JPH03263883A - Josephson junction element - Google Patents
Josephson junction elementInfo
- Publication number
- JPH03263883A JPH03263883A JP2061105A JP6110590A JPH03263883A JP H03263883 A JPH03263883 A JP H03263883A JP 2061105 A JP2061105 A JP 2061105A JP 6110590 A JP6110590 A JP 6110590A JP H03263883 A JPH03263883 A JP H03263883A
- Authority
- JP
- Japan
- Prior art keywords
- substrate
- film
- nucleus
- josephson junction
- forming
- 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.)
- Granted
Links
- 239000000758 substrate Substances 0.000 claims abstract description 42
- 239000013078 crystal Substances 0.000 claims abstract description 31
- 229910010272 inorganic material Inorganic materials 0.000 claims abstract description 19
- 239000011147 inorganic material Substances 0.000 claims abstract description 19
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 5
- 230000006911 nucleation Effects 0.000 claims description 20
- 238000010899 nucleation Methods 0.000 claims description 20
- 239000000203 mixture Substances 0.000 claims description 4
- 229910052788 barium Inorganic materials 0.000 claims description 3
- 229910052802 copper Inorganic materials 0.000 claims description 3
- 229910052727 yttrium Inorganic materials 0.000 claims description 3
- 229910052684 Cerium Inorganic materials 0.000 claims description 2
- 229910052692 Dysprosium Inorganic materials 0.000 claims description 2
- 229910052691 Erbium Inorganic materials 0.000 claims description 2
- 229910052688 Gadolinium Inorganic materials 0.000 claims description 2
- 229910052689 Holmium Inorganic materials 0.000 claims description 2
- 229910052779 Neodymium Inorganic materials 0.000 claims description 2
- 229910052777 Praseodymium Inorganic materials 0.000 claims description 2
- 229910052771 Terbium Inorganic materials 0.000 claims description 2
- 229910052775 Thulium Inorganic materials 0.000 claims description 2
- 229910052793 cadmium Inorganic materials 0.000 claims description 2
- 150000001875 compounds Chemical class 0.000 claims description 2
- 229910052746 lanthanum Inorganic materials 0.000 claims description 2
- 229910052745 lead Inorganic materials 0.000 claims description 2
- 229910052748 manganese Inorganic materials 0.000 claims description 2
- 229910052709 silver Inorganic materials 0.000 claims description 2
- 229910052719 titanium Inorganic materials 0.000 claims description 2
- 229910052720 vanadium Inorganic materials 0.000 claims description 2
- 229910052772 Samarium Inorganic materials 0.000 claims 1
- 229910052742 iron Inorganic materials 0.000 claims 1
- 229910052759 nickel Inorganic materials 0.000 claims 1
- 229910052716 thallium Inorganic materials 0.000 claims 1
- 238000000034 method Methods 0.000 abstract description 23
- 238000005530 etching Methods 0.000 abstract description 13
- 239000010432 diamond Substances 0.000 abstract description 11
- 229910003460 diamond Inorganic materials 0.000 abstract description 10
- 229910052594 sapphire Inorganic materials 0.000 abstract description 8
- 239000010980 sapphire Substances 0.000 abstract description 8
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 abstract description 4
- 238000010438 heat treatment Methods 0.000 abstract description 4
- 239000001301 oxygen Substances 0.000 abstract description 4
- 238000010884 ion-beam technique Methods 0.000 abstract description 3
- 229910009203 Y-Ba-Cu-O Inorganic materials 0.000 abstract 4
- 239000010408 film Substances 0.000 description 47
- 239000000463 material Substances 0.000 description 13
- 238000010586 diagram Methods 0.000 description 7
- 238000000151 deposition Methods 0.000 description 6
- 239000010409 thin film Substances 0.000 description 5
- 230000008021 deposition Effects 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 4
- 230000001133 acceleration Effects 0.000 description 3
- 238000001514 detection method Methods 0.000 description 3
- 239000007789 gas Substances 0.000 description 3
- 238000004544 sputter deposition Methods 0.000 description 3
- 229910014454 Ca-Cu Inorganic materials 0.000 description 1
- 229910052693 Europium Inorganic materials 0.000 description 1
- 229910052769 Ytterbium Inorganic materials 0.000 description 1
- 229910021417 amorphous silicon Inorganic materials 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 238000005229 chemical vapour deposition Methods 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 239000011365 complex material Substances 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000010894 electron beam technology Methods 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 230000001747 exhibiting effect Effects 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 239000012528 membrane Substances 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 230000010355 oscillation Effects 0.000 description 1
- 238000000059 patterning Methods 0.000 description 1
- 238000001552 radio frequency sputter deposition Methods 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 239000002887 superconductor Substances 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
Abstract
Description
【発明の詳細な説明】
［産業上の利用分野］
本発明はジョセフソン接合素子に係り、特にブリッジ型
ジョセフソン接合素子に関する。本発明は、マイクロ波
から赤外光にかけての電磁波検出、発振等に用いられる
ジョセフソン接合素子に好適に用いられるものである。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a Josephson junction device, and more particularly to a bridge type Josephson junction device. INDUSTRIAL APPLICATION This invention is suitably used for the Josephson junction element used for electromagnetic wave detection, oscillation, etc. from a microwave to infrared light.
し従来の技術〕
ジョセフソン接合の形式としては、ポイントコンタクト
型、サンドイッチ型（ＳＩＳ型）、準平面型、ブリッジ
型等さまざまな形態が提案されている。中でもブリッジ
型ジョセフソン接合素子は、素子形態が単純な構造であ
るために、各種の金属超伝導膜およびＢ１ＰｂＢａＯ超
伝導膜において、さまざまな形態の検討がなされてきて
いる。（Ｊａｐｎｊ。BACKGROUND ART Various types of Josephson junctions have been proposed, such as a point contact type, a sandwich type (SIS type), a quasi-plane type, and a bridge type. Among them, the bridge type Josephson junction element has a simple structure, and therefore various forms have been investigated in various metal superconducting films and B1PbBaO superconducting films. (Japanj.
Ａｐｐｌ、 Ｐｈｙｓ、、 ２２．５４４ （１９８３
） 、及び特開昭５９−２１０６７８）。Appl, Phys, 22.544 (1983
), and JP-A-59-210678).
これらのブリッジ型ジョセフソン接合素子は、基板全面
に超伝導膜を形成後、エツチング等によって所望のブリ
ッジを形成するのが一般的であった。In these bridge-type Josephson junction devices, a desired bridge was generally formed by etching or the like after forming a superconducting film over the entire surface of the substrate.
［発明が解決しようとする課題］
しかしながら、近年発見されたセラミクス超伝導膜、例
えばＹＢａ＊Ｃｕ５Ｏｔ−δ、 ＥｒＢａ１ＣｕｓＯ？
−δ（０〈δ＜ １ ） 、 Ｂ１５ｒＣａＣｕＯ系材
料では、その材料組成が複雑なこともあり、エツチング
により、たとえばＹ、 Ｂａ、 Ｃｕなどのエツチング
速度が異なるため、超伝導体の組成がエツチングにより
変化しやすいという問題があった。このためエツチング
の状態により超伝導特性を示さなくなったり、パターン
の結晶性、再現性、均一性も劣るという欠点があった。[Problem to be solved by the invention] However, ceramic superconducting films discovered in recent years, such as YBa*Cu5Ot-δ, ErBa1CusO?
-δ(0<δ<1), B15rCaCuO-based materials have complex material compositions, and the etching rates of Y, Ba, Cu, etc. differ due to etching. The problem was that it was easy to change. Therefore, depending on the state of etching, superconducting properties may not be exhibited, and the crystallinity, reproducibility, and uniformity of the pattern may be poor.
また、ブリッジ型粒界ジョセフソン接合のミリ波応答性
の検討はなされているものの（Ｊａｐｎ、Ｊ。Furthermore, although studies have been made on the millimeter wave response of bridge-type grain boundary Josephson junctions (Japan, J.
Ａｐｐｌ、 Ｐｈｙｓ、、 ２７．ＬＩＩＩＯ（１９８
８）） 、電磁波検出器として感度向上を目的とした素
子形態の検討には、まだいたっていない。Appl, Phys, 27. LIIIO (198
8)) We have not yet investigated the form of elements aimed at improving sensitivity as electromagnetic wave detectors.
本発明は、上記点に鑑みてなされたものであり、エツチ
ング操作を必要とせず、成膜操作のみで形成することの
できるジョセフソン接合素子を提供するものである。The present invention has been made in view of the above points, and provides a Josephson junction element that does not require an etching operation and can be formed only by a film forming operation.
［課題を解決するための手段］
本発明のジョセフソン接合素子は、基体上の所望の位置
に核を生成させ、この核を中心にして結晶を成長させて
形成される無機材料結晶と、この無機材料結晶を有する
基体上に形成された超伝導膜とを備えたことを特徴とす
る。[Means for Solving the Problems] The Josephson junction device of the present invention includes an inorganic material crystal formed by generating a nucleus at a desired position on a substrate and growing a crystal around this nucleus; A superconducting film formed on a substrate having an inorganic material crystal.
ここで、「核」とは次に説明する意味である。Here, "nucleus" has the meaning explained below.
体積面が飛来する原子と異なる種類の材料、特に非晶質
材料である場合、飛来する原子は基板表面を自由に拡散
し、又は再蒸発（脱離）する。そして原子同志の衝突の
末、核が形成され、その自由エネルギＧが最大となるよ
うな核（臨界核）の大きさｒｃ（＝−２σ。／ｇｖ）以
上になると、Ｇは減少し、核は安定に三次元的に成長を
続け、島状となる。ｒＣを越えた大きさの核を「安定核
」と呼び、本発明の説明に於いて、「核」と記した場合
は、この「安定核」を示すものとする。When the volume surface is a different type of material from the incoming atoms, particularly an amorphous material, the incoming atoms freely diffuse or re-evaporate (desorb) on the substrate surface. As a result of collisions between atoms, a nucleus is formed, and when the size of the nucleus (critical nucleus) at which its free energy G becomes maximum is rc (=-2σ./gv) or more, G decreases and the nucleus continues to grow stably in a three-dimensional manner, forming an island. A nucleus with a size exceeding rC is called a "stable nucleus", and in the description of the present invention, when "nucleus" is written, this "stable nucleus" is indicated.
核を形成することによって生ずる自由エネルギＧは、
Ｇ＝４ πｆ（θ） （ａ ａｒ”＋１／：Ｉｇｖ−
ｒ”）ｆ（θ）Ｊ／４ （２−３ｃｏｓθ＋ ｃｏｓ”
θ）ただし、ｒ：核の曲率半径
θ：核の接触角
ｇｖ：単位堆積当りの自由エネルギ
σ。：核と真空間の表面エネルギ
と表わされる。Ｇの変化の様子を第７図に示す。The free energy G generated by forming a nucleus is: G=4 πf(θ) (a ar”+1/:Igv−
r”)f(θ)J/4 (2-3cosθ+cos”
θ) where r: Radius of curvature of the nucleus θ: Contact angle of the nucleus gv: Free energy per unit deposition σ. : Expressed as the surface energy between the nucleus and vacuum. Figure 7 shows how G changes.
同図において、Ｇが最大値であるときの安定核の曲率半
径がｒｃである。In the figure, the radius of curvature of the stable nucleus when G is at its maximum value is rc.
本発明において、基体上の所望の位置に核を生成する方
法としては、Ｓｔ、サファイア等の基体上にエツチング
ライン等の凹部を形成し、この凹部に核を生成させる方
法があり、例えばダイヤモンドをエピタキシャル成長さ
せる場合には、Ｓｉ基板上にエツチングラインを縦横に
形成して凹部を形成すると、この凹部に選択的にダイヤ
モンドの核を生起させることができる（Ａｐｐｌ、 Ｐ
ｈｙｓ、Ｌｅｔｔ、５３（１９） ７ Ｎｏｖｅｍｂｅ
ｒ１９８８ ）。In the present invention, as a method for generating a nucleus at a desired position on a substrate, there is a method of forming a recess such as an etching line on a substrate such as St or sapphire, and generating a nucleus in this recess. In the case of epitaxial growth, if etching lines are formed vertically and horizontally on the Si substrate to form recesses, diamond nuclei can be selectively generated in these recesses (Appl, P.
hys, Lett, 53 (19) 7 November
r1988).
また、ＭｇＯ，Ｓｉｎｇ等の基体面に核形成密度の小さ
い非核形成面と、非晶質材料で構成され結晶成長して単
結晶となる核が唯一形成し得るに充分小さい面積を有し
、前記非核形成面の核形成密度より大きい核形成密度を
有する核形成面とを隣接した基体に結晶成長処理を施し
、該核形成面に結晶を生成させる方法があり、例えば、
Ｓｉを成長させる場合には、非核形成面となるＳｉＯ□
基体上に予め結晶成長して単結晶となる核が唯一形成し
得るに充分小さい非晶質材料からなる核形成面を形成す
ると、この非晶質窒化シリコン膜にＳｉの核を生起させ
ることができる（特開昭６３−１０７０１６号公報）。In addition, the substrate surface of MgO, Sing, etc. has a non-nucleation surface with a low nucleation density and an area small enough to form the only nucleus that is made of an amorphous material and becomes a single crystal through crystal growth, and There is a method in which crystal growth is performed on a substrate adjacent to a nucleation surface having a nucleation density higher than that of a non-nucleation surface, and crystals are generated on the nucleation surface.
When growing Si, SiO□ serves as a non-nucleation surface.
If a nucleation surface made of an amorphous material is formed on the substrate in advance and is small enough to form the only nucleus that will become a single crystal by crystal growth, it is possible to generate Si nuclei in this amorphous silicon nitride film. It is possible (Japanese Unexamined Patent Publication No. 107016/1983).
なお、非核形成面の構成材料の種類、形状等は、基体上
に選択的に成長させる無機物の種類及び成長法により適
宜設定すればよい。The type, shape, etc. of the material constituting the non-nucleation surface may be appropriately set depending on the type and growth method of the inorganic substance to be selectively grown on the substrate.
なお、無機材料結晶は上述した方法を用いて形成される
が、結晶成長は核を中心として成長した結晶同志が接す
るまで行われる。結晶同志は直径の１７５〜Ｉ／２程度
まで接することが望ましい。Note that the inorganic material crystal is formed using the method described above, and the crystal growth is performed until the crystals that have grown centering on the nucleus come into contact with each other. It is desirable that the crystals touch each other to a distance of about 175 to I/2 of the diameter.
なお、選択的に結晶を形成させる方法は、上述したもの
に限定されるものではなく、例えば選択デポジション法
、ＳＥＧ （５ｅｌｅｃｔｉｖｅ Ｅｐｉｔａｘｉａｌ
Ｇｒｏｗｔｈ）法等を用いることができる。Note that methods for selectively forming crystals are not limited to those described above, and include, for example, selective deposition method, SEG (5elective epitaxial
Growth method, etc. can be used.
本発明に用いる無機材料は、その上に超伝導材料を堆積
した場合、該堆積膜は超伝導性を示さなくなるような無
機材料であり、例えば、ダイヤモンドＳｉ、 Ｗ、 Ｇ
ａ、 Ａｓ、 ＩｎＰ等である。The inorganic material used in the present invention is such that when a superconducting material is deposited thereon, the deposited film no longer exhibits superconductivity, such as diamond Si, W, G, etc.
a, As, InP, etc.
本発明に用いる基体材料としては、その上に超伝導材料
を堆積した場合、該堆積膜が超伝導性を示すような基体
材料であり、例えば、ＭｇＯ、サファイア、 ５ｒＴｉ
Ｏｓ、 ＹＳＺ、ＬａＧａ０等である。なお、後述する
実施例においては基体材料の面方位を規定しているが（
実施例１ではサファイア（１００）面、実施例２ではＭ
ｇ０（１００）面を用いている）、かかる面方位以外の
ものも用いることができる。The base material used in the present invention is such that when a superconducting material is deposited thereon, the deposited film exhibits superconductivity, such as MgO, sapphire, 5rTi, etc.
These include Os, YSZ, LaGa0, etc. In addition, in the examples described later, the plane orientation of the base material is specified (
Sapphire (100) surface in Example 1, M in Example 2
g0 (100) plane), plane orientations other than this can also be used.
また成膜する超伝導膜は、粒界ジョセフソン接合を形成
しつる超伝導物質の薄膜であればいずれも用いることが
できるが、その化合物組成をＡ−Ｂ−Ｃ−Ｄと表わすと
き、ＡがＬａ、 Ｃｅ、 Ｐｒ、 Ｎｄ、 Ｐｍ。The superconducting film to be formed can be any thin film of superconducting material that forms grain boundary Josephson junctions, but when the compound composition is expressed as A-B-C-D, A are La, Ce, Pr, Nd, Pm.
Ｓａｄ、 Ｓｃ、 Ｅｕ、 Ｇｄ、 Ｔｂ、 Ｄｙ、
Ｈｏ、 Ｅｒ、 Ｔｍ、 Ｙｂ、 Ｌｕ、 Ｂｉ、 Ｔ
ｌおよびＹよりなる群より選ばれた一種以上の元素；Ｂ
がＢａ、 Ｃａ、 ＳｒおよびＰｂよりなる群から選ば
れた一種以上の元素；ＣがＶ、Ｔｉ、Ｃｒ、Ｍｎ、Ｆｅ
、Ｎｉ、Ｃｏ、Ａｇ、ＣｄおよびＣｕよりなる群から選
ばれた一種以上の元素；ＤがＳおよび０よりなる群から
選ばれた一種以上の元素である超伝導体が好ましく、こ
れらを用いた超伝導膜は選択的結晶成長された無機材料
上で良好に形成される。Sad, Sc, Eu, Gd, Tb, Dy,
Ho, Er, Tm, Yb, Lu, Bi, T
One or more elements selected from the group consisting of l and Y; B
is one or more elements selected from the group consisting of Ba, Ca, Sr and Pb; C is V, Ti, Cr, Mn, Fe
, Ni, Co, Ag, Cd and Cu; A superconductor in which D is one or more elements selected from the group consisting of S and 0 is preferable, and these are used. Superconducting films are well formed on selectively crystal grown inorganic materials.
基体上への超伝導膜の成膜方法としては、通常のスパッ
タ法、電子ビーム加熱法、抵抗加熱法。Methods for forming superconducting films on substrates include conventional sputtering, electron beam heating, and resistance heating.
ＭＥＢ法、 ＣＶＯ法、イオンビーム法などが適用でき
る。又該超伝導膜の厚さは適宜所望により設定すればよ
い。MEB method, CVO method, ion beam method, etc. can be applied. Further, the thickness of the superconducting film may be appropriately set as desired.
この様にして作成された超伝導膜は、必要に応じて熱処
理されるが、単結晶基板は超伝導膜との熱膨張係数の近
いものを選ぶことでさらにその耐久性を向上させること
もできる。The superconducting film created in this way is heat treated as necessary, but its durability can be further improved by selecting a single crystal substrate with a coefficient of thermal expansion similar to that of the superconducting film. .
［作用］
本発明は、基体上の所望の位置に核を生成させ、この核
を中心として、その上に超伝導材料を堆積した場合にそ
の堆積膜が超伝導性を示さなくなるような無機材料の結
晶を成長させ、この無機材料の結晶を有する前記基体上
に超伝導材料を堆積することで、無機材料の結晶の形成
されない基体上のみに超伝導性を示す超伝導膜を形成す
るものである。[Operation] The present invention produces an inorganic material that generates a nucleus at a desired position on a substrate, and when a superconducting material is deposited on the nucleus around this nucleus, the deposited film no longer exhibits superconductivity. By growing crystals of the inorganic material and depositing the superconducting material on the substrate having the crystals of the inorganic material, a superconducting film exhibiting superconductivity is formed only on the substrate where the crystals of the inorganic material are not formed. be.
基体上に結晶化された無機材料のパターンは超伝導膜の
パターンのネガパターンとなり、無機材料のパターンが
所望の位置に生起させた核を中心として無機材料の結晶
を成長させることで任意の位置に形成可能なため、超伝
導膜のパターンも任意の位置に形成可能となる。従って
、たて、横の巾を変えてマス目状に凹部を形成する方法
、たて、横の巾を変えて核形成面を配列させて形成する
方法等により選択的に核を生起させ、この核を中心とし
て結晶を成長させることで、無機材料のネガパターンを
形成し、次に超伝導薄膜を形成することで、簡単にジョ
セフソン接合アレイを形成することもできる。このよう
に、ジョセフソン接合アレイにすることによってノーマ
ル抵抗Ｒ８、および超伝導臨界電流値Ｉｃが大きくなり
、素子に印加できる電圧Ｖ ＝ＩｅＲ，４を上げること
ができ、電磁り
能となる。The pattern of the inorganic material crystallized on the substrate becomes a negative pattern of the pattern of the superconducting film, and the pattern of the inorganic material can be formed at any desired position by growing crystals of the inorganic material centering on the nucleus generated at the desired position. Since the superconducting film can be formed at any position, the superconducting film pattern can also be formed at any position. Therefore, nuclei can be selectively generated by forming recesses in a grid pattern by changing the vertical and horizontal widths, by arranging the nucleation surfaces by changing the vertical and horizontal widths, etc. By growing a crystal around this core, a negative pattern of inorganic material is formed, and then a superconducting thin film is formed to easily form a Josephson junction array. In this way, by forming a Josephson junction array, the normal resistance R8 and the superconducting critical current value Ic become large, and the voltage V 2 =IeR,4 that can be applied to the element can be increased, resulting in electromagnetic capability.
また、前述した基体状の凹部及び核形成面は、ＥＢ露光
バターニング等により１μｍ以下のバターニングが可能
であるので各ジョセフソン接合間距離を極めて小さ（す
ることができ接合数を大きくすることが可能で、電磁波
検出器として高感度発振器として高出力のものを得るこ
とが可能である。In addition, since the aforementioned base-like concave portions and nucleation surfaces can be patterned to a thickness of 1 μm or less by EB exposure patterning, etc., the distance between each Josephson junction can be made extremely small (and the number of junctions can be increased). It is possible to obtain a high-output electromagnetic wave detector as a highly sensitive oscillator.
［実施例］
以下、本発明の実施例について図面を用いて、より具体
的に説明する。なお、以下に説明する実施例はジョセフ
ソン接合をアレイ状に形成したものである。[Example] Hereinafter, an example of the present invention will be described in more detail with reference to the drawings. In the embodiment described below, Josephson junctions are formed in an array.
（実施例１）
第１図（Ａ）〜（Ｃ）、第２図に示す各工程によってジ
ョセフソン接合素子を形成した。ここで、第１図（Ａ）
〜（Ｃ）は本発明の実施例１の製造工程を説明するため
の工程図であり、第２図はジョセフソン接合素子の縦断
面図である。(Example 1) A Josephson junction element was formed through the steps shown in FIGS. 1A to 2C and FIG. Here, Fig. 1 (A)
-(C) are process diagrams for explaining the manufacturing process of Example 1 of the present invention, and FIG. 2 is a longitudinal cross-sectional view of a Josephson junction element.
まず第１図（Ａ）に示すように、サファイア（１００）
基体１上にエツチング等によって、たて１３μｍピッチ
、横１０μｍピッチでエツチングライン２をひいた。次
に、第１図（Ｂ）に示すように、基体１上にダイヤモン
ドをエピタキシャル成長させラインの交点上に半球上の
ダイヤモンド３を形成する。First, as shown in Figure 1 (A), sapphire (100)
Etching lines 2 were drawn on the substrate 1 by etching or the like at a vertical pitch of 13 μm and a horizontal pitch of 10 μm. Next, as shown in FIG. 1(B), diamond is epitaxially grown on the substrate 1 to form hemispherical diamonds 3 at the intersections of the lines.
次に第１図（１）に示すように、この基体１上にＹ−Ｂ
ａ−Ｃｕ−０をＩＣＢ法（クラスターイオンビーム法）
で成膜した。この時の成膜条件は、基板温度４００℃、
酸素分圧３ Ｘ １０−’Ｔｏｒｒで行い、蒸着材料と
してＹ、 Ｂａｄ、 Ｃｕをそれぞれ独立のクラスター
イオンガンにより、基板上の組成が、Ｙ：Ｂａ：Ｃｕ：
１：２：３になるように堆積速度を調節した。なお、Ｙ
用のクラスターイオンガンの加速電圧は１ ｋＶ、イオ
ン化電流は５０＋ｏＡとし、ＢａＯ用のクラスターイオ
ンガンの加速電圧は、０．５ｋＶ、イオン化電流は３０
ｍＡとし、Ｃｕ用の加速電圧は４ ｋＶ、イオン化電流
は２００ｍＡとした。なお堆積速度は２００人／ｗｉｎ
で、膜厚は５０００人だった。さらにこの基板を酸素雰
囲気中で９４０℃、１時間の熱処理を行い超伝導膜たる
Ｙ−Ｂａ−Ｃｕ−０膜を作成した。Next, as shown in FIG. 1 (1), Y-B
a-Cu-0 by ICB method (cluster ion beam method)
The film was formed using The film forming conditions at this time were: substrate temperature 400°C;
It was carried out at an oxygen partial pressure of 3 x 10-' Torr, and the composition on the substrate was changed to Y:Ba:Cu:
The deposition rate was adjusted to be 1:2:3. Furthermore, Y
The acceleration voltage of the cluster ion gun for BaO is 1 kV and the ionization current is 50+oA, and the acceleration voltage of the cluster ion gun for BaO is 0.5 kV and the ionization current is 30
mA, the acceleration voltage for Cu was 4 kV, and the ionization current was 200 mA. The deposition rate is 200 people/win.
The film thickness was 5,000 people. Further, this substrate was heat-treated at 940° C. for 1 hour in an oxygen atmosphere to produce a Y-Ba-Cu-0 film as a superconducting film.
このようにして作製したＹ−Ｂａ−Ｃｕ−０膜にＡｕ電
極をつけて液体Ｈｅを用いて抵抗を測定したところサフ
ァイア上のＹ−Ｂａ−Ｃｕ−０膜４ａは、７０にで抵抗
０となり超伝導性を示したが、ダイヤモンド３上のＹ−
Ｂａ−Ｃｕ−０膜４ｂは４にでも抵抗０にならず、超伝
導性を示さなかった。すなわち本発明の方法により、粒
界ジョセフソン接合が得られたことになる。When we attached an Au electrode to the Y-Ba-Cu-0 film prepared in this way and measured its resistance using liquid He, the resistance of the Y-Ba-Cu-0 film 4a on sapphire was 0 at 70°C. Although it showed superconductivity, Y- on diamond 3
The Ba-Cu-0 film 4b did not have zero resistance even at a temperature of 4, and did not exhibit superconductivity. In other words, a grain boundary Josephson junction was obtained by the method of the present invention.
なお、Ｙ−Ｂａ−Ｃｕ−Ｏｌｌ１４ ａで、ダイヤモン
ドが近づくことで巾がせまくなっている部分、例えば第
１図（Ｃ）中、１２（破線で図示）がジョセフソン接合
部である。In the Y-Ba-Cu-Oll 14a, the portion where the width becomes narrower as the diamond approaches, for example 12 (indicated by a broken line) in FIG. 1(C), is the Josephson junction.
（実施例２）
第３図（Ａ）〜（Ｃ）、第４図に示す各工程によってジ
ョセフソン接合素子を形成した。(Example 2) A Josephson junction element was formed through the steps shown in FIGS. 3(A) to 4(C) and FIG. 4.
ここで、第３図（Ａ）〜（Ｃ）は本発明の実施例２の製
造工程を説明するための工程図であり、第４図はジョセ
フソン接合素子の縦断面図である。Here, FIGS. 3A to 3C are process diagrams for explaining the manufacturing process of Example 2 of the present invention, and FIG. 4 is a longitudinal cross-sectional view of a Josephson junction element.
まず第３図（Ａ）に示すように、 Ｍｇ０（１００）基
体８上にマスクを利用したＲＳスパッタ法で無機材料結
晶を形成するための核形成面となる非晶質の５ｉｓＮ４
膜５を２０行２０列作成した。その際、５ｉＪ４膜５の
大きさは１μＷφとし、行間距離Ａを８μｍに固定し、
列間距離Ｂを１０〜１３μｍと変化させた。First, as shown in FIG. 3(A), amorphous 5isN4 is deposited on the Mg0(100) substrate 8 to serve as a nucleation surface for forming an inorganic material crystal by RS sputtering using a mask.
The membrane 5 was prepared in 20 rows and 20 columns. At that time, the size of the 5iJ4 film 5 was set to 1 μWφ, and the inter-row distance A was fixed to 8 μm.
The inter-row distance B was varied from 10 to 13 μm.
この基体上にＣＶＤ法でＳｉをエピタキシャル成長させ
たところ核５を中心にＳｉ６が成長した。たて方向にあ
る程度（直径の１１５〜１７２程度）接するまで成長さ
せた。この時の成膜条件は、原料ガスとしてＨＬＣとＢ
２とＳｉＨ＊Ｃ１□、５ｉＣ１４，ＳｉＨＣｌｍ、Ｓｉ
Ｆ４もしくは５ｉｔ（４との混合ガスを用いて、基体温
度７００〜１１００℃、圧力は約１００Ｔｏｒｒとした
。When Si was epitaxially grown on this substrate by the CVD method, Si6 grew around the nucleus 5. It was grown until it touched a certain extent (approximately 115 to 172 diameters) in the vertical direction. The film forming conditions at this time were HLC and B as source gases.
2 and SiH*C1□, 5iC14, SiHClm, Si
A mixed gas with F4 or 5it (4) was used, the substrate temperature was 700 to 1100°C, and the pressure was about 100 Torr.
この様にして作製した基体上にＢ１−３ｒ−Ｃａ−Ｃｕ
−０焼結体ターゲットを用いてＲＦスパッタ法で成膜し
たところＢ１−３ｒ−Ｃａ−Ｃｕ−０膜が形成された。B1-3r-Ca-Cu was placed on the substrate prepared in this way.
When a film was formed by RF sputtering using a -0 sintered target, a B1-3r-Ca-Cu-0 film was formed.
この時の成膜条件は、基体温度１００℃以下、 Ａｒガ
ス圧力０、５０ａ、スパッタパワー１００ｗで、堆積速
度５０人／ｍｉｎ 、膜厚は４０００人であった。さら
にこの基体を酸素雰囲気中で８５０℃１時間の熱処理を
行い、Ｔｃニア０にとなる超伝導薄膜たるＢ１−３ｒ−
Ｃａ−Ｃ：ｕ−０膜を作製した。The film forming conditions at this time were a substrate temperature of 100° C. or less, an Ar gas pressure of 0.50 μm, a sputtering power of 100 W, a deposition rate of 50 persons/min, and a film thickness of 4,000 persons. This substrate was further heat-treated at 850°C for 1 hour in an oxygen atmosphere to produce a superconducting thin film with Tc near 0.
A Ca-C:u-0 film was produced.
このようにして作製したＢ１−３ｒ−Ｃａ−Ｃｕ−０膜
は実施例１と同様にＭｇＯ基体上のＢ１−３ｒ−Ｃａ−
Ｃｕ−０膜７ａは超伝導性を示したが、Ｓｉ単結晶６上
のＢ１−３ｒ−Ｃａ−Ｃｕ−０膜７ｂは超伝導性を示さ
なかった。The B1-3r-Ca-Cu-0 film prepared in this way was prepared on a MgO substrate in the same manner as in Example 1.
Although the Cu-0 film 7a showed superconductivity, the B1-3r-Ca-Cu-0 film 7b on the Si single crystal 6 did not show superconductivity.
表１に得られた粒界ジョセフソン接合におりる列間距離
Ｂの変化による各特性の変化を示す。本発明の方法によ
り得られたジョセフソン接合は特にＩｃが大きく、Ｉｃ
Ｒ，積が大きいものであった。Table 1 shows changes in each characteristic due to changes in the inter-row distance B at the grain boundary Josephson junction. The Josephson junction obtained by the method of the present invention has a particularly large Ic.
R, the product was large.
なお、測定はＭｇＯ上のＢ１−５ｒ−Ｃａ−Ｃｕ−０膜
７ａの端（第３図（Ｃ）の上部と下部）に電極をつけ、
４端子法で測定した。In addition, the measurement was carried out by attaching electrodes to the edges of the B1-5r-Ca-Cu-0 film 7a on MgO (the upper and lower parts of FIG. 3(C)).
Measured using the 4-terminal method.
表Ｉ Ｂの値と評価結果
なお、第５図に示すような２μｍＸ２μｍのウィークジ
ャンクション部１個をもつ粒界ジョセフソン接合では、
１． ＝０．２ｍＡ、ＲＨ＝０．９ΩでＩｅＲ，ｌ＝０
．１．８ｍＶであった。Table I B values and evaluation results Note that in a grain boundary Josephson junction with one 2 μm x 2 μm weak junction as shown in Figure 5,
1. =0.2mA, IeR at RH=0.9Ω, l=0
．． It was 1.8 mV.
第５図中、１３はＢ１−３ｒ−Ｃａ−Ｃｕ−０膜、１５
は基体、１４（図中、破線で図示）はウィークジャンク
ション部である。In FIG. 5, 13 is a B1-3r-Ca-Cu-0 film, 15
14 is a base body, and 14 (indicated by a broken line in the figure) is a weak junction portion.
（実施例３）
実施例２と同様の工程でジョセフソン接合素子を形成し
た。ただし、５ｉｓＮ４膜５を３行３列とし、行間距離
を８μｍ９列間距離を１１μ口とした。(Example 3) A Josephson junction element was formed in the same process as in Example 2. However, the 5isN4 film 5 was arranged in 3 rows and 3 columns, with a distance between rows of 8 μm and a distance between 9 columns of 11 μm.
さらに、第６図に示すように、電極９としてＣｒ−Ａｕ
を抵抗加熱法で蒸着した。電磁波検出用電圧計１０、電
源１１を取りつけ、電磁波検出器を作製した。Further, as shown in FIG. 6, the electrode 9 is made of Cr-Au.
was deposited using a resistance heating method. An electromagnetic wave detection voltmeter 10 and a power source 11 were attached to produce an electromagnetic wave detector.
本実施例の電磁波検出器は、ジョセフソン接合間距離を
極めて小さくすることができ接合数を大きくすることが
可能で、電磁波検出器として高感度発振器であって、高
出力のものを得ることが可能であった。The electromagnetic wave detector of this embodiment can make the distance between Josephson junctions extremely small and increase the number of junctions, and is a highly sensitive oscillator as an electromagnetic wave detector, making it possible to obtain high output. It was possible.
［発明の効果］
以上、説明したように、本発明のジョセフソン接合素子
によれば、無機材料結晶のパターンを制御することで超
伝導膜のパターンを制御することが可能となり、粒界ジ
ョセフソン素子アレイを製作した場合、ＩｏＲ，積を大
きくすることができ、電磁波デバイスとしての周波数上
限を高くできる。[Effects of the Invention] As explained above, according to the Josephson junction device of the present invention, the pattern of the superconducting film can be controlled by controlling the pattern of the inorganic material crystal, and the grain boundary Josephson When an element array is manufactured, the IoR, product can be increased, and the upper limit of frequency as an electromagnetic wave device can be increased.
また、超伝導膜成形後のエツチング工程を必要としない
ため素子の再現性、結晶性、均一性を向上させることが
でき、品質の良い素子にすることができる。Furthermore, since an etching step after forming the superconducting film is not required, the reproducibility, crystallinity, and uniformity of the device can be improved, and the device can be of high quality.
第１図（Ａ）〜（Ｃ）は、本発明のジョセフソン接合素
子の実施例１の製造工程を説明するための工程図である
。
第２図は上記実施例１のジョセフソン接合素子の縦断面
図である。
第３図（Ａ）〜（Ｃ）は、本発明のジョセフソン接合素
子の実施例２の製造工程を説明するための工程図である
。
第４図は上記実施例２のジョセフソン接合素子の縦断面
図である。
第５図はウィークジャンクションをもつ粒界ジョセフソ
ン接合素子を示す概略的説明図である。
第６図は本発明のジョセフソン接合素子を用いた電磁波
検出器の概略的説明図である。
第７図は核の自由エネルギーＧと曲率半径γとの関係を
示す特性図である。
１．８二基体、３：エツチングライン、３：ダイヤモン
ド、４ａ：サファイア上のＹ−Ｂａ−Ｃｕ−０薄膜、４
ｂ＝ダイヤモンド上のＹ−Ｂａ−Ｃｕ−０薄膜、５：
５ｉｓＮｎ膜、６ ：Ｓｉ％７ａ ：ＭｇＯ上のＢ１−
５ｒ−Ｃａ−Ｃｕ−０膜、７ ｂ ： Ｓｔ上のＢ１−
３ｒ−Ｃａ−Ｃｕ−０膜、９：電極、１０：電磁波検出
用電圧計、１１：電源、１２：ジョセフソン接合部、１
３ ： Ｂ１−５ｒ−Ｃａ−Ｃｕ−０膜、１４：ウィー
クジャンクション部、１５：基体。FIGS. 1A to 1C are process diagrams for explaining the manufacturing process of Example 1 of the Josephson junction device of the present invention. FIG. 2 is a longitudinal sectional view of the Josephson junction element of Example 1. FIGS. 3A to 3C are process diagrams for explaining the manufacturing process of Example 2 of the Josephson junction device of the present invention. FIG. 4 is a longitudinal sectional view of the Josephson junction element of the second embodiment. FIG. 5 is a schematic explanatory diagram showing a grain boundary Josephson junction device having a weak junction. FIG. 6 is a schematic explanatory diagram of an electromagnetic wave detector using the Josephson junction element of the present invention. FIG. 7 is a characteristic diagram showing the relationship between nuclear free energy G and radius of curvature γ. 1.8 Two substrates, 3: Etched line, 3: Diamond, 4a: Y-Ba-Cu-0 thin film on sapphire, 4
b = Y-Ba-Cu-0 thin film on diamond, 5:
5isNn film, 6:Si%7a:B1- on MgO
5r-Ca-Cu-0 film, 7b: B1- on St
3r-Ca-Cu-0 film, 9: electrode, 10: electromagnetic wave detection voltmeter, 11: power supply, 12: Josephson junction, 1
3: B1-5r-Ca-Cu-0 film, 14: weak junction part, 15: substrate.
Claims (4)
心にして結晶を成長させて形成される無機材料結晶と、
この無機材料結晶を有する基体上に形成された超伝導膜
とを備えたジョセフソン接合素子。(1) An inorganic material crystal formed by generating a nucleus at a desired position on a substrate and growing a crystal around this nucleus;
A Josephson junction element comprising a superconducting film formed on a substrate having this inorganic material crystal.
に前記核を生成させた請求項１記載のジョセフソン接合
素子。(2) The Josephson junction element according to claim 1, wherein a recess is formed at a desired position on the substrate surface, and the nucleus is generated in the recess.
さい非核形成面と、単一核のみより結晶成長するに充分
小さい面積を有し、前記非核形成面の核形成密度より大
きい核形成密度を有する核形成面とを有し、この核形成
面に前記核を生成させた請求項１記載のジョセフソン接
合素子。(3) The substrate has a non-nucleation surface with a low nucleation density, which is arranged adjacent to the substrate, and an area that is sufficiently smaller for crystal growth than a single nucleus, and has a nucleation density larger than the nucleation density of the non-nucleation surface. 2. The Josephson junction device according to claim 1, further comprising a nucleation surface having a nucleation density, and said nuclei are generated on said nucleation surface.
わすとき、ＡがＬａ、Ｃｅ、Ｐｒ、Ｎｄ、Ｐｍ、Ｓｍ、
Ｓｃ、Ｅｕ、Ｇｄ、Ｔｂ、Ｄｙ、Ｈｏ、Ｅｒ、Ｔｍ、Ｙ
ｂ、Ｌｕ、Ｂｉ、ＴｌおよびＹよりなる群より選ばれた
一種以上の元素；ＢがＢａ、Ｃａ、ＳｒおよびＰｂより
なる群から選ばれた一種以上の元素；ＣがＶ、Ｔｉ、Ｃ
ｒ、Ｍｎ、Ｆｅ、Ｎｉ、Ｃｏ、Ａｇ、ＣｄおよびＣｕよ
りなる群から選ばれた一種以上の元素；ＤがＳおよびＯ
よりなる群から選ばれた一種以上の元素である請求項１
記載のジョセフソン接合素子。(4) When the compound composition of the superconducting film is expressed as A-B-C-D, A is La, Ce, Pr, Nd, Pm, Sm,
Sc, Eu, Gd, Tb, Dy, Ho, Er, Tm, Y
b, one or more elements selected from the group consisting of Lu, Bi, Tl and Y; B is one or more elements selected from the group consisting of Ba, Ca, Sr and Pb; C is V, Ti, C
one or more elements selected from the group consisting of r, Mn, Fe, Ni, Co, Ag, Cd and Cu; D is S and O
Claim 1 is one or more elements selected from the group consisting of
Josephson junction device as described.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2061105A JP2690588B2 (en) | 1990-03-14 | 1990-03-14 | Josephson junction element |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2061105A JP2690588B2 (en) | 1990-03-14 | 1990-03-14 | Josephson junction element |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH03263883A true JPH03263883A (en) | 1991-11-25 |
| JP2690588B2 JP2690588B2 (en) | 1997-12-10 |
Family
ID=13161468
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2061105A Expired - Fee Related JP2690588B2 (en) | 1990-03-14 | 1990-03-14 | Josephson junction element |
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| Country | Link |
|---|---|
| JP (1) | JP2690588B2 (en) |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6414977A (en) * | 1987-07-09 | 1989-01-19 | Matsushita Electric Ind Co Ltd | Superconducting device and manufacture thereof |
| JPH01203293A (en) * | 1988-02-08 | 1989-08-16 | Canon Inc | Formation of diamond crystal |
| JPH0244786A (en) * | 1988-08-05 | 1990-02-14 | Canon Inc | Manufacture of josephson element |
-
1990
- 1990-03-14 JP JP2061105A patent/JP2690588B2/en not_active Expired - Fee Related
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6414977A (en) * | 1987-07-09 | 1989-01-19 | Matsushita Electric Ind Co Ltd | Superconducting device and manufacture thereof |
| JPH01203293A (en) * | 1988-02-08 | 1989-08-16 | Canon Inc | Formation of diamond crystal |
| JPH0244786A (en) * | 1988-08-05 | 1990-02-14 | Canon Inc | Manufacture of josephson element |
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| Publication number | Publication date |
|---|---|
| JP2690588B2 (en) | 1997-12-10 |
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