JPH0796450B2 - Method for producing Bi-Pb-Sr-Ca-Cu-O superconductor thin film - Google Patents
Method for producing Bi-Pb-Sr-Ca-Cu-O superconductor thin filmInfo
- Publication number
- JPH0796450B2 JPH0796450B2 JP1080997A JP8099789A JPH0796450B2 JP H0796450 B2 JPH0796450 B2 JP H0796450B2 JP 1080997 A JP1080997 A JP 1080997A JP 8099789 A JP8099789 A JP 8099789A JP H0796450 B2 JPH0796450 B2 JP H0796450B2
- Authority
- JP
- Japan
- Prior art keywords
- thin film
- bscco
- bpscco
- phase
- 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.)
- Expired - Lifetime
Links
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
- Y02E40/60—Superconducting electric elements or equipment; Power systems integrating superconducting elements or equipment
Landscapes
- Inorganic Compounds Of Heavy Metals (AREA)
- Physical Vapour Deposition (AREA)
- Superconductors And Manufacturing Methods Therefor (AREA)
Description
【発明の詳細な説明】 （産業上の利用分野） 本発明はBi系超電導体の製造方法に係わり、特に、エレ
クトロニクス素子に好適な高い零抵抗臨界温度特性Tc
(ZERO)を示すBi−Pb−Sr−Ca−Cu−Ｏ（以下、BPSCCOと
言う。）超電導体薄膜の製造方法に関する。TECHNICAL FIELD The present invention relates to a method for manufacturing a Bi-based superconductor, and particularly to a high zero resistance critical temperature characteristic Tc suitable for an electronic device.
The present invention relates to a method for producing a Bi-Pb-Sr-Ca-Cu-O (hereinafter referred to as BPSCCO) superconductor thin film showing (ZERO) .
（従来技術） 超電導現象を生じる超電導体は、臨界温度Tc、臨界磁界
Hcそして臨界電流密度Jcの３つの臨界値が大きな値を示
し、更に、各々の臨界値が均整のとれた数値を示すこと
によって超電導体として評価されている。このような評
価基準に基づいて、種々の超電導体が発見されている。
超電導体の開発においては、常温に近い高いTcで超電導
を生じる高温超電導体の研究が盛んに行われており、特
に、液体窒素温度（77K）より高いTcを示すBi系のBi−S
r−Ca−Cu−Ｏ（以下、BSCCOと言う。）高温超電導体が
注目されている。(Prior Art) A superconductor that causes a superconducting phenomenon has a critical temperature Tc and a critical magnetic field.
The three critical values of Hc and critical current density Jc show a large value, and each critical value shows a well-balanced numerical value, so that it is evaluated as a superconductor. Various superconductors have been discovered based on such evaluation criteria.
In the development of superconductors, research on high-temperature superconductors that produce superconductivity at high Tc close to room temperature is being actively conducted, and in particular, Bi-based Bi-S alloys exhibiting Tc higher than liquid nitrogen temperature (77K).
Attention is paid to r-Ca-Cu-O (hereinafter referred to as BSCCO) high-temperature superconductor.
本発明者は、上記のBSCCO超電導体を弱結合ジョセフソ
ン接合に応用する目的で酸素ガス中のMgO基板にリアク
ティブ・スパッタリングによって、組成比がBi:Sr:Ca:C
u＝1:1:1:2のスパッタターゲットを用い、アニーリング
温度が約825℃で約１時間の処理したBSCCO薄膜を作製
し、Tc(ZERO)＝82Kが得られたことを報告した〔太田
浩：第49回応用物理学会学術講演会予稿集（第１分
冊）,p158,秋期（1988）〕。しかし、BSCCO超電導体
は、高Tc相が得られにくく、全体の多くは低Tc相が占め
ている。そこで、Biの一部をPbで置換したBPSCCO超電導
体が提案されている。具体的には、Bi、Pb、Srなどの全
ての構成元素を含む２つのシュウ酸塩を焼成して、BPSC
COの焼結体を作製する。焼成は、800℃で12時間仮焼き
し、ペレットに固めた後840℃で240時間以上本焼きして
Tc(ZERO)＝110Kが得られている〔M.Takano,J.Takada他:
Jpn.J.Appl.Phys.27（1988）L1041〕。The inventors of the present invention, by reactive sputtering on a MgO substrate in oxygen gas for the purpose of applying the above BSCCO superconductor to a weakly coupled Josephson junction, the composition ratio is Bi: Sr: Ca: C.
It was reported that Tc (ZERO) = 82K was obtained by producing a BSCCO thin film that was treated for 1 hour at an annealing temperature of about 825 ° C using a sputter target with u = 1: 1: 1: 2 [Ota Hiroshi: Proceedings of the 49th Japan Society of Applied Physics Academic Lecture (1st volume), p158, Autumn (1988)]. However, in the BSCCO superconductor, it is difficult to obtain a high Tc phase, and the low Tc phase occupies most of the whole. Therefore, a BPSCCO superconductor in which a part of Bi is replaced with Pb has been proposed. Specifically, two oxalates containing all the constituent elements such as Bi, Pb, and Sr are fired to obtain BPSC.
Create a sintered body of CO. Baking is performed by calcining at 800 ° C for 12 hours, solidifying into pellets, and then firing at 840 ° C for 240 hours or more.
Tc (ZERO) = 110K has been obtained [M. Takano, J. Takada et al:
Jpn.J.Appl.Phys.27 (1988) L1041].
一方、最近では、Pbを含むBi系超電導体の薄膜を作製す
る方法がいくつか提案されている。例えば、BPSCCO薄膜
を構成するBi、Pb、Srなどの全ての元素をシングルター
ゲットでスパッタして形成された薄膜を850℃で15時間
アニーリング処理して得られたTc(ZERO)＝107Kを示すBP
SCCO超電導薄膜〔Y.Hakuraku,Y.Aridome他:Jpn.J.Appl.
Phys.27,Nov.（1988）L2091−L2093〕や基板上にBi−Sr
−Ca−Cu−Ｏ、BiO2、PbOの薄膜を繰り返してサンドイ
ッチ状に積層して850℃でアニーリング処理し、Tc＝107
Kを示すBPSCCO超電導薄膜〔富士通：日経産業新聞,Dec.
5（1988）〕が作製されている。On the other hand, recently, there have been proposed some methods for forming a thin film of a Bi-based superconductor containing Pb. For example, Tc (ZERO) = 107K obtained by annealing a thin film formed by sputtering all the elements such as Bi, Pb, and Sr that compose the BPSCCO thin film with a single target at 850 ° C for 15 hours.
SCCO superconducting thin film (Y.Hakuraku, Y.Aridome et al .: Jpn.J.Appl.
Phys.27, Nov. (1988) L2091-L2093] and Bi-Sr on the substrate.
-Ca-Cu-O, BiO 2 , by repeating a thin film of PbO annealed at laminating to 850 ° C. in a sandwich-like, Tc = 107
BPSCCO superconducting thin film showing K (Fujitsu: Nikkei Sangyo Shimbun, Dec.
5 (1988)] has been produced.
（発明が解決しようとする課題） しかし、BPSCCO薄膜の作製においては、高Tc相を形成す
るためのPbの添加量の制御が難しいこと、また、薄膜形
成後のアニーリング処理温度が高いために、高Tc相を安
定して得るには薄膜形成工程を厳しい条件の下に行う必
要があった。更に、アニーリング処理時間が掛かりすぎ
るという課題があった。(Problems to be solved by the invention) However, in the production of a BPSCCO thin film, it is difficult to control the amount of Pb added to form a high Tc phase, and because the annealing treatment temperature after thin film formation is high, In order to obtain a high Tc phase stably, it was necessary to perform the thin film formation process under severe conditions. Further, there is a problem that the annealing treatment time is too long.
本発明は、エレクトロニクス素子に好適な高Tc(ZERO)が
安定して得られるBPSCCO薄膜を作製することを目的とす
る。An object of the present invention is to produce a BPSCCO thin film, which is suitable for electronic devices and which can stably obtain high Tc (ZERO) .
（課題を解決するための手段） 上記の課題は、BSCCO薄膜を形成した後、Pbの量を制御
して金属Pb薄膜を積層して、次いで熱（アニーリング）
処理を施ことによりBPSCCO薄膜とすることにより解決す
ることができる。(Means for Solving the Problem) The above problem is that after forming the BSCCO thin film, the amount of Pb is controlled to stack the metal Pb thin film, and then the heat (annealing) is performed.
It is possible to solve the problem by forming a BPSCCO thin film by applying a treatment.
BSCCO薄膜としては不活性ガスまたは酸素とアルゴンの
混合ガス中の基板上に、アクティブ・スパッタを行うこ
とにより形成されるアモルファスBSCCO薄膜を使用する
ことができる。As the BSCCO thin film, an amorphous BSCCO thin film formed by performing active sputtering on a substrate in an inert gas or a mixed gas of oxygen and argon can be used.
（作用） BSCCO薄膜の作製は、既に本発明者が蓄積したデータに
基づいてその組成比を極めて高精度に作製することがで
き、また、前記BSCCO薄膜上に金属Pb薄膜を一般的なス
パッタリング法により容易にPb量を制御して積層するこ
とができる。従って、前記積層膜を約850℃程度でアニ
ーリングすることにより容易にBSCCO基板中にPbを拡散
することができる。(Function) The BSCCO thin film can be prepared with extremely high composition ratio based on the data already accumulated by the present inventor, and the metal Pb thin film is formed on the BSCCO thin film by a general sputtering method. Thus, the Pb amount can be easily controlled to form a stack. Therefore, Pb can be easily diffused into the BSCCO substrate by annealing the laminated film at about 850 ° C.
Bi系超電導体は、高Tc相と低Tc相が混在しており、Bi系
原料にPbを加えて焼成したバルク状焼結体においては高
Tc相の単一相に近いものを実現できることがわかってい
る。しかし、薄膜ではPbが熱処理で気化し易いのでBSCC
O薄膜中に所定量のPbを加えにくかった。本発明は、あ
らかじめPbの気化量を考慮した上でPbを積層して熱処理
を行う。本発明によるBPSCCO薄膜は、低Tc相がかなり存
在しているものの、結晶粒界にPbが拡散して高Tc相が結
晶粒界でも途切れることなく連続的につながっているも
のと考えられる。これは、第２図に示す比抵抗曲線の零
抵抗臨界温度Tc(ZERO)が高Tc相の110Kであることから結
論することができる。Bi-based superconductors have a mixture of high Tc phase and low Tc phase, which is high in the bulk sintered body obtained by adding Pb to the Bi-based raw material and firing.
It has been found that it is possible to realize a Tc phase close to a single phase. However, in thin films, Pb is easily vaporized by heat treatment, so BSCC
It was difficult to add a predetermined amount of Pb to the O thin film. In the present invention, the heat treatment is performed by stacking Pb after considering the vaporization amount of Pb in advance. In the BPSCCO thin film according to the present invention, although the low Tc phase is considerably present, it is considered that Pb diffuses into the crystal grain boundaries and the high Tc phase is continuously connected without interruption even at the crystal grain boundaries. This can be concluded from the fact that the zero resistance critical temperature Tc (ZERO) of the resistivity curve shown in Fig. 2 is 110K in the high Tc phase.
（発明の効果） 本発明によって得られたBPSCCO超電導体薄膜は、本発明
者が作製した従来のBSCCO薄膜に比べ、Tc(ZERO)温度を2
0％向上することができた。(Effects of the Invention) The BPSCCO superconductor thin film obtained by the present invention has a Tc (ZERO) temperature of 2% as compared with the conventional BSCCO thin film produced by the present inventor.
It was possible to improve by 0%.
本発明は、BSCCO薄膜上に金属Pb薄膜を量的に制御して
スパッタリングし、次いでアニーリング処理することに
よりBSCCO薄膜中に所定量のPbを容易に拡散することが
できる。更に、アニーリング処理温度が低くしかも処理
時間が従来法に比べ極めて短時間で作製できるので、高
Tc相を安定して得ることができる。特に、高Tc相が結晶
粒界に形成されるためジョセフソン接合素子等のエレク
トロニクスに応用する場合に好適な方法である。In the present invention, a predetermined amount of Pb can be easily diffused in the BSCCO thin film by quantitatively controlling the sputtering of the metal Pb thin film on the BSCCO thin film and then performing the annealing treatment. Furthermore, since the annealing temperature is low and the processing time is much shorter than the conventional method,
The Tc phase can be stably obtained. In particular, since the high Tc phase is formed at the crystal grain boundary, it is a suitable method when applied to electronics such as Josephson junction devices.
（実施例） 以下に、本発明の実施例を説明する。(Example) Below, the Example of this invention is described.
第１図は、本発明の熱処理前の積層基板断面図である。
まず始めに、酸素およびアルゴンの混合ガス雰囲気
（O2:Ar＝6:18mTorr）でリアクティブ・スパッタにより
BSCCO薄膜を形成する。基板に用いるMgO（t1×10×10m
m）11をEXTRANガラスクリーナーで洗浄し、スパッタ用
チャンバー内に設けた加熱用の窒化ホウ素板上にセット
してMgO基板温度を約570℃で保持し、４インチスパッタ
ターゲットを用いてスパッタリングして厚さ１μｍのア
モルファスBSCCO薄膜12を形成した。この時のスパッタ
装置の動作条件は、高周波出力が150W、スパッタによる
成膜速度は12.5nm/minである。FIG. 1 is a sectional view of a laminated substrate before heat treatment according to the present invention.
First, by reactive sputtering in a mixed gas atmosphere of oxygen and argon (O 2 : Ar = 6: 18 mTorr).
Form BSCCO thin film. MgO used for the substrate (t1 × 10 × 10m
m) 11 was washed with EXTRAN glass cleaner, set on a boron nitride plate for heating provided in the sputtering chamber, the MgO substrate temperature was maintained at about 570 ° C, and sputtering was performed using a 4-inch sputter target. An amorphous BSCCO thin film 12 having a thickness of 1 μm was formed. The operating conditions of the sputtering apparatus at this time are a high-frequency output of 150 W and a film formation rate by sputtering of 12.5 nm / min.
次に、上記BSCCO薄膜上に高純度のPb薄膜、即ち、金属P
b薄膜13を形成する。Pbの成膜条件は、４インチスパッ
タターゲットにより、高周波出力150W、アルゴンガス雰
囲気中で、成膜速度は200nm/minで保持し、BSCCO薄膜上
に厚さ135nmの金属Pb薄膜を形成した。この時点におけ
る組成比は、Bi:Pb:Sr:Ca:Cu＝１（1.34）:2:2:4であ
る。この２層から成る積層膜をアルゴンガス中で825℃
で１時間、そして815℃で１時間、その後急冷する。Pb
の積層量は、Pbが熱処理中に一部気化して失われること
を考慮して、あらかじめ拡散量に気化量を加えた積層量
が好ましい。Next, a high-purity Pb thin film, that is, metal P, is formed on the BSCCO thin film.
b The thin film 13 is formed. The Pb film formation conditions were a high-frequency output of 150 W with a 4-inch sputtering target, an argon gas atmosphere, and a film formation rate of 200 nm / min, and a 135 nm-thick metal Pb thin film was formed on the BSCCO thin film. The composition ratio at this point is Bi: Pb: Sr: Ca: Cu = 1 (1.34): 2: 2: 4. The laminated film consisting of these two layers is heated to 825 ° C in argon gas.
At 815 ° C for 1 hour and then quenched. Pb
Considering that Pb is partially vaporized and lost during the heat treatment, the layered amount is preferably a layered amount obtained by adding the vaporized amount to the diffusion amount in advance.
以上の工程によって得られたBPSCCO薄膜は第２図に示す
ように、Tc(ZERO)＝110Kが得られた。また、Jcの値は77
Kにおいて3000A/cm2であった。本BPSCCO薄膜は、Pbを添
加しない場合に比べて盤状の結晶粒径をもっている。As shown in FIG. 2, the BPSCCO thin film obtained by the above steps had Tc (ZERO) = 110K. Also, the value of Jc is 77
It was 3000 A / cm 2 at K. This BPSCCO thin film has a plate-like crystal grain size as compared with the case where Pb is not added.
なお、最終的に得られたBPSCCO薄膜における、（Bi＋P
b）:Sr:Ca:Cu組成比は化学量論的に定まる値2:2:2:3で
あった。In the finally obtained BPSCCO thin film, (Bi + P
The b): Sr: Ca: Cu composition ratio was 2: 2: 2: 3, which was stoichiometrically determined.
第１図は、本発明のBPSCCO薄膜の積層断面を示す図。 第２図は、本発明の実施例に基づく温度−比抵抗曲線
図、 （符号の説明） 11……MgO基板、12……BSCCO薄膜、 13……金属Pb薄膜。FIG. 1 is a view showing a laminated cross section of a BPSCCO thin film of the present invention. FIG. 2 is a temperature-specific resistance curve diagram based on an embodiment of the present invention, (description of symbols) 11 ... MgO substrate, 12 ... BSCCO thin film, 13 ... metal Pb thin film.
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.6 識別記号 庁内整理番号 ＦＩ 技術表示箇所 // Ｈ０１Ｂ 12/06 ＺＡＡ ─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. 6 Identification code Office reference number FI technical display location // H01B 12/06 ZAA
Claims (1)
の薄膜上に金属Pb薄膜を積層して、組成比Bi:Pb:Sr:Ca:
Cu＝1:1.34:2:2:4の薄膜を得、次いで熱処理を施しBi−
Pb−Sr−Ca−Cu−Ｏ超電導薄膜（組成比（Bi＋Pb）:Sr:
Ca:Cu＝2:2:2:3）を作成する方法。1. A Bi-Sr-Ca-Cu-O thin film is formed, a metal Pb thin film is laminated on the thin film, and the composition ratio Bi: Pb: Sr: Ca:
A Cu = 1: 1.34: 2: 2: 4 thin film was obtained, and then heat treated to obtain Bi-
Pb-Sr-Ca-Cu-O superconducting thin film (composition ratio (Bi + Pb): Sr:
How to create Ca: Cu ＝ 2: 2: 2: 3).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1080997A JPH0796450B2 (en) | 1989-03-31 | 1989-03-31 | Method for producing Bi-Pb-Sr-Ca-Cu-O superconductor thin film |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1080997A JPH0796450B2 (en) | 1989-03-31 | 1989-03-31 | Method for producing Bi-Pb-Sr-Ca-Cu-O superconductor thin film |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH02258629A JPH02258629A (en) | 1990-10-19 |
| JPH0796450B2 true JPH0796450B2 (en) | 1995-10-18 |
Family
ID=13734127
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1080997A Expired - Lifetime JPH0796450B2 (en) | 1989-03-31 | 1989-03-31 | Method for producing Bi-Pb-Sr-Ca-Cu-O superconductor thin film |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0796450B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2785038B2 (en) * | 1989-05-09 | 1998-08-13 | 富士通株式会社 | Manufacturing method of superconductor film |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH02141426A (en) * | 1988-11-21 | 1990-05-30 | Hitachi Ltd | Manufacturing method of oxide superconductor |
-
1989
- 1989-03-31 JP JP1080997A patent/JPH0796450B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH02258629A (en) | 1990-10-19 |
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