JPS6161717B2 - - Google Patents
Info
- Publication number
- JPS6161717B2 JPS6161717B2 JP56119217A JP11921781A JPS6161717B2 JP S6161717 B2 JPS6161717 B2 JP S6161717B2 JP 56119217 A JP56119217 A JP 56119217A JP 11921781 A JP11921781 A JP 11921781A JP S6161717 B2 JPS6161717 B2 JP S6161717B2
- Authority
- JP
- Japan
- Prior art keywords
- thin film
- gas
- lithium
- oxides
- titanium
- 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
Links
- 239000010409 thin film Substances 0.000 claims description 26
- 239000010936 titanium Substances 0.000 claims description 22
- 239000007789 gas Substances 0.000 claims description 21
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 claims description 18
- 239000000203 mixture Substances 0.000 claims description 10
- 229910052786 argon Inorganic materials 0.000 claims description 9
- 238000004544 sputter deposition Methods 0.000 claims description 9
- 229910052744 lithium Inorganic materials 0.000 claims description 7
- 238000004519 manufacturing process Methods 0.000 claims description 7
- 239000000843 powder Substances 0.000 claims description 7
- 229910052719 titanium Inorganic materials 0.000 claims description 7
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims description 5
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 claims description 5
- 239000000758 substrate Substances 0.000 claims description 5
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims description 4
- 238000002156 mixing Methods 0.000 claims description 3
- SOQBVABWOPYFQZ-UHFFFAOYSA-N oxygen(2-);titanium(4+) Chemical class [O-2].[O-2].[Ti+4] SOQBVABWOPYFQZ-UHFFFAOYSA-N 0.000 claims description 2
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 claims description 2
- 230000007704 transition Effects 0.000 description 7
- 238000000034 method Methods 0.000 description 6
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 4
- 239000010408 film Substances 0.000 description 4
- 239000011812 mixed powder Substances 0.000 description 4
- 239000002887 superconductor Substances 0.000 description 4
- 229910010413 TiO 2 Inorganic materials 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 229910052596 spinel Inorganic materials 0.000 description 3
- 239000011029 spinel Substances 0.000 description 3
- 229910018068 Li 2 O Inorganic materials 0.000 description 2
- 229910012465 LiTi Inorganic materials 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 2
- 235000019441 ethanol Nutrition 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 238000001755 magnetron sputter deposition Methods 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 238000000137 annealing Methods 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000000151 deposition Methods 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 229910002804 graphite Inorganic materials 0.000 description 1
- 239000010439 graphite Substances 0.000 description 1
- 238000007731 hot pressing Methods 0.000 description 1
- 239000012212 insulator Substances 0.000 description 1
- FUJCRWPEOMXPAD-UHFFFAOYSA-N lithium oxide Chemical class [Li+].[Li+].[O-2] FUJCRWPEOMXPAD-UHFFFAOYSA-N 0.000 description 1
- 229910001947 lithium oxide Inorganic materials 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 239000004570 mortar (masonry) Substances 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 229910052594 sapphire Inorganic materials 0.000 description 1
- 239000010980 sapphire Substances 0.000 description 1
- 238000005245 sintering Methods 0.000 description 1
- 238000005477 sputtering target Methods 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N60/00—Superconducting devices
- H10N60/80—Constructional details
- H10N60/85—Superconducting active materials
Description
【発明の詳細な説明】
本発明は、Li1+xTi2-xO4よりなる超伝導体を超
伝導を利用したデバイス等への応用に際して必要
となる酸化物超伝導薄膜の製造方法に関するもの
である。[Detailed Description of the Invention] The present invention relates to a method for producing an oxide superconducting thin film, which is necessary when applying a superconductor made of Li 1+x Ti 2-x O 4 to devices using superconductivity. It is something.
Li1+xTi2-xO4はスピネル構造の酸化物であつ
て、酸化物超伝導体の中では10K以上の超伝導転
移温度を有するために、超伝導デバイスへの応用
が考えられる。これは組成が−0.25≦ｘ≦0.2の
範囲では超伝導転移を起こし、ｘ＞0.2では絶縁
性を示すようになる。このことは、たとえば、ト
ンネル型ジヨセフソン接合において同一結晶構造
の酸化物で接合を作製することができるようにな
るために、超伝導体と絶縁体との間の熱膨張率の
差が小さくて、従来上記接合素子の問題点であつ
たヒートサイクルに対する安定性を大きく改善で
きる可能性がある。ところが、Li1+xTi2-xO4超伝
導体の製造方法として焼結法、ホツトプレス法ス
ウエージング法、熔融法などが試みられたが、こ
れらの方法で製造したものは全て塊状であつて薄
膜形状のものは全く得られていなかつた。 Li 1+x Ti 2-x O 4 is an oxide with a spinel structure and has a superconducting transition temperature of 10 K or higher among oxide superconductors, so it can be considered for application to superconducting devices. This material undergoes a superconducting transition in the composition range of -0.25≦x≦0.2, and exhibits insulating properties in the range of x>0.2. This means that, for example, in tunnel-type Josephson junctions, the difference in thermal expansion coefficients between superconductors and insulators is small, so that the junctions can be made with oxides with the same crystal structure. There is a possibility that stability against heat cycles, which has been a problem with conventional bonding elements, can be greatly improved. However, although sintering, hot pressing, swaging, and melting methods have been tried as methods for producing Li 1+x Ti 2-x O 4 superconductors, the materials produced by these methods are all lumpy. However, nothing in the form of a thin film was obtained at all.
本発明の目的は、上記に説明したように従来技
術では得ることのできなかつたLi1+xTi2-xO4より
なる酸化物超伝導薄膜を得ることのできる製造方
法を提供することにある。 As explained above, an object of the present invention is to provide a manufacturing method capable of obtaining an oxide superconducting thin film consisting of Li 1+x Ti 2-x O 4 which could not be obtained using conventional techniques. be.
上記の目的のための、本発明の酸化物超伝導薄
膜の製造方法は、Li1+xTi2-xO4で示されるものに
おいて、−0.25≦ｘ≦0.2であるような組成を有す
るものにして、リチウム、チタニウム、リチウム
の酸化物、チタニウムの酸化物、およびリチウム
とチタニウムを共に含む酸化物等よりなる群中よ
り選択された二種類以上のものを混合してなる粉
末混合物、あるいはそれを反応させた粉末生成
物、もしくはその焼結体をターゲツトとし、アル
ゴンガスまたはアルゴンガスに少量の水素ガスを
含む混合ガス雰囲気中、雰囲気ガス圧力約１〜
10Pa、パワー約250〜450Wにおいてスパツタリ
ングすることにより基体表面上に酸化物薄膜を形
成し、次いで、該酸化物薄膜を約860〜940℃の温
度において結晶化して酸化物超伝導薄膜とするこ
とよりなるものである。 The method for producing an oxide superconducting thin film of the present invention for the above purpose is a film represented by Li 1+x Ti 2-x O 4 having a composition such that −0.25≦x≦0.2. and a powder mixture of two or more selected from the group consisting of lithium, titanium, lithium oxides, titanium oxides, oxides containing both lithium and titanium, or the like. The target is a powdered product obtained by reacting or a sintered body thereof, in an atmosphere of argon gas or a mixed gas containing argon gas and a small amount of hydrogen gas, at an atmospheric gas pressure of about 1 to
By forming an oxide thin film on the substrate surface by sputtering at 10 Pa and power of about 250 to 450 W, and then crystallizing the oxide thin film at a temperature of about 860 to 940°C to obtain an oxide superconducting thin film. It is what it is.
このような本発明の製造方法によれば、従来技
術では得られなかつたLi1+xTi2-xO4よりなる超伝
導薄膜の製造を可能とするものである。 According to the manufacturing method of the present invention, it is possible to manufacture a superconducting thin film made of Li 1+x Ti 2-x O 4 which could not be obtained using conventional techniques.
本発明におけるスパツタリング用ターゲツトは
以下の様にして製造できる。原料粉末は、例えば
(イ) Li、Ti、TiO2；
(ロ) Li2O、Ti、TiO2；
(ハ) Li2O、Ti2O3、TiO2；
(ニ) Li2Ti2O5、Ti2O3；
などの適当な組み合わせで、Li1+xTi2-xO4で示さ
れるものにおいて、−0.25≦ｘ≦0.2なる組成とな
るように配合し混合する。この混合粉末、あるい
は混合粉末を不活性雰囲気中もしくは還元性雰囲
気中で、約900℃の温度で反応させて得られた
Li1+xTi2-xO4粉末をターゲツトに使用することが
できるが、良好な膜質のものを得るため、および
膜の堆積速度を速くするためには不適当であり、
そのためには塊状のものが良い。その最も簡便な
ものは、上記の混合粉末あるいは反応させた粉末
を不活性雰囲気中もしくは還元性雰囲気中、約
900℃の温度処理により製造したLi1+xTi2-xO4焼
結体である。 The sputtering target of the present invention can be manufactured as follows. The raw material powder is, for example, (a) Li, Ti, TiO 2 ; (b) Li 2 O, Ti, TiO 2 ; (c) Li 2 O, Ti 2 O 3 , TiO 2 ; (d) Li 2 Ti 2 O 5 , Ti 2 O 3 ; and the like, are blended and mixed so that the composition expressed by Li 1+x Ti 2-x O 4 satisfies −0.25≦x≦0.2. This mixed powder or mixed powder is obtained by reacting it at a temperature of about 900°C in an inert atmosphere or a reducing atmosphere.
Although Li 1+x Ti 2-x O 4 powder can be used as a target, it is not suitable for obtaining good film quality and increasing the film deposition rate.
For that purpose, chunks are best. The simplest method is to mix the above mixed powder or reacted powder in an inert atmosphere or a reducing atmosphere, and to
It is a Li 1+x Ti 2-x O 4 sintered body manufactured by temperature treatment at 900°C.
本発明におけるスパツタリングにおいては、タ
ーゲツトの組成と形成された薄膜の組成との間の
組成ずれを小さくするために、RFマグネトロン
スパツタリング法を利用することが望ましい。こ
の場合の雰囲気ガスには、アルゴンガスもしくは
アルゴンガスに少量の水素ガスを加えた混合ガス
を使用する。スパツタリングの条件は、使用する
装置に依存するので一概には言えないが、おおむ
ね雰囲気圧力は１〜10Pa、入力パワーは250〜
450W、陽極電圧は2.2〜3.2kV、陽極電流は180〜
250ｍＡ程度が適当である。雰囲気圧力が高過ぎ
ると薄膜を形成できない場合があり、低過ぎると
組成ずれが大きい場合がある。入力パワーが大き
い場合は薄膜の表面荒れを起こすようになる。 In the sputtering of the present invention, it is desirable to use the RF magnetron sputtering method in order to reduce the compositional deviation between the composition of the target and the composition of the formed thin film. As the atmospheric gas in this case, argon gas or a mixed gas of argon gas and a small amount of hydrogen gas is used. The conditions for sputtering cannot be generalized as they depend on the equipment used, but generally the atmospheric pressure is 1 to 10 Pa, and the input power is 250 to 250 Pa.
450W, anode voltage is 2.2~3.2kV, anode current is 180~
Approximately 250mA is appropriate. If the atmospheric pressure is too high, it may not be possible to form a thin film, and if the atmospheric pressure is too low, there may be large composition deviations. If the input power is large, the surface of the thin film will become rough.
上記のスパツタリング後の薄膜は無定形あるい
は一部結晶化したもので、電気抵抗率が高く、超
伝導転移を起こさない。そこで、不活性雰囲気中
あるいは還元性雰囲気中、約860〜940℃の温度で
加熱を行う。これによつてスピネル構造が出現
し、薄膜は超伝導転移を起こすようになる。加熱
の際にLi1+xTi2-xO4薄膜と基板とが反応しないよ
うに、基板材質を選択する必要がある。 The thin film after sputtering is amorphous or partially crystallized, has high electrical resistivity, and does not undergo superconducting transition. Therefore, heating is performed at a temperature of about 860 to 940°C in an inert atmosphere or a reducing atmosphere. As a result, a spinel structure appears and the thin film undergoes a superconducting transition. It is necessary to select the substrate material so that the Li 1+x Ti 2-x O 4 thin film and the substrate do not react during heating.
以下に、本発明を実施例につき、それにより製
せられた薄膜の超伝導転移特性を示すグラフを参
照して詳細に説明する。 Hereinafter, the present invention will be explained in detail with reference to examples and graphs showing the superconducting transition characteristics of thin films produced thereby.
実施例
原料粉末Li2Ti2O5とTi2O3を各１モル秤量し、
エチルアルコールとメノウ石を用いて約５時間湿
式混合を行つた後、エチルアルコールを乾燥除去
し、さらにメノウ乳鉢を用いて約30分間混合し
た。Example Weighed 1 mole each of raw powder Li 2 Ti 2 O 5 and Ti 2 O 3 ,
After performing wet mixing using ethyl alcohol and agate for about 5 hours, the ethyl alcohol was removed by drying, and further mixing was carried out for about 30 minutes using an agate mortar.
この混合粉末をグラフアイト製のダイスに充填
し、約６時間、アルゴンガスと水素ガスの混合ガ
ス雰囲気中、約900℃の温度でホツトプレスを行
つた。ひび割れを防ぐために、引き続き同温度で
アニールを行つた。 This mixed powder was filled into a graphite die, and hot pressed at a temperature of about 900° C. in a mixed gas atmosphere of argon gas and hydrogen gas for about 6 hours. Annealing was continued at the same temperature to prevent cracks.
このようにして製造した100φのLiTi2O4焼結
体をターゲートとした。スパツタリングはプレー
ナ型RFマグネトロンスパツタリング装置を用い
て行つた。雰囲気ガスはアルゴンガスを使用し、
１〜9Paの各種の雰囲気ガス圧力下において、
330Wで50〜60分間、100〜300℃のサフアイア基
板上に薄膜を堆積させた。得られた薄膜の厚さは
１〜1.5μｍ、膜形成速度は170〜260Å／minで
あつた。 The 100φ LiTi 2 O 4 sintered body thus produced was used as a target. Sputtering was performed using a planar RF magnetron sputtering device. Argon gas is used as the atmosphere gas.
Under various atmospheric gas pressures of 1 to 9 Pa,
Thin films were deposited on sapphire substrates at 100–300 °C for 50–60 min at 330 W. The thickness of the obtained thin film was 1 to 1.5 μm, and the film formation rate was 170 to 260 Å/min.
これらの薄膜は淡青黒色から青黒色を呈したも
のであり、無定形あるいは一部結晶化していた。
これを水素ガス中、900℃の温度で結晶化したと
ころ、全て青黒色を呈し、スピネル相が成長し
た。 These thin films were pale blue-black to blue-black in color and were amorphous or partially crystallized.
When this was crystallized in hydrogen gas at a temperature of 900°C, it all exhibited a blue-black color and a spinel phase grew.
スパツタリング雰囲気ガス圧力が１、３、６、
9Paの各圧力下で製造した各場合の、上記の薄膜
の低温における電気抵抗率を測定し、グラフに示
したのが第１図である。 Sputtering atmosphere gas pressure is 1, 3, 6,
FIG. 1 shows the measured electrical resistivity at low temperature of the thin film produced under each pressure of 9 Pa and shown in a graph.
第１図のグラフから分るように、雰囲気ガス圧
力が３〜9Paの場合の薄膜の低温における超伝導
転移温度は10.9〜11.3K、転移幅は0.3〜0.7Kであ
つて、これらの値は他の方法で製造した塊状の化
学量論比組成であるLiTi2O4と同等である。 As can be seen from the graph in Figure 1, when the atmospheric gas pressure is 3 to 9 Pa, the superconducting transition temperature of the thin film at low temperature is 10.9 to 11.3 K, the transition width is 0.3 to 0.7 K, and these values are It is equivalent to the bulk stoichiometric composition of LiTi 2 O 4 produced by other methods.
以上説明したように、スパツタリング法を用い
た本発明により、超伝導デバイス等への応用に必
要な酸化物超伝導薄膜の製造が可能となつた。 As explained above, the present invention using the sputtering method has made it possible to manufacture oxide superconducting thin films necessary for application to superconducting devices and the like.
第１図は本発明の実施例において、スパツタリ
ングの雰囲気ガスであるアルゴンガスの圧力を、
１〜9Paの範囲で、変えて製造した各酸化物超伝
導薄膜の低温における電気抵抗率の測定値をグラ
フで示したものである。
Figure 1 shows the pressure of argon gas, which is the atmospheric gas for sputtering, in an embodiment of the present invention.
This is a graph showing the measured values of the electrical resistivity at low temperatures of various oxide superconducting thin films manufactured at different temperatures in the range of 1 to 9 Pa.
Claims (1)
0.25≦ｘ≦0.2であるような組成を有するものに
して、リチウム、チタニウム、リチウムの酸化
物、チタニウム酸化物、およびリチウムとチタニ
ウムを共に含む酸化物等よりなる群中より選択さ
れた二種類以上のものを混合してなる粉末混合
物、あるいはそれを反応させた粉末生成物、もし
くはその焼結体をターゲツトとし、アルゴンガス
またはアルゴンガスに少量の水素ガスを含む混合
ガス雰囲気中、雰囲気ガス圧力１〜10Pa、パワ
ー250〜450Wにおいてスパツタリングすることに
より基体上に酸化物薄膜を形成し、次いで、該酸
化物薄膜を860〜940℃の温度において結晶化して
超伝導薄膜とすることからなることを特徴とする
酸化物超伝導薄膜の製造方法。1 Li 1+x Ti 2-x O 4 , −
Two or more types having a composition such that 0.25≦x≦0.2 and selected from the group consisting of lithium, titanium, oxides of lithium, titanium oxides, oxides containing both lithium and titanium, etc. The target is a powder mixture formed by mixing these, a powder product obtained by reacting the same, or a sintered body thereof, and the atmospheric gas pressure is 1 in an atmosphere of argon gas or a mixed gas containing argon gas and a small amount of hydrogen gas. It is characterized by forming an oxide thin film on a substrate by sputtering at ~10Pa and power of 250~450W, and then crystallizing the oxide thin film at a temperature of 860~940℃ to form a superconducting thin film. A method for producing an oxide superconducting thin film.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP56119217A JPS5821880A (en) | 1981-07-31 | 1981-07-31 | Manufacture of oxide superconductive thin film |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP56119217A JPS5821880A (en) | 1981-07-31 | 1981-07-31 | Manufacture of oxide superconductive thin film |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5821880A JPS5821880A (en) | 1983-02-08 |
| JPS6161717B2 true JPS6161717B2 (en) | 1986-12-26 |
Family
ID=14755846
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP56119217A Granted JPS5821880A (en) | 1981-07-31 | 1981-07-31 | Manufacture of oxide superconductive thin film |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5821880A (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS62105075A (en) * | 1985-10-31 | 1987-05-15 | Furuno Electric Co Ltd | Fish detecting method |
| JP2585561B2 (en) * | 1987-01-30 | 1997-02-26 | 株式会社日立製作所 | Oxide superconducting material |
| JP2595584B2 (en) * | 1987-11-26 | 1997-04-02 | 三菱マテリアル株式会社 | Manufacturing method of target material for forming superconducting film without residual strain |
-
1981
- 1981-07-31 JP JP56119217A patent/JPS5821880A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5821880A (en) | 1983-02-08 |
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