JPH01308806A - Production of filmy superconductor - Google Patents

Abstract

PURPOSE:To obtain the title superconductor through CVD process with enhanced film formation rate and improved critical temperature and mechanical strength, by making raw materials into metal complex gases and also mixing a fluorine source gas. CONSTITUTION:A vaporized ligand (e.g. hexafluoroacetylacetone) is put into each of containers 11, 12, 13, while plural kinds of raw materials (e.g. Ba compound, Y compound, Cu compound) are put into respective containers 1, 2, 3. Thence, the ligand in the containers 11, 12, 13 is transferred through a carrier gas (e.g. Ar) to the respective containers 1, 2, 3 followed by heating using respective heaters 8 to convert the raw materials in the containers 1, 2, 3 into metal complex gases, respectively, which are then introduced into a reaction chamber 5. Simultaneously, oxygen 10 and a fluorine source gas 15 are also introduced into said chamber 5 followed by heating the resultant mixed gas using a heater 8 to cause chemical reactions, thus forming the objective filmy superconductor on a substrate 9.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for manufacturing a film-like superconductor by a CVD method.

[Prior Art] Screen printing methods and sputtering methods are known as methods for manufacturing film-like superconductors.

However, in the screen printing method using powdered raw materials, the superconductor becomes a low-density, non-oriented polycrystalline body, so a high critical current density cannot be expected, and high-temperature treatment for sintering is required. Since it is necessary, it has the disadvantage that it is not suitable for IC implementation. On the other hand, methods using sputtering have the disadvantages that the superconductor film formation rate is slow, the composition tends to be unstable, and it is difficult to increase the size of the equipment because the film is formed in a vacuum. Ta.

Here, as one of the methods for manufacturing thin films, there is a CVD method that is excellent in composition, crystal orientation, adhesion strength with the base material, control of film formation, etc., and this CVD method is used to manufacture film-like superconductors. That is what is being considered.

[Problems to be Solved by the Invention] When using the CVD method to produce a film-like superconductor, the superconductor raw material is vaporized and introduced into a reaction chamber to cause a gas phase reaction to produce a superconducting film. I will do it.

In order to realize the production of a film-like superconductor by such a CVD method, it is necessary to solve the following problems. That is, in order to increase the film formation rate, it is necessary to increase the vapor pressure of the superconducting raw material and to control the vapor pressure of each raw material (raw material gas) in accordance with the composition of the superconductor.

Furthermore, it is known that when a certain amount of fluorine is contained, the critical temperature Tc of a superconductor can be increased as shown in Table 1, and the density ρ and transverse rupture strength σ can also be increased (according to the applicant) Special Application No. 1983-19053 (January 29, 1988)
(see Japanese application), etc.).

There has been a demand for realizing such excellent effects due to fluorine content also by CVD method.

The present invention was made in view of the above-mentioned conventional circumstances, and
The purpose of this study is to realize the production of a film-like superconductor by a method and to incorporate fluorine into the superconductor.

(Leaving space below) 1-1 in Table 1 1-2 in Table 1-3 1-3 in Table 1-4 1-4 in Table 1-5 1-6 in Table 1 2-1 Table 2-2 Table 2-3 Table 2-4 Table 2-5 Table 2-6 [Means and actions for solving the problem above] The present invention, which solves the problems and realizes the production of a film-like superconductor by the CVD method, includes a step of converting one of a plurality of types of superconducting raw materials into a metal complex gas, and a step of using the plurality of types of superconducting raw material gases together with a fluorine source gas. The method is characterized by comprising a step of introducing the method into a reaction chamber and causing a chemical reaction to form a film-like superconductor.

That is, by complexing the metal elements of the superconducting raw material, the vapor pressure when the superconducting raw material is turned into a vapor phase is increased, and the production rate of the superconductor is accelerated. In addition, by appropriately selecting the ligands of this complex, it is possible to change the vapor pressure of the metal complex gas appropriately and cause the reaction to occur at a vapor pressure that corresponds to the composition ratio of each constituent element of the superconducting material that is the final product. can. Then, when reacting the superconducting raw material gas in the reaction chamber, a fluorine source gas is supplied to cause the produced superconductor to contain fluorine.゛Furthermore, the present invention, which solves the above problems and realizes the production of a film-like superconductor by the CVD method, includes a step of converting a superconducting raw material into a metal complex gas using a fluorine-containing ligand, and a step of converting the plurality of types of The method is characterized by comprising a step of introducing a superconducting raw material gas into a reaction chamber to generate a chemical reaction to form a film-like superconductor.

That is, when the metal elements of the superconducting raw material are complexed, fluorine is added thereto, and a fluorine-containing superconductor is produced by the reaction of these metal complex gases in a reaction chamber. In addition,
Sublimation of a fluorine-free ligand complex in a fluorine-containing ligand atmosphere, or sublimation of a fluorine-free ligand complex gas together with a fluorine-containing ligand gas in a reaction chamber. A fluorine-free ligand may be replaced with a fluorine-containing ligand by transporting the fluorine-containing ligand to a fluorine-containing ligand.

Here, the ligand is selected depending on the type of metal complex, and HFA is selected as a fluorine-containing one.
(Hexaf 1uoroacetylacetone
), etc., and DPM as one that does not contain fluorine.
(D i p i va I oymethane),
THF (Tetrahydrofuran), DMF
(Dimethylformamide), dioxane, diethyl ether, dimethylacetamide, etc. are used. In addition, as a fluorine source gas, for example, F2, CF3
Br etc. are used.

[Effects of the Invention] According to the production method of the present invention, by using a metal complex gas as the superconducting raw material, it is possible to increase the vapor pressure of the superconducting raw material gas under relatively low temperature conditions, and to improve the production of film-like superconductors. Productivity can be improved. Furthermore, by incorporating fluorine into the superconducting raw material gas or introducing fluorine into the reaction chamber, it is possible to incorporate fluorine into the superconductor produced in the reaction chamber, improving the critical temperature of the superconductor and improving mechanical properties. Strength can be improved.

[Embodiment] First, an example of an apparatus for carrying out the present invention will be described based on FIG. 1.

In the figure, 1.2.3 are raw material containers containing metal elements or metal complexes, which are the raw materials for superconductors, and vaporized ligands are stored upstream of these raw material containers 1.2.3. Ligand containers 11.12.13 are provided, these ligand containers 11.12.13 being source containers 1.2.3.
are connected to each. Usually, a complex gas is created by adding a ligand to a compound of a superconducting element, for example,
A metal complex gas can also be obtained by directly complexing Ba metal with a ligand.

A reaction vessel 5 is provided downstream of the raw material vessel 1.2.3,
The raw material vessels 1.2.3 are each connected to a reaction vessel 5. An oxygen supply source 10 is connected to the reaction vessel 5, and a vacuum pump 7 is also connected via a trap 6. Further, a heater 8 is provided in each of the raw material containers 1.2.3, the reaction container 5, and the pipe line from the raw material container 1.2.3 to the reaction container 5.

In the CVD apparatus having the above configuration, a substrate 9 on which a superconductor is deposited in a film form is installed inside the reaction vessel 5, and the inside of the reaction vessel 5 is depressurized by the vacuum pump 7 and heated by the heater 8 to start producing the superconductor. do.

That is, when a metal complex gas containing a fluorine-containing ligand is introduced into the reaction chamber, the fluorine-containing ligand is accommodated in any or all of the ligand containers 11, 12, and 13. Then, argon gas Ar is supplied as a carrier gas from the upstream side of the ligand container 11.12.13,
The ligand gas contained in the ligand container 11.12.13 is carried on Ar gas and supplied to the raw material container 1.2.3. Then, under heating conditions by the heater 8, the raw material container 1.
The superconductor raw material in step 2.3 is a fluorine-containing metal complex gas (including adducts resulting from the addition reaction of ligands), and this metal complex gas is carried on Ar gas and supplied to the reaction vessel 5. Note that during the transfer from the raw material container 1.2.3 to the reaction container 5, the temperature of the metal complex gas is maintained by heating by the heater 8.

In this way, the metal complex gas (
For example, a chemical reaction is caused in the reaction vessel 5 by supplying Ba complex gas from raw material container 1, Y complex gas from raw material container 2, Cu complex gas from raw material container 3, and supplying oxygen 02 from an oxygen source. A predetermined superconducting material containing fluorine is deposited on the substrate 9 to produce a film-like superconductor.

Here, even if the raw material contained in the raw material container does not contain fluorine, it may be sublimated under the fluorine-containing ligand gas supplied from the ligand container or the fluorine-containing ligand gas When mixed with the fluorine-containing ligand and transported to the reaction vessel, a metal complex gas formed by a fluorine-containing ligand or a metal complex gas coexisting with a fluorine-containing ligand gas can be introduced into the reaction vessel.

On the other hand, when superconducting raw material gas is introduced into the reaction chamber together with fluorine source gas, the ligand contained in the ligand container 11.12.13 and the raw material contained in the raw material container 1.2.3 contain fluorine. A superconductor containing fluorine can be produced by introducing a fluorine source gas into the reaction container 5 from the fluorine source 15 connected to the reaction container 5. . In this case, of course, a ligand or a raw material containing fluorine may be used.

The above-mentioned apparatus is an example of producing a Ba-Y-Cu-0-based superconductor, but when producing a B1-5r-Ca-Cu-0-based superconductor, a raw material container is added to the above-mentioned apparatus. For the receiver, it is sufficient to add one more system equipped with a ligand container.

Next, an example in which a film-like superconductor was produced using the above-described apparatus will be described below.

<Example 1> This example is an example of producing a Ba-Y-Cu-0 based superconductor.

Ba (HFA) is used as a metal complex gas as a superconducting raw material.
As the ligand gases, HFA was used for Ba(HFA)2, and HFA was used for Y(HFA)3. Note that since Cu(HFA)2 is stable, the ligand supplied from the ligand container to the raw material container was not used.

Furthermore, Ar gas was used as a carrier gas.

In addition, in each raw material container, Ba(HFA) 2 gas with a vapor pressure of 4 mmHg at 200°C, Y(HFA) 3 gas with a vapor pressure of 2 mmHg at 120°C, and 6 vapor pressure at 100°C.
Cu(HFA)2 gas of mmHg was obtained. Then, these metal complex gases are introduced into the reaction vessel together with 02 gas,
A chemical reaction was carried out at a reaction pressure of 10 to 100 Torr and a reaction temperature of 350°C.

After the reaction, the sample was placed in an oxygen atmosphere at 600°C for 10
As a result of heat treatment for several hours, a uniform film of fluorine-containing superconductor (YBa2Cu:+C)r-δ:F) with a critical temperature Tc = 95 and a critical current density Jc = 5X10'A/cm2 was produced. .

In addition, Y(DPM)3 may be used instead of Y(HFA)3, or Cu(DPM) may be used instead of Cu(HFA)2.
2 may be used, and even in this case, the amount of fluorine added to the superconductor could be ensured by the fluorine-containing ligand, and a superconductor similar to the above was obtained. Furthermore, He may be used as the carrier gas instead of Ar.

<Example 2> This example is an example of producing a B 1-5r-Ca-Cu-0-based superconductor.

Bi(OC2H
5) 3 gases, 5r (HFA) 2 gases, Ca (HFA)
2 gas, Cu (HFA) 2 gas, and HFA, Ca (HFA) for 5r (HFA) 2 as a ligand gas.
) HFA was used for 2.

Further, Ar (or He) gas was used as a carrier gas.

In addition, in each raw material container, B i (OC2H5)3 gas with a vapor pressure of 1 mmHg at 120°C, 80°C
5r(HFA)2 gas with vapor pressure lmmHg at 80°C, (HFA)2 gas with vapor pressure lmmHg at 150°
Cu(HFA)2 gas with a vapor pressure of 1.5 mmHg was obtained at C. Then, these metal complex gases were introduced into a reaction vessel together with 02 gas, and a chemical reaction was carried out at a reaction pressure of 10 to 100 Torr and a reaction temperature of 350°C. After the reaction, the sample was heat-treated in the atmosphere at 750°C for 30 hours, and as a result, the critical temperature Tc = 100, and the critical current density Jc = IX10.
'A/cm2 fluorine-containing superconductor (BiCaS
A uniform film of rCu20x:F) was produced.

<Example 3> This example is an example of producing a Ba-Y-Cu-0 based superconductor.

As superconducting raw materials, Ba is Ba(AcAc)2, Y is Y
(ACAC)3 and Cu were used by heating and gasifying Cu(AcAc)2 under HFA gas.

Further, Ar (or He) gas was used as a carrier gas.

In addition, Ba(HFA)2HFA gas of 4 mmHg at 200°C, Y(HFA)3-HFA gas of 2 mmHg at 120°C, and Cu(HFA)2-HF of 6 mmHg at 100°C were generated by reaction with HFA in each reaction vessel.
I got A gas.

Then, these metal complex gases are introduced into the reaction vessel together with the 02 gas, and the reaction pressure is 10 to 100T.

rr, chemical reaction was carried out at a reaction temperature of 350°C. After the reaction, the sample was heat-treated in an oxygen atmosphere at 600°C for 10 hours, resulting in a fluorine-containing superconductor (YBa2Cu3
A uniform film of 07-δ:F) was produced.

<Example 4> This example is an example of producing a B 1-5r-Ca-Cu-0-based superconductor.

As superconducting raw materials, Bi and Cu are respectively Bi(OC2
Using H5)3 gas and Cu (HFA)2 gas, Sr,
Ca is the respective metal alkoxide 5r (OC2H5)
2. Ca (OC2H5)2 was heated and gasified under HFA gas.

Further, Ar (or He) gas was used as a carrier gas.

Regarding Bi and Cu, Bi(OC2H5)3 with a vapor pressure of 1 mmHg at 120°C in each raw material container.
Cu(HF) gas, vapor pressure 1.5 mmHg at 150°C
A) Two gases, Sr and Ca, were produced by reaction with HFA in a raw material container at 80°C with a vapor pressure of 1 mm.
H'g of 5r(HFA)2 gas, vapor pressure l at 80℃
mmHg (, a(HFA)2 gas was obtained.

Then, these metal complex gases were introduced into a reaction vessel together with 02 gas, and a chemical reaction was carried out at a reaction pressure of 10 to 100 Torr and a reaction temperature of 350°C. Then, the sample after reaction was
As a result of heat treatment in the atmosphere at 50°C for 30 hours, a fluorine-containing superconductor (BiCaS r Cu20x: F) was produced.
A uniform film was produced.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of a manufacturing apparatus according to an embodiment of the present invention. 1.2.3 is a raw material container, 5 is a reaction container, 7 is a vacuum pump, 9 is a substrate, 10 is an oxygen supply source, 11.12.13 is a ligand container, and 15 is a fluorine source gas supply source. Patent applicant Mitsubishi Metals Corporation

Claims (2)

[Claims] (1) A step of converting one of multiple types of superconducting raw materials into a metal complex gas, and introducing the multiple types of superconducting raw material gases together with a fluorine source gas into a reaction chamber to generate a chemical reaction to form a film-like superconductor. A method for producing a film-like superconductor, comprising the steps of: (2) A step of converting the superconducting raw material into a metal complex gas using a fluorine-containing ligand, and introducing the plurality of types of superconducting raw material gases into a reaction chamber to generate a chemical reaction to form a film-like superconductor. A method for producing a film-like superconductor, comprising the steps of: