultrahigh-speed sensors for minute magnetic fields, electromagnetic waves, and light. However, since conventional Josephson junction devices used metallic superconducting materials (such as niobium and lead) with low critical temperatures, extremely low temperatures were required to operate the Josephson junction devices. Therefore, we have no choice but to use liquid helium, which is expensive and unevenly distributed as a resource.
This was an obstacle to practical application.
一方、近年、酸化物系において液体窒素温度を越える臨
界温度をもつ超伝導体（酸化物超伝導体）が発見された
。これらの超伝導体（酸化物超伝導体）を用いれば、液
体窒素冷却で動作するジョセフソン接合素子ができ、実
用化が期待できる。On the other hand, in recent years, oxide-based superconductors (oxide superconductors) with critical temperatures exceeding liquid nitrogen temperatures have been discovered. If these superconductors (oxide superconductors) are used, Josephson junction devices that operate under liquid nitrogen cooling can be created, which is expected to be put to practical use.
ジョセフソン接合素子は２つの超伝導体を非常に薄い絶
縁体や常伝導体で挾んだものである。その絶縁体や常伝
導体の厚さは、物質に依存するが、酸化物超伝導体は一
般にコヒーレント長が非常に短いため、酸化物超伝導体
に絶縁物を挟んだＳＩＳ接合タイプでは数ｒ＋ｍ以下の
非常に薄い絶縁体を形成しなければならない。超伝導体
に常伝導体を挟んだＳＮＳ接合タイプではＳＩＳ接合タ
イプより条件は緩いが、厚さ数１０ｎｍの常伝導体膜を
形成しなければならず微細加工の限界を越えていた。A Josephson junction device consists of two superconductors sandwiched between a very thin insulator or normal conductor. The thickness of the insulator or normal conductor depends on the material, but since oxide superconductors generally have a very short coherence length, an SIS junction type in which an insulator is sandwiched between an oxide superconductor has a thickness of several r+m. A very thin insulator must be formed. The conditions for the SNS junction type, in which a normal conductor is sandwiched between a superconductor, are less strict than for the SIS junction type, but it requires the formation of a normal conductor film several tens of nanometers thick, which exceeds the limits of microfabrication.
つまり上記のような非常に薄い絶縁体や常伝導体膜を超
伝導体の上に形成し、さらにその上に超伝導体を形成す
るということは非常に困難である。In other words, it is extremely difficult to form a very thin insulator or normal conductor film as described above on a superconductor and then form a superconductor on top of it.
また、酸化物超伝導体は酸化物の為、極めて反応性が激
しく、また作成温度も高２Ｍ（５００°Ｃ）が要求され
るため、接合近傍の界面はぼやけたものとなってしまう
。Furthermore, since the oxide superconductor is an oxide, it is extremely reactive and requires a high production temperature of 2M (500°C), resulting in a blurred interface near the junction.
以上の理由より従来の酸化物超伝導体を用いたジョセフ
ソン接合素子は、自然に生じた粒界を利用するものが殆
どで、試料依存性が高く、信頼性は極めて低かった。従
って、人為的に粒界を制御して、信頼性の高いジョセフ
ソン接合素子を作ることが求められていた。For the above reasons, most conventional Josephson junction devices using oxide superconductors utilize naturally occurring grain boundaries, are highly sample dependent, and have extremely low reliability. Therefore, there has been a need to artificially control grain boundaries to produce highly reliable Josephson junction elements.
「発明の目的」
本発明は酸化物超伝導体を用いたジョセフソン接合素子
における常伝導体膜を微細加工を用いずに形成すること
及び酸化物超伝導体と常伝導体膜との接合を低温で形成
してその接合界面を明確なものとすることを目的とする
。``Object of the Invention'' The present invention is directed to forming a normal conductor film in a Josephson junction device using an oxide superconductor without using microfabrication, and to bonding the oxide superconductor and the normal conductor film. The purpose is to form it at a low temperature and make the bonding interface clear.
（発明の構成）
本発明は、基板上に酸化物超伝導薄膜を形成する工程、
前記基板および薄膜を冷却することによって薄膜にクラ
ックを形成し前記薄膜を分断する工程、および前記クラ
ックを金属で満たし、超伝導体−常伝導体一超伝導体接
合（ＳＮＳ接合）を形成することによってジョセフソン
素子を作製する方法を提供するものである。また、本発
明は、酸化物超伝導体が一般に熱膨張率が各種基板材料
に比べて大きく、そのため温度変化によりクラックが発
生しやすいという問題点をもつことを逆に利用して酸化
物超伝導体に人為的な粒界を形成することを特長とする
。(Structure of the Invention) The present invention includes a step of forming an oxide superconducting thin film on a substrate,
forming a crack in the thin film and dividing the thin film by cooling the substrate and the thin film; and filling the crack with metal to form a superconductor-normal conductor-superconductor junction (SNS junction). The present invention provides a method for manufacturing a Josephson device using the following method. In addition, the present invention utilizes the fact that oxide superconductors generally have a larger coefficient of thermal expansion than various substrate materials, which causes cracks to occur easily due to temperature changes. It is characterized by the formation of artificial grain boundaries in the body.
即ち、本発明は基板として酸化物超伝導体より熱膨張率
が小さい材料を用いることにより、表面に酸化物超伝導
薄膜を形成した後基板を冷却すると薄膜と基板の熱膨張
率の違いにより応力が生じこの応力により幅５０μｍ以
下の粒界（クラック）が形成され、更にこのクラック付
近に金属を形成してジョセフソン接合素子を形成すると
いう発明である。つまり、酸化物超伝導薄膜と酸化物超
伝導薄膜との間に微細加工を必要とせず５０μｍ以下の
厚さで常伝導体となる金属膜を形成させることができる
。また酸化物超伝導薄膜と金属の接合は低温で形成され
るため、その接合界面はぼやけることがなく明確にする
ことができる。That is, in the present invention, by using a material with a coefficient of thermal expansion smaller than that of an oxide superconductor as a substrate, when the substrate is cooled after forming an oxide superconducting thin film on the surface, stress is reduced due to the difference in coefficient of thermal expansion between the thin film and the substrate. This stress causes grain boundaries (cracks) with a width of 50 μm or less to be formed, and metal is further formed in the vicinity of these cracks to form a Josephson junction element. In other words, a metal film that becomes a normal conductor and has a thickness of 50 μm or less can be formed between the oxide superconducting thin films and the oxide superconducting thin film without requiring microfabrication. Furthermore, since the bond between the oxide superconducting thin film and the metal is formed at a low temperature, the bond interface can be clearly defined without blurring.
基板上に酸化物超伝導体が形成されているのを冷却する
と、膨張率の違いより基板と薄膜の間に応力が働く。通
常だと薄膜が均一なため応力が分散されてしまい、結果
的にクラックは起きたり、起きなかったりと規則性は全
くない。しかし本発明においては予めクラックを生じさ
せたい場所をくびれさせたり、その場所にミシン目をつ
くったりすることによって、確実にクラック即ちジョセ
フソン接合に必要な粒界を生じさせることができる。When an oxide superconductor formed on a substrate is cooled, stress occurs between the substrate and the thin film due to the difference in expansion coefficient. Normally, because the thin film is uniform, the stress is dispersed, and as a result, cracks may occur or not, with no regularity at all. However, in the present invention, cracks, that is, grain boundaries necessary for Josephson bonding, can be reliably generated by constricting the area where a crack is desired to occur or creating perforations there.
このクラック付近に金属を形成することにより、金属と
その両側の超伝導体とでジョセフソン接合を形成するこ
とができる。By forming metal near this crack, a Josephson junction can be formed between the metal and the superconductor on both sides.
以下の実施例により更に本発明を説明する。The invention is further illustrated by the following examples.
（実施例１）
第１図に本発明のジョセフソン接合素子を作る工程を説
明するための基板の断面図を示す。第１図Ａの基板１と
してはサファイヤを、酸化物超伝導薄膜３としてはＹＢ
ａｚ Ｃｕ＊ Ｏｙの化学式で表せられる材料を用いた
。(Example 1) FIG. 1 shows a cross-sectional view of a substrate for explaining the process of making a Josephson junction element of the present invention. Sapphire is used as the substrate 1 in FIG. 1A, and YB is used as the oxide superconducting thin film 3.
A material represented by the chemical formula az Cu*Oy was used.
基板１上にｒｆスパッタ法により単結晶酸化物超伝導薄
膜３を堆積した。そのときの成膜条件等を以下の表に表
す。A single crystal oxide superconducting thin film 3 was deposited on a substrate 1 by RF sputtering. The film forming conditions etc. at that time are shown in the table below.
ターゲット Ｙ Ｂ ａ ｚ Ｃｕ ｓ Ｏｙ
基板 サファイヤ２面
基板温度 ６００″Ｃ
雰囲気 Ａｒ（６０χ）、０ｚ（４０χ）ガス
圧力 ０．４％
ｒｆ大入力 １３０Ｗ
堆積速度 ３ ｎｍ／ｍｉｎ
膜厚 ５００ｎｍ
後熱処理 １ａｔｏｍＯｚ中で基板温度４００”
Ｃで３０分
こうしてできた膜は抵抗測定の結果、９１にで抵抗が零
となった。Target Y B az Cu s Oy
Substrate Sapphire 2-sided substrate temperature 600"C Atmosphere Ar (60χ), 0z (40χ) Gas pressure 0.4% RF large input 130W Deposition rate 3 nm/min Film thickness 500nm Post-heat treatment Substrate temperature 400" in 1 atomOz
As a result of resistance measurement of the film thus formed at C for 30 minutes, the resistance became zero at 91.
この膜をイオンミリング法によってエツチングして、第
２図で示されるようにクビレ１３を幅数１０μｍ以下、
例えば約０．５μｍに形成した。This film is etched by ion milling to form the constrictions 13 with a width of several tens of μm or less, as shown in FIG.
For example, it is formed to have a thickness of about 0.5 μm.
同図において、９は基板、１１はその上に形成された酸
化物超伝導体薄膜を示す。In the figure, reference numeral 9 indicates a substrate, and reference numeral 11 indicates an oxide superconductor thin film formed thereon.
次に第３図に示す真空蒸着装置１５内に基板１９を基板
ホルダ１７に設置した。チャンバー内を排気後、液体窒
素を循環させて基板１９を約１００Ｋまで冷却した。こ
の過程で熱膨張率の違いによって生じる応力のため、第
１図Ｂに示すように膜のクビレ部分に幅約数１０ｎｍの
クラック５が生じた。Next, the substrate 19 was placed in the substrate holder 17 in the vacuum evaporation apparatus 15 shown in FIG. After the chamber was evacuated, liquid nitrogen was circulated to cool the substrate 19 to about 100K. During this process, due to the stress caused by the difference in coefficient of thermal expansion, a crack 5 with a width of about 10 nm was generated in the constricted part of the film, as shown in FIG. 1B.
更にこの状態のまま、蒸発源２３を加熱して酸化物超伝
導体と反応性の弱い金属、例えば金や銀の金属膜７をク
ビレの部分のみにマスク２１を用いて厚さ約２０ｒｖに
堆積した。こうして第１図Ｃのような酸化物超伝導体−
常伝導体一酸化物超伝導体接合を形成して、ジョセフソ
ン接合素子が得られた。Further, in this state, the evaporation source 23 is heated to deposit a metal film 7 of a metal having weak reactivity with the oxide superconductor, such as gold or silver, to a thickness of about 20 rv only on the constricted part using the mask 21. did. In this way, an oxide superconductor as shown in Figure 1C -
A Josephson junction device was obtained by forming a normal conductor monoxide superconductor junction.
ここで得られたジョセフソン接合素子の電流・電圧特性
を、７７にで調べたところ、第４図に示すように、ＳＮ
Ｓ接合特有の非線型性が現れ、確かにジョセフソン接合
が形成されていることが分かった。The current/voltage characteristics of the Josephson junction device obtained here were investigated in 1977, and as shown in Figure 4, the SN
Nonlinearity peculiar to S junctions appeared, and it was found that a Josephson junction was indeed formed.
（実施例２）
第５図に別の実施例の基板の平面図を示す。基板２５上
に形成された酸化物超伝導薄膜２７に対してエツチング
法によって、ミシン目２９をパタニングする。このパタ
ーンは幅０．５μｍ、ミシン目の間隔は５μｍの等間隔
とした。その他の工程は実施例１と同じであるから省略
するが、温度変化と基板と薄膜の熱膨張率の違いを利用
することによりこのミシン目を境にクラックが形成され
る。このように本発明はエツチングパターンを変える事
によって種々のバリエーションが可能である。(Example 2) FIG. 5 shows a plan view of a substrate of another example. Perforations 29 are patterned on the oxide superconducting thin film 27 formed on the substrate 25 by an etching method. The width of this pattern was 0.5 μm, and the perforations were equally spaced at 5 μm intervals. Other steps are the same as in Example 1 and will therefore be omitted, but cracks are formed at the perforations by utilizing temperature changes and differences in thermal expansion coefficients between the substrate and the thin film. As described above, the present invention allows various variations by changing the etching pattern.
（実施例３）
第６図に本実施例に使用するスパッタ装置の概略図を示
す。本実施例では超伝導薄膜の成膜、パターニング、及
び金属膜の形成を同一の装置で連続して行う為マルチチ
ャンバ方式とした。即ち、本実施例に用いたスパッタ装
置は電力系及び排気系、ガス系を持つ３つの独立したチ
ャンバからなり、基板を第１のチャンバから第２のチャ
ンバへまた第２のチャンバから第３のチャンバへ移動す
る為の機構が設けられている。以下にそのプロセスを説
明する。(Example 3) FIG. 6 shows a schematic diagram of a sputtering apparatus used in this example. In this example, a multi-chamber system was used to continuously perform the formation of a superconducting thin film, patterning, and formation of a metal film in the same apparatus. That is, the sputtering apparatus used in this example consists of three independent chambers each having a power system, an exhaust system, and a gas system, and the substrate is transferred from the first chamber to the second chamber and from the second chamber to the third chamber. A mechanism is provided for movement into the chamber. The process will be explained below.
本実施例において、先ず第１のチャンバ３１において基
板３７上に酸化物超伝導体ＹＢａｚＣｕ３０Ｖをスパッ
タ法により形成した。その時の成膜条件を以下に記す。In this example, first, an oxide superconductor YBazCu30V was formed on the substrate 37 in the first chamber 31 by sputtering. The film forming conditions at that time are described below.
ターゲット ＹＢａ２Ｃｕ３０゜基板
サファイヤＲ面
基板温度 ６００°Ｃ
雰囲気 ０２５０％。Target YBa2Cu30° substrate
Sapphire R side substrate temperature 600°C atmosphere 0250%.
ガス圧力 １００ｍＴｏｒｒ
ｒｆ人力 １３０Ｗ
膜厚 ５００ ｎｍ
Ａｒ５０％
成膜された薄膜は単結晶であった。これを酸素雰囲気で
、６００°Ｃを保ったまま保持した。Gas pressure: 100 mTorr RF manual power: 130 W Film thickness: 500 nm Ar: 50% The deposited thin film was a single crystal. This was maintained at 600°C in an oxygen atmosphere.
次にこの基板を第２のチャンバ３３へ移動する（図面で
は移動機構は省略した）。このチャンバ内を１０ ”’
Ｔｏｒｒに真空引きし、電子ビームまたはレーザービー
ム４１及びマスク４５を用いて酸化物超伝導薄膜のバタ
ーニングを行う。この時のパタンは実施例１と同様にク
ビレのあるパターンとした。この工程のときも成膜時と
同じ基板温度（６００°Ｃ）を保つようにした。Next, this substrate is moved to the second chamber 33 (the moving mechanism is omitted in the drawing). 10"' inside this chamber
A vacuum is drawn to Torr, and the oxide superconducting thin film is patterned using an electron beam or a laser beam 41 and a mask 45. The pattern at this time was a concave pattern similar to that in Example 1. During this step, the same substrate temperature (600° C.) as during film formation was maintained.
更に、基板を第３のチャンバ３５へ移動した。Furthermore, the substrate was moved to the third chamber 35.
このチャンバ内において、基板温度を室温まで冷却した
。これによって酸化物超伝導薄膜には微細なりラックが
形成される。そしてターゲットに設置した銀をマスク４
７を用いて、クラックの付近のみに厚さ約２０ｎｍに成
膜した。In this chamber, the substrate temperature was cooled to room temperature. As a result, fine racks are formed in the oxide superconducting thin film. Then mask the silver placed on the target 4
No. 7 was used to form a film with a thickness of about 20 nm only in the vicinity of the crack.
このようにしてジョセフソン接合素子を形成した。In this way, a Josephson junction element was formed.
本実施例によって酸化物超伝導薄膜を基板上に形成する
工程から、クラックの形成、そしてジョセフソン接合の
形成まで一貫して一つの装置で連続した工程で作ること
ができた。さらに３つのチャンバはそれぞれが互いに独
立しているため、同時に３つのチャンバで別々の工程を
行うことが出来るため、無駄が無く生産性を高めるため
に有利な方法である。According to this example, the entire process from forming an oxide superconducting thin film on a substrate to forming cracks and forming Josephson junctions could be performed in one continuous process using one device. Furthermore, since the three chambers are independent from each other, different processes can be performed in the three chambers at the same time, which is an advantageous method for eliminating waste and increasing productivity.
本発明において形成されたクラックは冷却や昇温等の温
度変化の為、その幅が変動する可能性があるが、動作温
度は常に一定であるから、素子の特性も使用する範囲に
おいては一定である。The cracks formed in the present invention may vary in width due to temperature changes such as cooling or temperature rise, but since the operating temperature is always constant, the characteristics of the device are also constant within the range of use. be.
さらに基板としてＳｉやＳｉＯ□を用いても良い。Furthermore, Si or SiO□ may be used as the substrate.
（効果）
本発明によって従来、微細加工の域を越えた酸化物超伝
導体のジョセフソン接合素子の作製が、従来とは全く異
なる熱膨張率の違いと温度変化の利用という全く新しい
方法によって作製することができた。(Effects) With the present invention, Josephson junction devices of oxide superconductors, which were conventionally beyond the scope of microfabrication, can be fabricated using a completely new method that utilizes differences in thermal expansion coefficients and temperature changes. We were able to.
本発明は実施例のみに制限されるものでなく、つまり薄
膜と基板の熱膨張率の違いと温度変化を利用して粒界を
作ることが発明の要であり、薄膜や基板の種類、クラッ
クの大きさ、形状等は必要に応じて変えることができる
。The present invention is not limited only to the examples; in other words, the essence of the invention is to create grain boundaries by utilizing the difference in thermal expansion coefficient between the thin film and the substrate and temperature changes, and the type of thin film and substrate, cracks and The size, shape, etc. can be changed as necessary.
第１図は本発明のジョセフソン接合を作る工程を断面図
により示す。
第２図は実施例１の基板の平面図を示す。
第３図は蒸着装置を示す。
第４図は本発明のジョセフソン接合素子の電流・電圧特
性を示す。
縦軸：電流（ｍＡ） 、横軸：電圧（Ｖ）第５図は別の
実施例の基板の平面図を示す。
第６図は実施例３で用いたスパッタリング装置を示す。
基板 ３ 酸化物超伝導薄膜
クラック ７ 金属膜
基板 １１ 酸化物超伝導薄膜３ クビレ
１５ 蒸着装置
７ 基板ホルダ １９ 基板
ｌ マスク ２３ 蒸着源
４ 排気装置 ２５ 基板
７ 酸化物超伝導膜
９ ミシン目
１ 第１のチャンバ
３ 第２のチャンバ
５ 第３のチャンバ
７ 基板 ３９ ターゲット
１ 電子ビーム装置またはレーザ
３
タ
ゲラ
ト
５及び４
マスク
（Ｂ）
ｋ−
弔
図
Ｎ２
＾−一
弔
図
第６
図FIG. 1 shows, in cross-sectional view, the process of making a Josephson junction according to the present invention. FIG. 2 shows a plan view of the substrate of Example 1. FIG. 3 shows a vapor deposition apparatus. FIG. 4 shows the current/voltage characteristics of the Josephson junction element of the present invention. Vertical axis: current (mA), horizontal axis: voltage (V) FIG. 5 shows a plan view of a substrate of another embodiment. FIG. 6 shows the sputtering apparatus used in Example 3. Substrate 3 Oxide superconducting thin film crack 7 Metal film substrate 11 Oxide superconducting thin film 3 Cracks
15 Vapor deposition device 7 Substrate holder 19 Substrate l Mask 23 Vapor deposition source 4 Exhaust device 25 Substrate 7 Oxide superconducting film 9 Perforation 1 First chamber 3 Second chamber 5 Third chamber 7 Substrate 39 Target 1 Electron beam device Or Laser 3 Tagerato 5 and 4 Mask (B) k- Funeral diagram N2 ^-One funeral diagram Fig. 6
Claims (1)
基板を冷却して前記薄膜にクラックを生じさせることに
より前記薄膜を分断する工程と、前記クラック付近に金
属を形成することにより酸化物超伝導体−常伝導体−酸
化物超伝導体の接合を形成する工程を含む、ジョセフソ
ン接合素子の作製方法。 ２、特許請求の範囲第１項において前記酸化物超伝導薄
膜は単結晶であるジョセフソン接合素子の作製方法。 ３、特許請求の範囲第１項において前記クラックは幅５
０ｎｍ以下であるジョセフソン接合素子の作製方法。 ４、サファイヤＲ面基板上にＹＢａ＿２Ｃｕ＿３Ｏ＿ｙ
で表される酸化物超伝導薄膜を形成する工程と、前記薄
膜に化学的または物理的なエッチング処理を施して幅１
０μｍ以下のクビレを形成する工程と、前記基板および
薄膜を１００Ｋ以下に冷却して前記クビレ部分に幅５０
μｍ以下のクラックを形成して前記薄膜を分断する工程
と、前記クラック付近に金属を形成することによって超
伝導体−常伝導体−超伝導体接合を作る工程を含むジョ
セフソン接合素子の作製方法。[Claims] 1. A step of forming an oxide superconducting thin film on a substrate, a step of dividing the thin film by cooling the substrate and causing cracks in the thin film, and a step of forming a metal near the cracks. A method for producing a Josephson junction device, comprising the step of forming an oxide superconductor-normal conductor-oxide superconductor junction by forming. 2. A method for manufacturing a Josephson junction device according to claim 1, wherein the oxide superconducting thin film is a single crystal. 3. In claim 1, the crack has a width of 5
A method for manufacturing a Josephson junction device having a thickness of 0 nm or less. 4. YBa_2Cu_3O_y on sapphire R-plane substrate
A process of forming an oxide superconducting thin film represented by
A step of forming a constriction of 0 μm or less, and cooling the substrate and thin film to 100K or less to form a constriction with a width of 50 μm.
A method for producing a Josephson junction element, comprising: dividing the thin film by forming cracks of less than μm in size; and forming a superconductor-normal conductor-superconductor junction by forming metal near the cracks. .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1249904A JPH03110879A (en) | 1989-09-26 | 1989-09-26 | Production of josephson junction element |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1249904A JPH03110879A (en) | 1989-09-26 | 1989-09-26 | Production of josephson junction element |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH03110879A true JPH03110879A (en) | 1991-05-10 |
Family
ID=17199937
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1249904A Pending JPH03110879A (en) | 1989-09-26 | 1989-09-26 | Production of josephson junction element |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH03110879A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007032905A (en) * | 2005-07-26 | 2007-02-08 | Ishikawajima Harima Heavy Ind Co Ltd | Cooler |
| JP2007524198A (en) * | 2003-12-31 | 2007-08-23 | スーパーパワー インコーポレイテッド | Superconductor article and method of making and using the same |
-
1989
- 1989-09-26 JP JP1249904A patent/JPH03110879A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007524198A (en) * | 2003-12-31 | 2007-08-23 | スーパーパワー インコーポレイテッド | Superconductor article and method of making and using the same |
| JP2007032905A (en) * | 2005-07-26 | 2007-02-08 | Ishikawajima Harima Heavy Ind Co Ltd | Cooler |
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