JP2721439B2 - Method of forming oxide superconductor on semiconductor - Google Patents
Method of forming oxide superconductor on semiconductorInfo
- Publication number
- JP2721439B2 JP2721439B2 JP3141839A JP14183991A JP2721439B2 JP 2721439 B2 JP2721439 B2 JP 2721439B2 JP 3141839 A JP3141839 A JP 3141839A JP 14183991 A JP14183991 A JP 14183991A JP 2721439 B2 JP2721439 B2 JP 2721439B2
- Authority
- JP
- Japan
- Prior art keywords
- film
- oxide superconductor
- substrate
- oxygen
- semiconductor
- 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
- 239000002887 superconductor Substances 0.000 title claims description 58
- 238000000034 method Methods 0.000 title claims description 33
- 239000004065 semiconductor Substances 0.000 title claims description 29
- 239000000758 substrate Substances 0.000 claims description 49
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 36
- 239000001301 oxygen Substances 0.000 claims description 36
- 229910052760 oxygen Inorganic materials 0.000 claims description 36
- 238000001179 sorption measurement Methods 0.000 claims description 22
- 239000011575 calcium Substances 0.000 claims description 13
- 230000001590 oxidative effect Effects 0.000 claims description 12
- 229910052788 barium Inorganic materials 0.000 claims description 9
- 238000010438 heat treatment Methods 0.000 claims description 9
- DSAJWYNOEDNPEQ-UHFFFAOYSA-N barium atom Chemical compound [Ba] DSAJWYNOEDNPEQ-UHFFFAOYSA-N 0.000 claims description 7
- 229910052791 calcium Inorganic materials 0.000 claims description 6
- 229910052716 thallium Inorganic materials 0.000 claims description 6
- 229910052727 yttrium Inorganic materials 0.000 claims description 6
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 claims description 5
- 229910052797 bismuth Inorganic materials 0.000 claims description 5
- 229910052712 strontium Inorganic materials 0.000 claims description 5
- BKVIYDNLLOSFOA-UHFFFAOYSA-N thallium Chemical compound [Tl] BKVIYDNLLOSFOA-UHFFFAOYSA-N 0.000 claims description 5
- VWQVUPCCIRVNHF-UHFFFAOYSA-N yttrium atom Chemical compound [Y] VWQVUPCCIRVNHF-UHFFFAOYSA-N 0.000 claims description 5
- JCXGWMGPZLAOME-UHFFFAOYSA-N bismuth atom Chemical compound [Bi] JCXGWMGPZLAOME-UHFFFAOYSA-N 0.000 claims description 4
- CIOAGBVUUVVLOB-UHFFFAOYSA-N strontium atom Chemical compound [Sr] CIOAGBVUUVVLOB-UHFFFAOYSA-N 0.000 claims description 3
- 239000010408 film Substances 0.000 description 109
- 239000010410 layer Substances 0.000 description 24
- 229910052751 metal Inorganic materials 0.000 description 14
- 239000002184 metal Substances 0.000 description 14
- 239000010409 thin film Substances 0.000 description 10
- 230000015572 biosynthetic process Effects 0.000 description 8
- 239000007789 gas Substances 0.000 description 8
- 238000007740 vapor deposition Methods 0.000 description 8
- 239000000470 constituent Substances 0.000 description 3
- 238000001704 evaporation Methods 0.000 description 3
- 230000008020 evaporation Effects 0.000 description 3
- 238000007738 vacuum evaporation Methods 0.000 description 3
- 238000004140 cleaning Methods 0.000 description 2
- 238000000151 deposition Methods 0.000 description 2
- 230000008021 deposition Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000000097 high energy electron diffraction Methods 0.000 description 2
- 238000000608 laser ablation Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000002128 reflection high energy electron diffraction Methods 0.000 description 2
- 238000004544 sputter deposition Methods 0.000 description 2
- 229910005542 GaSb Inorganic materials 0.000 description 1
- 229910000673 Indium arsenide Inorganic materials 0.000 description 1
- CBENFWSGALASAD-UHFFFAOYSA-N Ozone Chemical compound [O-][O+]=O CBENFWSGALASAD-UHFFFAOYSA-N 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000003795 desorption Methods 0.000 description 1
- -1 easily oxidized) Chemical compound 0.000 description 1
- 238000000407 epitaxy Methods 0.000 description 1
- 238000010233 in-situ elemental analysis Methods 0.000 description 1
- RPQDHPTXJYYUPQ-UHFFFAOYSA-N indium arsenide Chemical compound [In]#[As] RPQDHPTXJYYUPQ-UHFFFAOYSA-N 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000001883 metal evaporation Methods 0.000 description 1
- 238000001465 metallisation Methods 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 239000002356 single layer 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
- Inorganic Compounds Of Heavy Metals (AREA)
- Physical Vapour Deposition (AREA)
- Superconductor Devices And Manufacturing Methods Thereof (AREA)
- Superconductors And Manufacturing Methods Therefor (AREA)
Description
【０００１】[0001]
【産業上の利用分野】この発明は、半導体の下地の上側
に、酸化雰囲気中で下地を加熱して、酸化物超電導体膜
を形成する方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming an oxide superconductor film on a semiconductor base by heating the base in an oxidizing atmosphere.
【０００２】[0002]
【従来の技術】従来より、Ｓｉ等の半導体基板上に酸化
物超電導体膜を成膜する方法として、下記の文献に開示
された技術が知られている。2. Description of the Related Art Conventionally, as a method of forming an oxide superconductor film on a semiconductor substrate of Si or the like, a technique disclosed in the following document is known.
【０００３】文献１：ジャパニーズ・ジャーナル・オブ
・アプライド・フィジックス（Ｊａｐａｎｅｓｅ Ｊｏ
ｕｒｎａｌ ｏｆ Ａｐｐｌｉｅｄ Ｐｈｙｓｉｃ
ｓ），２ ７（８），１９８８，ｐｐ．Ｌ１５２４−Ｌ１
５２６。Reference 1: Japanese Journal of Applied Physics (Japanese Jones)
urnal of Applied Physic
s), 2 7 (8) , 1988, pp. L1524-L1
526.
【０００４】文献２：アプライド・フィジックス・レタ
ーズ（Ａｐｐｌｉｅｄ Ｐｈｙｓｉｃｓ Ｌｅｔｔｅｒ
ｓ），５２（２４），１９８８，ｐｐ．２０６８−２０
７０。Reference 2: Applied Physics Letters
s), 52 (24), 1988, p. 2068-20
70.
【０００５】文献３：アプライド・フィジックス・レタ
ーズ（Ａｐｐｌｉｅｄ Ｐｈｙｓｉｃｓ Ｌｅｔｔｅｒ
ｓ），５３（２０），（１９８８），ｐｐ．１９６７−
１９６９。Reference 3: Applied Physics Letters
s), 53 (20), (1988) pp. 1967-
1969.
【０００６】文献４：ジャパニーズ・ジャーナル・オブ
・アプライド・フィジックス（Ｊａｐａｎｅｓｅ Ｊｏ
ｕｒｎａｌ ｏｆ Ａｐｐｌｉｅｄ Ｐｈｙｓｉｃ
ｓ），２７（１２），１９８８，ｐｐ．Ｌ２４４２−Ｌ
２４４４。Reference 4: Japanese Journal of Applied Physics (Japanese Jones)
urnal of Applied Physic
s), 27 (12), 1988, pp. L2442-L
2444.
【０００７】これら文献に開示の技術によれば、基板上
に格子定数の整合を図る目的でスパッタ法により形成し
たバッファ層を介して酸化物超電導体膜を成膜するか
（文献１、２および３）、或いは基板上にレーザアブレ
ーション法で直接酸化物超電導体膜を成膜する（文献
４）方法である。According to the techniques disclosed in these documents, an oxide superconductor film is formed on a substrate via a buffer layer formed by a sputtering method for the purpose of matching the lattice constant (see Documents 1, 2 and 3) Or a method of forming an oxide superconductor film directly on a substrate by a laser ablation method (Reference 4).
【０００８】しかしながら、この公知の技術では、スパ
ッタ法で基板上にバッファ層を形成しこのバッファ層上
に酸化物超電導体膜を形成するか、或いはレーザアブレ
ーション法で基板上に直接酸化物超電導体膜を形成する
方法であるため、電気的導電性が得られなかったし、Ｓ
ｉ基板と酸化物超電導体膜との界面が乱れてしまい、こ
のため、良質の酸化物超電導体・半導体接合を形成する
ことが出来なかった。However, in this known technique, a buffer layer is formed on a substrate by a sputtering method and an oxide superconductor film is formed on the buffer layer, or an oxide superconductor film is directly formed on the substrate by a laser ablation method. Because of the method of forming a film, electrical conductivity could not be obtained and S
The interface between the i-substrate and the oxide superconductor film was disturbed, so that a high-quality oxide superconductor-semiconductor junction could not be formed.
【０００９】そこで、この出願に係る発明者等は、半導
体上に、蒸着法により金属超薄膜を原子層のオーダでの
平坦膜として形成することによって、従来よりも接合の
改善を図れる方法を既に提案している（特願平０１−１
４５０６６号、特願平０２−１３８９１４号および特願
平０２−１３８９１５号）。Therefore, the inventors of the present application have already developed a method of improving the junction by forming an ultrathin metal film as a flat film on the order of atomic layers on a semiconductor by vapor deposition. Proposal (Japanese Patent Application No. 01-1)
No. 45066, Japanese Patent Application Nos. 02-138914 and 02-138915).
【００１０】ところが、発明者等が既に提案しているこ
れら技術は、良質の半導体・酸化物超電導体接合を得る
ことを目的とした、限定された技術である。この技術に
つき、図２を参照して簡単に説明する。この技術によれ
ば、図２に示すように、例えば、半導体基板としてのシ
リコン（Ｓｉ）基板８０上に、金属の超薄膜を原子層の
オーダで平坦膜８２として形成し、この平坦膜８２上に
酸化物超電導体の構成元素であるビスマス（Ｂｉ）ある
いはタリウム（Ｔｌ）の超薄膜８４を形成し、次にその
上側に酸化物超電導体膜８６を成長させている。[0010] However, these techniques already proposed by the inventors are limited techniques aimed at obtaining a high-quality semiconductor-oxide superconductor junction. This technique will be briefly described with reference to FIG. According to this technique, as shown in FIG. 2, for example, an ultrathin metal film is formed as a flat film 82 on the order of atomic layers on a silicon (Si) substrate 80 as a semiconductor substrate. Then, an ultrathin film 84 of bismuth (Bi) or thallium (Tl), which is a constituent element of the oxide superconductor, is formed, and an oxide superconductor film 86 is grown on the ultrathin film 84.
【００１１】[0011]
【発明が解決しようとする課題】しかしながら、発明者
等が提案している先行技術では、ＢｉやＴｌが比較的酸
化されにくく、また、その下側の金属超薄膜との結合が
比較的弱い元素であるため、酸化物超電導体膜を成膜す
るさいに酸素がその下側の金属超薄膜の金属元素や半導
体元素と結合し易くなり、従って、ＢｉやＴｌの金属元
素が金属超薄膜中や下地の半導体基板の表面から離脱し
てしまう。また、金属超薄膜が下地の半導体基板表面か
ら離脱してしまうこともある。このため、下地表面に酸
化物が形成されてしまい、従って、酸化物超電導体膜の
膜質が悪くなってしまう。However, in the prior art proposed by the inventors, Bi and Tl are relatively hard to be oxidized, and an element whose bonding to the metal ultra-thin film below is relatively weak. Therefore, when the oxide superconductor film is formed, oxygen is easily bonded to the metal element or the semiconductor element of the metal ultrathin film under the oxide superconductor film. It is separated from the surface of the underlying semiconductor substrate. In addition, the metal ultra-thin film may be separated from the surface of the underlying semiconductor substrate. For this reason, an oxide is formed on the surface of the base, and accordingly, the quality of the oxide superconductor film deteriorates.
【００１２】そこで、この発明は、上述した従来および
先行する技術が有する問題点を出来るだけ解消しようと
してなされたものであり、従って、この発明の目的は、
半導体の上側に良質の酸化物超電導体膜を形成する方法
を提供することにある。Accordingly, the present invention has been made to solve the problems of the above-mentioned conventional and prior arts as much as possible.
An object of the present invention is to provide a method for forming a high-quality oxide superconductor film on a semiconductor.
【００１３】[0013]
【課題を解決するための手段】この目的の達成を図るた
め、この発明の形成方法によれば、半導体の下地の上側
に、酸化雰囲気中でこの下地を加熱して、酸化物超電導
体膜を形成するに当たり、下地上に、直接原子層のオー
ダで平坦な酸素吸着膜を形成する工程と、この酸素吸着
膜上に酸化物超電導体膜を成膜する工程とを含むことを
特徴とする。In order to achieve this object, according to the method of the present invention, an oxide superconductor film is formed on an upper surface of a semiconductor substrate by heating the substrate in an oxidizing atmosphere. The method is characterized by including a step of directly forming a flat oxygen adsorption film on the order of an atomic layer on a base, and a step of forming an oxide superconductor film on the oxygen adsorption film.
【００１４】この発明の実施に当り、好ましくは、酸化
物超電導体膜をビスマス（Ｂｉ）系とするとき、酸素吸
着膜を、ストロンチュウム（Ｓｒ）またはカルシウム
（Ｃａ）とするのが良い。In practicing the present invention, when the oxide superconductor film is preferably made of bismuth (Bi), the oxygen adsorption film is preferably made of strontium (Sr) or calcium (Ca).
【００１５】また、この発明の他の実施例においては、
好ましくは、酸化物超電導体膜をタリウム（Ｔｌ）系と
するとき、酸素吸着膜を、バリウム（Ｂａ）またはカル
シウム（Ｃａ）とするのが良い。In another embodiment of the present invention,
Preferably, when the oxide superconductor film is made of thallium (Tl), the oxygen adsorption film is preferably made of barium (Ba) or calcium (Ca).
【００１６】また、この発明のさらに他の実施例におい
ては、好ましくは、酸化物超電導体膜をイットリウム
（Ｙ）系とするとき、酸素吸着膜を、バリウム（Ｂａ）
またはイットリウム（Ｙ）とするのが良い。In still another embodiment of the present invention, preferably, when the oxide superconductor film is made of yttrium (Y), the oxygen adsorption film is made of barium (Ba).
Alternatively, it is preferable to use yttrium (Y).
【００１７】[0017]
【作用】上述したこの発明の構成によれば、半導体の下
地上に直接原子層のオーダで酸素吸着膜を設ける。従っ
て、酸化雰囲気中で酸素吸着膜上に酸化物超電導体膜を
成膜する際に、下地側に侵入する酸素がこの酸素吸着膜
でほとんど吸着されてしまうか、散乱させられるため、
下地の半導体に達する酸素を著しく低減させることが出
来る。従って、下地の半導体と結合する酸素が著しく減
少し、このため、これら半導体および金属の規則的配列
が破壊されたり、あるいは、半導体表面に不所望な酸化
物が形成される恐れが低減される。その結果、良質な超
電導体膜を形成することが可能となるとともに、半導体
と酸化物超電導体との接合も良質な接合となる。According to the structure of the present invention described above, an oxygen adsorption film is provided directly on the underlayer of a semiconductor in the order of atomic layers. Therefore, when an oxide superconductor film is formed on an oxygen-adsorbing film in an oxidizing atmosphere, oxygen that penetrates into the underlying layer is almost absorbed or scattered by the oxygen-adsorbing film.
Oxygen reaching the underlying semiconductor can be significantly reduced. Accordingly, the amount of oxygen bonded to the underlying semiconductor is significantly reduced, thereby reducing the risk of destroying the regular arrangement of the semiconductor and the metal or forming an undesired oxide on the semiconductor surface. As a result, a high-quality superconductor film can be formed, and the bonding between the semiconductor and the oxide superconductor is also high-quality.
【００１８】[0018]
【実施例】以下、図を参照して、この発明の実施例につ
き説明する。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.
【００１９】尚、図は、この発明が理解出来る程度に各
構成成分を概略的に示してあるにすぎない。It should be noted that the drawings only show each component schematically so that the present invention can be understood.
【００２０】図３は、この発明の実施に用いる真空蒸着
装置の一例を示す概略図である。FIG. 3 is a schematic view showing an example of a vacuum evaporation apparatus used for carrying out the present invention.
【００２１】先ず、この装置を用いた成膜工程の全体の
流れの一例を概略的に説明し、その後、この発明の具体
例につき説明する。First, an example of an overall flow of a film forming process using this apparatus will be schematically described, and then, a specific example of the present invention will be described.
【００２２】＜成膜工程の概略説明＞ この装置は、従来公知の真空蒸着装置であるので、その
詳細な説明は省略するが、金属の蒸発源としてクヌーセ
ンセル（Ｋセルともいう）を具え、成膜中にその場で元
素分析を行うオージェ分析器および結晶性を観測するＲ
ＨＥＥＤ装置を具えた構造となっている。<Schematic Description of Film Forming Step> Since this apparatus is a conventionally known vacuum evaporation apparatus, its detailed description is omitted, but a Knudsen cell (also called a K cell) is provided as a metal evaporation source. Auger analyzer for in-situ elemental analysis during film formation and R for observing crystallinity
It has a structure with a HEED device.
【００２３】そして、ここでは、下地として、半導体基
板、例えば、Ｓｉ基板を用いる。この基板上面に、酸素
吸着膜を形成し、この酸素吸着膜上に酸化物超電導体薄
膜を形成する例につき説明する。Here, a semiconductor substrate, for example, a Si substrate is used as a base. An example in which an oxygen adsorption film is formed on the upper surface of the substrate and an oxide superconductor thin film is formed on the oxygen adsorption film will be described.
【００２４】前処理工程 先ず、成膜室１０のサセプタ１２に半導体下地としての
Ｓｉ基板１４を取り付ける。次に、排気系１８を用いて
成膜室１０を１０-11 Ｔｏｒｒ程度にまで真空排気す
る。Pretreatment Step First, a Si substrate 14 as a semiconductor base is mounted on the susceptor 12 in the film forming chamber 10. Next, the film forming chamber 10 is evacuated to about 10 −11 Torr using the exhaust system 18.
【００２５】サセプタ１２により基板１４を加熱（例え
ば、約１０００℃以上に加熱）して基板のクリーニング
を行う。基板１４の清浄状態をオージェ分析器２０およ
びまたはＲＨＥＥＤ装置（電子銃を２２で示し、観察用
窓を２４で示してある）で確認する。The substrate 14 is heated by the susceptor 12 (for example, heated to about 1000 ° C. or higher) to clean the substrate. The clean state of the substrate 14 is confirmed by an Auger analyzer 20 and / or a RHEED device (an electron gun is indicated by 22 and an observation window is indicated by 24).
【００２６】酸素吸着膜の成膜工程 次に、清浄済み基板１４上に酸素吸着膜を成膜する。こ
の場合、真空排気を１０-10 Ｔｏｒｒ程度かそれよりも
良い真空度にした後、金属の蒸着を、主として次のよう
な手順で行って成膜を行う。ここで、原子オーダの平坦
な酸素吸着膜とは、金属原子が規則的に配列していて原
子層のオーダで平坦な膜と見做し得る状態にある膜のこ
とである。従って、酸素吸着膜は、原子の２次元層であ
っても良く、この２次元層が数層積み重なった状態にあ
る層であっても良い。Next, an oxygen adsorption film is formed on the cleaned substrate 14. In this case, after evacuation is reduced to about 10 −10 Torr or a better degree of vacuum, metal deposition is performed mainly by the following procedure to form a film. Here, the flat oxygen adsorption film in the atomic order is a film in which metal atoms are regularly arranged and can be regarded as a flat film in the order of an atomic layer. Therefore, the oxygen adsorption film may be a two-dimensional layer of atoms or a layer in which several layers of the two-dimensional layer are stacked.
【００２７】まず、基板１４を酸化物超電導薄膜形成温
度に保持する→ビームシャッタ３６〜４４のうち所要の
ビームシャッタを開く→Ｋセル２６〜３４のうちの対応
する所要のＫセルから金属を蒸発させて基板に蒸着させ
る→ビームシャッタを閉じる→蒸着量の測定を行い（オ
ージェ分析器２０）、平坦な酸素吸着膜となっているこ
とを確認する。First, the substrate 14 is maintained at the temperature for forming the oxide superconducting thin film. → A required beam shutter among the beam shutters 36 to 44 is opened → Evaporation of metal from the corresponding required K cell among the K cells 26 to 34. Then, the beam shutter is closed, the beam shutter is closed, and the deposition amount is measured (Auger analyzer 20), and it is confirmed that a flat oxygen adsorption film is formed.
【００２８】また、超薄膜の酸素吸着膜は、基板１４を
常温に保持して、酸化物超電導薄膜形成の温度で成膜す
るときの蒸着量よりも多い蒸着量で蒸着した後、加熱し
て形成しても良い。The ultrathin oxygen-adsorbing film is deposited at a temperature higher than the temperature at which the oxide superconducting thin film is formed while keeping the substrate 14 at room temperature, and then heated. It may be formed.
【００２９】また、このサイクルを同一または異なる金
属につき繰り返すことによってそれぞれの層が重なり合
った重畳層としての一つの酸素吸着膜を得ることが出来
る。By repeating this cycle for the same or different metals, one oxygen-adsorbing film can be obtained as a superposed layer in which the respective layers overlap.
【００３０】酸化物超電導体膜の成膜 次に、主として次のような手順で酸化物超電導体膜の成
膜を行う。Next, an oxide superconductor film is formed mainly by the following procedure.
【００３１】Ｓｉ基板１４を、酸化ガス中で、金属超薄
膜から金属元素が離脱しない温度に加熱する→酸化物超
電導体膜を構成する成分元素の蒸発源であるＫセルを加
熱する（例えば、Ｙまたはタリウム（Ｔｌ）のＫセル２
６、ＣｕのＫセル３４、ＣａのＫセル３２、Ｓｒまたは
ＢａのＫセル２８等）→バルブ４６を開いてソースガス
源４８からノズル５０を経て酸化ガスを基板１４に向け
て吹き付ける（酸素雰囲気にする）→ビームシャッタ３
６、４４、４２、３８を開き基板１４上に成膜した酸素
吸着膜上に酸化物超電導体膜の成膜を行う→ビームシャ
ッタ３６、４４、４２、３８を閉じる→基板の加熱を停
止する→基板温度が２００℃以下となったことを確認し
てから酸化ガスの供給を停止する。The Si substrate 14 is heated in an oxidizing gas to a temperature at which the metal element does not separate from the ultra-thin metal film. → The K-cell, which is the evaporation source of the constituent elements constituting the oxide superconductor film, is heated (for example, Y or thallium (Tl) K cell 2
6, Cu K cell 34, Ca K cell 32, Sr or Ba K cell 28) → Open valve 46 and blow oxidizing gas from source gas source 48 to substrate 14 through nozzle 50 (oxygen atmosphere). ) → Beam shutter 3
6, 44, 42, and 38 are opened to form an oxide superconductor film on the oxygen-adsorbing film formed on the substrate 14 → Close the beam shutters 36, 44, 42, and 38 → Stop heating the substrate → After confirming that the substrate temperature is 200 ° C. or lower, supply of the oxidizing gas is stopped.
【００３２】＜具体的実施例の説明＞ 以上のような工程を経て、この発明の酸化物超電導体膜
を半導体上に形成することができるが、以下、図１およ
び図３を参照して、その具体例につき説明する。なお、
この実施例では、半導体下地としてＳｉ基板を用い、そ
の（１００）面上に酸素吸着膜としてバリウム（Ｂａ）
膜を成膜し、このＢａ膜の上に一例としてＹ−Ｂａ−Ｃ
ｕ−Ｏ系酸化物超電導体膜を成膜する例につき説明す
る。<Explanation of Specific Embodiment> The oxide superconductor film of the present invention can be formed on a semiconductor through the above-described steps. Hereinafter, referring to FIGS. 1 and 3, A specific example will be described. In addition,
In this embodiment, a Si substrate is used as a semiconductor base, and barium (Ba) is formed on its (100) plane as an oxygen adsorption film.
A film is formed, and on this Ba film, for example, Y-Ba-C
An example of forming a uO-based oxide superconductor film will be described.
【００３３】この実施例では、まず、Ｓｉ基板１４の表
面を清浄して純粋なＳｉ原子面を形成する。この清浄を
行う方法としては、Ｓｉエピタキシーで行なわれている
加熱蒸発クリニーング法、その他の方法があるが、ここ
では、例えば、基板１４に対して１０００°Ｃ以上の通
電加熱を行なう。In this embodiment, first, the surface of the Si substrate 14 is cleaned to form a pure Si atomic plane. As a method of performing this cleaning, there is a heating evaporation cleaning method performed by Si epitaxy, and other methods. In this case, for example, the substrate 14 is heated by heating at 1000 ° C. or more.
【００３４】次に、この清浄済のＳｉ基板１４の表面
に、バリウム（Ｂａ）の超薄膜５４を成膜する。この成
膜方法は、既に説明したように、適当な条件のもとで、
蒸着して行なう。Next, an ultra-thin film 54 of barium (Ba) is formed on the surface of the cleaned Si substrate 14. As described above, this film formation method is performed under appropriate conditions.
Performed by vapor deposition.
【００３５】まず、成膜室１０内を１０-10 トル（Ｔｏ
ｒｒ）程度かそれ以上の超高真空に排気し、清浄済の基
板１４の温度を８６０℃とする。First, the inside of the film forming chamber 10 is set to 10 -10 torr (To
rr) Evacuation is performed to an ultra-high vacuum of about rr) or more, and the temperature of the cleaned substrate 14 is set to 860 ° C.
【００３６】次に、ＢａのＫセル２８を加熱し、ビーム
シャッタ３８を開き、そして蒸着を開始する。Ｂａの蒸
着速度を６．９×１０11個／ｃｍ2 ・ｓとしおよびＢａ
の全入射原子数を約３．４×１０14個／ｃｍ2 以上とす
る。このように設定することにより、ＢａがＳｉ基板１
４上に被着して成膜された蒸着層５４は、原子層オーダ
の平坦な２次元層となっている（図１の（Ａ））。Ｂａ
原子は、３．４×１０14個／ｃｍ2 程度しか吸着しな
い。周知のように、成長様式の測定は、オージェ分析器
２０およびまたはＲＨＥＥＤ装置（２２および２４）で
行なう。Next, the Ba K cell 28 is heated, the beam shutter 38 is opened, and vapor deposition is started. The deposition rate of Ba was 6.9 × 10 11 / cm 2 · s and Ba was deposited.
Is set to about 3.4 × 10 14 atoms / cm 2 or more. By setting as described above, Ba is converted into the Si substrate 1.
The vapor deposition layer 54 deposited and formed on the substrate 4 is a flat two-dimensional layer on the order of an atomic layer (FIG. 1A). Ba
Atomics adsorb only 3.4 × 10 14 atoms / cm 2 . As is well known, growth mode measurements are made with an Auger analyzer 20 and / or RHEED devices (22 and 24).
【００３７】次に、このようにして成膜されたＢａの平
坦膜（酸素吸着膜）５４上にＹ系の酸化物超電導体膜を
成膜する（図１の（Ｂ））。Next, a Y-based oxide superconductor film is formed on the Ba flat film (oxygen adsorption film) 54 thus formed (FIG. 1B).
【００３８】このため、まず、サセプタ１２に超薄膜で
あるＢａの平坦膜５４が成膜されている状態で成膜室１
０ないを１０-10 Ｔｏｒｒ程度よりも良い真空度に排気
を行ない、その後、基板１４を加熱する。そして、基板
１４がある適当な温度（酸化物超電導薄膜形成温度より
低い温度）に上昇した後、酸化ガスを成膜室内に導入し
て酸化させる。これは、Ｂａが脱離するのを軽減するた
めである。For this reason, first, in the state where the ultra-thin Ba flat film 54 is formed on the susceptor 12,
Evacuation is performed to a degree of vacuum better than about 10 −10 Torr, and then the substrate 14 is heated. Then, after the substrate 14 is heated to a certain appropriate temperature (a temperature lower than the temperature at which the oxide superconducting thin film is formed), an oxidizing gas is introduced into the film forming chamber to be oxidized. This is to reduce the desorption of Ba.
【００３９】次に、酸化ガスの導入を停止し、さらに、
高い温度、すなわち、酸化物超電導薄膜形成温度まで、
基板１４を加熱する。この基板１４の温度は、成膜に際
しての種々の条件により異なるが、酸化雰囲気中でＢａ
の原子が基板表面から離脱を開始する温度よりも低い温
度である必要がある。Next, the introduction of the oxidizing gas is stopped.
High temperature, that is, up to the oxide superconducting thin film formation temperature,
The substrate 14 is heated. The temperature of the substrate 14 varies depending on various conditions during film formation.
Must be lower than the temperature at which the atoms start to detach from the substrate surface.
【００４０】尚、上述した例では、加熱の途中で酸化ガ
スを導入したが、加熱途中で酸化ガスを導入しなくて
も、酸化物超電導体薄膜の成膜は可能である。In the above-described example, the oxidizing gas is introduced during the heating, but the oxide superconductor thin film can be formed without introducing the oxidizing gas during the heating.
【００４１】Ｂａの場合には、オゾンの基板１４への入
射分子数Γｏ3 が酸素雰囲気中で基板温度が８００℃で
も、Ｓｉ基板面から離脱しないので、状況により異なる
が、８００℃以下の適当な温度に加熱保持する。そし
て、Ｙ、Ｂａ、ＣａおよびＣｕの各Ｋセル２６、２８、
３２、３４を所定の温度で加熱する。次に、それぞれの
ビームシャッタ３６、３８、４２、４４を開き蒸着を行
なう。そして、このＹ系酸化物超電導体膜５６を設計上
の膜厚にまで成膜したとき、シャッタを閉じて既に説明
した手順を経て成膜を終了する。なお、成膜状態は、Ｒ
ＨＥＥＤ装置（２２，２４）で観測した。その結果、平
坦膜の上側に成膜される酸化物超電導体膜５６を構成す
る各原子が平坦膜５４上に整然と配列した膜となってい
ることが確認された。従って、酸化物超電導体膜５６の
膜質は高品質の膜質となっている。In the case of Ba, the number of molecules of ozone incident on the substrate 14 Γo 3 does not depart from the Si substrate surface even when the substrate temperature is 800 ° C. in an oxygen atmosphere. To a suitable temperature. Then, each K cell 26, 28 of Y, Ba, Ca and Cu,
32 and 34 are heated at a predetermined temperature. Next, the respective beam shutters 36, 38, 42 and 44 are opened to perform vapor deposition. Then, when the Y-based oxide superconductor film 56 is formed to a designed thickness, the shutter is closed and the film formation is completed through the above-described procedure. Note that the film formation state is R
Observation was performed with a HEED device (22, 24). As a result, it was confirmed that the atoms constituting the oxide superconductor film 56 formed on the upper side of the flat film were arranged on the flat film 54 in an orderly manner. Therefore, the quality of the oxide superconductor film 56 is high.
【００４２】上述した各実施例は、この発明の単なる好
適例を示したにすぎず、従って、この発明は、上述した
実施例に限定されるものではない。The embodiments described above are merely preferred examples of the present invention, and therefore, the present invention is not limited to the above-described embodiments.
【００４３】上述した実施例では、Ｙ系の酸化物超電導
体膜を成膜する例において、酸素吸着膜としてＢａ膜を
設ける例につき説明したが、Ｂａ膜の代わりに、他の酸
化され易い元素で例えば、イットリウム（Ｙ）であって
も良い。また、タリウム（Ｔｌ）系の酸化物超電導体膜
を成膜する場合には、酸素吸着膜として、Ｃａまたはバ
リウム（Ｂａ）を用いるのが良い。また、ビスマス（Ｂ
ｉ）系の酸化物超電導体を成膜する場合には、酸素吸着
膜として、ストロンチウム（Ｓｒ）またはカルシウム
（Ｃａ）を用いるのが良い。これら、Ｓｒ，Ｃａ，Ｂ
ａ，Ｙは酸化物超電導体膜の構成元素であるので、酸素
吸収膜と酸化物超電導体膜との間の整合性も良く、従っ
て、これらの元素は成膜に好適である。In the above-described embodiment, an example in which a Ba film is provided as an oxygen-adsorbing film in the example of forming a Y-based oxide superconductor film has been described. Instead of the Ba film, other easily oxidizable elements are used. For example, yttrium (Y) may be used. When forming a thallium (Tl) -based oxide superconductor film, Ca or barium (Ba) is preferably used as the oxygen adsorption film. In addition, bismuth (B
In the case of forming an i) -based oxide superconductor, strontium (Sr) or calcium (Ca) is preferably used as the oxygen adsorption film. These Sr, Ca, B
Since a and Y are constituent elements of the oxide superconductor film, the compatibility between the oxygen absorbing film and the oxide superconductor film is good, and therefore, these elements are suitable for film formation.
【００４４】また、上述した例では、酸素に酸化され易
い元素を用いた例であるが、アルミニウム（Ａｌ）のよ
うな、酸素の吸着性の良い元素であっても良い。従っ
て、この発明では、酸素吸着膜には、酸化され易い膜は
もとより、酸素を吸着する膜をも含めた膜と解するもの
とする。In the above-described example, an element which is easily oxidized to oxygen is used. However, an element having a high oxygen-adsorbing property, such as aluminum (Al), may be used. Therefore, in the present invention, the oxygen-adsorbing film is understood to be a film that includes not only a film that is easily oxidized but also a film that adsorbs oxygen.
【００４５】また、上述した実施例では、Ｂａの超薄膜
は、蒸着により直接または蒸着と加熱処理とにより、金
属の原子層オーダでの平坦膜として基板上に成膜すれば
良く、その平坦膜は一層構造はもとより、同一または異
種金属の蒸着膜の二層以上の重畳層構造であっても良
い。In the above-described embodiment, the ultra-thin Ba film may be formed on the substrate as a flat film on the order of the atomic layer of metal by vapor deposition directly or by vapor deposition and heat treatment. May have a single-layer structure, or a superposed layer structure of two or more layers of the same or different metal deposited films.
【００４６】さらに、上述した実施例では、半導体下地
としてＳｉ基板とし、また、酸化物超電導体としてＹ系
の超電導体につき説明したが、これに限定されるもので
はなく、半導体下地としてＳｉ以外の他の酸素を吸着し
易い（酸化され易いことも含む。）半導体、例えば、Ｇ
ａＡｓ，ＧａＳｂまたはＩｎＡｓを使用することが出来
るし、成膜面も（１００）面に限定されるものでなく、
また、Ｂｉ系、Ｔｌ系或いはその他の適当な酸化物超電
導体膜であっても良い。Furthermore, in the above-described embodiment, the description has been made of the Si substrate as the semiconductor base and the Y-based superconductor as the oxide superconductor. However, the present invention is not limited to this. A semiconductor that easily adsorbs other oxygen (including easily oxidized), for example, G
aAs, GaSb or InAs can be used, and the film formation surface is not limited to the (100) surface.
Further, a Bi-based, Tl-based or other suitable oxide superconductor film may be used.
【００４７】また、上述した各実施例において例示され
た種々の数値的条件およびその他の諸条件は、使用する
それぞれの材料およびまたは材質等によって変わるの
で、これらは上述した実施例に何等限定されるものでは
ない。The various numerical conditions and other conditions exemplified in each of the above-described embodiments vary depending on the respective materials and / or materials used, and are therefore not limited to the above-described embodiments. Not something.
【００４８】また、酸化物超電導体膜の成膜法は、元素
の同時蒸着法について説明したが、それぞれの元素用の
シャッタの開閉を順次に行う、レイヤ（ｌａｙｅｒ）−
バイ（ｂｙ）−レイヤ（ｌａｙｅｒ）成長法を用いても
良い。The method of forming the oxide superconductor film has been described with reference to the simultaneous vapor deposition method of the elements. However, the layer is formed by sequentially opening and closing the shutters for the respective elements.
A by-layer growth method may be used.
【００４９】[0049]
【発明の効果】上述した説明からも明らかなように、こ
の発明によれば、半導体上に直接原子層のオーダで酸素
吸着膜を平坦な超薄膜として成膜した後、この酸素吸着
膜上に、酸化雰囲気中で、酸化物超電導体膜を成膜す
る。従って、酸化物超電導体膜の成膜の際に酸素はこの
酸素吸着膜には入り込むが、そのほとんどがここで吸着
されるか、散乱される。そのため、この酸素吸着膜を通
過して、その下側の下地にまで達する酸素の量は著しく
低減される。その結果、基板表面には、不所望の酸化物
が形成されたりする恐れが従来よりも低減される。従っ
て、酸化物超電導体膜が形成される下地の表面は、結晶
配列の乱れは従来よりも低減し、その上側に成膜される
酸化物超電導体膜の膜質は従来よりも高品質となる。そ
の結果、酸化物超電導体と半導体との接合の品質も従来
よりも良質となることが期待出来る。As is apparent from the above description, according to the present invention, an oxygen adsorption film is formed as a flat ultra-thin film on the order of an atomic layer directly on a semiconductor, and then formed on the oxygen adsorption film. Then, an oxide superconductor film is formed in an oxidizing atmosphere. Therefore, when the oxide superconductor film is formed, oxygen enters the oxygen adsorption film, but most of the oxygen is adsorbed or scattered here. Therefore, the amount of oxygen passing through the oxygen-adsorbing film and reaching the underlying substrate is significantly reduced. As a result, the possibility that an undesired oxide is formed on the substrate surface is reduced as compared with the related art. Therefore, on the surface of the base on which the oxide superconductor film is formed, the disorder of the crystal arrangement is reduced as compared with the conventional case, and the quality of the oxide superconductor film formed thereon is higher than that of the conventional case. As a result, it can be expected that the quality of the junction between the oxide superconductor and the semiconductor will also be higher than before.
【図１】図１の（Ａ）〜（Ｂ）は、この発明の酸化物超
電導体を半導体上に形成する方法の一実施例の説明に供
する工程図である。FIGS. 1A and 1B are process diagrams for explaining an embodiment of a method for forming an oxide superconductor on a semiconductor according to the present invention.
【図２】図２は、先行技術の説明図である。FIG. 2 is an explanatory diagram of the prior art.
【図３】図３は、この発明の実施に用いる真空蒸着装置
の構造の一例を示す概略図である。FIG. 3 is a schematic view showing an example of a structure of a vacuum evaporation apparatus used for carrying out the present invention.
１４…半導体基板 ５４…酸素吸着膜（例えば、Ｂａの平坦膜） ５６…酸化物超電導体膜（例えば、Ｙ系酸化物超電導体
膜）14 semiconductor substrate 54 oxygen adsorption film (for example, a flat film of Ba) 56 oxide superconductor film (for example, Y-based oxide superconductor 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 Ｃ２３Ｃ 14/24 Ｃ２３Ｃ 14/24 Ｈ０１Ｂ 13/00 ５６５ Ｈ０１Ｂ 13/00 ５６５Ｄ // Ｈ０１Ｂ 12/06 ＺＡＡ 12/06 ＺＡＡ Continuation of the front page (51) Int.Cl. 6 Identification number Office reference number FI Technical display location C23C 14/24 C23C 14/24 H01B 13/00 565 H01B 13/00 565D // H01B 12/06 ZAA 12/06 ZAA
Claims (4)
前記下地を加熱して、酸化物超電導体膜を形成するに当
たり、 下地上に、直接原子層のオーダで平坦な酸素吸着膜を形
成する工程と、 該酸素吸着膜上に酸化物超電導体膜を成膜する工程とを
含むことを特徴とする酸化物超電導体膜を半導体上に形
成する方法。An oxide superconductor film is formed on an upper surface of a semiconductor substrate by heating the substrate in an oxidizing atmosphere to form an oxide superconductor film. And forming an oxide superconductor film on the oxygen-adsorbing film. A method for forming an oxide superconductor film on a semiconductor, comprising:
をビスマス（Ｂｉ）系とするとき、前記酸素吸着膜を、
ストロンチュウム（Ｓｒ）またはカルシウム（Ｃａ）と
することを特徴とする方法。2. When the oxide superconductor film according to claim 1 is made of bismuth (Bi), the oxygen adsorbing film is
A method comprising strontium (Sr) or calcium (Ca).
をタリウム（Ｔｌ）系とするとき、前記酸素吸着膜を、
バリウム（Ｂａ）またはカルシウム（Ｃａ）とすること
を特徴とする方法。3. When the oxide superconductor film according to claim 1 is made of thallium (Tl), the oxygen adsorption film is
A method comprising barium (Ba) or calcium (Ca).
をイットリウム（Ｙ）系とするとき、前記酸素吸着膜
を、バリウム（Ｂａ）またはイットリウム（Ｙ）とする
ことを特徴とする方法。4. The method according to claim 1, wherein when the oxide superconductor film is made of yttrium (Y), the oxygen adsorption film is made of barium (Ba) or yttrium (Y). .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3141839A JP2721439B2 (en) | 1991-06-13 | 1991-06-13 | Method of forming oxide superconductor on semiconductor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3141839A JP2721439B2 (en) | 1991-06-13 | 1991-06-13 | Method of forming oxide superconductor on semiconductor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH04365383A JPH04365383A (en) | 1992-12-17 |
| JP2721439B2 true JP2721439B2 (en) | 1998-03-04 |
Family
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3141839A Expired - Lifetime JP2721439B2 (en) | 1991-06-13 | 1991-06-13 | Method of forming oxide superconductor on semiconductor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2721439B2 (en) |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2650188B2 (en) * | 1987-10-01 | 1997-09-03 | 富士通株式会社 | Method of forming electrical contact between superconductor and semiconductor |
| JP2525050B2 (en) * | 1989-06-09 | 1996-08-14 | 沖電気工業株式会社 | Method for forming oxide superconductor / semiconductor junction |
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1991
- 1991-06-13 JP JP3141839A patent/JP2721439B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH04365383A (en) | 1992-12-17 |
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