JPH04113683A - Manufacture of thin film device - Google Patents
Manufacture of thin film deviceInfo
- Publication number
- JPH04113683A JPH04113683A JP2232938A JP23293890A JPH04113683A JP H04113683 A JPH04113683 A JP H04113683A JP 2232938 A JP2232938 A JP 2232938A JP 23293890 A JP23293890 A JP 23293890A JP H04113683 A JPH04113683 A JP H04113683A
- Authority
- JP
- Japan
- Prior art keywords
- layer
- thin film
- oxide
- oxide superconductor
- 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 56
- 238000004519 manufacturing process Methods 0.000 title claims description 12
- 239000002887 superconductor Substances 0.000 claims abstract description 74
- 229910052751 metal Inorganic materials 0.000 claims abstract description 29
- 239000002184 metal Substances 0.000 claims abstract description 25
- 239000010408 film Substances 0.000 claims abstract description 23
- 238000000137 annealing Methods 0.000 claims abstract description 17
- 238000010030 laminating Methods 0.000 claims abstract description 5
- 238000000034 method Methods 0.000 claims description 28
- 239000000758 substrate Substances 0.000 claims description 15
- 230000000737 periodic effect Effects 0.000 claims description 6
- 230000007704 transition Effects 0.000 claims description 5
- 229910052804 chromium Inorganic materials 0.000 abstract description 7
- 229910052742 iron Inorganic materials 0.000 abstract description 7
- 230000000873 masking effect Effects 0.000 abstract description 7
- 229910052759 nickel Inorganic materials 0.000 abstract description 6
- 229910052733 gallium Inorganic materials 0.000 abstract description 3
- 229910052782 aluminium Inorganic materials 0.000 abstract 1
- 239000010410 layer Substances 0.000 description 64
- 239000004020 conductor Substances 0.000 description 11
- 239000000463 material Substances 0.000 description 10
- 239000012212 insulator Substances 0.000 description 7
- 239000000203 mixture Substances 0.000 description 7
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 5
- 238000010586 diagram Methods 0.000 description 5
- 239000001301 oxygen Substances 0.000 description 5
- 229910052760 oxygen Inorganic materials 0.000 description 5
- 238000002441 X-ray diffraction Methods 0.000 description 4
- 239000013078 crystal Substances 0.000 description 4
- 238000001704 evaporation Methods 0.000 description 4
- 239000007789 gas Substances 0.000 description 4
- 229910052758 niobium Inorganic materials 0.000 description 4
- 229910052761 rare earth metal Inorganic materials 0.000 description 4
- GQPLMRYTRLFLPF-UHFFFAOYSA-N Nitrous Oxide Chemical compound [O-][N+]#N GQPLMRYTRLFLPF-UHFFFAOYSA-N 0.000 description 3
- 238000001816 cooling Methods 0.000 description 3
- 238000009792 diffusion process Methods 0.000 description 3
- 230000008020 evaporation Effects 0.000 description 3
- 238000010884 ion-beam technique Methods 0.000 description 3
- 238000006467 substitution reaction Methods 0.000 description 3
- 229910004247 CaCu Inorganic materials 0.000 description 2
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 239000000470 constituent Substances 0.000 description 2
- 230000008878 coupling Effects 0.000 description 2
- 238000010168 coupling process Methods 0.000 description 2
- 238000005859 coupling reaction Methods 0.000 description 2
- 238000000151 deposition Methods 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 239000011229 interlayer Substances 0.000 description 2
- 150000002500 ions Chemical class 0.000 description 2
- 229910052748 manganese Inorganic materials 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 238000004544 sputter deposition Methods 0.000 description 2
- 229910052721 tungsten Inorganic materials 0.000 description 2
- 229910052720 vanadium Inorganic materials 0.000 description 2
- 229910052725 zinc Inorganic materials 0.000 description 2
- 229910014454 Ca-Cu Inorganic materials 0.000 description 1
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 1
- 238000005299 abrasion Methods 0.000 description 1
- 229910052784 alkaline earth metal Inorganic materials 0.000 description 1
- 150000001342 alkaline earth metals Chemical class 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 238000005229 chemical vapour deposition Methods 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 229910001882 dioxygen Inorganic materials 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005566 electron beam evaporation Methods 0.000 description 1
- 238000010894 electron beam technology Methods 0.000 description 1
- 238000005530 etching Methods 0.000 description 1
- 238000010304 firing 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
- 238000007737 ion beam deposition Methods 0.000 description 1
- 238000001659 ion-beam spectroscopy Methods 0.000 description 1
- 238000000608 laser ablation Methods 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000001272 nitrous oxide Substances 0.000 description 1
- 238000005192 partition Methods 0.000 description 1
- 238000005240 physical vapour deposition Methods 0.000 description 1
- 229910052697 platinum Inorganic materials 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- -1 rO2 Substances 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 238000001004 secondary ion mass spectrometry Methods 0.000 description 1
- 229910052709 silver Inorganic materials 0.000 description 1
- 238000001771 vacuum deposition Methods 0.000 description 1
- 238000007740 vapor deposition Methods 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)
本発明は薄膜デバイスの製造方法に関し、更に詳しくは
、酸化物高温超伝導体を用いた、ジョセフソン素子など
に有用な薄膜デバイスの製造方法に関するものである。[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a method for manufacturing a thin film device, and more specifically, a method for manufacturing a thin film device using an oxide high temperature superconductor, which is useful for Josephson elements and the like. It is related to.
〈従来の技術〉
近年、従来より研究されてきたNb、ないしN b s
S nやN b a G e等のAlS型化合物(β
W型結晶構造)の超伝導体に代わる超伝導体として、C
u−0層を結晶構造中に含む酸化物超伝導体の研究が活
発である。<Prior art> Nb or Nb s, which has been studied in recent years
AlS type compounds (β
C as a superconductor to replace the superconductor with W-type crystal structure
Oxide superconductors containing a u-0 layer in their crystal structure are actively researched.
このような酸化物超伝導体の典型的な材料としては、Y
−Ba−Cu−0系(臨界温度Tc>90K) 、B
i−5r−Ca−Cu系(臨界温度Tc −80〜ll
0K) 、あるいはTfl−BaCa−Cu−0系(臨
界温度T c −90〜120K )などが知られてい
る。A typical material for such an oxide superconductor is Y
-Ba-Cu-0 system (critical temperature Tc>90K), B
i-5r-Ca-Cu system (critical temperature Tc -80~ll
0K), or the Tfl-BaCa-Cu-0 system (critical temperature Tc -90 to 120K).
そしてこれらの材料を電子デバイスであるジョセフソン
素子として用いる場合における最重要技術がジョセフソ
ン接合の形成である。このジョセフソン接合は、−船釣
には、蒸着法、スパッタ蒸着法、あるいはレーサーアブ
レーションなどによって形成される。The most important technique when using these materials as a Josephson element, which is an electronic device, is the formation of a Josephson junction. This Josephson junction is formed by a vapor deposition method, a sputter deposition method, or a laser ablation method.
ところが、上記のような材料はその相関長か極めて短か
く、且つ材料表面が劣化し易いことが確認されている。However, it has been confirmed that the correlation length of the above-mentioned materials is extremely short, and the material surface is easily deteriorated.
また、これらの材料の薄膜を間隙を形成するための中間
層を介して積層化してジョセフソン接合を形成した場合
、超伝導材料と中間層の格子整合性が悪いと、隣接する
超伝導層の特性が劣化したり、中間層からリーク電流が
生したりするため、再現性のよいS/N/S (超伝導
体/常伝導体(導電体)/超伝導体)接合が得られなか
ったり、あるいはS/I/S (超伝導体/絶縁体/超
伝導体)接合の場合でもリーク電流が生したり、超伝導
結合が得られないなどの欠点がある。In addition, when a Josephson junction is formed by stacking thin films of these materials with an interlayer intervening to form a gap, if the lattice matching between the superconducting material and the interlayer is poor, the adjacent superconducting layer may Due to properties deterioration and leakage current generated from the intermediate layer, S/N/S (superconductor/normal conductor (conductor)/superconductor) junction with good reproducibility may not be obtained. Alternatively, even in the case of S/I/S (superconductor/insulator/superconductor) junction, there are drawbacks such as leakage current and failure to obtain superconducting coupling.
これらの欠点を解決するため、例えば積層型薄膜デバイ
スの場合、従来は以下の(a)〜(C)ような方法か提
案されている。In order to solve these drawbacks, for example, in the case of a stacked thin film device, the following methods (a) to (C) have been proposed.
(a)酸化物超伝導体上に絶縁膜を形成した後、従来型
(フォノン型)の超伝導体(例えばNbないしNb系合
金、pbないしpb化合物)を積層する方法。(a) A method in which an insulating film is formed on an oxide superconductor, and then a conventional (phonon type) superconductor (for example, Nb or Nb-based alloy, pb or pb compound) is laminated.
(b)酸化物超伝導体上に、中間層として金属超伝導体
の酸素の少ない材料、または通常基板に用いられるMg
0SSrTiO、ZrO2などの材料を積層し、この上
に超伝導体を積層する方法。(b) Oxygen-poor material of metal superconductor as an intermediate layer on oxide superconductor, or Mg usually used for substrate
A method of stacking materials such as 0SSrTiO and ZrO2, and then stacking a superconductor on top of them.
(C)酸化物超伝導体上に、この酸化物超伝導体のうち
の希土類元素やアルカリ土金属を他の元素で置換して絶
縁体層を形成し、この絶縁体層の上に酸化物超伝導体を
積層する方法。(C) An insulator layer is formed on the oxide superconductor by replacing rare earth elements and alkaline earth metals in the oxide superconductor with other elements, and an oxide layer is formed on the insulator layer. How to stack superconductors.
〈発明が解決しようとする課題〉
しかしながら、上記(a)の方法の場合には、従来型の
超伝導体を用いていることから、液体ヘリウム温度でし
かデバイスを作動させることができないという問題があ
る。<Problem to be solved by the invention> However, in the case of method (a) above, since a conventional superconductor is used, there is a problem that the device can only be operated at the temperature of liquid helium. be.
また(b)の方法では、中間層として金属超伝導体の酸
素の少ない材料を用いる場合には、アニーリング時にお
ける酸素の拡散の制御性が悪いためシャープな界面が得
難いし、またMgOなどの基板材料を用いた場合ではM
gなどの拡散によって特性の良い膜が得難いという問題
がある。In addition, in method (b), when a metal superconductor with low oxygen content is used as the intermediate layer, it is difficult to obtain a sharp interface due to poor controllability of oxygen diffusion during annealing, and it is difficult to obtain a sharp interface when the intermediate layer is made of a metal superconductor with low oxygen content. When using materials, M
There is a problem in that it is difficult to obtain a film with good characteristics due to the diffusion of g and the like.
更に(C)の方法では、超伝導特性を示すCu−0層と
希土類元素などとの結合が弱いため、超伝導特性から絶
縁特性に変えるためには上記置換を多量(50%以上)
にしなければならないという問題がある。Furthermore, in method (C), the bond between the Cu-0 layer, which exhibits superconducting properties, and rare earth elements, etc. is weak, so in order to change from superconducting properties to insulating properties, a large amount of the above substitution (50% or more) is required.
The problem is that it has to be done.
一方、マイクロブリッジ型の薄膜デバイスでは、上述方
法に加えて、紫外光やイオンビームの照射などにより超
伝導膜を破壊しあるいは取除き、これによって非超伝導
体部分を形成する方法が行なわれている。On the other hand, in microbridge-type thin film devices, in addition to the above-mentioned methods, a method is used in which the superconducting film is destroyed or removed by irradiation with ultraviolet light or ion beams, thereby forming a non-superconducting portion. There is.
紫外光の場合、通常の光源では超伝導特性が完全には壊
れ難いため、エキシマレーザなどの高出力のものを用い
る必要があるし、またイオンビームの場合も同様にガス
イオンを用いる必要がある。In the case of ultraviolet light, the superconducting properties are difficult to completely destroy with normal light sources, so it is necessary to use a high-power source such as an excimer laser, and in the case of ion beams, it is also necessary to use gas ions. .
しかしながら、これらエキシマレーザによる紫外光照射
やガスイオンによる超伝導膜のエツチングによるパター
ン形式は生産性が悪く、工業上量産する場合の適用は困
難であるという問題がある。However, these patterns using ultraviolet light irradiation using an excimer laser or etching the superconducting film using gas ions have poor productivity and are difficult to apply to industrial mass production.
〈課題を解決するための手段〉
本発明者はこれらの問題を解決すべく鋭意研究の所、S
/N/S結合またはS/I/S結合に用いられる常伝導
体または絶縁体として、上記の酸化物超伝導体を構成す
る元素の一部を、Znなどの周期表II族b亜族元素、
Aβ、 Gaなどの周期表III族b亜族元素、あるい
はFe。<Means for Solving the Problems> In order to solve these problems, the present inventor has conducted extensive research and developed S.
As a normal conductor or insulator used for the /N/S bond or the S/I/S bond, some of the elements constituting the above oxide superconductor may be a group II group b subgroup element of the periodic table such as Zn. ,
Group III group b subgroup elements of the periodic table, such as Aβ, Ga, or Fe.
Co、Ni、PtなとのCu以外の遷移元素で置換する
ことにより、臨界温度Tcがデバイス使用温度より低い
常伝導体層または絶縁体層を構成できることを知得した
。It has been found that by substituting a transition element other than Cu such as Co, Ni, or Pt, a normal conductor layer or an insulator layer having a critical temperature Tc lower than the device operating temperature can be constructed.
また、このような積層構造を備えた薄膜デバイスは、基
板上に形成した酸化物超伝導体層の薄膜の上に上記金属
薄膜を積層した後にアニーング処理するか、あるいは、
アニーリングによって酸化物超伝導体となる薄膜組成上
に上記金属薄膜を積層した後にアニーリング処理するこ
とによって得られることを見出した。Further, a thin film device having such a laminated structure can be produced by laminating the metal thin film on a thin film of an oxide superconductor layer formed on a substrate, and then subjecting it to an annealing treatment.
It has been found that this can be obtained by laminating the above metal thin film on a thin film composition that becomes an oxide superconductor by annealing and then annealing the film.
本発明は以上の知得に基づくもので、基板上にCuを含
有する酸化物超伝導体層を設け、前記酸化物超伝導体層
に接して酸化物層を設けてなる薄膜デバイスの製造方法
であって、前記酸化物層が、前記酸化物超伝導体層、ま
たはアニーリングにより前記酸化物超伝導体層となる薄
膜の上に、前記酸化物超電導体層中に含まれる金属元素
とは異なる元素の金属薄膜を積層した後、アニーリング
処理して得られたものであることを要旨とする薄膜デバ
イスの製造方法である。The present invention is based on the above knowledge, and is a method for manufacturing a thin film device, which comprises providing an oxide superconductor layer containing Cu on a substrate, and providing an oxide layer in contact with the oxide superconductor layer. wherein the oxide layer is formed on the oxide superconductor layer or on the thin film that becomes the oxide superconductor layer by annealing, and is different from the metal element contained in the oxide superconductor layer. This is a method for manufacturing a thin film device, the gist of which is that the thin film device is obtained by stacking elemental metal thin films and then subjecting them to an annealing treatment.
上記酸化物層は、前記酸化物超伝導体と同しまたはCu
を含有する他の酸化物超伝導体を構成する元素の一部を
、Cuを置換し得る元素、即ち周期表II族b亜族元素
1周期表III族b亜族元素、またはCu以外の遷移元
素で置換した酸化物層である。The oxide layer is the same as the oxide superconductor or Cu
A part of the elements constituting other oxide superconductors containing This is an oxide layer substituted with an element.
本発明において酸化物超伝導体は、具体的には例えば、
YBa Cu OなどのLB2Cu O、−(L
:希土類元素、B:アルカリ土類)、Bi Sr
CaCu O、BiSr CaCu OBi
Sr Ca2 28−δ’ 2 2+y
Cu OないしB125r2Ca2Cu2−y
3 10
0 Bi B B Cu 031
0−δ’ 2 lx Ily n 2n
+4(x+yさn+1、n−1,2,3)で示されるも
の、あるいはTρ Ba Ca Cu2 2
n−1n
O(n−1,2,3)で示される、Tnと2n+4
Cu−0の2次元平面を含む酸化物なとが挙げられる。In the present invention, the oxide superconductor is specifically, for example,
LB2CuO, -(L
: rare earth element, B: alkaline earth), Bi Sr
CaCu O, BiSr CaCu OBi
Sr Ca2 28-δ' 2 2+y
Cu O or B125r2Ca2Cu2-y
3 10 0 Bi B B Cu 031
0-δ' 2 lx Ily n 2n
+4 (x+y n+1, n-1, 2, 3) or Tρ Ba Ca Cu2 2
An example is an oxide containing a two-dimensional plane of Tn and 2n+4 Cu-0, represented by n-1n O (n-1,2,3).
また、金属薄膜を形成する金属は、少なくとも上記酸化
物超電導体層に含まれる金属元素を含有することが必要
であり、値Znなどの周期表II族b亜族元素、An、
Gaなどの周期表III族b亜族元素、あるいはFe、
Co、Ni、Pt等のCu以外の遷移元素、特にAρ、
Ga。Further, the metal forming the metal thin film must contain at least the metal elements contained in the oxide superconductor layer, including elements of Group II b subgroup of the periodic table such as Zn, An,
Group III group b subgroup elements of the periodic table such as Ga, or Fe,
Transition elements other than Cu such as Co, Ni, and Pt, especially Aρ,
Ga.
Fe、Co、NiまたはCrが使用される。Fe, Co, Ni or Cr are used.
金属薄膜を積層する具体的な方法としては、真空蒸着法
、イオンビーム蒸着法、スパッタ蒸着法などの公知の物
理蒸着法や化学蒸着法が挙げられる。Specific methods for laminating metal thin films include known physical vapor deposition methods and chemical vapor deposition methods such as vacuum deposition, ion beam deposition, and sputter deposition.
アニーリングは、通常公知の条件で行なわれる。例えば
YBaCuO(希土類元素)2 37−δ
の場合には、900〜970℃で0.5〜24時間焼成
すれば良い。またB 12 S r 2 Ca CLJ
20 g(Bi系)の場合は、800〜890℃で0
.5〜24時間焼成すれば良い。冷却はいずれの場合も
24時間程度かけて600℃位まで冷却し、その後、放
冷することにより行う。Annealing is normally performed under known conditions. For example, in the case of YBaCuO (rare earth element) 2 37 -δ, firing may be performed at 900 to 970°C for 0.5 to 24 hours. Also B 12 S r 2 Ca CLJ
In the case of 20 g (Bi type), it is 0 at 800-890℃.
.. It is sufficient to bake for 5 to 24 hours. In either case, cooling is performed by cooling to about 600° C. over about 24 hours, and then allowing it to cool.
また本発明の製造方法を用いてジョセフソン結合を形成
する場合は更に、上記酸化物層に接してCuを含有する
酸化物超伝導体層を設け、即ち2つの酸化物超伝導体部
の間に上記酸化物層を配する構成とすれば良い。Further, when forming a Josephson bond using the manufacturing method of the present invention, an oxide superconductor layer containing Cu is further provided in contact with the oxide layer, that is, between two oxide superconductor parts. The structure may be such that the oxide layer is disposed on the oxide layer.
一方、薄膜デバイスを構成する酸化物超伝導体層は基板
に対してC軸配向、あるいはA軸ないしB軸配向してい
ることが好ましく、更にこれら各隔部内に粒界か存在し
ない方が良い。On the other hand, it is preferable that the oxide superconductor layer constituting the thin film device has a C-axis orientation, or an A-axis or B-axis orientation with respect to the substrate, and it is further preferable that no grain boundaries exist in each of these partitions. .
薄膜デバイス各層の膜厚は、−様な膜が形成されまたバ
ルクと同様の膜厚を示す限り、できるだけ薄い方が好ま
しい。具体的には、酸化物超伝導層は30〜5000人
が、また酸化物層(絶縁体層、常伝導層)はそれぞれ2
0〜1000人が選ばれる。The thickness of each layer of the thin film device is preferably as thin as possible, as long as a -like film is formed and the thickness is similar to that of the bulk. Specifically, 30 to 5,000 people were involved in the oxide superconducting layer, and 2 people each in the oxide layer (insulator layer, normal conductor layer).
0 to 1000 people will be selected.
基板上に酸化物超伝導体層またはアニーリングにより酸
化物超伝導体層となる薄膜は、平坦で−様な膜が形成さ
れる従来からの成膜法、例えば分子線蒸着(MBE)、
電子ビーム蒸着法。An oxide superconductor layer on a substrate or a thin film that becomes an oxide superconductor layer by annealing can be formed by conventional film deposition methods that form a flat, -like film, such as molecular beam evaporation (MBE),
Electron beam evaporation method.
スパッター蒸着法、レーザーアブレーンヨンなどでそれ
ぞれ形成される。They are formed by sputter deposition, laser abrasion, etc.
アニーリングにより酸化物超伝導体層となる薄膜は、そ
の組成が上記酸化物超伝導体層の組成とほとんど同じで
良く、即ち若干0が過剰であったり、あるいはFか混入
していても良い。The composition of the thin film that becomes an oxide superconductor layer by annealing may be almost the same as the composition of the oxide superconductor layer, that is, it may have a slight excess of 0 or may contain F.
第1図(A)〜(C)は一対のマイクロブリッジ型の薄
膜デバイスを形成する例を示したものである。この薄膜
デバイスにおいて酸化物超伝導体層に接して絶縁体層あ
るいは常伝導層を形成する場合、まず第1図(A)のよ
うに基板2上に酸化物超伝導体層1(あるいはアニーリ
ングにより酸化物超伝導体層となる薄膜組成)を形成し
、次いてこの酸化物超伝導体層1の上に例えば第1図(
B)のような形状のマスキング3を載せる、この状態で
マスキング3を通して酸化物超伝導体層1の上に第1図
(C)のように金属薄膜4を蒸着し、その後にアニーリ
ング処理するという方法を採ることができる。FIGS. 1A to 1C show an example of forming a pair of microbridge type thin film devices. When forming an insulating layer or a normal conducting layer in contact with an oxide superconductor layer in this thin film device, first, as shown in FIG. A thin film composition (which will become an oxide superconductor layer) is formed, and then, on top of this oxide superconductor layer 1, for example,
A masking 3 having the shape shown in B) is placed on the oxide superconductor layer 1. In this state, a thin metal film 4 is deposited on the oxide superconductor layer 1 through the masking 3 as shown in FIG. 1C, and then annealing is performed. method can be adopted.
また第2図(A)はマイクロブリッジ型の薄膜デバイス
からなるジョセフソン素子の一例を示したもので、基板
平面上の図において左右に形成された2つの超伝導体層
(超伝導体膜)Sの中央の結合部分を、両側の超伝導体
層Sより薄くあるいは上記方法により細くし、またこの
結合部分の上下に常伝導体層(常伝導体膜)Nを接して
設けた構造のものである。Fig. 2 (A) shows an example of a Josephson element consisting of a microbridge type thin film device, in which two superconductor layers (superconductor films) are formed on the left and right sides of the substrate plane. A structure in which the connecting part at the center of S is made thinner than the superconductor layers S on both sides or made thinner by the method described above, and normal conductor layers (normal conductor films) N are provided above and below this connecting part in contact with each other. It is.
上記構造においては、常伝導体層Nは超伝導体層Sの結
合部の細くなった超伝導性部分の一部のみであってもよ
い。第2図(B)はその例で、超伝導体層Sの結合部の
細くなった個所に設けた孔部分を非超伝導化(図では常
伝導化して常伝導体層Nを形成)し、所謂SQUIDt
M造とした例である。In the above structure, the normal conductor layer N may be only a part of the superconducting portion of the superconductor layer S where the bonding portion becomes thin. Figure 2 (B) is an example of this, in which the hole provided at the narrowed part of the bonding part of the superconductor layer S is made non-superconducting (in the figure, it is made normal conductor to form the normal conductor layer N). , the so-called SQUIDt
This is an example of M construction.
上記の細くなった超伝導性部分や孔部分なとは、上記マ
スキング方法、あるいは従来の紫外線やイオンビーム照
射によって、その周りを絶縁体化して絶縁体層を形成す
ることによって得ても良い。The above-mentioned narrowed superconducting portions and hole portions may be obtained by forming an insulator layer around them by using the above-described masking method or conventional ultraviolet or ion beam irradiation.
以上説明した構造の他、例えば積層型の薄膜デバイスに
おいて、薄膜デバイス上に別の膜を形成して追加の機能
を発現させたり、超伝導体層と基板との間に公知のバッ
ファ層(Z r O2、MgO等)を挿入する構造とし
ても良い。更に必要ならば保護膜を設けても、勿論良い
。In addition to the structure described above, for example, in a stacked thin film device, another film may be formed on the thin film device to express an additional function, or a known buffer layer (Z) may be formed between the superconductor layer and the substrate. It is also possible to have a structure in which a material (e.g., rO2, MgO, etc.) is inserted. Furthermore, it is of course possible to provide a protective film if necessary.
〈作 用〉
上記のアニーリング処理により、酸化物超伝導体層の上
に酸化物層が形成された薄膜デバイスが得られる。<Function> Through the above annealing treatment, a thin film device in which an oxide layer is formed on the oxide superconductor layer is obtained.
これは、酸化物還元電位の考察によれば、アニーリング
処理によって酸化物超伝導体の構成元素中のCuが金属
薄膜中の金属元素と置換され、あるいは上記構成元素中
の酸素が金属元素により奪われる反応が起こることに因
ると推察される。This is due to the fact that Cu in the constituent elements of the oxide superconductor is replaced by the metal element in the metal thin film due to the annealing treatment, or oxygen in the constituent elements is taken away by the metal element, according to the consideration of oxide reduction potential. It is assumed that this is due to the reaction that occurs.
そして、この酸化物層は、これが接する酸化物超伝導体
より臨界温度が低く、またその臨界温度Tcの制御が容
易で、更に結晶性並びに酸化物超伝導体層との格子整合
性が良好であるので、この酸化物層を備えることで、上
記の欠点や問題がなく、デバイスを構成する酸化物超伝
導体の臨界温度で作動させることが可能な薄膜デバイス
を得ることができる。This oxide layer has a lower critical temperature than the oxide superconductor with which it is in contact, the critical temperature Tc can be easily controlled, and furthermore, it has good crystallinity and lattice matching with the oxide superconductor layer. Therefore, by providing this oxide layer, it is possible to obtain a thin film device that does not have the above-mentioned drawbacks and problems and can be operated at the critical temperature of the oxide superconductor constituting the device.
またアニーリング処理の際における金属薄膜と酸化物超
伝導体の反応は極めて迅速であり、また金属元素が膜厚
方向に一様に分布することが、!MMS(二次イオン質
量分析法)により確認された。Furthermore, the reaction between the metal thin film and the oxide superconductor during the annealing process is extremely rapid, and the metal elements are evenly distributed in the film thickness direction! Confirmed by MMS (secondary ion mass spectrometry).
更に上記のように金属薄膜を積層した後にアニーリング
処理してこの金属薄膜から酸化物層を得るという方法を
採ることで、マイクロブリッジ型の薄膜デバイスにおい
て非超伝導体部分を形成する場合でも、上述のように容
易に適用できる。Furthermore, by adopting the method described above in which a metal thin film is laminated and then subjected to an annealing treatment to obtain an oxide layer from this metal thin film, even when forming a non-superconducting portion in a microbridge type thin film device, the above method can be achieved. can be easily applied as
〈実施例〉 以下、実施例を説明する。<Example> Examples will be described below.
SrO,CaO,Bi O、CuOの酸化物の粉体を
金属元素の組成て2:2:2:3の割合で混合し、また
これにMn、W、N i、V。Powders of oxides of SrO, CaO, BiO, and CuO are mixed in a ratio of metal elements of 2:2:2:3, and Mn, W, Ni, and V are mixed therein.
Cr、Fe、Co及びZnの酸化物の粉体を金属元素の
組成で適当な割合混合し、これらを粉砕し更に混合した
。Powders of oxides of Cr, Fe, Co, and Zn were mixed in appropriate proportions according to the composition of metal elements, and these were ground and further mixed.
そして、Mg0(1(1(1)からなる基板上において
、この混合物を800℃で5時間仮焼し、次いで850
〜870℃で空気中で24時間焼成し、50℃/hrで
冷却するなどして、上記基板上に薄膜を形成した。Then, on a substrate consisting of Mg0(1(1)), this mixture was calcined at 800°C for 5 hours, and then at 850°C.
A thin film was formed on the substrate by baking in air at ~870°C for 24 hours and cooling at 50°C/hr.
この薄膜をX線回折により調べた所、Bi系の8OK相
の結晶構造を備えた酸化物超伝導体のBi S「2Ca
Cu208であることが確認された。When this thin film was examined by X-ray diffraction, it was found that BiS'2Ca is an oxide superconductor with a Bi-based 8OK phase crystal structure.
It was confirmed that it was Cu208.
第3図はこの薄膜においてCuの一部をMnW、Ni、
V、Cr、Fe、Co、Znなどの元素によりX(原子
96)たけ置換した場合の臨界温度Tc (K)の低
下を示したもので、これらの元素の置換量を変えること
で臨界温度Tcの制御を容易に行なえることが判る。尚
、第3図において白丸部分は非超伝導成分てない個所を
示す。Figure 3 shows that in this thin film, part of Cu is replaced with MnW, Ni,
This shows the decrease in critical temperature Tc (K) when X (96 atoms) is substituted with elements such as V, Cr, Fe, Co, and Zn. By changing the amount of substitution of these elements, the critical temperature Tc can be lowered. It can be seen that the control can be easily carried out. Incidentally, in FIG. 3, white circles indicate areas where there is no non-superconducting component.
次に、上記と同様の方法によって、Bi系の高Tc相の
結晶構造を備えた酸化物超伝導体であるBi S「2C
a2Cu301oからなる薄膜を形成した。Next, by the same method as above, BiS "2C", which is an oxide superconductor with a Bi-based high Tc phase crystal structure
A thin film made of a2Cu301o was formed.
この薄膜においてCuの一部をW、Crなどの元素によ
りX(原子96)だけ置換した場合における臨界温度T
c (K)の変化を調べた。In this thin film, the critical temperature T when a portion of Cu is replaced by X (96 atoms) with elements such as W and Cr
Changes in c (K) were investigated.
結果は第4図の通りで、実施例1と同様に上記元素の置
換量を変えることで臨界温度Tcの制御を容易に行なえ
ることが判明した。The results are as shown in FIG. 4, and it was found that the critical temperature Tc can be easily controlled by changing the amount of substitution of the above elements as in Example 1.
以上はBi系の酸化物超伝導体の例であるか、例えばY
BCO系においてもCo、Feなどの元素の置換により
同様に臨界温度Tcの制御を容易に行えることが確認さ
れた。The above are examples of Bi-based oxide superconductors, or for example Y
It has been confirmed that the critical temperature Tc can be similarly easily controlled in the BCO system by replacing elements such as Co and Fe.
そしてこれら実験結果から、積層構造において十分よい
整合性が採られれば、S/N/S結合としてよい動作を
することが予想される。From these experimental results, it is expected that if sufficient matching is achieved in the laminated structure, it will work well as an S/N/S coupling.
実施例1
酸素ガスO:亜酸化窒素ガスN20=9=1の割合の混
合ガスからなる3 X l(1’torrの雰囲気中で
、多元蒸着装置により電子ビームと抵抗加熱を併用し、
S r T I O3(100)からなる基板上にY、
Cu、Baを同時蒸着して500人の厚さでYBa
Cu Oを積層し、更に2 37−δ
この上に200人の厚さでCOを蒸着した。尚、蒸着速
度はl(1人/gfnて、また基板温度は850℃とし
た。Example 1 Oxygen gas O: nitrous oxide gas N20 was mixed with a gas mixture in the ratio of 9=1 (in an atmosphere of 1'torr, using a combination of electron beam and resistance heating with a multi-source evaporation device,
Y on a substrate made of S r T I O3 (100),
Co-deposited Cu and Ba to a thickness of 500 YBa
CuO was laminated, and 237-δ CO was further deposited thereon to a thickness of 200 nm. The deposition rate was 1 person/gfn, and the substrate temperature was 850°C.
上記の薄膜デバイスを酸素分圧20Otorr下で5時
間保持し、次いて30℃/hourで冷却した。The above thin film device was held under an oxygen partial pressure of 20 Otorr for 5 hours, and then cooled at 30° C./hour.
得られた薄膜の面内の超伝導特性を測定した所、臨界温
度Tc<4にであり、Coを含む層により超伝導特性が
消失しており、界面での拡散が十分高いことが判った。When we measured the in-plane superconducting properties of the obtained thin film, we found that the critical temperature Tc<4, the superconducting properties disappeared due to the Co-containing layer, and it was found that the diffusion at the interface was sufficiently high. .
実施例2
実施例1と同じ条件で、Bi O、SrOCab、C
uをMg0(100)からなる基板上に同時蒸着して、
Bi25「2CaCu2ox(500人)の薄膜を作製
した。尚、基板温度は75(1”cとした。Example 2 Under the same conditions as Example 1, BiO, SrOCab, C
By co-evaporating u onto a substrate made of Mg0(100),
A thin film of Bi25"2CaCu2ox (500 people) was prepared. The substrate temperature was 75 (1"c).
この薄膜をX線回折した。このX線回折像は第5図の通
りで、Bi系80に相のC軸配向を示した。またこの薄
膜における市内の電流特性は第6図の通りである。This thin film was subjected to X-ray diffraction. This X-ray diffraction image is as shown in FIG. 5, and showed the C-axis orientation of the Bi-based 80 phase. Furthermore, the current characteristics within the city in this thin film are as shown in FIG.
上記の膜上に、Ag、Cr、Ni、Feを室温でそれぞ
れ200人積層し、800℃で1時間熱処理した。Ag
を積層した膜量外では、超伝導転移がみられなくなった
。特にCrによる抵抗増加が著しかった。On the above film, 200 layers each of Ag, Cr, Ni, and Fe were laminated at room temperature, and heat treated at 800° C. for 1 hour. Ag
Superconducting transitions were no longer observed outside the amount of laminated films. In particular, the increase in resistance due to Cr was remarkable.
更に、同様にして作製したB l 2 S r 2 C
aCuO上に所定形状のマスキングを通して8+δ
Cr、Fe、Mnをそれぞれ200人蒸着口、次いて8
00℃で熱処理して、第2図(^)に見られようなマイ
クロブリジを作製した。ブリッジ幅は100μmであっ
た。抵抗温度曲線は第6図とほぼ同じものが得られ、超
伝導転移も80にで起った。Furthermore, B l 2 S r 2 C produced in the same manner
8+δ Cr, Fe, and Mn were deposited on aCuO through 200 evaporation ports each through masking of a predetermined shape, and then 8
A micro bridge as shown in Fig. 2 (^) was prepared by heat treatment at 00°C. The bridge width was 100 μm. A resistance temperature curve almost the same as that shown in FIG. 6 was obtained, and superconducting transition also occurred at 80°C.
一方、抵抗値は1桁以上も上昇し、所望のブリッジ構造
が得られていることが判り、弱結合超伝導デバイスとし
て使用可能であることが判った。On the other hand, the resistance value increased by more than one order of magnitude, indicating that the desired bridge structure was obtained, and that it could be used as a weakly coupled superconducting device.
〈発明の効果〉
以上のように本発明によれば、前記した従来技術の欠点
や問題がなく、デバイスを構成する酸化物超伝導体の臨
界温度で作動させることが可能な薄膜デバイスの製造方
法を提供することができる。<Effects of the Invention> As described above, according to the present invention, there is provided a method for manufacturing a thin film device that does not have the drawbacks and problems of the prior art described above and can be operated at the critical temperature of the oxide superconductor that constitutes the device. can be provided.
第1図(A)〜(C)は本発明に係わるの薄膜デバイス
の製造工程の説明図、第2図(^) 、 (B)は本発
明に係わるマイクロブリッジ型の薄膜デバイスの説明図
、第3図は本発明に係わるBi系の8(IK相の酸化物
における臨界温度Tcの低下を示したグラフ、第4図は
同しくBi系Tc高相における臨界温度Tcの低下を示
したグラフ、第5図は実施例2において得られた積層膜
のX線回折結果のグラフ、第6図はこの膜の面内電流特
性を示したグラフである。
1・・・超伝導体膜、2・・・基板、3・・マスキング
、4・・・金属薄膜、S・・超伝導体層、N・・・常伝
導体層。
特許出願人 三菱化成株式会社
代 理 人 尾 股 行
雄第
図(A)
第
図(B)
第
図(C)
X(原
第2rgJ(A)
第2図(B)
植
図
X(原
雫
%)
瀉5図
坑6rg:J
絶
χ・l
温
1良(KlFigures 1 (A) to (C) are explanatory diagrams of the manufacturing process of a thin film device according to the present invention, Figures 2 (^) and (B) are explanatory diagrams of a microbridge type thin film device according to the present invention, FIG. 3 is a graph showing the decrease in the critical temperature Tc in the Bi-based 8 (IK phase) oxide according to the present invention, and FIG. 4 is a graph similarly showing the decrease in the critical temperature Tc in the Bi-based Tc high phase. , FIG. 5 is a graph of the X-ray diffraction results of the laminated film obtained in Example 2, and FIG. 6 is a graph showing the in-plane current characteristics of this film. 1... Superconductor film, 2 ...Substrate, 3.. Masking, 4.. Metal thin film, S.. Superconductor layer, N.. Normal conductor layer. Patent applicant: Mitsubishi Kasei Corporation Agent Yuki Omata
Male Diagram (A) Diagram (B) Diagram (C) 1 good (Kl
Claims (1)
前記酸化物超伝導体層に接して酸化物層を設けてなる薄
膜デバイスの製造方法であって、 前記酸化物層が、前記酸化物超伝導体層ま たはアニーリングにより前記酸化物超伝導体層となる薄
膜の上に、前記酸化物超電導体層中に含まれる金属元素
とは異なる元素の金属薄膜を積層した後、アニーリング
処理して得られたものであることを特徴とする薄膜デバ
イスの製造方法。 2、前記酸化物層が、前記酸化物超伝導体と同じまたは
Cuを含有する他の酸化物超伝導体を構成する元素の一
部を、周期表II族b亜族元素、周期表III族b亜族元素
、またはCu以外の遷移元素で置換した酸化物層である
ことを特徴とする請求項1記載の製造方法。[Claims] 1. An oxide superconductor layer containing Cu is provided on a substrate,
A method for manufacturing a thin film device comprising an oxide layer provided in contact with the oxide superconductor layer, wherein the oxide layer is bonded to the oxide superconductor layer or to the oxide superconductor layer by annealing. A method for producing a thin film device, characterized in that the thin film is obtained by laminating a metal thin film of an element different from the metal element contained in the oxide superconductor layer on the thin film, and then annealing the film. . 2. The oxide layer may contain some of the elements constituting the same oxide superconductor or other oxide superconductor containing Cu, an element of group II group b of the periodic table, a group III group of the periodic table. 2. The manufacturing method according to claim 1, wherein the oxide layer is substituted with a subgroup b element or a transition element other than Cu.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2232938A JPH04113683A (en) | 1990-09-03 | 1990-09-03 | Manufacture of thin film device |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2232938A JPH04113683A (en) | 1990-09-03 | 1990-09-03 | Manufacture of thin film device |
Publications (1)
Publication Number | Publication Date |
---|---|
JPH04113683A true JPH04113683A (en) | 1992-04-15 |
Family
ID=16947204
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP2232938A Pending JPH04113683A (en) | 1990-09-03 | 1990-09-03 | Manufacture of thin film device |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH04113683A (en) |
-
1990
- 1990-09-03 JP JP2232938A patent/JPH04113683A/en active Pending
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