WO2008038856A1

WO2008038856A1 - Method and apparatus for fabrication of thin film superconductor by spray pyrolysis chemical vapor deposition method

Info

Publication number: WO2008038856A1
Application number: PCT/KR2006/005148
Authority: WO
Inventors: Gye-Won Hong; Hee-Gyoun Lee; Ho-Jin Kim
Original assignee: Korea Polytechnic University
Current assignee: Korea Polytechnic University
Priority date: 2006-09-28
Filing date: 2006-12-01
Publication date: 2008-04-03
Anticipated expiration: 2009-03-28

Abstract

Disclosed herein is a method and apparatus for fabrication of a thin film superconductor. Specifically, provided is a method and apparatus for fabrication of a thin film superconductor using spray pyrolysis chemical vapor deposition, comprising dissolving an inorganometallic compound as a raw material in distilled water to prepare a precursor solution, spraying the resulting precursor solution in a state of fine droplets, and coating an epitaxial thin film on a substrate (such as a ceramic material, a nickel metal, a nickel alloy, stainless steel or the like) via a pyrolysis process. The method comprises dissolving an inorganometallic compound having a water-solubility in distilled water to prepare a precursor solution; processing the precursor solution into droplets having a size of several μm to several tens of μm and storing the droplets in a raw material storage; transferring the droplets in the storage to a main pipe via a pump and simultaneously supplying the droplets, in conjunction with carrier and reactant gases supplied by operation of a valve, to a nozzle; heating the droplets sprayed from the nozzle by an auxiliary heat source to evaporate the distilled water, thereby preparing fine-sized particles of the inorganometallic compound; elevating a temperature of a heater formed in a table, such that the resulting particles react with the reactant gas to form an oxide; uniformly forming a film of the oxide at opposite sides on a single crystal substrate having a certain texture provided to the table via conveyers, by a ∧ shaped stainless steel plate, thereby forming an oxide template having a certain texture on the upper part of the substrate, and sufficiently heating the single crystal substrate prepared by forming an oxide buffer layer on the resulting oxide template to form an oxide thin film; and subjecting the resulting oxide thin film to an oxygen heat-treatment to complete a thin film superconductor having superconducting properties. That is, the present invention provides a method for fabrication of a thin film superconductor made of REBa2Cu3O7-x (RE = a rare-earth element selected from the group consisting of Y, La, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and any combination thereof), using a precursor solution prepared by dissolving an inexpensive inorganometallic compound in distilled water. Therefore, the present invention enables production of superconductors at a significantly lower cost, as compared to the use of a conventional expensive β-chelate compound, i.e., 2,2,6,6-tetramethyl-3,5-heptanedione (tmhd).

Description

METHOD AND APPARATUS FOR FABRICATION OF THIN FILM SUPERCONDUCTOR BY SPRAY PYROLYSIS

CHEMICAL VAPOR DEPOSITION METHOD

Technical Field

[1] The present invention relates to a method and apparatus for fabrication of a thin film superconductor. More specifically, the present invention relates to a method and apparatus for fabrication of a thin film superconductor using spray pyrolysis chemical vapor deposition, comprising dissolving an inorganometallic compound as a raw material in distilled water to prepare a precursor solution, spraying the resulting precursor solution in a state of fine droplets, and coating an epitaxial thin film on a substrate (such as a ceramic material, a nickel metal, a nickel alloy, stainless steel or the like) via a pyrolysis process.

Background Art

[2] Hitherto, in order to deposit a superconducting thin film of REBa2Cu3O7-x (RE = a rare-earth element selected from the group consisting of yttrium (Y), lanthanum (La), Neodymium (Nd), Samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu) and any combination thereof) having a superconductivity on a substrate such as nickel having a { 100}<001> texture, a nickel alloy, a metal plate having an epitaxial coating of an oxide on the nickel alloy, a template having a coating of an oxide having a certain texture on stainless steel, or a single crystal substrate, by using a chemical vapor deposition (CVD) method, organometallic compounds have been used as an initial raw material. Specifically, the raw material which has been conventionally used in the preparation of high-temperature superconducting thin films having excellent characteristics was 2,2,6,6-tetramethyl-3,5-heptanedione (tmhd) which is a β-chelate compound having a relatively low-volatilization temperature and a chemical stability.

[3] Generally, a metal-organic chemical vapor deposition (MOCVD) method is usually carried out by heating to volatilize respective β-chelate compounds of Y(tmhd)3, Ba(tmhd)2 and Cu(tmhd)2 as solid-state raw materials, in order to meet a cation ratio of a final superconducting product (for example, Y:Ba:Cu=l:2:3) or dissolving the raw materials in THF (tetrahydrofuran) followed by evaporation, transferring the resulting volatilized or evaporated materials to a substrate and depositing them thereon via a chemical reaction.

[4] However, β-chelate compounds of Y(tmhd)3, Ba(tmhd)2 and Cu(tmhd)2, the raw materials used in the above deposition process, are very expensive. In particular, Ba(tmhd)2 suffers from problems associated with poor process reproducibility, due to high- volatilization temperature and chemical instability. Disclosure of Invention

Technical Problem

[5] Therefore, the present invention has been made in view of the above problems, and it is an object of the present invention to provide a method and apparatus for fabrication of a thin film superconductor via a spray pyrolysis chemical vapor deposition method, which uses relatively inexpensive inorganometallic compounds such as nitrates, chlorides and sulfates of metals, instead of using expensive organometallic compounds as an initial raw material, and involves epitaxial deposition of a superconducting thin film of REBa2Cu3O7-x (RE = a rare-earth element selected from the group consisting of Y, La, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and any combination thereof) on a metal template which had the epitaxial deposition of at least one ceramic buffer film (formed of a material selected from the group consisting of CeO2, MgO, YSZ, SrTiCβ, LaAlCβ, RuSrO, Gd2O3, Y2O3 and any combination thereof) on a base metal having a { 100}<001> texture, or on ceramic single crystals, by using a chemical method.

Technical Solution

[6] In accordance with an aspect of the present invention, the above and other objects can be accomplished by the provision of a method for fabrication of a thin film superconductor, comprising:

[7] dissolving an inorganometallic compound having a water-solubility in distilled water to prepare a precursor solution;

[8] processing the precursor solution into droplets having a size of several D to several tens of D and storing the droplets in a raw material storage;

[9] transferring the droplets in the storage to a main pipe via a pump and simultaneously supplying the droplets, in conjunction with carrier and reactant gases supplied by operation of a valve, to a nozzle;

[10] heating the droplets sprayed from the nozzle by an auxiliary heat source to evaporate the distilled water, thereby preparing fine-sized particles of the inorganometallic compound;

[11] elevating a temperature of a heater formed in a table such that the resulting particles react with the reactant gas to form an oxide;

[12] uniformly forming a film of the inorganometallic compound particles via the reaction with reactant gas, on a single crystal substrate introduced into the table, at opposite sides about a vertex of a Λ shaped stainless steel plate provided on the table, thereby forming an oxide template having a certain texture on the upper part of the single crystal substrate, and sufficiently heating the single crystal substrate prepared by forming an oxide buffer layer on the oxide template to form an oxide thin film; and

[13] subjecting the oxide thin film to an oxygen heat-treatment to complete a thin film superconductor having superconducting properties.

[14] In an embodiment of the present invention, the Λ shaped stainless steel plate has grooves on both sides thereof and is therefore placed on the table in a width direction thereof such that the single crystal substrate is introduced into the grooves, or the Λ shaped stainless steel plate is placed on the table in a length direction thereof such that the single crystal substrate is introduced into right/left sides of the stainless steel plate.

[15] In another embodiment of the present invention, the inorganometallic compound is a water-soluble metal nitrate, chloride or sulfate and is dissolved in distilled water, pure water or ultra pure water.

[16] In another embodiment of the present invention, a thin film of REBa2Cu3O7-x (RE

= a rare-earth element selected from the group consisting of yttrium (Y), lanthanum (La), Neodymium (Nd), Samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu) and any combination thereof), prepared by spray pyrolysis chemical vapor deposition using the above-mentioned inorganometallic compound as a raw material, has a cation composition ratio of RE:Ba:Cu=l:2:3.

[17] In another embodiment of the present invention, the concentration of the precursor solution containing the inorganometallic compound dissolved in distilled water is in the range of 0.01 to 0.30 M.

[18] In another embodiment of the present invention, preparation of droplets of the precursor solution having a size of several D to several tens of D is carried out using a method including forming the precursor solution into fine droplet mist using a vibrator having a frequency of more than several thousand Hz and transferring the resulting mist toward a substrate via a carrier gas flowing at a constant rate, or a method including discharging the precursor solution at a constant flow rate of 0.1 to 1.0 mL/ min into an injection nozzle using a micrometering pump, allowing for collision of the solution with the high-pressure carrier gas and reactant gas to thereby form fine droplets and transferring the fine droplets toward the substrate.

[19] In another embodiment of the present invention, an inert gas such as argon (Ar) or nitrogen (N2) gas is used as the carrier gas, and O2 or NO2 gas is used as the reactant gas.

[20] In another embodiment of the present invention, the metal substrate having a certain texture is a substrate including a layer of a cubic metal or alloy thereof such as heat- rolled nickel (Ni), an Ni-based alloy (Ni-W, Ni-Cr, or Ni-Cr-W), Ag or an Ag alloy, or an Ni-Ag composite and a ceramic intermediate layer for preventing the reaction with a superconducting layer on the metal surface and transferring the crystallinity of a biaxially oriented texture, or the single crystal substrate is made of single crystals such as MgO, LaAlCβ or SrTiCβ. [21] In another embodiment of the present invention, upon performing the spray pyrolysis chemical vapor deposition, the working pressure is in the range of 500 to 760

Torr when a vibrator is used, or the working pressure is in the range of 1 to 760 Torr when an air atomizing nozzle is used. [22] In another embodiment of the present invention, in order to obtain superconducting properties after deposition of the thin film, the oxide thin film is maintained in an atmosphere furnace at 500 to 3000 scm of oxygen gas and a temperature of 500°C for 1 to 15 hours. [23] In accordance with another aspect of the present invention, there is provided an apparatus for fabrication of a thin film superconductor via spray pyrolysis chemical vapor deposition utilizing an inorganometallic compound as a raw material, comprising: [24] a raw material storage for storing a raw material solution, prepared by dissolving a water-soluble inorganometallic compound in distilled water, in the form of fine droplets; [25] a nozzle for spraying the raw material solution in the state of fine droplets on a substrate, the solution being transferred via a main pipe by a pump provided on one side of the raw material storage; [26] a valve connected via an auxiliary pipe to one side of the main pipe and for supplying a carrier gas or a mixed gas of a carrier gas and a reactant gas to the nozzle; [27] auxiliary heat sources for supplying additional heat and positioned on right/left sides of the nozzle; [28] a table having, on a central part thereof, a heater for providing a stable heat supply such that the droplets of the raw material solution sprayed from the nozzle are deposited on the substrate to thereby form a thin film;

[29] conveyers for transferring the substrate and installed at both ends of the table; and

[30] reels for winding a single crystal substrate or a wire rod wound in one direction to an opposite direction by transferring the substrate or rod by the conveyers and installed at both ends of the conveyers. [31] In another embodiment of the present invention, a Λ shaped stainless steel plate is provided on the upper part of the table in which the heater is formed, and the stainless steel plate has grooves on both sides thereof and is therefore placed in a width direction of the table, or the stainless steel plate is placed in a length direction of the table. [32] FlG. 1 is a process flow chart illustrating a fabrication process of a thin film super- conductor according to the present invention; FlG. 2 is a view showing different fabrication embodiments in a spray pyrolysis chemical vapor deposition apparatus used for fabrication of a thin film superconductor according to the present invention; FlG. 3 is a graph showing results of X-ray diffraction analysis for a superconducting thin film fabricated according to a method of the present invention; FlG. 4 is an electron micrographs showing a microstructure of a superconducting thin film fabricated according to a method of the present invention; FlG. 5 is a graph showing measurement results of a critical current density for a superconducting thin film fabricated according to a method of the present invention; FlG. 6 is a block diagram of a spray pyrolysis chemical vapor deposition apparatus according to the present invention; FlG. 7 is a second embodiment showing a spray pyrolysis chemical vapor deposition apparatus according to the present invention; and FlG. 8 is a spray embodiment of a raw material solution which is sprayed from a nozzle according to the present invention.

Description of Drawings

[33] The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

[34] FlG. 1 is a process flow chart illustrating a fabrication process of a thin film superconductor according to the present invention;

[35] FlG. 2 is a view showing different fabrication embodiments in a spray pyrolysis chemical vapor deposition apparatus used for fabrication of a thin film superconductor according to the present invention;

[36] FlG. 3 is a graph showing results of X-ray diffraction analysis for a superconducting thin film fabricated according to a method of the present invention;

[37] FlG. 4 is an electron micrograph showing a microstructure of a superconducting thin film fabricated according to a method of the present invention;

[38] FlG. 5 is a graph showing measurement results of a critical current density for a superconducting thin film fabricated according to a method of the present invention;

[39] FlG. 6 is a block diagram of a spray pyrolysis chemical vapor deposition apparatus according to the present invention;

[40] FlG. 7 is a second embodiment showing a spray pyrolysis chemical vapor deposition apparatus according to the present invention; and

[41] FlG. 8 is a spray embodiment of a raw material solution which is sprayed from a nozzle according to the present invention.

Best Mode

[42] Hereinafter, a fabrication process of a thin film superconductor via a spray pyrolysis chemical vapor deposition method will be described with reference to the accompanying drawings.

[43] FlG. 1 is a process flow chart illustrating a fabrication process of a thin film superconductor, wherein a water-soluble inorganometallic compound is dissolved in distilled water to thereby prepare a precursor solution. The inorganometallic compounds that can be used in the present invention include, for example metal nitrates, metal chlorides and metal sulfates, and are dissolved in distilled water, pure water or ultra pure water. As the inorganometallic compound, compounds of REBa2Cu3O7-x (RE = a rare-earth element selected from the group consisting of Y, La, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and any combination thereof) are mixed in a ratio of RE:Ba:Cu=l:2:3 which may be slightly outside a stoichiometric value, depending upon experimental conditions. In order to achieve complete dissolution, the resulting solution may be stirred using a magnetic bar. The concentration of the precursor solution containing the inorganometallic compound dissolved in distilled water is in the range of 0.01 to 0.30 M (SlO).

[44] The thus-prepared precursor solution is processed into droplets having a size of several D to several tens of D and stored in a raw material storage 11 (S20).

[45] Next, the thus-stored droplets in the storage 11 are transferred to a main pipe 1 Ib via a pump 11a while simultaneously being supplied to a nozzle 12, in conjunction with carrier and reactant gases supplied by operation of a valve 13. Preparation and transfer of the droplets may be carried out in two ways as follows. First, as shown in FlG. 2A, fine droplet mist is formed using a vibrator having a frequency of more than several thousand Hz and the resulting mist is transferred toward a substrate by the carrier gas flowing at a constant rate. Alternatively, as shown in FlG. 2B, the precursor solution at a constant flow rate of 0.1 to 1.0 mL/min is discharged into a fine injection nozzle using a micrometering pump and the solution is allowed to collide with the high-pressure carrier gas and reactant gas to thereby form fine droplets which are then transferred toward the substrate. Herein, the micrometering pump may be used by controlling a pressure, even though it may be not suitable for vacuum applications. Inert gas such as argon (Ar) or nitrogen (N2) gas may be used as the carrier gas, whereas O2 or NO2 gas may be used as the reactant gas (S30).

[46] Next, the droplets having a size of several D to several tens of D, sprayed from the nozzle 12, are heated by an auxiliary heat source 14 to evaporate the distilled water, thereby preparing fine-sized particles of the inorganometallic compound. Herein, the distilled water is evaporated by heating it to a temperature of 100 to 200°C (S40).

[47] Then, a temperature of a heater 15a formed in a table 15 is elevated to ensure that the resulting fine particles of the inorganometallic compound react with the reactant gas to form an oxide (S50). [48] Next, the inorganometallic compound particles react with the reactant gas to uniformly form a film on a single crystal substrate 20 introduced into the table 15, at opposite sides about the vertex of a Λ shaped stainless steel plate 30, 30a provided on the table 15, thereby forming an oxide template having a certain texture on the upper part of the single crystal substrate 20, and sufficiently heating the single crystal substrate 20 prepared by forming an oxide buffer layer on the thus-formed oxide template to form an oxide thin film. The metal substrate having a certain texture is a substrate including a layer of a cubic metal or alloy thereof such as heat-rolled nickel (Ni), an Ni-based alloy (Ni-W, Ni-Cr, Ni-Cr-W or the like), Ag or an Ag alloy, an Ni- Ag composite and a ceramic intermediate layer coated for preventing the reaction with a superconducting layer on the metal surface and transferring the crystallinity of a biaxially oriented texture, and the single crystal substrate is made of single crystals such as MgO, LaAlCβ or SrTiCβ. Upon performing the spray pyrolysis chemical vapor deposition, the working pressure is in the range of 500 to 760 Torr when a vibrator is used, or the working pressure is in the range of 1 to 760 Torr when an air atomizing nozzle is used. As such, a uniform superconducting phase satisfying a desired cation ratio (for example, Y:Ba:Cu=l:2:3) is formed via chemical reactions (S60).

[49] The Λ shaped stainless steel plate 30 has grooves 31 on both sides thereof and is therefore placed on the table 15 in a width direction thereof such that the single crystal substrate 20 is introduced into the grooves 31, or otherwise the Λ shaped stainless steel plate 30a is placed on the table 15 in a length direction thereof such that the single crystal substrate 20 is introduced into right/left sides of the stainless steel plate 30a.

[50] Finally, an oxygen heat-treatment of the oxide thin film is followed to complete a thin film superconductor having superconducting properties. In order to obtain desired superconducting properties following the deposition of the thin film, the oxide thin film is maintained in an atmosphere furnace at 500 to 3000 scm of oxygen gas and a temperature of 400 to 500°C for 1 to 15 hours (S70).

[51] FIG. 3 is a graph showing results of X-ray diffraction analysis for a superconducting thin film fabricated according to the present invention. Herein, since an amount of current flowing along the a- or b-axis direction in the superconducting phase is significantly higher than that of current flowing along the c-axis direction, the superconducting c-axis should grow in the direction perpendicular to the substrate, upon fabrication of the superconducting thin film, in order to ensure sufficient and smooth flow of current. In addition, the results of X-ray diffraction analysis showed only the growth in the (001) direction, thus representing that the superconducting film has grown in the c-axis direction.

[52] FIG. 4 shows microscopic examination results for a microstructure of a super- conducting thin film sample, representing that superconducting crystal grains were formed. FlG. 4A is an electron micrograph showing a surface microstructure of a superconducting thin film, thus representing that the superconducting thin film obtained in this experiment has a smooth surface morphology, upon taking into consideration uniformity of thin-film deposition, no defects such as occurrence of pores and the surface flatness of the thin film, in conjunction with the above X-ray diffraction analysis results of FlG. 3 showing that the superconducting thin film was well deposited as desired.

[53] FlG. 4B is an electron micrograph of the microstructure of the superconducting thin film taken at a higher magnification (X 40000) than FlG. 4A (X 5000). Microscopic observation at a high power (X 40000) also showed that the thin film is uniformly and well deposited.

[54] FlG. 5 is a graph showing measurement results of a critical current density for a superconducting thin film fabricated according to the present invention. In order to become a high-quality superconductor, a superconductor of interest should be a material that is capable of providing the highest flow rate of current per sectional area. The superconducting thin film fabricated by this experiment has a thickness of 0.176 D and a width of 4 mm, and exhibits a current density of 0.43 MA/cm2 at current of 3 A which corresponds to a value capable of providing a current flow of 430,00OA per sectional area (1 cm2).

[55] FlG. 6 is a block diagram of a spray pyrolysis chemical vapor deposition apparatus according to the present invention, wherein FIGS. 6 A and 6B show side and plan views of the apparatus, respectively. Referring to FlG. 6, a spray pyrolysis chemical vapor deposition apparatus 10 comprises a raw material storage 11 for storing a raw material solution, prepared by dissolving a water-soluble inorganometallic compound in distilled water, in the form of fine droplets (small water droplets); a nozzle 12 for spraying the raw material solution in the state of droplets on a substrate 20, the solution being transferred via a main pipe 1 Ib by a pump 11a provided on one side of the raw material storage 11 ; a valve 13 connected via an auxiliary pipe 13a to one side of the main pipe lib and for supplying a carrier gas or a mixed gas of a carrier gas and a reactant gas to the nozzle 12; auxiliary heat sources 14 for supplying additional heat and positioned on right/left sides of the nozzle 12; a table 15 having, on a central part thereof, a heater 15a for providing a stable heat supply such that the droplets of the raw material solution sprayed from the nozzle 12 are deposited on the substrate 20 to thereby form a thin film; conveyers 16 for transferring the substrate 20 and installed at both ends of the table 15; and reels 17 installed at both ends of the conveyers 16 and for winding a single crystal substrate 20 or a wire rod (a short wire rod and a long wire rod longer than several tens of meters) wound in one direction to an opposite direction by transferring the substrate or rod by the conveyers 16.

[56] The Λ shaped stainless steel plate 30 is provided on the upper part of the table 15 in which the heater 15a is formed. Herein, the stainless steel plate 30 has grooves 31 on both sides thereof, as shown in FlG. 6C and is therefore placed in a width direction of the table 15, such that the oxide thin film is formed on the single crystal substrate 20 introduced into the table 15 by the conveyers 16 as the substrate 20 passes through the grooves 31 of the stainless steel plate 30.

[57] FlG. 7 is a second embodiment showing a spray pyrolysis chemical vapor deposition apparatus according to the present invention, wherein FIGS. 7 A and 7B show side and plan views of the apparatus, respectively. Even though the apparatus of FlG. 7 has the same constitution as that of FlG. 6, the stainless steel plate 30a having a shape as shown in FlG. 7C is placed in a length direction of the table 15, and two conveyers 16 and two reels 17 are respectively provided at opposite sides about the stainless steel plates 30a.

[58] The reason of forming the stainless steel plates 30,30a into a Λ shape is to achieve uniform formation of the film on the single crystal substrate 20 by uniformly spraying the raw material solution at opposite sides about the Λ shaped stainless steel plates 30,30a, as shown in FlG. 8B, because spraying of the raw material solution from the nozzle 12 is localized at the central part of the single crystal substrate 20, as shown in FIG. 8A.

Industrial Applicability

[59] As apparent from the above description, the present invention provides a method for fabrication of a thin film superconductor made of REBa2Cu3O7-x (RE = a rare-earth element selected from the group consisting of Y, La, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and any combination thereof), using a precursor solution prepared by dissolving an inexpensive inorganometallic compound in distilled water. Therefore, the present invention enables production of superconductors at a significantly lower cost, as compared to the use of a conventional expensive β-chelate compound, i.e., 2,2,6,6-tetramethyl-3,5-heptanedione (tmhd).

[60] Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

Claims

[1] A method for fabrication of a thin film superconductor via spray pyrolysis chemical vapor deposition utilizing an inorganometallic compound as an initial raw material, comprising: dissolving an inorganometallic compound having a water-solubility in distilled water to prepare a precursor solution; processing the precursor solution into droplets having a size of several D to several tens of D and storing the droplets in a raw material storage; transferring the droplets in the storage to a main pipe via a pump and simultaneously supplying the droplets, in conjunction with carrier and reactant gases supplied by operation of a valve, to a nozzle; heating the droplets sprayed from the nozzle by an auxiliary heat source to evaporate the distilled water, thereby preparing fine-sized particles of the inorganometallic compound; elevating a temperature of a heater formed in a table, such that the resulting particles react with the reactant gas to form an oxide; uniformly forming a film of the inorganometallic compound particles via the reaction with reactant gas, on a single crystal substrate introduced into the table, at opposite sides about a vertex of a Λ shaped stainless steel plate provided on the table, thereby forming an oxide template having a certain texture on the upper part of the single crystal substrate, and sufficiently heating the single crystal substrate prepared by forming an oxide buffer layer on the oxide template to form an oxide thin film; and subjecting the oxide thin film to an oxygen heat-treatment to complete a thin film superconductor having superconducting properties.

[2] The method according to claim 1, wherein the Λ shaped stainless steel plate has grooves on both sides thereof and is therefore placed on the table in a width direction thereof such that the single crystal substrate is introduced into the grooves, or the Λ shaped stainless steel plate is placed on the table in a length direction thereof such that the single crystal substrate is introduced into right/left sides of the stainless steel plate.

[3] The method according to claim 1, wherein the inorganometallic compound is a water-soluble metal nitrate, chloride or sulfate and is dissolved in distilled water, pure water or ultra pure water.

[4] The method according to claim 1, wherein a thin film of REBa2Cu3O7-x (RE = a rare-earth element selected from the group consisting of yttrium (Y), lanthanum (La), Neodymium (Nd), Samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu) and any combination thereof), prepared by spray pyrolysis chemical vapor deposition using the inorganometallic compound as a raw material, has a cation composition ratio of RE:Ba:Cu=l:2:3.

[5] The method according to claim 1, wherein the concentration of the precursor solution containing the inorganometallic compound dissolved in distilled water is in the range of 0.01 to 0.30 M.

[6] The method according to claim 1, wherein preparation of droplets of the pr ecursor solution having a size of several D to several tens of D is carried out using a method including forming the precursor solution into fine droplet mist using a vibrator having a frequency of more than several thousand Hz and transferring the resulting mist toward a substrate via a carrier gas flowing at a constant rate, or a method including discharging the precursor solution at a constant flow rate of 0.1 to 1.0 mL/min into an injection nozzle using a micrometering pump, allowing for collision of the solution with the high-pressure carrier gas and reactant gas to thereby form fine droplets and transferring the fine droplets toward the substrate.

[7] The method according to claim 1, wherein an inert gas such as argon (Ar) or nitrogen (N2) gas is used as the carrier gas, and O2 or NO2 gas is used as the reactant gas.

[8] The method according to claim 1, wherein the metal substrate having a certain texture is a substrate including a layer of a cubic metal or alloy thereof such as heat-rolled nickel (Ni), an Ni-based alloy (Ni-W, Ni-Cr, or Ni-Cr-W), Ag or an Ag alloy, or an Ni-Ag composite and a ceramic intermediate layer for preventing the reaction with a superconducting layer on the metal surface and transferring the crystallinity of a biaxially oriented texture, or the single crystal substrate is made of single crystals such as MgO, LaAlCβ or SrTiCβ.

[9] The method according to claim 1, wherein, upon performing the spray pyrolysis chemical vapor deposition, the working pressure is in the range of 500 to 760 Torr when a vibrator is used, or the working pressure is in the range of 1 to 760 Torr when an air atomizing nozzle is used.

[10] The method according to claim 1, wherein, in order to obtain superconducting properties after deposition of the thin film, the oxide thin film is maintained in an atmosphere furnace at 500 to 3000 scm of oxygen gas and a temperature of 500°C for 1 to 15 hours.

[11] An apparatus for fabrication of a thin film superconductor via spray pyrolysis chemical vapor deposition utilizing an inorganometallic compound as a raw material, comprising: a raw material storage for storing a raw material solution, prepared by dissolving a water-soluble inorganometallic compound in distilled water, in the form of fine droplets; a nozzle for spraying the raw material solution in the state of fine droplets on a substrate, the solution being transferred via a main pipe by a pump provided on one side of the raw material storage; a valve for supplying a carrier gas or a mixed gas of a carrier gas and a reactant gas to the nozzle and connected via an auxiliary pipe to one side of the main pipe; auxiliary heat sources for supplying additional heat and positioned on right/left sides of the nozzle; a table having, on a central part thereof, a heater for providing a stable heat supply such that the droplets of the raw material solution sprayed from the nozzle are deposited on the substrate to thereby form a thin film; conveyers for transferring the substrate and installed at both ends of the table; and reels for winding a single crystal substrate or a wire rod wound in one direction to an opposite direction by transferring the substrate or rod by the conveyers and installed at both ends of the conveyers.

[12] The apparatus according to claim 11, wherein a Λ shaped stainless steel plate is provided on the upper part of the table in which the heater is formed, and the stainless steel plate has grooves on both sides thereof and is therefore placed in a width direction of the table, or the stainless steel plate is placed in a length direction of the table.