JPH04305985A - Manufacture of superconductive element - Google Patents
Manufacture of superconductive elementInfo
- Publication number
- JPH04305985A JPH04305985A JP3096388A JP9638891A JPH04305985A JP H04305985 A JPH04305985 A JP H04305985A JP 3096388 A JP3096388 A JP 3096388A JP 9638891 A JP9638891 A JP 9638891A JP H04305985 A JPH04305985 A JP H04305985A
- Authority
- JP
- Japan
- Prior art keywords
- gas
- thin film
- etching
- oxide superconductor
- superconductor thin
- 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
- 238000004519 manufacturing process Methods 0.000 title claims description 6
- 239000010409 thin film Substances 0.000 claims abstract description 40
- 238000000034 method Methods 0.000 claims abstract description 33
- 238000005530 etching Methods 0.000 claims abstract description 31
- 239000000758 substrate Substances 0.000 claims abstract description 11
- 239000002887 superconductor Substances 0.000 claims description 40
- 238000001312 dry etching Methods 0.000 claims description 7
- 239000007789 gas Substances 0.000 abstract description 67
- 239000010408 film Substances 0.000 abstract description 8
- 239000000203 mixture Substances 0.000 abstract description 8
- 239000003990 capacitor Substances 0.000 abstract description 2
- 239000012495 reaction gas Substances 0.000 abstract description 2
- 239000013078 crystal Substances 0.000 description 5
- 238000010586 diagram Methods 0.000 description 5
- 125000001153 fluoro group Chemical group F* 0.000 description 5
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 4
- 125000004430 oxygen atom Chemical group O* 0.000 description 4
- 230000000052 comparative effect Effects 0.000 description 3
- 230000007547 defect Effects 0.000 description 3
- 238000001020 plasma etching Methods 0.000 description 3
- KZBUYRJDOAKODT-UHFFFAOYSA-N Chlorine Chemical compound ClCl KZBUYRJDOAKODT-UHFFFAOYSA-N 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- 238000004544 sputter deposition Methods 0.000 description 2
- 238000001039 wet etching Methods 0.000 description 2
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 1
- 229910002480 Cu-O Inorganic materials 0.000 description 1
- 229910052691 Erbium Inorganic materials 0.000 description 1
- 229910052689 Holmium Inorganic materials 0.000 description 1
- 229910002370 SrTiO3 Inorganic materials 0.000 description 1
- 238000002441 X-ray diffraction Methods 0.000 description 1
- 125000004429 atom Chemical group 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 238000005229 chemical vapour deposition Methods 0.000 description 1
- 239000000460 chlorine Substances 0.000 description 1
- 229910052801 chlorine Inorganic materials 0.000 description 1
- 238000000151 deposition Methods 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000010849 ion bombardment Methods 0.000 description 1
- 238000010884 ion-beam technique Methods 0.000 description 1
- 229910052747 lanthanoid Inorganic materials 0.000 description 1
- 150000002602 lanthanoids Chemical group 0.000 description 1
- 238000001755 magnetron sputter deposition Methods 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 238000005240 physical vapour deposition Methods 0.000 description 1
- 238000000992 sputter etching Methods 0.000 description 1
Landscapes
- Superconductor Devices And Manufacturing Methods Thereof (AREA)
Abstract
Description
【０００１】0001
【産業上の利用分野】本発明は、超電導特性に優れた超
電導素子を製造する方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a superconducting element having excellent superconducting properties.
【０００２】0002
【従来の技術】近年、液体窒素温度で超電導を示す酸化
物超電導体が見出され、電子デバイス等の多くの分野で
応用研究がなされている。ところで、酸化物超電導体を
集積回路装置等の電子デバイスに応用するには、酸化物
超電導体薄膜を微細加工する技術開発が不可欠であり、
例えばドライエッチング法やウエットエッチング法等の
応用が研究されている。BACKGROUND OF THE INVENTION In recent years, oxide superconductors that exhibit superconductivity at liquid nitrogen temperatures have been discovered, and applied research is being carried out in many fields such as electronic devices. By the way, in order to apply oxide superconductors to electronic devices such as integrated circuit devices, it is essential to develop technology for microfabrication of oxide superconductor thin films.
For example, applications such as dry etching methods and wet etching methods are being studied.
【０００３】0003
【発明が解決しようとする課題】しかしながら、前述の
方法には、いずれにも問題があり、実用に到ってない。
つまり、ドライエッチング法について言えば、エッチン
グガスに適当なガスがなく、例えばＣＨ４ ガスは、エ
ッチングの際Ｃ，ＣＯ，ＣＯ２ 等のガスが発生し、こ
れらの発生ガスが酸化物超電導体と反応して酸化物超電
導体薄膜の臨界温度（Ｔｃ）を低下させる。又Ｃｌ２
等の塩素系ガスは、酸化物超電導体との間で蒸気圧の低
い化合物を反応生成せしめ、この化合物が回路となる酸
化物超電導体薄膜上にカスとして付着して残ってしまう
。又Ａｒガスは酸化物超電導体薄膜を物理的にエッチン
グするので酸化物超電導体薄膜はダメージを受けて結晶
構造に欠陥を生じてＴｃが低下し、しかもエッチング速
度が遅いというような種々の欠点があった。又、ウエッ
トエッチング法には、エッチング液により酸化物超電導
体薄膜の結晶粒界が損傷して酸化物超電導体薄膜全体が
超電導を示さなくなるという問題があった。[Problems to be Solved by the Invention] However, all of the above-mentioned methods have problems and have not been put to practical use. In other words, regarding the dry etching method, there is no suitable etching gas. For example, CH4 gas generates gases such as C, CO, and CO2 during etching, and these gases react with the oxide superconductor. to lower the critical temperature (Tc) of the oxide superconductor thin film. Also Cl2
These chlorine-based gases react with the oxide superconductor to generate compounds with low vapor pressure, and these compounds remain as residue on the oxide superconductor thin film that forms the circuit. Furthermore, since Ar gas physically etches the oxide superconductor thin film, the oxide superconductor thin film is damaged and defects occur in the crystal structure, resulting in a decrease in Tc and various drawbacks such as slow etching speed. there were. Furthermore, the wet etching method has a problem in that the etching solution damages the crystal grain boundaries of the oxide superconductor thin film, so that the entire oxide superconductor thin film no longer exhibits superconductivity.
【０００４】0004
【課題を解決する為の手段】本発明は、かかる状況に鑑
み、酸化物超電導体薄膜のドライエッチング法における
エッチングガスについて種々研究した結果、エッチング
ガスにＳＦ６ ガスとＯ２ ガスの混合ガスを用いるこ
とにより超電導特性に優れた酸化物超電導体回路パター
ンを形成し得ることを知見し、更に研究を重ねて本発明
を完成するに到ったものである。即ち、本発明は、基板
上に酸化物超電導体薄膜を形成し、この薄膜にドライエ
ッチングを施して回路を形成する超電導素子の製造方法
において、エッチングガスにＳＦ６ ガスとＯ２ ガス
の混合ガスを用いることを特徴とする超電導素子の製造
方法である。[Means for Solving the Problems] In view of the above circumstances, the present invention, as a result of various studies on etching gases in dry etching methods for oxide superconductor thin films, proposes to use a mixed gas of SF6 gas and O2 gas as the etching gas. They found that it was possible to form an oxide superconductor circuit pattern with excellent superconducting properties by using the method, and after further research, they completed the present invention. That is, the present invention provides a method for manufacturing a superconducting element in which an oxide superconductor thin film is formed on a substrate and a circuit is formed by performing dry etching on this thin film, in which a mixed gas of SF6 gas and O2 gas is used as an etching gas. This is a method for manufacturing a superconducting element characterized by the following.
【０００５】本発明方法において、エッチングガスにＳ
Ｆ６ ガスとＯ２ ガスの混合ガスを用いることにより
、得られる超電導素子の特性が優れる理由は、ＳＦ６
ガスは、酸化物超電導体薄膜を選択的且つ化学的にエッ
チングするので、エッチング速度が速い上、酸化物超電
導体薄膜が組成的変動や結晶構造欠陥を受けにくいこと
の他に、ＳＦ６ ガスだけを用いると、電流の流れ易い
Ｃｕ−Ｏ原子面のＯ原子の位置する格子点の空孔にＳＦ
６ ガスのＦ原子がトラップされて超電導特性が低下す
るのであるが、ＳＦ６ ガスにＯ２ ガスを混合するの
で、前記のトラップされたＦ原子がＯ原子と置換して超
電導特性の低下が防止されることによるものである。尚
、ＳＦ６ ガスとＯ２ ガスの混合比率は２：１が望ま
しい。その理由はＯ２ ガスの混合比率を上げ過ぎると
十分なエッチング速度が得られなくなり、又ＳＦ６ ガ
スの混合比率を上げ過ぎるとトラップされたＦ原子がＯ
原子と置換されずに酸化物超電導体薄膜中に残り、超電
導特性が低下する為である。In the method of the present invention, S is added to the etching gas.
The reason why the characteristics of the obtained superconducting element are excellent by using a mixed gas of F6 gas and O2 gas is that SF6
Since the gas selectively and chemically etches the oxide superconductor thin film, the etching rate is high, and the oxide superconductor thin film is less susceptible to compositional fluctuations and crystal structure defects. When used, SF is applied to the vacancy at the lattice point where the O atom is located on the Cu-O atomic plane where current easily flows.
6 F atoms in the gas are trapped and the superconducting properties deteriorate, but since O2 gas is mixed with the SF6 gas, the trapped F atoms are replaced with O atoms and the deterioration of the superconducting properties is prevented. This is due to a number of things. Note that the mixing ratio of SF6 gas and O2 gas is preferably 2:1. The reason for this is that if the mixing ratio of O2 gas is increased too much, a sufficient etching rate cannot be obtained, and if the mixing ratio of SF6 gas is increased too much, the trapped F atoms are
This is because they remain in the oxide superconductor thin film without being replaced with atoms, resulting in a decrease in superconducting properties.
【０００６】本発明方法において、基板上に形成する酸
化物超電導体薄膜には、ＹＢａ２ Ｃｕ３ Ｏ７−ｘ
， 及び前記酸化物超電導体のＹをＨｏ，Ｅｒ等のラン
タノイド元素で置換した組成の酸化物超電導体，又はＴ
ｌ２ Ｂａ２ Ｃａ１ Ｃｕ２ Ｏｘ ，Ｔｌ２ Ｂａ
２ Ｃａ２ Ｃｕ３ Ｏ１０−ｙ，Ｂｉ２ Ｓｒ２ Ｃ
ａ１ Ｃｕ２ Ｏｘ ，Ｂｉ２ Ｓｒ２ Ｃａ２ Ｃｕ
３ Ｏ１０−ｙ及びこれらの酸化物超電導体にＰｂを添
加した酸化物超電導体等が用いられる。又基板上に酸化
物超電導体薄膜を形成する方法としては通常のＰＶＤ法
やＣＶＤ法等の任意の方法が用いられる。又上記酸化物
超電導体薄膜に回路パターンを形成する方法としては、
通常の方法、例えば前記酸化物超電導体薄膜上にレジス
ト膜を形成し、回路となす部位以外の酸化物超電導体薄
膜上のレジスト膜を除去してエッチングする方法により
形成されるもので、エッチング方法としては、プラズマ
エッチング法、ＲＩＢＥ（ＲＥＡＣＴＩＶＥ ＩＯＮ
ＢＥＡＭ ＥＴＣＨＩＮＧ）法又はＲＩＥ（ＲＥＡＣＴ
ＩＶＥ ＩＯＮ ＥＴＣＨＩＮＧ） 法等が好適であ
る。In the method of the present invention, the oxide superconductor thin film formed on the substrate contains YBa2 Cu3 O7-x
, and an oxide superconductor having a composition in which Y in the oxide superconductor is replaced with a lanthanide element such as Ho or Er, or T
l2 Ba2 Ca1 Cu2 Ox , Tl2 Ba
2 Ca2 Cu3 O10-y, Bi2 Sr2 C
a1 Cu2 Ox , Bi2 Sr2 Ca2 Cu
3 O10-y and oxide superconductors obtained by adding Pb to these oxide superconductors are used. Further, as a method for forming the oxide superconductor thin film on the substrate, any method such as the usual PVD method or CVD method can be used. Further, as a method for forming a circuit pattern on the oxide superconductor thin film,
It is formed by a normal method, for example, a method in which a resist film is formed on the oxide superconductor thin film and etched by removing the resist film on the oxide superconductor thin film other than the part that will form the circuit. For example, plasma etching method, RIBE (REACTIVE ION
BEAM ETCHING) method or RIE (REACT
IVE ION ETCHING) method etc. are suitable.
【０００７】[0007]
【作用】本発明方法ではドライエッチングのエッチング
ガスにＳＦ６ ガスとＯ２ ガスの混合ガスを用いる。
而して、混合ガスのうちのＳＦ６ ガスにより、酸化物
超電導体薄膜の所定部分が選択的且つ化学的にエッチン
グされて、エッチングが高速度に、且つ前記薄膜に結晶
構造欠陥を生ぜずになされる。又エッチング後の薄膜内
に残存するＦ原子は、Ｏ２ ガスのＯ原子で置換されて
、回路となる酸化物超電導体薄膜部分は組成変動を生ぜ
ず、高い超電導特性が得られる。[Operation] In the method of the present invention, a mixed gas of SF6 gas and O2 gas is used as the etching gas for dry etching. Thus, a predetermined portion of the oxide superconductor thin film is selectively and chemically etched by the SF6 gas in the mixed gas, and the etching is performed at a high speed and without causing crystal structure defects in the thin film. Ru. Further, the F atoms remaining in the thin film after etching are replaced by O atoms of O2 gas, so that the portion of the oxide superconductor thin film that forms the circuit does not undergo compositional fluctuation, and high superconducting properties are obtained.
【０００８】[0008]
【実施例】以下に本発明方法を実施例により詳細に説明
する。
実施例１
基板となすＳｒＴｉＯ３ 板状体の（１００）面上にＹ
Ｂａ２ Ｃｕ３ Ｏ７−ｘ 組成の酸化物超電導体薄膜
をＲＦマグネトロンスパッタリング法により形成した。
前記スパッタリングは、ターゲットにＹＢａ２ Ｃ
ｕ３ Ｏ７−ｘ 組成の焼結体を用い、スパッタリング
ガスにＡｒ１０ｓｃｃｍ／Ｏ２１０ｓｃｃｍ の混合ガ
スを用い、前記ガス圧を４００ｍＴｏｒｒ，基板温度を
７００℃，ＲＦ電力を１５０Ｗ，成膜速度を１Å／ｓｅ
ｃ の条件で行った。次にこの基板上に形成した酸化物
超電導体薄膜を１気圧の酸素雰囲気中で室温に冷却した
。得られた酸化物超電導体薄膜は、厚さが０．５μｍ
で、表面が滑らかな光沢のある黒色を呈するものであっ
た。この薄膜の結晶構造をＸ線回折法により調べたとこ
ろ、（００Ｌ）の回折ピークが検出され、この薄膜は基
板面の垂線方向にＣ軸が配向した結晶膜であることが確
認された。[Examples] The method of the present invention will be explained in detail below using examples. Example 1 Y on the (100) plane of a SrTiO3 plate serving as a substrate.
An oxide superconductor thin film having a composition of Ba2Cu3O7-x was formed by RF magnetron sputtering. The sputtering is performed using YBa2C on the target.
A sintered body having a composition of u3O7-x was used, a mixed gas of Ar10sccm/O210sccm was used as the sputtering gas, the gas pressure was 400mTorr, the substrate temperature was 700°C, the RF power was 150W, and the deposition rate was 1 Å/sec.
It was conducted under the conditions of c. Next, the oxide superconductor thin film formed on this substrate was cooled to room temperature in an oxygen atmosphere of 1 atmosphere. The obtained oxide superconductor thin film has a thickness of 0.5 μm.
The surface was smooth and glossy black. When the crystal structure of this thin film was examined by X-ray diffraction, a diffraction peak of (00L) was detected, and it was confirmed that this thin film was a crystalline film with the C axis oriented in the direction perpendicular to the substrate surface.
【０００９】しかるのち前記酸化物超電導体薄膜上に図
１に示した工程に従って、マイクロブリッジを形成した
。即ち、先ず、基板１上に形成した酸化物超電導体薄膜
２上にレジスト膜３を塗布し（図イ）、次いでこのレジ
スト膜３をプリベーキングのあとフォトマスクを用いて
露光し、現像し、次いでポストベーキングを行って、回
路を形成する部位にマスク４を残し（図ロ）、次いで上
方からＳＦ６ ガスとＯ２ ガスの混合ガスのプラズマ
を照射して露出した酸化物超電導体薄膜部分をエッチン
グして除去した（図ハ）。しかるのち前記マスク４を取
り除いて基板１上に幅４５０μｍ ，長さ６００μｍ
の酸化物超電導体薄膜のマイクロブリッジ５を作製した
。尚、前記マイクロブリッジ５の中央部分に幅２μｍ
，長さ１５μｍ のチャンネル１５を形成した（図ニ）
。Thereafter, a microbridge was formed on the oxide superconductor thin film according to the steps shown in FIG. That is, first, a resist film 3 is coated on the oxide superconductor thin film 2 formed on the substrate 1 (Figure A), and then, after prebaking, this resist film 3 is exposed to light using a photomask and developed. Next, post-baking is performed to leave the mask 4 in the area where the circuit will be formed (Figure 2), and then plasma of a mixed gas of SF6 gas and O2 gas is irradiated from above to etch the exposed oxide superconductor thin film portion. (Fig. C). After that, the mask 4 was removed and a pattern with a width of 450 μm and a length of 600 μm was formed on the substrate 1.
A microbridge 5 of an oxide superconductor thin film was fabricated. In addition, a width of 2 μm is provided at the center portion of the micro bridge 5.
, a channel 15 with a length of 15 μm was formed (Figure 2).
.
【００１０】次に、上述の工程のうちの酸化物超電導体
薄膜をエッチングする工程を図を参照して具体的に説明
する。用いたエッチング装置は、図２に示した平行平板
型スパッタエッチング装置である。この装置はチャンバ
６内に陽極７と、陰極８を兼ねるサンプル載置台９とが
設けられており、陽極７は接地され、陰極８にはコンデ
ンサー１０を介して高周波電源１１が接続されている。
反応ガスは導入口１２を通してチャンバ６内に導入され
、反応後排気口１３から排気される。排気口１３はチャ
ンバ６内の圧力調整の作用も果たす。而して、前記エッ
チング装置内のサンプル載置台９上にサンプル１４を乗
せ、次いでチャンバ６内を排気したのち、エッチングガ
スを導入口１２から導入してチャンバ６内の圧力を１０
ｍＴｏｒｒ に調整した。しかるのち、高周波電力を印
加してエッチングガスをイオン化して、前記酸化物超電
導体薄膜の所定箇所をエッチングして選択的に除去した
。上記の高周波電力は、４００Ｗを超えるとイオン衝撃
によるダメージが生じるので低めの２００Ｗに抑えて行
った。エッチングガスのＳＦ６ ガスとＯ２ ガスの混
合比率は、２：１，１：９，９：１の３通りに変えた。Next, the step of etching the oxide superconductor thin film among the above-mentioned steps will be specifically explained with reference to the drawings. The etching apparatus used was a parallel plate type sputter etching apparatus shown in FIG. In this apparatus, an anode 7 and a sample mounting table 9 which also serves as a cathode 8 are provided in a chamber 6. The anode 7 is grounded, and the cathode 8 is connected to a high frequency power source 11 via a capacitor 10. The reaction gas is introduced into the chamber 6 through the inlet 12 and exhausted through the exhaust port 13 after the reaction. The exhaust port 13 also serves to regulate the pressure within the chamber 6. Then, the sample 14 is placed on the sample mounting table 9 in the etching apparatus, and after the inside of the chamber 6 is evacuated, etching gas is introduced from the inlet 12 to reduce the pressure inside the chamber 6 to 10%.
Adjusted to mTorr. Thereafter, high-frequency power was applied to ionize the etching gas, and predetermined portions of the oxide superconductor thin film were etched and selectively removed. The above-mentioned high frequency power was kept low at 200 W since damage caused by ion bombardment would occur if it exceeded 400 W. The mixing ratio of SF6 gas and O2 gas as etching gases was changed in three ways: 2:1, 1:9, and 9:1.
【００１１】比較例１
エッチングガスにＳＦ６ ガスだけを用いた他は、実施
例１と同じ方法によりマイクロブリッジを形成した。
比較例２
エッチングガスにＣＨ４ ガス又はＣｌ２ ガス又はＡ
ｒガスを用いた他は、実施例１と同じ方法によりそれぞ
れマイクロブリッジを形成した。このようにして作製し
たマイクロブリッジのうち、実施例１でＳＦ６ ガスと
Ｏ２ ガスの混合比率を１：９にしてエッチングしたも
のは、エッチング速度が混合比率を２：１にしてエッチ
ングしたものに比べて１／３と遅く、又混合比率を９：
１にしてエッチングしたものはＦ原子がＯ原子と置換さ
れずに残存した為、Ｔｃが、混合比率を２：１にしてエ
ッチングしたものより３Ｋ程度低下した。又比較例１，
２のマイクロブリッジは、酸化物超電導体薄膜の回路に
組成変動や損傷が生じて、いずれもＴｃが７７Ｋ未満の
低い値のものとなった。実施例１でＳＦ６ ガスとＯ２
ガスの混合比率を２：１にしてエッチングしたマイク
ロブリッジを、図３に示した計測用回路に接続し、７０
Ｈｚのランプ波形電流Ｉを流して、マイクロブリッジ５
のチャンネル１５の両端に掛かる電圧Ｖと、負荷抵抗Ｒ
両端の直流電圧を測定して求めた電流Ｉとをそれぞれオ
シロスコープのＸ軸とＹ軸に入力してＩ−Ｖの関係を表
示した。尚、９．９５ＧＨｚのマイクロ波を照射した状
態でも測定を行った。又マイクロブリッジ回路は液体窒
素中に浸漬して７７Ｋに冷却した。結果は図４に示した
。Comparative Example 1 A microbridge was formed by the same method as in Example 1, except that only SF6 gas was used as the etching gas. Comparative Example 2 Etching gas: CH4 gas or Cl2 gas or A
Each microbridge was formed by the same method as in Example 1 except that r gas was used. Among the microbridges fabricated in this manner, those etched with a mixture ratio of SF6 gas and O2 gas of 1:9 in Example 1 had an etching speed compared to those etched with a mixture ratio of 2:1. and slow to 1/3, and the mixing ratio is 9:
In the case etched with a mixing ratio of 1:1, F atoms remained without being replaced with O atoms, so Tc was lowered by about 3K than in the case etched with a mixing ratio of 2:1. Also, comparative example 1,
In the micro bridges No. 2, compositional fluctuations and damage occurred in the circuit of the oxide superconductor thin film, and both of them had a low Tc value of less than 77K. In Example 1, SF6 gas and O2
The microbridge etched with a gas mixing ratio of 2:1 was connected to the measurement circuit shown in Figure 3, and
A ramp waveform current I of Hz is applied to the micro bridge 5.
The voltage V applied across channel 15 and the load resistance R
The current I obtained by measuring the DC voltage at both ends was input into the X-axis and Y-axis of the oscilloscope, respectively, to display the I-V relationship. Note that measurements were also conducted under the condition of 9.95 GHz microwave irradiation. Further, the microbridge circuit was immersed in liquid nitrogen and cooled to 77K. The results are shown in Figure 4.
【００１２】図４より明らかなように、本発明例品（実
施例１）は、マイクロ波を照射しない時は、ａ１ の線
形を示した。これはジョセフソン素子のＩ−Ｖ特性と一
致するものであった。又この時の臨界電流密度（Ｊｃ）
は、５×１０４ Ａ／ｃｍ２ に相当し、高い値のもの
であった。マイクロ波を照射したときの線形はａ２ で
示したように、シャピロステップｓ１，ｓ２ が観測さ
れた。このシャピロステップの電圧は、照射したマイク
ロ波の周波数により決まる電圧〔（ｈ／２ｅ）・ｎ・ν
＝２０．６μｖ・ｎ〕の位置に出現するもので、マイク
ロブリッジがジョセフソン素子として動作していること
を立証するものである。尚、ＳＦ６ ガスとＯ２ ガス
の混合比率を１：９、又は９：１にしてエッチングした
マイクロブリッジについても、同様のＩ−Ｖ関係線図が
得られた。As is clear from FIG. 4, the product of the present invention (Example 1) exhibited a linear shape of a1 when not irradiated with microwaves. This coincided with the IV characteristic of the Josephson element. Also, the critical current density (Jc) at this time
was equivalent to 5×104 A/cm2, which was a high value. Shapiro steps s1, s2 were observed in the linear shape when the microwave was irradiated, as shown by a2. The voltage of this Shapiro step is determined by the frequency of the irradiated microwave [(h/2e)・n・ν
=20.6 μv·n], which proves that the microbridge operates as a Josephson element. Note that similar IV relationship diagrams were obtained for microbridges etched with a mixture ratio of SF6 gas and O2 gas of 1:9 or 9:1.
【００１３】[0013]
【効果】以上述べたように、本発明方法によれば、ドラ
イエッチングのエッチングガスにＳＦ６ ガスとＯ２
ガスの混合ガスを用いるので、エッチングが高速度で且
つ組成変動を起こさずになされ、従って、超電導特性に
優れた超電導素子を効率よく製造することができ、工業
上顕著な効果を奏する。[Effect] As described above, according to the method of the present invention, SF6 gas and O2 are used as the etching gas for dry etching.
Since a gas mixture is used, etching can be performed at high speed and without causing compositional fluctuations. Therefore, superconducting elements with excellent superconducting properties can be efficiently manufactured, and this is a remarkable industrial effect.
【図１】本発明方法の態様例を示す工程説明図である。FIG. 1 is a process explanatory diagram showing an embodiment of the method of the present invention.
【図２】本発明方法で用いるエッチング装置の態様例を
示す要部説明図である。FIG. 2 is an explanatory diagram of main parts showing an embodiment of an etching apparatus used in the method of the present invention.
【図３】マイクロブリッジの超電導特性を計測する為の
回路図である。FIG. 3 is a circuit diagram for measuring superconducting characteristics of a microbridge.
【図４】本発明方法により得られたマイクロブリッジの
Ｉ−Ｖ関係線図である。FIG. 4 is an IV relationship diagram of a microbridge obtained by the method of the present invention.
１ 基板 ２ 酸化物超電導体薄膜 ３ レジスト膜 ４ マスク ５ マイクロブリッジ 1 Board 2 Oxide superconductor thin film 3 Resist film 4 Mask 5 Micro bridge
Claims (1)
、この薄膜にドライエッチングを施して回路を形成する
超電導素子の製造方法において、エッチングガスにＳＦ
６ ガスとＯ２ ガスの混合ガスを用いることを特徴と
する超電導素子の製造方法。1. A method for manufacturing a superconducting element in which an oxide superconductor thin film is formed on a substrate and a circuit is formed by performing dry etching on this thin film, in which SF is added to the etching gas.
6. A method for manufacturing a superconducting element, characterized by using a mixed gas of gas and O2 gas.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3096388A JPH04305985A (en) | 1991-04-02 | 1991-04-02 | Manufacture of superconductive element |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3096388A JPH04305985A (en) | 1991-04-02 | 1991-04-02 | Manufacture of superconductive element |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH04305985A true JPH04305985A (en) | 1992-10-28 |
Family
ID=14163577
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3096388A Pending JPH04305985A (en) | 1991-04-02 | 1991-04-02 | Manufacture of superconductive element |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH04305985A (en) |
-
1991
- 1991-04-02 JP JP3096388A patent/JPH04305985A/en active Pending
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