JPH01161786A - Superconducting device - Google Patents
Superconducting deviceInfo
- Publication number
- JPH01161786A JPH01161786A JP62318772A JP31877287A JPH01161786A JP H01161786 A JPH01161786 A JP H01161786A JP 62318772 A JP62318772 A JP 62318772A JP 31877287 A JP31877287 A JP 31877287A JP H01161786 A JPH01161786 A JP H01161786A
- Authority
- JP
- Japan
- Prior art keywords
- film
- oxide superconductor
- superconducting element
- metal film
- josephson junction
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 239000002887 superconductor Substances 0.000 claims abstract description 30
- 229910052751 metal Inorganic materials 0.000 claims abstract description 19
- 239000002184 metal Substances 0.000 claims abstract description 19
- 239000004065 semiconductor Substances 0.000 claims abstract description 17
- 239000000758 substrate Substances 0.000 claims abstract description 10
- 239000010931 gold Substances 0.000 claims description 4
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 claims description 4
- 229910052761 rare earth metal Inorganic materials 0.000 claims description 3
- 229910052692 Dysprosium Inorganic materials 0.000 claims description 2
- 229910052691 Erbium Inorganic materials 0.000 claims description 2
- 229910052693 Europium Inorganic materials 0.000 claims description 2
- 229910052689 Holmium Inorganic materials 0.000 claims description 2
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 claims description 2
- 229910052769 Ytterbium Inorganic materials 0.000 claims description 2
- 230000002950 deficient Effects 0.000 claims description 2
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical group [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 claims description 2
- 229910052737 gold Inorganic materials 0.000 claims description 2
- 229910052741 iridium Inorganic materials 0.000 claims description 2
- GKOZUEZYRPOHIO-UHFFFAOYSA-N iridium atom Chemical compound [Ir] GKOZUEZYRPOHIO-UHFFFAOYSA-N 0.000 claims description 2
- 229910052758 niobium Inorganic materials 0.000 claims description 2
- 239000010955 niobium Substances 0.000 claims description 2
- GUCVJGMIXFAOAE-UHFFFAOYSA-N niobium atom Chemical group [Nb] GUCVJGMIXFAOAE-UHFFFAOYSA-N 0.000 claims description 2
- 229910052697 platinum Inorganic materials 0.000 claims description 2
- 229910052709 silver Inorganic materials 0.000 claims description 2
- 239000004332 silver Substances 0.000 claims description 2
- 229910052715 tantalum Inorganic materials 0.000 claims description 2
- GUVRBAGPIYLISA-UHFFFAOYSA-N tantalum atom Chemical compound [Ta] GUVRBAGPIYLISA-UHFFFAOYSA-N 0.000 claims description 2
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 claims description 2
- 229910052721 tungsten Inorganic materials 0.000 claims description 2
- 239000010937 tungsten Substances 0.000 claims description 2
- 229910052727 yttrium Inorganic materials 0.000 claims description 2
- 229910052765 Lutetium Inorganic materials 0.000 claims 1
- 229910052775 Thulium Inorganic materials 0.000 claims 1
- VEALVRVVWBQVSL-UHFFFAOYSA-N strontium titanate Chemical group [Sr+2].[O-][Ti]([O-])=O VEALVRVVWBQVSL-UHFFFAOYSA-N 0.000 claims 1
- 230000008878 coupling Effects 0.000 abstract description 11
- 238000010168 coupling process Methods 0.000 abstract description 11
- 238000005859 coupling reaction Methods 0.000 abstract description 11
- 239000013078 crystal Substances 0.000 abstract description 5
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 abstract description 4
- 241000238366 Cephalopoda Species 0.000 abstract description 3
- 239000007788 liquid Substances 0.000 abstract description 3
- 229910052757 nitrogen Inorganic materials 0.000 abstract description 2
- 229910003097 YBa2Cu3O7−δ Inorganic materials 0.000 abstract 3
- 229910002370 SrTiO3 Inorganic materials 0.000 abstract 1
- 239000010408 film Substances 0.000 description 44
- 230000004907 flux Effects 0.000 description 6
- 238000010586 diagram Methods 0.000 description 4
- 238000005516 engineering process Methods 0.000 description 4
- 238000000034 method Methods 0.000 description 3
- 230000020169 heat generation Effects 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 150000002739 metals Chemical class 0.000 description 2
- 239000010409 thin film Substances 0.000 description 2
- KZBUYRJDOAKODT-UHFFFAOYSA-N Chlorine Chemical compound ClCl KZBUYRJDOAKODT-UHFFFAOYSA-N 0.000 description 1
- 229910000846 In alloy Inorganic materials 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000000151 deposition Methods 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000002845 discoloration Methods 0.000 description 1
- 238000001312 dry etching Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 239000001307 helium Substances 0.000 description 1
- 229910052734 helium Inorganic materials 0.000 description 1
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 description 1
- 239000012212 insulator Substances 0.000 description 1
- 229910000765 intermetallic Inorganic materials 0.000 description 1
- 238000003475 lamination Methods 0.000 description 1
- 238000001459 lithography Methods 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229910000510 noble metal Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 238000000059 patterning Methods 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 238000004088 simulation Methods 0.000 description 1
- 238000004544 sputter deposition Methods 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
- 230000002123 temporal effect Effects 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
Abstract
Description
【発明の詳細な説明】
［発明の目的］
（産業上の利用分野）
本発明は、酸化物超電導体膜を用いて構成されたジョセ
フソン接合をもち、位相モードで動作する超電導素子に
関する。DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a superconducting element having a Josephson junction constructed using an oxide superconductor film and operating in a phase mode.
（従来の技術）
超高密度電子素子や超高速電子素子の開発は、これまで
、シリコンおよび化合物半導体を中心として進められて
来た。従来の半導体素子の高密度化、高速化は、高度の
微細加工技術、均質で完全性の高い結晶作成技術および
シミュレーションを利用した素子設計技術によりなし遂
げられてきた。(Prior Art) The development of ultra-high-density electronic devices and ultra-high-speed electronic devices has so far focused on silicon and compound semiconductors. High density and high speed conventional semiconductor devices have been achieved through advanced microfabrication technology, homogeneous and highly perfect crystal creation technology, and device design technology using simulation.
半導体素子の更なる高密度化、高速化を図る上で今後ま
すます重要になる問題は、発熱である゛。これは、結晶
の完全性や微細加工技術とは別に、半導体素子の高密度
化や高速化の限界を与える大きい要因になると考えられ
る。Heat generation is an issue that will become increasingly important in the future as the density and speed of semiconductor devices are further increased. This is considered to be a major factor that limits the ability to increase the density and speed of semiconductor devices, in addition to crystal perfection and microfabrication technology.
電子素子の発熱の点で、半導体素子に比べて優れている
のは、ジョセフソン接合素子に代表される超電導素子で
ある。しかし、超電導素子はこれまでのところ、本格的
な実用化の目途が立っていない、その理由は、液体ヘリ
ウム温度という超低温でないと動作しないこと、超電導
材料として金属或いは金属間化合物を用いるため酸化さ
れ易いこと、ジョセフソン接合素子の場合は、その絶縁
膜として用いる金属酸化物の時間的、空間的−様性が得
られないこと、等にある。Superconducting devices, such as Josephson junction devices, are superior to semiconductor devices in terms of heat generation. However, so far, there is no prospect of full-scale practical use of superconducting elements.The reason is that they only operate at extremely low temperatures, such as the temperature of liquid helium, and because they use metals or intermetallic compounds as superconducting materials, they cannot be oxidized. In the case of a Josephson junction element, the temporal and spatial characteristics of the metal oxide used as the insulating film cannot be obtained.
最近発見された、希土類元素を含有するペロブスカイト
構造の酸化物超電導体は、高い臨界温度をもち、これら
のジョセフソン接合素子の欠点を解消するものとして期
待されている。しかしながら、酸化物超電導体は８００
℃以上の高温での熱処理が必要であるため、酸化物超電
導体／絶縁体／酸化物超電導体のトンネル接合を制御性
よく形成することが困難である。そこで、酸化物超電導
体膜のパターンによって、二つの超電導体バンク部とこ
れらを量子力学的に弱結合する弱結合部を構成する、弱
結合ジョセフソン素子が考えられる。Recently discovered oxide superconductors with a perovskite structure containing rare earth elements have a high critical temperature and are expected to overcome the drawbacks of these Josephson junction devices. However, oxide superconductors have 800
Since heat treatment at a high temperature of .degree. C. or higher is required, it is difficult to form an oxide superconductor/insulator/oxide superconductor tunnel junction with good controllability. Therefore, a weakly coupled Josephson element can be considered in which a pattern of an oxide superconductor film constitutes two superconductor bank parts and a weak coupling part that weakly couples them quantum mechanically.
しかしながら酸化物超電導体は、コヒーレンス長がＣ軸
方向で１０人程度、Ｃ面内でも１００人程変色極めて短
い。従って上述のような弱結合のジョセフソン接合を形
成するためには、［１００Å以下の微細加工技術が必要
であり、現在のりソグラフィ技術では不可能である。However, the coherence length of oxide superconductors is about 10 in the C-axis direction, and the discoloration is extremely short by about 100 in the C-plane. Therefore, in order to form a weakly coupled Josephson junction as described above, a microfabrication technique of 100 Å or less is required, which is impossible with the current lamination lithography technique.
一方、酸化物超電導体膜／金属膜／酸化物超電導体膜、
或いは酸化物超電導体膜／半導体膜／酸化物超電導体膜
の積層構造により弱結合ジョセフソン接合を形成するこ
ともできる。この場合は、弱結合部を構成する金属膜ま
たは半導体膜の厚みを数１００人〜数１０００人とする
ことで、比較的制御性よく形成することができる。しか
しこの構造では、オフ時の抵抗が低いため、通常の電圧
モー″ド・ジョセフソン素子には使用できない。On the other hand, oxide superconductor film/metal film/oxide superconductor film,
Alternatively, a weakly coupled Josephson junction can be formed using a laminated structure of oxide superconductor film/semiconductor film/oxide superconductor film. In this case, by setting the thickness of the metal film or semiconductor film constituting the weak coupling portion to several hundred to several thousand layers, it is possible to form the weak coupling portion with relatively good controllability. However, this structure cannot be used as a normal voltage-mode Josephson device because its off-state resistance is low.
（発明が解決しようとする問題点）
以上のｊうに超電導素子は、発熱が少ない点で従来の半
導体素子の高密度化や高速化の限界を越えるものとして
注目されるが、主として材料特性による制約から実用化
に至っていない。(Problems to be Solved by the Invention) The above-described superconducting device is attracting attention as a device that exceeds the limits of high density and high speed of conventional semiconductor devices in that it generates little heat, but it is mainly limited by material properties. Since then, it has not been put into practical use.
本発明は上記の点に鑑み、液体窒素温度以上の高温で動
作可能で、安定な動作をする超電導素子を提供すること
を目的とする。In view of the above points, it is an object of the present invention to provide a superconducting element that can operate at a high temperature higher than the liquid nitrogen temperature and operates stably.
［発明の構成コ
（問題点を解決するための手段）
本発明にかかる超電導素子は、位相モードで動作するジ
ョセフソン接合素子であって、ジョセフソン接合を、基
板上に形成された酸化物超電導体膜／金属膜または半導
体膜／酸化物超電導体膜の積層構造により構成したこと
を特徴とする。[Configuration of the Invention (Means for Solving the Problems) The superconducting device according to the present invention is a Josephson junction device that operates in a phase mode, in which the Josephson junction is formed using an oxide superconductor formed on a substrate. It is characterized by having a laminated structure of body film/metal film or semiconductor film/oxide superconductor film.
本発明における酸化物超電導体膜としては、希土類元素
を含むペロブスカイト構造の各種酸化物を用い得る。金
属膜としては、金、銀、白金等の貴金属、ニオブ、タン
タル、タングステン、イリジウムなどの高融点金属が好
ましい。As the oxide superconductor film in the present invention, various oxides having a perovskite structure containing rare earth elements can be used. As the metal film, noble metals such as gold, silver, and platinum, and high melting point metals such as niobium, tantalum, tungsten, and iridium are preferable.
（作用）
酸化物超電導体膜／金属膜または半導体膜／酸化物超電
導体膜の積層構造からなるジョセフソン接合は、金属膜
または半導体膜のコヒーレンス長が大きいために１μｍ
程度以下で弱結合部を構成することができる。従って微
細加工を要せず、高温で動作し、且つ安定したジョセフ
ソン接合特性を示す。ただこの積層構造は、絶縁膜を用
いたものと異なり、オフ時の抵抗が数１０μΩ以下と極
めて小さい。そのため、電圧モードで用いることはでき
ない。本発明ではこの様な積層構造のジョセフソン接合
を用い、磁束量子を信号媒体とする動作モード即ち、フ
ラクソイドの運動時のみ電圧が発生する位相モードで動
作させることにより、安定した特性を示す低消費電力の
超電導素子が得られる。(Function) A Josephson junction consisting of a stacked structure of oxide superconductor film/metal film or semiconductor film/oxide superconductor film has a coherence length of 1 μm due to the large coherence length of the metal film or semiconductor film.
It is possible to form a weak coupling portion with less than a certain degree. Therefore, it does not require microfabrication, operates at high temperatures, and exhibits stable Josephson junction characteristics. However, unlike those using insulating films, this laminated structure has an extremely low resistance of several tens of μΩ or less when off. Therefore, it cannot be used in voltage mode. In the present invention, a Josephson junction with such a laminated structure is used, and by operating in an operation mode in which magnetic flux quanta are used as a signal medium, that is, in a phase mode in which voltage is generated only when the fluxoid moves, low power consumption with stable characteristics can be achieved. A power superconducting element is obtained.
（実施例） 以下、本発明の詳細を図面を参照して説明する。(Example) Hereinafter, details of the present invention will be explained with reference to the drawings.
具体的な実施例の説明に先だって、本発明で用いる位相
モード超電導素子即ちフラクソイド論理回路の原理を、
第５図および第６図により説明する。前述のように本発
明でのジョセフソン接合はオフ時の抵抗が低いため、電
圧モードでは動作できない。第５図に示すように、弱結
合ジョセフソン接合Ｓに対してインダクタンスＬを負荷
として接続した論理回路を構成すると、フラクソイド（
端子電圧の時間積分）に対して電流は第６図のように変
化する。従って、Ａ点とＢ点を安定点として、電力を消
費することなく論理動作ができる。Prior to explaining specific embodiments, the principle of the phase mode superconducting element, that is, the fluxoid logic circuit used in the present invention, will be explained as follows.
This will be explained with reference to FIGS. 5 and 6. As described above, the Josephson junction according to the present invention has a low resistance when off, so it cannot operate in voltage mode. As shown in Fig. 5, when a logic circuit is constructed in which an inductance L is connected as a load to a weakly coupled Josephson junction S, a fluxoid (
The current changes as shown in FIG. 6 with respect to the time integral of the terminal voltage. Therefore, with point A and point B as stable points, logic operations can be performed without consuming power.
これが位相モード論理回路の原理である。This is the principle of phase mode logic circuits.
第１図は、一実施例の論理回路であ、す、２個の直流ス
クイド（ｄｃｓＱＵ Ｉ Ｄ）Ｑｌ、Ｑ２を構成し、こ
れらを抵抗結合したものである。第１図は概略平面図で
あり、第２図はそのＡ−Ａ−断面図である。基板１はこ
の実施例ではＳｒ Ｔｉ ０３結晶基板であり、この上
に酸化物超電導体膜としてＹ Ｂ ａ２ Ｃｕｉ Ｏ７
−Ｊ膜を用いて回路が構成されている。即ち、二つのｄ
ｃｓ ＱＵ Ｉ Ｄ−Ｑｌ 、 Ｑ２を構成する超電
導ループは、第１のＹ Ｂ ａ２ ＣＬ１３Ｏ７−４膜
２と第２のＹ Ｂ ａ２ Ｃｕｓ Ｏ７−４膜４により
形成されている。これらの膜形成は、酸素含有率２５％
のＡｒガス雰囲気中（１０ｍ ｔｏｒｒ）で、基板を６
５０℃に加熱した状態でスパッタリングにより行い、こ
れをＥＢレジストを用いて塩素ガスを含むドライエツチ
ングによりパターン形成する。各超電導ループの線幅は
２０μｍである。一方のｄｃｓＱＵＩＤ−Ｑｌを構成す
るループ内には二つのジョセフソン接合Ｊｌ、Ｊ２が形
成され、他方のｄ＋ｅｓＱＵＩＤ−Ｑ２を構成するルー
プ内にも同様にジョセフソン接合Ｊ３．Ｊ４が形成され
ている。各ジョセフソン接合部は、第２図に示したよう
に第１のＹ Ｂ ａｚｃ ｕ３Ｏ７−Ｊ膜２のパターン
形成された端部に上に金属膜としてＡｕｕｓを積層し、
更にこの上に第２のＹ Ｂ ａ２ｃ ｕ、、０□−６膜
４のパターン形成された端部が積層された構造としてい
る。Ａｕｕｓは、一方のｄｃｓＱＵＩＤ−Ｑｌ側で８０
０人とし、他方のｄｅｓＱＵＩＤ−Ｑ２側では１７００
人としている。二つのｄｅＳＱＵＩＤ−Ｑｌ、Ｑ２は、
結合抵抗Ｒにより結合されている。FIG. 1 shows a logic circuit of one embodiment, which includes two DC SQUIDs Q1 and Q2, which are resistance-coupled. FIG. 1 is a schematic plan view, and FIG. 2 is a sectional view taken along the line AA. In this example, the substrate 1 is a Sr Ti 03 crystal substrate, on which Y B a2 Cui O7 is deposited as an oxide superconductor film.
-A circuit is constructed using the J film. That is, two d
The superconducting loop constituting cs QUID-Ql, Q2 is formed by the first YBa2 CL13O7-4 film 2 and the second YBa2 Cus O7-4 film 4. These films are formed at an oxygen content of 25%.
In an Ar gas atmosphere (10 m torr), the substrate was
Sputtering is performed in a state heated to 50° C., and a pattern is formed using an EB resist by dry etching containing chlorine gas. The line width of each superconducting loop is 20 μm. Two Josephson junctions Jl and J2 are formed in the loop constituting one dcsQUID-Q1, and similarly Josephson junctions J3. J4 is formed. Each Josephson junction is formed by depositing Auus as a metal film on the patterned end of the first YBazc u3O7-J film 2 as shown in FIG.
Furthermore, the patterned end portion of the second YBa2cu, 0□-6 film 4 is laminated thereon. Auus is 80 on one dcsQUID-Ql side
0 people, and 1700 people on the other desQUID-Q2 side.
I'm with people. The two deSQUID-Ql, Q2 are
They are coupled by a coupling resistor R.
結合抵抗Ｒはこの実施例では、Ａｕｌｎ合金膜５により
形成している。各ｄｅＳＱＵＩＤ−Ｑｌ。In this embodiment, the coupling resistor R is formed of an Auln alloy film 5. Each deSQUID-Ql.
Ｑ２の電流端子部は、Ｙ Ｂ ａ２ Ｃ０３Ｏ７−Ｊ膜
２，４をパッド状にパターン形成し、ここに図では省略
したが端子電極を形成している。各ｄｃｓ、ＱＵＩＤＱ
ｌおよびＱ２の臨界磁界ＬＩｃはそれぞれ、磁束量子を
Φ。とじて、１．８Φ０および０．３Φ０であった。The current terminal portion of Q2 is formed by patterning the YB a2 C03O7-J films 2 and 4 into a pad shape, and a terminal electrode is formed here, although not shown in the figure. Each dcs, QUIDQ
The critical magnetic fields LIc of l and Q2 each define a flux quantum of Φ. The total diameter was 1.8Φ0 and 0.3Φ0.
第３図は、この様に構成された位相モード超電導論理回
路の等価回路である。この論理回路では、各ｄｃｓＱ
ＩＵＤ−Ｑ＋ 、Ｑ２ゲート電流を制御することによっ
て、一方に侵入した磁束を結合抵抗Ｒを介して他方に転
送する、という動作ができる。FIG. 3 shows an equivalent circuit of the phase mode superconducting logic circuit constructed in this manner. In this logic circuit, each dcsQ
By controlling the IUD-Q+ and Q2 gate currents, it is possible to transfer the magnetic flux that has entered one to the other via the coupling resistor R.
スタティック方法によりこの論理動作を確認した実験結
果を説明する。先ず、左側のｄｃｓＱＵＩＤ−Ｑｔにゲ
ート電流１ｇｂを与え、ｎ−０の状態に設定する。次い
でゲート電流１ ｇｃを印加することにより、このｄｃ
ｓＱＵＩＤ−Ｑｌは、ｎ−１の状態にスイッチする。こ
れは、左側のジョセフソン接合Ｊ１から磁束が侵入した
ことを示す。次に、Ｉ ｇｃを０に戻すと、ジョセフソ
ン接合Ｊ２から磁束が追出され、他方のｄｅｓＱＵＩＤ
−Ｑ２に侵入する。各ｄｃｓ ＱＵ Ｉ Ｄ−Ｑｌ、
Ｑ２内の磁束の有無は、第４図に示すしきい値特性を観
測することにより、確認できた。We will explain the experimental results that confirmed this logical operation using a static method. First, a gate current of 1 GB is applied to the left dcsQUID-Qt to set it to the n-0 state. Then, by applying a gate current of 1 gc, this dc
sQUID-Ql switches to state n-1. This indicates that magnetic flux has entered from the Josephson junction J1 on the left. Then, returning I gc to 0 forces the flux out of Josephson junction J2 and forces the other desQUID
- Infiltrate Q2. Each dcs QU I D-Ql,
The presence or absence of magnetic flux in Q2 could be confirmed by observing the threshold characteristics shown in FIG.
こうしてこの実施例によれば、二つの
ｄｃｓＱＵＩＤを抵抗結合した、位相モードで動作する
フラクソイド論理回路が得られる。この実施例によれば
、ジョセフソン接合を構成する弱結合部が金属膜である
ため、オフ時の抵抗が低いが、位相モードにより電力を
消費することなく、論理動作を行うことができる。そし
て薄いトンネル絶縁膜によりジョセフソン接合を構成す
る場合に比べ、製造は容易である。Thus, according to this embodiment, a fluxoid logic circuit operating in phase mode is obtained in which two dcsQUIDs are resistively coupled. According to this embodiment, since the weak coupling portion constituting the Josephson junction is a metal film, the resistance during off-state is low, but logic operation can be performed without consuming power due to the phase mode. Furthermore, manufacturing is easier than in the case where a Josephson junction is formed using a thin tunnel insulating film.
本発明は上記実施例に限られるものではない。例えば酸
化物超電導体薄膜として、一般にＡ Ｂ ａ２ｃ ｕ３
Ｏ ｔ−ａ （Ａは、Ｙ、Ｙｂ、Ｈｏ、Ｄｙ。The present invention is not limited to the above embodiments. For example, as an oxide superconductor thin film, generally A B a2c u3
O ta (A is Y, Yb, Ho, Dy.
Ｅｕ、 Ｅｒ、Ｔｎ＋、Ｌｕから選ばれた一種）で表わ
される欠陥ペロブスカイト型酸化物を用いることができ
る。また、（Ｓｒ＋−ｘＬａｘ） ２ Ｃｕ ０４−ｙ
（但し、ＳｒをＢａ、Ｃａで置換したものを含む）で表
わされる層状ペロブスカイト型酸化物を用いることもで
きる。弱結合部は金属膜に代って半導体膜を用いること
も可能である。A defective perovskite type oxide represented by a type selected from Eu, Er, Tn+, and Lu can be used. Also, (Sr+-xLax) 2 Cu 04-y
(However, layered perovskite-type oxides represented by oxides such as those in which Sr is replaced with Ba or Ca) can also be used. It is also possible to use a semiconductor film instead of a metal film for the weak coupling portion.
その他事発明は、その趣旨を逸脱しない範囲で種々変形
して実施することができる。Other aspects of the invention can be implemented with various modifications without departing from the spirit thereof.
［発明の効果コ
以上述べたように本発明によれば、酸化物超電導体薄膜
／金属膜または半導体膜／酸化物超電導体膜の積層構造
によるジョセフソン接合を用いて位相モード論理回路を
構成することにより、製造が容易で、高温で安定な特性
を示す低消費電力の超電導素子を得ることができる。[Effects of the Invention] As described above, according to the present invention, a phase mode logic circuit is constructed using a Josephson junction with a laminated structure of oxide superconductor thin film/metal film or semiconductor film/oxide superconductor film. As a result, it is possible to obtain a superconducting element that is easy to manufacture and has low power consumption and exhibits stable characteristics at high temperatures.
第１図は本発明の一実施例の超電導論理回路素子を示す
平面図、第２図は第１図のＡ−Ａ−断面図、第３図はそ
の論理回路の等価回路図、第４図はその論理回路の動作
を説明するための図、第５図はフラクソイド論理回路の
原理を説明するための等価回路図、第６図はその特性を
示す図である。
１・−３ｒＴｉ０３結晶基板、２．４−・・Ｙ Ｂ ａ
２ Ｃｕｉ Ｏｔ−ａ膜、３− Ａ ｕ膜、５・＝Ａｕ
Ｉｎ合金膜、Ｑ１＊ ０２ ”’ｄｅＳ ＱＵ Ｉ Ｄ
ｌＪ １〜Ｊ４・・・ジョセフソン接合、Ｒ・・・結合
抵抗。
出願人代理人 弁理士 鈴江武彦FIG. 1 is a plan view showing a superconducting logic circuit element according to an embodiment of the present invention, FIG. 2 is a sectional view taken along line A-A in FIG. 1, FIG. 3 is an equivalent circuit diagram of the logic circuit, and FIG. is a diagram for explaining the operation of the logic circuit, FIG. 5 is an equivalent circuit diagram for explaining the principle of the fluxoid logic circuit, and FIG. 6 is a diagram showing its characteristics. 1.-3rTi03 crystal substrate, 2.4-...Y Ba
2 Cui Ot-a film, 3- Au film, 5・=Au
In alloy film, Q1*02”'deS QU I D
lJ 1-J4...Josephson junction, R...coupling resistance. Applicant's agent Patent attorney Takehiko Suzue
Claims (7)
超電導素子において、前記ジョセフソン接合は、基板上
に酸化物超電導体膜／金属膜または半導体膜／酸化物超
電導体膜の積層構造により構成されていることを特徴と
する超電導素子。(1) In a superconducting element having a Josephson junction and operating in a phase mode, the Josephson junction is formed by a laminated structure of an oxide superconductor film/metal film or a semiconductor film/oxide superconductor film on a substrate. A superconducting element characterized by:
記酸化物超電導体膜は希土類元素を含むペロブスカイト
型酸化物である特許請求の範囲第１項記載の超電導素子
。(2) The superconducting element according to claim 1, wherein the substrate is strontium titanate, and the oxide superconductor film is a perovskite oxide containing a rare earth element.
Ｈｏ、Ｄｙ、Ｅｕ、Ｅｒ、Ｔｍ、Ｌｕから選ばれた一種
）で表わされる欠陥ペロブスカイト型酸化物である特許
請求の範囲第１項記載の超電導素子。(3) The oxide superconductor film has ABa_2Cu_3O_7_-_δ (A is Y, Yb,
The superconducting element according to claim 1, which is a defective perovskite-type oxide represented by one selected from Ho, Dy, Eu, Er, Tm, and Lu.
で表わされる層状ペロブスカイト型酸化物である特許請
求の範囲第１項記載の超電導素子。(4) The oxide superconductor film is (Sr_1_-_xLa_x)_2CuO_4_-_y
The superconducting element according to claim 1, which is a layered perovskite type oxide represented by:
５０００Åである特許請求の範囲第１項記載の超電導素
子。(5) The metal film or semiconductor film has a film thickness of 1000 to
The superconducting element according to claim 1, which has a thickness of 5000 Å.
の範囲第１項記載超電導素子。(6) The superconducting element according to claim 1, wherein the metal film is gold, silver, or platinum.
またはイリジウムである特許請求の範囲第１項記載超電
導素子。(7) The superconducting element according to claim 1, wherein the metal film is niobium, tantalum, tungsten, or iridium.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62318772A JPH01161786A (en) | 1987-12-18 | 1987-12-18 | Superconducting device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62318772A JPH01161786A (en) | 1987-12-18 | 1987-12-18 | Superconducting device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH01161786A true JPH01161786A (en) | 1989-06-26 |
Family
ID=18102775
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP62318772A Pending JPH01161786A (en) | 1987-12-18 | 1987-12-18 | Superconducting device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH01161786A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH098370A (en) * | 1995-06-16 | 1997-01-10 | Hitachi Ltd | Oxide superconducting circuit |
| US5962866A (en) * | 1991-01-22 | 1999-10-05 | Biomagnetic Technologies, Inc. | Microbridge superconductor device utilizing stepped junctions |
| CN106575667A (en) * | 2014-07-02 | 2017-04-19 | 哥本哈根大学 | A semiconductor josephson junction and a transmon qubit related thereto |
-
1987
- 1987-12-18 JP JP62318772A patent/JPH01161786A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5962866A (en) * | 1991-01-22 | 1999-10-05 | Biomagnetic Technologies, Inc. | Microbridge superconductor device utilizing stepped junctions |
| JPH098370A (en) * | 1995-06-16 | 1997-01-10 | Hitachi Ltd | Oxide superconducting circuit |
| CN106575667A (en) * | 2014-07-02 | 2017-04-19 | 哥本哈根大学 | A semiconductor josephson junction and a transmon qubit related thereto |
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