JPS63292524A - Manufacture of superconductive film - Google Patents

Abstract

PURPOSE:To form film-shaped high temp. superconductor by supplying Cu, O, and two specific elements to the base in the form of gas of atoms or compound, and by affixing this complex oxides by chemical gaseous phase growing method. CONSTITUTION:Element A, element B, Cu and O are at least supplied to the surface of a base in the form of gas of atoms or compound to provide affixation of complex oxides. Here element A is either of Sc, Y, and elements of lanthanum type (atomic number 57-71), while element B either of such group IIa elements as Be, Mg, Ca, Sr, Ba. As a film is formed on the crystalline base, the accuracy is higher than any sintered body as well as it is possible to integrate with a device of Si or CaAs.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for manufacturing superconducting thin films. In particular, it relates to a manufacturing method using chemical vapor deposition.

Conventional technology As high temperature superconductors, niobium nitride (NbN) and germanium niobium (Nb s
G e ), etc. were known, but the superconducting transition temperature of these materials was at most 24°.

On the other hand, perovskite-based ternary compounds are expected to have even higher transition temperatures, and Ba-La-Cu-0-based high-temperature superconductors have been proposed (J, G, f3endorz and
K. A. Muller, Zeitschrift fur P.
hysik, ) -Condensed Matter
64, 189-193 (1986)].

Furthermore, ] Y-Ba-Cu-0 is a higher temperature superconducting material 1
1”- materials (M, K, WnM,
K, Wn, etc., Physical Review Letters (Ph
ysicalReview Letters) Vol.
, 5B, No. 9, 908-910 (1987)
).

Problems to be Solved by the Invention However, Y-Ba-Cu-0 based materials can only be formed through the process of sintering using current technology, and therefore only ceramic powder or block shapes can be obtained.

On the other hand, when this type of material is put to practical use, there is a strong demand for processing it into a thin film, but with conventional techniques, it is extremely difficult to process the material into a thin film.

The present inventors discovered that a thin film-like high-temperature superconductor is formed when a thin film of this type of material is deposited on a substrate by chemical vapor deposition. Invented a manufacturing method.

Means to solve the problem The basic structure of the superconducting thin film formed by the manufacturing method of the present invention is as follows:
The method is characterized in that at least element A, element B, Cu, and oxygen are supplied as atomic or compound gases to the surface of the substrate to deposit the composite oxide. The inventors
The present invention was based on the discovery that this type of superconducting thin film can be formed by depositing the above composite oxide on a heated substrate by chemical vapor deposition. Here, A is Sc, Y, and lanthanum-based elements (atomic number 57-7
At least one of 1), B is Be or Mg.

Indicates at least one type of Ila group elements such as Ca, Sr, and Ba.

Function The method for producing a superconducting thin film according to the present invention is characterized in that the superconducting thin film is thinned by chemical vapor deposition. In other words, thin film formation using chemical vapor phase and growth methods reconstitutes the superconductor on the substrate from the particle level by supplying ultrafine particles of atomic or compound gas containing the constituent atoms of the superconductor onto the substrate. Because the superconductor is deposited as a sintered body, the composition of the superconductor formed is essentially homogeneous compared to conventional sintered bodies. In addition, since a gas is used, it is easily possible to deposit superconductors at high speed and over a large area. Therefore, using the present invention, it is possible to deposit superconductors with very high precision over a large area at high speed.

Embodiments An embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 1, a chemical vapor deposition method was used to deposit the composite oxide film 12 on the substrate 11.

The element B, the element B, and Cu are supplied to the substrate 11 in the form of atomic or compound gases. Element B is an LA group element and is an active metal, and there are only a few volatile organic metals, and many of them are unstable. The present inventors discovered that bis(1,1,1,ts, rs, rs-
Hexafluoro-2゜4-pentandeonato) B (■)
(B-Be2Mq.

Ca, Sr, Ba) were discovered and used. Other raw material gases for A and Cu are tris(2,2,6,6-titramethyl-3,
5-Heptandeona) ) A (Ill) (A=Y,
Sc or atomic number ts-r-71) bis(1,1,1
, 5; 5,5-hexafluoro-2,4-pentanedeonato)copper(II) was used. A composite oxide 12 was formed on the substrate 11 using the raw material gases of the element He, the B element, and Cu as described above. Toward that time, elements, B elements, Cu raw materials 1
6' - FA is the atomic ratio of element A, element B, and Cu in the gas.

When FB・FCu, the inventors...
It was confirmed that if the temperature is within the range of (1), superconducting phenomena can be observed even if there is a slight difference in the critical temperature. The relationship between the atomic ratio in the raw material gas of this composite oxide is not limited to the type of raw material gas, but also depends on the normal pressure during chemical vapor deposition.

The present inventor has discovered that any method such as low pressure chemical vapor deposition, plasma chemical vapor deposition, photochemical vapor deposition, etc. is effective as long as the atomic ratio in the raw material gas is matched. confirmed.

To form a thin film superconductor, first, a coating 12 of an AB-Cu-0 composite oxide is deposited on a substrate 11 by chemical vapor deposition.

In this case, this composite oxide 1o is usually formed at a high temperature of several 100°C, and superconductivity, such as liquid nitrogen temperature (-195°C
), the inventors have confirmed that the adhesion 12 between the base 11 and the coating 12 is particularly poor and the coating 12 is damaged.

Furthermore, as a result of investigating the detailed thermal characteristics of the substrate for various materials, the present inventors found that the linear thermal expansion coefficient a〉10/
It was confirmed that if it was C, the coating would not be damaged and could be put to practical use. For example, the present inventors have confirmed that if quartz glass with α<10-6/''C is used as the substrate, the coating 12 will have numerous cracks and become a discontinuous coating, making it difficult to put it to practical use.

Furthermore, the present inventors have discovered that there is an optimal material for the base body 11 shown in FIG. 1 from the viewpoint of functionality.

In other words, in order to form the highly crystalline complex oxide coating 12 on the surface 13 of the substrate 11, a single crystal substrate is effective. As a result of detailed investigation into the optimal substrate material, the present inventors confirmed that single crystals such as magnesium oxide, sapphire (a-A1203), spinel, strontium titanate, silicon, and gallium arsenide are effective as the substrate 11. did. However, since this is to effectively grow the film 12 with high crystallinity 17.- on the surface 13, it is sufficient that at least the substrate surface 13 is a single crystal.

The present inventors have confirmed that so-called sintered porcelain is more effective as a base material than a single crystal when processing this type of superconductor into an arbitrary shape, such as a cylinder, and have also found the most suitable porcelain material. I found it. That is, the present inventors have found that alumina, magnesium oxide, derconium oxide, steatite, forsterite, beryllia, spinel, etc. are used as the porcelain substrate to provide optimal adhesion of the superconducting coating 12 to the substrate 11 through processing of the substrate, etc. confirmed. In this case as well, it is preferable that even the surface of the substrate is made of this type of porcelain, as in the case of single crystals.

Furthermore, the substrate is Cu, Ni, Ti, Mo, Nb, Ta,
W.

When a composite oxide was deposited on a metal such as Mn, a superconducting phenomenon was confirmed, although the adhesion was not as good as in the case of the above-mentioned porcelain or single crystal. Oxides and nitrides on the above metals.

When a composite oxide was attached after attaching a heat-resistant coating such as carbide, the adhesion was improved compared to that on metal, and superconductivity was also confirmed. Also, Ni, Ti, Mo, Nb
.

The base is made of at least one of Ta, W, and Mn, or an alloy containing these metals, and the surface of this base is oxidized.

Superconductivity was confirmed even when the composite oxide was deposited after nitriding and carbonizing. This is thought to be because the composite oxide formed on the metal or heat-resistant coating is composed of amorphous or A-B-Cu-0 system microcrystals that exhibit superconductivity, and therefore exhibits a superconducting phenomenon.

Furthermore, when the composite oxide 12 formed satisfying the above atomic ratio conditions is post-treated with oxygen, the superconducting transition temperature does not change, but the critical current at the superconducting transition temperature increases by several orders of magnitude after the treatment. It was confirmed that there is a tendency to It was also confirmed that the resistance at room temperature was reduced by several orders of magnitude after oxygen post-treatment.

In order to deeply understand this embodiment, more specific examples will be described below.

(Specific Example 1) A magnesium oxide single crystal (1oo) plane was used as the substrate 11, and atmospheric pressure chemical 19-single vapor phase growth method was used as the chemical vapor growth method. A Y-Ba-Cu-0 composite oxide will be described as an example of an 8-B-Cu-0-based composite oxide. Tris ((C
H3)2CH3COCHCOCH3(CH3)2)Y2
Bis(CF3COCHCOCF3)Ba 3 and bis(cF3coCHCoCF3)Cu4 were used. For oxygen, pure oxygen 5 was used.

Inert gas (He
, Ne, Ar, Kr, Xe) and H2.

Here, Ar gas 8 was used. Y, Ba, C
In order to satisfy the formula (1) for the atomic ratio in each compound of u, the containers 5 and 6.7 containing each compound were heated to 180'C.
.

The temperature was kept constant at 130''C and 126°C.
, 0.2, 0.11/1 ln. by this,
The atomic ratio of Y, Ba, and Cu was set to 1:1:3.

Oxygen gas 5 was flowed at 0.273/win, H2 gas 9 was used as the reducing gas, and the flow rate was 0.1137 sin. In addition, Ar gas 10 was flowed to maintain the total pressure at one atmosphere. The substrate temperature is determined by the temperature of each compound and the reducing gas (H2
The temperature was set to be higher than the minimum temperature at which single elements of Y 2 , Ba, and Cu begin to be liberated by reaction with gas 9). In this case, Y, B
Among the compounds a and Cu, the Cu compound is the lowest (250″
C) Therefore, the substrate temperature is 250°C or higher and 450°C.
I made it. When the composite oxide film 12 was deposited on the substrate 11 for 6 hours under the above conditions, the film thickness was about 6.2 μm. The formed composite oxide film was further treated with oxygen in C1 pure oxygen at a substrate temperature of 600'' for 2 hours, and then slowly cooled for 3 to 4 hours.

This composite oxide film 12 had a superconducting transition temperature of 90°.

In this case, when the substrate temperature was 250° C. or less, the adhesion of the composite oxide to the substrate surface was poor. Further, at temperatures above 8oO°C, each compound decomposed quickly and did not form a composite oxide.

Here, the film thickness is 6.2 μm, but the film thickness is 0.1 μm.
It was confirmed that superconductivity occurs when the thickness is 10 μm or more, and when the thickness is 10 μm or more.

Further, the adhesion rate of the composite oxide 12 to the substrate 11 is 0.
．． Superconductivity occurs between 1≦D≦10 μm/hr21 t・
-7 I was born. At 10 μm/hr or more, no composite oxide was formed, and at 0.1 μm/hr or less, no superconducting phenomenon could be confirmed.

Here, the total pressure inside the device 1 was kept constant at 1 atm, but the occurrence of superconductivity was confirmed even when the total pressure P was set in the range of 0.01≦P≦3 atm. When the total pressure is greater than 3 atm, no composite oxide is formed, and 0,01
No superconducting phenomenon was observed below atmospheric pressure.

Regarding the oxygen post-treatment, it was confirmed that although there was no change in the superconducting transition temperature, the critical current at the superconducting transition temperature was improved by more than 1.5 orders of magnitude.

As described above, according to this embodiment, a superconductor can be made into a thin film by using atmospheric pressure chemical vapor deposition using Y, Ba, and Cu compound gases and oxygen as raw material gases. can.

(Specific Example 2) A specific example 2 will be described with reference to the drawings. As the chemical vapor deposition method, a chemical vapor deposition method using electron cyclotron resonance (ECR) plasma was used as shown in FIG. The basic structure of the chemical vapor deposition method using ECR plasma is microwave (2.45 GHz
) and the magnetic field 22 under ECR conditions. Oxygen 5 to the device 21
is introduced to create oxygen plasma 23, and Y is introduced near the base 11.
, Ba, and Cu are introduced, and the oxygen plasma 23 is caused to react with the compound gases of Y, Ba, and Cu, so that the composite oxide 12 is deposited on the substrate 11. Composite oxide 12 is the same as in specific example 1 (Y-Ba-C
This was done on the u-0 system.

The raw material gases of Y, Ba, and Cu are tris(2,2,6,6-titramethyl-3.5-hebutanedeonato)yttrium(III)Y(CH3)2 as in Specific Example 1.
COCHCO(CH3)2)22. Bis(1,1,1,
5,5,5-hexafluoro-2°4-pentanedeonato)Barium(II)Ba(CF3CQCHCOCF3
)23 , bis(1,1゜1.5,5,5-hexafluoro-2,4-pentanedeonato)copper(II)Cu(C
F3COCHCOCF3) 24 pieces were used. Pure oxygen 6 was used as oxygen.

Volume 23 containing compounds 2 and 3.4 of Y, Ba, and Cu
・ ・ Containers 6, 7, and 8 are 180″C and 130″C11, respectively.
The temperature was kept constant at 26°C. Y generated in containers 6, 7.8
, Ba, and Cu compound gases are directly supplied to the device 21.
introduced within. Each compound gas inlet 24 is connected to the base 1.
5crn#1' from 1. The base body 11 has a thermal expansion coefficient of 1
A sapphire substrate with an R of σ6(1,'C) or more was used. The substrate temperature was 260°C for the same reason as in specific example 1.
It was set to °C. The atomic ratio of Y, Ba, and Cu is FY, FBa
, Fou, it is made to satisfy. Here, FY:FBa:Fcu-1=1=3. And the flow rate of oxygen was set to 20 sec. In addition, pure hydrogen 9 was used as a reducing gas and was flowed at 2 Bacm. Device 21
The total pressure within was approximately 10'Torr. The power of the microwave was set to 200W. Under the above conditions, base 1
Composite oxide 1 with a evaporation time of 6 hours and a film thickness of 7.2 μm was deposited on 1.
2 was deposited. The formed composite oxide 12 was further treated using oxygen ECR plasma in the same apparatus. Processing was performed for 10 minutes at a substrate temperature of 200° C., an oxygen gas flow rate of 10108° C., and a microwave power of 200 W. The superconducting transition temperature of composite oxide 12 thus obtained was 900.

Although a total pressure of 10 Torr was used here, it was confirmed that superconductivity occurred if the total pressure P was in the range of 10-5≦P≦10-2 Torr. When the total pressure was less than 10-5, no superconducting phenomenon was observed, and when it was greater than 10-2, no composite oxide could be formed.

As described above, according to this example, a composite oxide that exhibits superconductivity at low substrate temperature and low gas pressure is produced by using Y, Ba, and Cu compound gases and oxygen as raw material gases and using ECR plasma. can be formed. In addition, in specific examples 1 and 2, Y.

The atomic ratio of Ba and Cu was 1:1:3, but the formula (
The occurrence of superconductivity was confirmed in all cases where the atomic ratio satisfied 1).

Although a symmetrical β-diketone compound was used as the raw material gas for Y, Ba, and Cu, an asymmetrical β-diketone compound may be used. Also, cyclobentamp 25 ·, -.

Enyl compounds, such as cyclopentanedenyl copper trimethylphosphorus (C5H5Cu(CH3)3P), dicyclopentanedenyl halium ((C5H5)2Ba), and organometallic compounds with volatility and sublimation properties such as alkyl compounds. The occurrence of superconductivity was confirmed.

The means for supplying the shredded Y, Ba, and Cu is Y, Ba.

At least one type of alloy of Cu is heated, electron beam,
The generation of superconductivity was confirmed even with thermal heating methods such as sputtering, electron beam methods, and sputtering methods.

In addition, in specific examples 1 and 2, a normal pressure chemical vapor deposition method and a chemical vapor deposition method using ECR plasma were shown. In addition, in the case of photochemical vapor deposition, the substrate temperature is
Even when the composite oxide 12 was formed by heating the composite oxide 12 at 660 nm or less and irradiating it with an argon ion laser as a light source, the occurrence of superconductivity was confirmed. In addition, the present inventors have confirmed that direct current plasma, low frequency plasma, high frequency plasma, and microwave plasma are all effective for plasma chemical vapor deposition.

Furthermore, when ions in the plasma were accelerated by applying an electric field, a composite oxide with improved adhesion was obtained. When the speed was reduced, the surface of the composite oxide was flat. The superconducting transition temperature hardly changed.

Regarding oxygen post-treatment, there is no change even if the formed composite oxide is treated with different equipment. Furthermore, in addition to using thermal treatment or plasma as a post-treatment with oxygen, engineering heat treatment methods such as laser light, infrared rays, or heating methods using electron beams can be applied.

In addition, a compound film of element B, element B, and Cu is deposited on the surface of the substrate by chemical vapor deposition or physical vapor deposition, and then an oxygen beam, oxygen ions, oxygen radicals, etc. are applied to form a compound film. It is also possible to form a composite oxide on the surface of the substrate by irradiating the inside of the substrate.

The details of changes in superconducting properties due to changes in constituent elements A and B of this kind of A-B-Cu-0 based composite oxide superconductor are not clear. However, it is true that A indicates trivalence and B indicates divalence. Although the explanation has been given using an example of Y as an element, the use of Sc, La, and even lanthanum series elements (atomic numbers 57 to 71) does not change the essential characteristics of the invention, except that the superconducting transition temperature changes. .

Even in B elements, changes in group 1a elements such as Sr, Ca, and Ba change the superconducting transition temperature by about 10°, but this does not essentially change the characteristics of the present invention.

Effects of the Invention Particularly, the superconductor according to the present invention is characterized in that the superconductor is formed into a thin film by chemical vapor deposition. In other words, thinning the film by chemical vapor deposition involves supplying ultrafine particles of atomic or compound gas containing the constituent atoms of the superconductor onto the substrate, and then chemically depositing the superconductor from the particle level onto the substrate. Because the superconductor is reconstituted and deposited, the composition of the formed superconductor is essentially homogeneous compared to conventional sintered bodies. In addition, since a gas is used, it is easily possible to deposit superconductors at high speed and over a large area. Therefore, a superconductor with very high precision is realized with the present invention.

As explained above, according to the method for producing a superconducting thin film of the present invention, it is formed in the form of a thin film on, for example, a crystalline substrate, so it is essentially more precise than a sintered body.
It can be integrated with devices such as aAs, and is also used in the production of various superconducting devices such as Josephson elements. In particular, the transition temperature of this type of compound superconductor may be room temperature, so the range of conventional practical use is wide, and the industrial value of the present invention is high.

[Brief explanation of drawings]

Fig. 1 is a basic configuration diagram of a superconducting thin film formed by the superconducting thin film manufacturing method according to one embodiment of the present invention, and a schematic diagram of an apparatus for atmospheric pressure chemical vapor deposition according to specific embodiment 1. FIG. 2 is a schematic diagram of an apparatus for chemical vapor deposition using ECR plasma according to a second specific example of the invention. 1... Apparatus for atmospheric pressure chemical vapor deposition method, 11...
...Base, 12...Composite oxide, 21...
...Equipment for chemical vapor deposition using ECR plasma. Figure 1? 9 Exhaust Figure 2 ↓ 29 Exhaust

Claims (40)

[Claims] (1) At least element A, element B, Cu, and oxygen are supplied onto the substrate in the form of atomic or compound gases, and the elements A, B, and Cu are
A method for producing a superconducting thin film, which comprises depositing a composite oxide. Here, element A is at least one of Sc, Y, and lanthanum elements (atomic numbers 57 to 71), and B
The element indicates at least one element among alkaline earth elements. (2) The method for producing a superconducting thin film according to claim 1, characterized in that the chemical vapor deposition method is a chemical vapor deposition method under normal pressure or reduced pressure. (3) The method for producing a superconducting thin film according to claim 1, wherein a plasma chemical vapor deposition method is used as the chemical vapor deposition method. (4) The method for producing a superconducting thin film according to claim 1, wherein a photochemical vapor deposition method is used as the chemical vapor deposition method. (5) The superconducting thin film according to claim 1, wherein an organometallic compound such as an alkyl compound β-diketone chelate compound or a cyclopentanedienyl compound is used as the compound gas containing element A. manufacturing method. (6) The superconductor according to claim 1, wherein an organometallic compound such as an alkyl compound, a β-diketone chelate compound, or a cyclopentanedienyl compound is used as the compound gas containing element B. Method for manufacturing thin films. (7) The superconducting thin film according to claim 1, characterized in that an organometallic compound such as an alkyl compound, a β-diketone chelate compound, or a cyclopentanedienyl compound is used as the compound gas containing Cu. manufacturing method. (8) The method for producing a superconducting thin film according to claim 3, wherein a chemical vapor deposition method using electron cyclotron resonance plasma is used as the chemical vapor deposition method. (9) A compound containing element A, element B, and Cu, or an inert gas such as Kr or the like is used for He, Ne, Ar, or Xe as a gas for transporting an alkyl compound of a compound containing each of the above elements. A method for manufacturing a superconducting thin film according to any one of claims 5, 6, and 7. (10) Gases that transport β-diketone compounds among compounds containing element A, element B, and Cu or compounds containing each of the above elements include He, Ne, Ar, Xe, and Kr.
The method for producing a superconducting thin film according to any one of claims 5, 6, and 7, characterized in that an inert gas such as or H_2 is used. (11) Compounds containing element A, element B, Cu, and among compounds containing each of the above elements, gases that transport cyclopentadienyl compounds include He, Ne, Ar, and
Inert gas such as e, Kr or H_2, CO_2, H_
The method for producing a superconducting thin film according to any one of claims 5, 6, and 7, characterized in that 2O, O_2, and air are used. (12) Element A or an alloy containing the element is heated by at least one of heater heating method, electron beam heating method, and sputtering method.
2. The method for producing a superconducting thin film according to claim 1, wherein the superconducting thin film is supplied onto the substrate in a gaseous state using a gaseous substance. (13) Element B or an alloy containing the element is made into a gas by using a heater heating method, an electron beam heating method, or a sputtering method, and is supplied onto the substrate. Method for manufacturing superconducting thin films. (14) Claim 1, characterized in that Cu or a Cu alloy is supplied onto the substrate in a gaseous state using at least one of a heater heating method, an electron beam heating method, and a sputtering method. The method for producing the superconducting thin film described above. (15) A β-diketone compound containing element A, element B, and Cu or a β-diketone compound containing each of the above elements is used, and the substrate temperature is desired to be 250°C or higher. The method for producing a superconducting thin film according to any one of Items 6, 7, and 10. (16) A cyclopentanedenyl compound containing element A, element B, and Cu or a cyclopentanedenyl compound containing each of the above elements is used, and the substrate temperature is set to 420° C. or higher. Section, Section 6,
The method for producing a superconducting thin film according to any one of Items 7 and 11. (17) In the plasma chemical vapor deposition method, the superconducting thin film according to claim 3 is characterized in that ions in the plasma are accelerated by an electric field to deposit the composite oxide on the substrate. Production method. (18) Production of a superconducting thin film according to claim 3, characterized in that in the plasma chemical vapor deposition method, ions in the plasma are decelerated by an electric field to deposit the composite oxide on the substrate. Method. (19) As a substrate, linear thermal expansion coefficient a>10^-^6(1
2. The method of manufacturing a superconducting thin film according to claim 1, characterized in that a material having a temperature of 100%/°C) is used. (20) Magnesium oxide, sapphire (
20. The method for producing a superconducting thin film according to claim 19, characterized in that at least one of single crystals such as α-Al_2O_3), spinel, strontium titanate, silicon, and gallium arsenide is used. (21) The method for producing a superconducting thin film according to claim 19, characterized in that the substrate is made of porcelain such as alumina, magnesium oxide, zirconium oxide, steatite, forsterite, beryllia, or spinel. (22) Cu, Ni, Ti, Mo, Nb, Ta on the substrate
2. The method for producing a superconducting thin film according to claim 1, wherein one of metals such as , W, Mn, and Fe, or an alloy containing these metals, such as stainless steel, is used. (23) Claim 1, characterized in that after forming a heat-resistant coating on the surface of the substrate, the composite oxide is attached.
A method for producing a superconducting thin film as described in . (24) The method for producing a superconducting thin film according to claim 23, wherein the heat-resistant coating is made of a metal oxide, nitride, or carbide. (25) The substrate is Ni, Ti, Mo, Nb, Ta, W,
Claim 23, characterized in that the substrate is made of at least one type of Mn or an alloy containing these metals, and the surface of the substrate is oxidized, nitrided, or carbonized before the composite oxide is attached. A method for producing a superconducting thin film as described in . (26) A patent claim characterized in that a compound of element A, element B, and Cu, or a gas of a compound containing each of the above elements is irradiated with light energy of 550 nm or less to deposit a composite oxide on a substrate. The method for producing a superconducting thin film according to item 4. (27) The method for producing a superconducting thin film according to claim 1, wherein the composite oxide is formed on the substrate while flowing a reducing gas. (28) The method for producing a superconducting thin film according to claim 27, characterized in that H_2 is used as the reducing gas. (29) The method for producing a superconducting thin film according to claim 1, wherein the composite oxide is formed on the substrate and then post-treated with oxygen. (30) As an oxygen post-treatment, the substrate temperature is 600°C to 80°C.
The method for producing a superconducting thin film according to claim 29, characterized in that the temperature is 0°C. (31) The method for producing a superconducting thin film according to claim 29, wherein oxygen is excited and ions or radicals are used as the oxygen post-treatment. (32) A method for producing a superconducting thin film according to claim 31, characterized in that plasma is used as a means for exciting oxygen. (33) The method for producing a superconducting thin film according to claim 32, wherein electron cyclotron resonance plasma is used as a method for exciting oxygen. (34) Regarding oxygen post-treatment using resonance plasma, oxygen pressure P is set to 10^-^4≦P≦10^-^2 Torr.
34. A method for producing a superconducting thin film according to claim 33. (35) The method for producing a superconducting thin film according to claim 33, wherein the substrate temperature is set to 400° C. or lower in the oxygen post-treatment using resonance plasma. (36) Speed D (μ
2. The method for producing a superconducting thin film according to claim 1, characterized in that (m/hr) satisfies 0.1≦D≦10. (37) The atomic ratio of the elements A, B, and Cu in the atomic or compound gas is supplied as 0.5≦B/A≦4 and 0.5≦Cu/A+B≦4. A method for producing a superconducting thin film according to claim 1. (38) As the chemical vapor deposition method, normal pressure, reduced pressure, or photochemical vapor deposition method is used, and the total pressure P_T during the formation of the composite oxide is set to 0.01≦P_T≦10 atmospheres. A method for producing a superconducting thin film according to claim 2 or 4. (39) As the chemical vapor deposition method, a plasma chemical vapor deposition method is used, and the total pressure P_T during the formation of the composite oxide is reduced to 0.
．． The method for manufacturing a superconducting thin film according to claim 3, characterized in that 1 Torr≦P_T≦100 Torr. (40) As the chemical vapor deposition method, electron cyclotron resonance plasma is used, and the total pressure P_ during the formation of the composite oxide is
9. The method of manufacturing a superconducting thin film according to claim 8, wherein T is set to 10^-^5≦P_T≦10^-^2 Torr.