JPH0772337B2 - Method for manufacturing oxide superconductor - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing an oxide superconductor having a laminated structure and excellent superconducting properties.

"Prior art" Oxide superconductors that have been discovered one after another in recent years are promising because the critical temperature at which they transition to the superconducting state is extremely higher than that of conventionally known alloy-based or intermetallic compound-based superconductors. Application development as a new superconducting material.

In such a background, attempts have been made to produce various oxide superconductors having excellent superconducting properties, but many of the oxide superconductors have anisotropy in which a current easily flows in a specific direction of the crystal axis. Due to the above relationships, it is considered that a thin film manufacturing method capable of controlling the direction of the crystal axis is advantageous when manufacturing an oxide superconductor.

This thin film manufacturing method has been rapidly developed in the field of semiconductor manufacturing in recent years, and various methods such as a CVD method (chemical vapor deposition method), a sputtering method, a molecular beam epitaxy method, and a laser deposition method are used. Attempts have been made to produce oxide superconductors, and trial production of oxide superconductors with critical current densities of hundreds of thousands to millions of A / cm ² has been made.

[Problems to be Solved by the Invention] Under such circumstances, attempts have been made to produce thin films of oxide superconductors having various structures. When producing thin oxide superconducting layers, a multilayer film structure is used. However, in the case of manufacturing an oxide superconductor by forming the second layer oxide superconducting layer after forming the first layer oxide superconducting layer, it will be described below. Sometimes it caused problems.

First, a first oxide superconducting layer is formed on a substrate by using a predetermined manufacturing apparatus, and then a second oxide superconducting layer is formed by using a manufacturing apparatus different from the above manufacturing apparatus. In the case where the manufacturing conditions are changed even if the same manufacturing apparatus is used, the substrate is taken out from the manufacturing apparatus after the first oxide superconducting layer is formed, and the substrate is taken out for a predetermined time (for example, 1 hour). It may be stored for a day), and the substrate may be set in the next manufacturing apparatus to form a second oxide superconducting layer. In such a case, impurities in the atmosphere are mixed into the surface portion of the oxide superconducting layer or the surface portion of the oxide superconducting layer is contained in the surface portion of the oxide superconducting layer while the first layer oxide superconducting layer is stored in the atmosphere. Decomposition products may occur.

That is, for example, Y-Ba-Cu-O-based oxide superconductors and the like tend to easily react with H ₂ O or CO ₃ in the atmosphere, and as a result of the reaction, Ba (OH) ₂ , BaCO _3, etc. There is a problem in that the superconducting properties of the surface portion of the oxide superconducting layer are deteriorated due to the generation of decomposition products of. When the first oxide superconducting layer was actually stored in the atmosphere for 1 day, it was confirmed that carbon was present when the surface portion was analyzed by Auger spectroscopy.

Further, when the second layer oxide superconducting layer is formed on the first layer oxide superconducting layer whose surface portion is deteriorated in this way, when the first layer oxide superconducting layer and the second layer oxide superconducting layer are formed. In some cases, the adhesive force with respect to the oxide superconducting layer of No. 2 decreased, and a peeling phenomenon occurred between both layers. Further, when the second oxide superconducting layer is formed on the first oxide superconducting layer, if the decomposition products and the like are present on the surface portion as described above, the second oxide superconducting layer is formed. Will not grow epitaxially enough,
There is a problem that the crystal orientations of the first and second oxide superconducting layers are mismatched and desired superconducting characteristics cannot be obtained.

The invention according to claim 1 is made in order to solve the above-mentioned problems, and when forming a multi-layered oxide superconductor having a plurality of oxide superconducting layers having the same crystal structure on a substrate,
Adhesion between each oxide superconducting layer is strong, peeling between layers does not occur easily, and the next oxide superconducting layer is grown on the previously formed oxide superconducting layer with good crystal matching. It is an object of the present invention to provide a manufacturing method capable of forming a film while forming a film.

The invention according to claim 2 has been made to solve the above-mentioned problems, and a first layer oxide superconducting layer is formed on a substrate by sputtering, and then the first layer oxide superconducting layer is formed. When the second oxide superconducting layer having the same blood phase structure as that of the first oxide superconducting layer is formed by the CVD method after the layer is stored in the atmosphere, the adhesion between the oxide superconducting layers is Adhesive strength is strong, peeling between layers is not likely to occur, and the next oxide superconducting layer can be formed on the previously formed oxide superconducting layer while growing the next oxide superconducting layer with good crystal matching. The purpose is to provide a manufacturing method.

[Means for Solving the Problems] In order to solve the above problems, the invention according to claim 1 provides an oxide superconductor having a laminated structure by laminating a plurality of oxide superconducting layers on a base material by a film forming method. A method of forming, when forming the next oxide superconducting layer of the same crystal structure after the oxide superconducting layer formed earlier, by irradiating the surface of the oxide superconducting layer formed earlier with an acceleration beam After removing the surface portion of the oxide superconducting layer by sputter etching, the next oxide superconducting layer is formed, and the surface portion is removed so that the oxide superconducting layer is aligned with the previous oxide superconducting layer having a regular crystal structure. The following oxide superconducting layer is formed while being epitaxially grown.

In order to solve the above-mentioned problems, the invention according to claim 2 forms a first oxide superconducting layer on a substrate by sputtering, and then forms the first oxide superconducting layer in the atmosphere. And then depositing a second oxide superconducting layer having the same crystal structure as the first oxide superconducting layer by the CVD method. Before forming the layer, the surface of the first oxide superconducting layer is irradiated with an accelerating beam to remove the air-polluted portion of the surface portion of the oxide superconducting layer by sputter etching, and then the second layer The first oxide oxide superconducting layer is formed, and the air-polluted portion of the surface portion is removed, and the crystal structure is arranged without any contaminated portion.
The second oxide superconducting layer is formed while being epitaxially grown by the CVD method so as to be aligned with the oxide superconducting layer of the first layer.

"Action" Since the impurity layer on the surface of the oxide superconducting layer formed earlier is removed by sputter etching with an accelerating beam and the next oxide superconducting layer is formed, both oxide superconducting layers adhere well. . Since the impurity layer on the surface portion of the oxide superconducting layer formed earlier is removed by sputter etching, the crystal orientation of the oxide superconducting layer to be formed next matches the crystal orientation of the preceding oxide superconducting layer.

The present invention will be described in more detail below.

1 to 4 show the manufacturing method of the present invention in Y-Ba-Cu.
This is for explaining an example applied to a method of manufacturing an —O-based superconductor, and in this example, after forming a first oxide superconducting layer by using the sputtering apparatus shown in FIG. A case will be described in which the surface of the first oxide superconducting layer is sputter-etched using an accelerating beam, and then the second oxide superconducting layer is formed by the plasma CVD apparatus shown in FIG.

To carry out this example, first, a plate-shaped substrate 10 as shown in FIG. 1 is prepared. As the constituent material of the base material 10,
It is preferable to use a non-oxidizing material having a melting point of 800 ° C. or higher. Specifically, a noble metal such as Ag or an alloy thereof, a single metal such as Ti, Ta, Zr, Hf, V, Nb, or Cu- Ni alloy, Cu-Al alloy, Ni-Al alloy, Ti-V alloy, or
A metal material such as monel metal or stainless steel, quartz glass, sapphire, or ceramics such as magnesium oxide or strontium titanate is used.
The reason for using such a non-oxidizing material is to prevent the base material 10 from being oxidized and deprived of oxygen from the oxide superconducting layer during heat treatment performed in a later step.

Next, as shown in FIG. 1, a first oxide superconducting layer 11 is formed on the upper surface of the substrate 10 by using the sputtering apparatus shown in FIG. To form the first oxide superconducting layer 11, a sputtering apparatus is used in this example, but thin film formation such as a CVD method (chemical vapor deposition method), a vacuum vapor deposition method, a molecular beam epitaxy method, or a laser vapor deposition method. You are also free to use the means. The oxide superconducting layer 11 formed here is A-
B-C-O (where A is Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu,
Group IIIa element of the periodic table such as Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, etc., or one or more of Ba, Bi, Tl,
Is a periodic table II a group elements and K such as Be, Mg, Ca, Sr, Ba, Ra.
1 or 2 or more of them are shown, and C is 1 or 2 or more of elements of Group Ib of the periodic table such as Cu, Ag and Au and Nb and K. ) System, and to exemplify an actual system, Y-Ba-Cu-O system, Bi-Sr-Ca-Cu-O system, Tl-Ca system.
-Ba-Cu-O system, La-Cu-O system, Ba-K-Bi-O system and the like.

The sputtering apparatus shown in FIG. 3 comprises a high-frequency sputtering apparatus S and an oxygen ion source 2 for ion beam assist, which are arranged in parallel.

This sputtering apparatus S includes three first beam sources 1 and a substrate.
A plate-shaped base material holder 3 for holding 10 and this base material holder 3
3 plate-shaped targets 4 facing each other at a predetermined interval,
It is composed of 5 and 6. The first beam source 1
Is equipped with a source for generating ions, neutral atoms or neutral molecules, or mixed particles thereof, and is attached to the source to extract and accelerate these particles by an extraction electrode,
It is a device that irradiates accelerated particles toward targets 4, 5, 6. A bias power supply 7 is connected to the base material holder 3 so that plasma can be generated in the space between the base material holder 3 and the targets 4, 5 and 6 by the power supply 7. In addition, the base material holder 3 and the targets 4, 5,
Both 6 are placed under a low pressure such as vacuum, and the space between the two is an inert gas atmosphere such as argon gas or an inert gas atmosphere containing oxygen. The base material holder 3 is provided with a heater for heating the base material 10 to be held to a temperature suitable for film formation.

The targets 4, 5 and 6 are the above-mentioned ABCC-
A metal or alloy target containing at least one of the elements A, B and C, which are the constituent elements of the O-based oxide superconducting layer, or a composite oxide containing all elements, or an oxide superconductor. Target etc. can be used. Here, if the ion current to each target is controlled by using the target composed of the A element as the target 4, the target composed of the B element as the target 5, and the target composed of the C element as the target 6, the first film is formed.
The composition ratio of the superconducting layer 11 of the first layer can be adjusted to a desired value. Further, it is also possible to omit two of the targets 4, 5 and 6 and use only one target to perform sputtering using a target of an oxide superconductor.

An oxygen ion source 2 is arranged near the sputtering device 1. This oxygen ion source 2 is directed toward the first layer oxide superconducting layer 11 being formed on the base material 10 held by the base material holder 3 so as to direct oxygen ions, atomic oxygen, and molecular oxygen. Accelerated irradiation is carried out as a beam containing oxygen alone or two or more kinds.

If such a device is used, the substrate holder 3 and the target
Generates an electric field and a magnetic field between 4,5,6, and the first beam source 1
Target particles such as argon ionized by 4.
It is possible to cause the neutral atoms and molecules of the target material sputtered by the collision with the opposing surfaces of 5, 6 to be deposited on the surface of the base material 10. Simultaneously with this deposition, the first layer oxide superconducting layer 11 is irradiated with oxygen ions from the oxygen ion source 2. By such a treatment, the first layer oxide superconducting layer 11 can be formed while sufficiently introducing oxygen.

After the oxide superconducting layer 11 of the first layer is formed by the above operation, the substrate 10 is taken out from the sputtering apparatus 1 and preparation for forming the oxide superconducting layer of the second layer is performed.

If the base material 10 is left in the atmosphere during this preparation, the surface of the first oxide superconducting layer 11 is contaminated with dust in the air or a layer of decomposition products is formed. As a result, the surface is contaminated. If the second layer of oxide superconducting layer is formed on the first layer of oxide superconducting layer 11 in this state, the adhesive force between both layers may be reduced and the layers may be separated from each other in some cases. Problem arises.

Therefore, before forming the second oxide superconducting layer, the surface of the first oxide superconducting layer 11 is sputter-etched with an accelerating beam. In order to perform the sputter etching, the sputtering apparatus shown in FIG. 3 is used, and the sputtering atmosphere is set to any one of Ar gas atmosphere, Ne gas atmosphere, He gas atmosphere, Xe gas atmosphere, and then the base material. 10 is mounted as a target, the bias power source 7 is operated in a vacuum atmosphere, and the first beam source 1 is operated to generate an electric field and a magnetic field to generate plasma,
The upper oxide superconducting layer 11 on the first layer may be irradiated with an accelerating beam and sputter-etched.

The accelerating voltage of the extraction electrode when irradiating the accelerating beam is preferably in the range of 200 eV to 2 keV. Accelerating voltage is 200
Below eV, the etching rate becomes small and the efficiency is poor,
When it is 2 keV or more, defects such as oxygen escape from the surface portion of the oxide superconducting layer 11 of the first layer are generated, a large amount of energy is wasted, and the temperature of the base material 10 rises, which is not preferable. In this case, the thickness of the first layer oxide superconducting layer 11 etched by sputter etching is 0.
The range of 01 to 0.2 μm is preferable. If it is 0.01 μm or less, the effect of sputter etching is insufficient, and 0.2 μm
If it is above, the portion removed by sputter etching becomes too thick, which is not preferable.

FIG. 4 shows an example of a plasma CVD apparatus suitable for use in forming the second oxide superconducting layer. In addition,
The apparatus for forming the second oxide superconducting layer may be a sputtering apparatus S as shown in FIG. 3, a vacuum vapor deposition apparatus, a molecular beam epitaxy apparatus, a laser vapor deposition apparatus or the like.

The plasma CVD apparatus P shown in FIG.
A vacuum container 21 connected to the lower part of the plasma generating cylinder 20 and a gas phase source supply device 22 connected to the vacuum container 21 are mainly configured.

A high-frequency coil 24 is attached to the outer peripheral side of the plasma generation cylinder 20, and a carrier gas supply pipe 25 is connected to the upper end of the plasma generation cylinder 20. The vacuum container 21 is connected to a vacuum exhaust device (not shown) so that the inside of the vacuum container 21 can be evacuated, and a heater is provided at the center of the vacuum container 21.
26 is provided, and the base material 10 can be installed on the upper surface of the central portion of the heater 26.

Further, the vapor source gas supply device 22 includes bubblers 28, 29, and each bubbler 28, 29 is connected to a vacuum vessel 21 by a connection pipe 27.
And the tip end portion 27a of the connection pipe 27 faces the lower end opening portion of the plasma generation cylinder 20. The bubbler 28 contains a vapor phase source of Y and Cu, for example, an acetylacetone compound of these elements, a diketone compound such as a hexafluoroacetylacetone compound, a metal complex such as a cyclopentadienyl compound, and the bubbler 29. It contains an organometallic complex of Ba or an inorganic compound of Cu.

Then, each gas bubbler 2 is supplied by the gas source gas supply device 22.
After mixing the carrier gas with the volatile gas generated from 8 and 29 to make a gas phase source gas, this gas phase source gas is connected to the pipe 27.
It can be sent to the inside of the vacuum container 21 via. As the carrier gas supplied to the bubblers 28, 29, hydrogen gas, nitrogen gas, argon gas, etc. are preferably used, and when using a gas phase source that is difficult to vaporize at room temperature and normal pressure, each bubbler is used. Generation of volatile gas can be promoted by heating 28, 29 or reducing the pressure of the bubblers 28, 29.

In order to form the second oxide superconducting layer 12, it is installed in the center of the heater 26 of the vacuum container 21 of the base material 10, the inside of the vacuum container 21 is evacuated, and the gas phase source 22 The gas phase source gas, the gas phase source gas of Ba, and the oxygen gas are sent to the lower side of the plasma generation cylinder 20, while the plasma in which the oxygen source gas such as the oxygen gas or the nitrous oxide gas and the inert gas are mixed from the gas supply pipe 25. The generating gas is sent to the plasma generating cylinder 20, and the high frequency coil 24 is operated to generate the plasma flame F inside the plasma generating cylinder 20. Further, the heater 26 is operated to preheat the base material 10 to about 600 to 1000 ° C.

The gas-phase source gas supplied from the tip of the connecting pipe 27 to the plasma flame F is decomposed by the heat of the plasma flame F,
Y reacting with oxygen existing around the plasma flame F
It becomes a fine powder of a mixed oxide of Ba and Cu and is sprayed on the surface of the coated wire.

At this time, since the base material 10 is preheated to about 800 to 1000 ° C. by the heat of the plasma flame F and the heat of the heater 26, the vapor phase source gas reacts with oxygen in the atmosphere due to the high temperature atmosphere. A second Ba—Cu—O-based oxide superconducting layer 12 is produced. Once the second oxide superconducting layer 12 has been formed, if necessary, in an oxygen atmosphere, etc.
A heat treatment of heating to 800 ° C. or higher for 0.1 to several tens of hours is performed to promote diffusion of elements and stabilize each oxide superconducting layer 11 and 12.

In addition, when the oxide superconducting layer 12 of the second layer is generated, the oxidizing property of nitrous oxide (N ₂ O) gas or the like which decomposes and releases oxygen from the gas source gas supply device 22 at about 300 ° C. The gas may be sent to supply sufficient oxygen when the oxide superconducting layer 12 is formed.

As described above, when the second oxide superconducting layer 12 is formed after the surface portion of the first oxide superconducting layer 11 is removed by sputter etching using an accelerating beam, Since the oxide superconducting layer 12 of the second layer can be formed while being epitaxially grown while being aligned with the crystal orientation of the oxide superconducting layer 11 of the first layer, the oxide superconducting layer of the first layer can be formed.
A second oxide superconducting layer 12 aligned with the crystal orientation 11 can be formed. Therefore, the oxide superconducting layer 12 having desired superconducting properties can be formed. In addition, the first layer oxide superconducting layer 11
On the other hand, since the second oxide superconducting layer 12 is excellent in conformity, both superconducting layers 11 and 12 are well adhered to each other and are not separated.

The base material 10 used in the practice of the present invention may be tape-shaped, linear, tubular or the like, and when a tape-shaped base material is used, an oxide superconducting layer is formed only on one surface of the base material. You may. In addition, although the case where the oxide superconductor having a two-layer structure is formed has been described in this example, when the oxide superconductor having a structure having three or more layers is formed, the same operation as described above is repeated for each layer. If the layers are laminated in such a manner, it is possible to form an oxide superconductor having a multi-layer structure having excellent superconducting properties without causing separation between layers.

[Example] Based on the method of the present invention, a Y-Ba-Cu-O-based oxide superconductor having a two-layer structure was manufactured.

A substrate made of magnesium oxide is used as a base material, and a high-frequency sputtering apparatus having _one target is used to form the first oxide superconducting layer, and the target is Y ₁ Ba ₂ Cu ₃ O ₇ An oxide target having a composition of _−δ was used. The atmosphere during sputtering is 100% Ar gas atmosphere, the pressure is set to 0.25Pa, and the substrate temperature during film formation is 70
The temperature was 0 ° C. The ion current density of the oxygen ion source is 500.
μA / cm ² , accelerating voltage is set to 500 eV, and sputtering is performed.
An oxide superconducting layer having a thickness of 1 μm was formed on the substrate.

Next, this oxide superconducting layer was stored in the atmosphere for 1 day, then re-installed as a targate of the high frequency sputtering apparatus, the atmosphere was set to 100% Ar gas atmosphere, and the acceleration voltage of the extraction electrode was set to 1 keV. Then, sputter etching was performed with an accelerating beam to remove a portion of 0.05 μm from the surface of the first oxide superconducting layer.

After that, a second layer oxide superconducting layer was formed on the first layer oxide superconducting layer using the plasma CVD apparatus shown in FIG. The tris-cyclopentadienyl compound of Y and the bis-acetylacetone compound of Cu were used as the gas phase source in this apparatus, and nitrogen gas was used as the carrier gas of each gas phase source. Further, BaCO ₃ from the supply pipe of the carrier gas in the plasma generating tube by mixed gas of Ar gas and N ₂ O gas
Powder was supplied, the degree of vacuum of the plasma generating cylinder was set to 1 Torr, and the substrate temperature was set to 850 ° C. to form a second oxide superconducting layer having a thickness of 1 μm.

As a result of measuring the critical temperature (Tc) and the critical current density (Jc) of the two-layer structure oxide superconductor manufactured by the above process, Tc = 89K Jc = 3 × 10 ⁵ A / cm ² excellent value I was able to confirm that it exhibited. It was also confirmed that the second oxide superconducting layer was in good contact with the first oxide superconducting layer.

"Effect of the invention" As described above, according to the invention of claim 1, the oxide superconducting layer is formed on the substrate, and then the surface portion of the oxide superconducting layer is removed by sputter etching using an accelerating beam. After the impurity layer on the surface is removed, the next oxide superconducting layer having the same crystal structure is formed. The compound superconducting layer can be epitaxially grown, whereby the next oxide superconducting layer can be formed on the preceding oxide superconducting layer with good crystal matching. Therefore, the adhesion between the oxide superconducting layer formed first and the oxide superconducting layer formed next becomes good. Therefore, even an oxide superconductor in which a plurality of oxide superconducting layers are laminated can exhibit good superconducting properties.

According to the invention of claim 2, the first oxide superconducting layer is formed on the base material by sputtering, and then the first oxide superconducting layer is stored in the atmosphere. , After that, when the second oxide superconducting layer having the same crystal structure as that of the first oxide superconducting layer is formed by the CVD method, before forming the second oxide superconducting layer. Then, the surface of the oxide superconducting layer of the first layer is irradiated with an accelerating beam to remove the air polluted portion of the surface portion of the oxide superconducting layer by sputter etching, and then the oxide superconducting layer of the second layer is removed. Is formed, and the air-polluted portion of the surface portion is removed, and the second layer oxide superconducting layer is formed so as to be aligned with the first-layer oxide superconducting layer having a crystal structure without any contaminated portion. CV layer
Since the film is formed while epitaxially growing by the D method,
It is possible to epitaxially grow the next oxide superconducting layer on the oxide superconducting layer in which the impurity portion of the surface is removed and the crystal structure is regular and the amount of impurities is small. The superconducting layer can be formed with good crystal matching. Therefore, the adhesion between the oxide superconducting layer formed first and the oxide superconducting layer formed next becomes good. Therefore, even an oxide superconductor in which a plurality of oxide superconducting layers are laminated can exhibit good superconducting properties.

Further, even when the first oxide superconducting layer is formed on the base material by sputtering and the second oxide superconducting layer is formed thereon by the CVD method, A second oxide superconducting layer can be formed on the second oxide superconducting layer with good crystal matching, and a multi-layered oxide superconducting layer having good adhesion is formed on a substrate. An oxide superconductor having the same can be manufactured.

[Brief description of drawings]

1 to 4 are for explaining one embodiment of the present invention. FIG. 1 is a sectional view showing a state in which a first superconducting layer is formed on a base material, and FIG. 2 is a sectional view showing a state in which a second superconducting layer is formed on the superconducting layer of FIG. 3, FIG. 3 is a configuration diagram of a sputtering apparatus, and FIG. 4 is a sectional view of a plasma CVD apparatus. 1 ... First beam source, 10 ... Substrate, 11 ... First superconducting layer, 12 ... Second superconducting layer, S ... Sputtering device, P ... Plasma CVD device.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical display location H01B 13/00 ZAA Z 7244-5G (72) Inventor Mikio Nakagawa 1-5 Kiba, Koto-ku, Tokyo No. 1 within Fujikura Electric Line Co., Ltd. (72) Inventor Sakuno Kono 1-5-1, Kiba, Koto-ku, Tokyo Inside Fujikura Electric Line Co., Ltd. (72) Inventor Yu Koyamauchi 1-1-5, Kiba, Koto-ku, Tokyo Fujikura Densen Co., Ltd. (72) Inventor Tomoaki Shinada 1 20-20 Kitakousan, Otaka-cho, Midori-ku, Nagoya-shi, Aichi Chubu Electric Power Co., Inc. Research Planning Department (72) Inventor Sugimoto Minami-ku, Hiroshima State 4-34-3 Chugoku Electric Power Co., Inc. Technical Research Institute (72) Inventor, Kiichiro Watanabe 2- 1-47 Shiobara Minami-ku, Fukuoka City, Fukuoka Prefecture Kyushu Electric Power Co., Inc. Research Institute (56 ) Reference JP-A-61-79762 (JP, A)

Claims (2)

[Claims] 1. A method of forming an oxide superconductor having a laminated structure by laminating a plurality of oxide superconducting layers on a base material by a film forming method, the method being the same after the previously formed oxide superconducting layer. In forming the next oxide superconducting layer having a crystal structure, the surface of the oxide superconducting layer previously formed is irradiated with an accelerating beam to remove the surface portion of the oxide superconducting layer by sputter etching to remove the next The oxide superconducting layer is formed, and the next oxide superconducting layer is epitaxially grown so as to be aligned with the previous oxide superconducting layer whose surface has been removed and whose crystal structure is regular. Manufacturing method of oxide superconductor. 2. A first oxide superconducting layer is formed on a substrate by sputtering, and then the first oxide superconducting layer is stored in the atmosphere, and then the first oxide superconducting layer is formed by a CVD method. A method for forming a second oxide superconducting layer having the same crystal structure as that of the first oxide superconducting layer, the method comprising: forming a first layer before forming a second oxide superconducting layer; The surface of the oxide superconducting layer of the eye is irradiated with an accelerating beam to remove the air polluted portion of the surface portion of the oxide superconducting layer by sputter etching, and then a second oxide superconducting layer is formed. The second oxide superconducting layer is formed by the CVD method so that the air polluted portion of the surface portion is removed and the second oxide superconducting layer is aligned with the first oxide superconducting layer having a crystal structure without any contaminated portion. A method for manufacturing an oxide superconductor, which comprises forming a film while epitaxially growing the film.