JPH055181A - Reactor for mocvd - Google Patents

Abstract

PURPOSE:To prevent modification of an oxide superconducting film due to floating fine particles which are produced by deposition of the source gas on the inner wall of reactor. CONSTITUTION:A reactor 1 is equipped with a supply port 11 to introduce the source gas for the formation of thin oxide superconducting film, and with a discharge port 16 for the residual gas. A high frequency heater coil 4 is provided around this reactor in the area corresponding to the reaction substrate 2 which accepts deposition of the thin oxide superconducting film. Also, a resistor-type heating means 3 is provided in the area where no high frequency heater coil is disposed around the reactor 1. Thereby, a thin oxide superconducting film having excellent uniformly of compsn. and stable super-conductivity can be formed with this cold wall-type MOCVD reactor.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reactor capable of forming an oxide superconducting film by the MOCVD method without mixing a reactor deposit.

[0002]

2. Description of the Related Art A high temperature reaction substrate in which a raw material gas containing an element for forming an oxide superconductor, which is obtained by gasifying a powder raw material such as a β-diketone chelate compound of Y, Ba or Cu, is placed in a reactor. There is known a MOCVD method in which an oxide superconducting film is attached by supplying it on top to cause a decomposition reaction.

Conventionally, as a reactor for arranging the above reaction substrate, a high frequency heating coil is attached to the outer periphery of the reactor having a source gas supply port and a residual gas exhaust port to which an oxide superconducting film is attached. There was known a cold wall type that was partially arranged corresponding to. However, there has been a problem that the raw material gas is deposited in the reactor to form fine powder, which floats to deteriorate the oxide superconducting film formed on the reaction substrate and deteriorate the superconducting property.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to obtain a cold wall type reactor which does not cause the above-mentioned floating problem of deposited fine powder of raw material gas.

[0005]

According to the present invention, a high-frequency heating coil is provided on the outer periphery of a reactor having a supply port for a raw material gas for forming an oxide superconducting film and an exhaust port for a residual gas. MOCVD, which is partially arranged corresponding to a reaction substrate to be attached, and in which an electric resistance type heating means is arranged in a portion where the high frequency heating coil is not arranged on the outer periphery of the reactor. A reactor for use is provided.

[0006]

[Function] Usually, the reaction substrate in the reactor in a depressurized state is heated through the high-frequency heating coil while the source gas is supplied from the supply port, and the reaction substrate is thermally decomposed and reacted.
An oxide superconducting film is formed and attached on the reaction substrate. By heating the reactor by the electric resistance type heating means in a portion other than the portion where the high frequency heating coil is arranged on the outer circumference of the reactor, generation of fine powder due to deposition of the raw material gas is prevented. The residual gas, which is a decomposition gas of the raw material gas, is exhausted to the outside of the reactor through the exhaust port.

[0007]

EXAMPLE FIG. 1 shows a batch type embodiment, and FIG. 2 shows a continuous film forming type example. 1 is a reactor, 2 is a reaction substrate,
3 is an electric resistance type heating means and 4 is a high frequency heating coil. In addition, 11 is a source gas supply port, 12 is a holding stand, 1
Reference numeral 4 is an introduction path, 16 is an exhaust port for residual gas, and 5 is a fiber-type radiation thermometer.

As shown in FIGS. 1 and 2, a reactor 1 having a source gas supply port 11 for forming an oxide superconducting film and a residual gas exhaust port 16 is used. It may have a plurality of supply ports and exhaust ports. The reactor is not limited, but is preferably formed of a transparent heat-resistant material such as quartz glass.

In the batch type reactor 1 illustrated in FIG. 1, a single reaction substrate 2 can be held via a holding table 12. The holding table 12 is arranged and fixed at the center of the reactor via a support plate 13.

In the continuous film forming type reactor 1 illustrated in FIG.
The reaction substrate 2 made of a long body such as a tape or a wire is continuously and sequentially introduced through the introduction path 14 as shown by an arrow, and the reactor 1
An oxide superconducting film can be continuously formed on the reaction substrate 2 while passing through the inside. Reference numeral 15 is a partition wall provided in the introduction passage 14 in order to increase the maintenance rate of the reduced pressure state in the reactor 1 and to suppress the intrusion of impurities.

As is apparent from FIGS. 1 and 2, a high frequency heating coil 4 is partially arranged on the outer periphery of the reactor 1. The high frequency heating coil 4 is for heating the reaction substrate 2 and decomposing and reacting the raw material gas on the reaction substrate 2 to form an oxide superconducting film. Therefore, the high frequency heating coil 4
Are partially provided at positions corresponding to the arrangement of the reaction substrate 2. The heating temperature of the reaction substrate 2 is appropriately determined according to the decomposition / reaction temperature of the raw material gas. It is preferable that the temperature is precisely controlled via the radiation thermometer 5 or the like in order to stably form an oxide superconducting film having excellent superconducting properties.

In the present invention, in addition to the high frequency heating coil 4, an electric resistance type heating means 3 is arranged on the outer periphery of the reactor 1. The electric resistance type heating means 3 is for heating the reactor 1 in order to prevent the raw material gas from being deposited on the inner wall of the reactor 1 to generate fine powder.

Therefore, the electric resistance type heating means 3 is provided in the outer peripheral portion of the reactor which does not reach the temperature capable of preventing the generation of the fine powder in the high frequency heating coil 4. The heating temperature is a temperature at which the gas state of the raw material gas can be maintained, and is appropriately determined according to the gasification temperature (evaporation temperature) of the raw material gas.
Generally, the temperature is 200 ° C. or higher, and particularly 230 ° C. or higher, which is a temperature slightly higher than the highest gasification temperature of each raw material. The electric resistance type heating means may be appropriately formed by, for example, a method of winding a resistor tape or a resistance wire around the outer circumference of the reactor.

In the MOCVD reactor of the present invention, the source gas is supplied from the supply port 11 to the exhaust port 16 as shown by the arrow to form the oxide superconducting film on the reaction substrate 2 and the residual gas. Etc. are exhausted. A carrier gas is used as needed to supply the source gas and exhaust the residual gas. As the carrier gas, an inert gas such as argon gas, nitrogen gas or helium gas is generally used.

Examples of the above-mentioned reaction substrate include substrates and tapes made of various ceramics or various metals such as silver and its alloys, especially high melting point alloys such as silver-platinum alloys and silver-palladium alloys, and the like. A wire rod or the like having an appropriate form is used.

In the present invention, various oxide superconducting films can be formed. There is no particular limitation on the type of the superconductor. For example, YBa ₂ Cu ₃ O _y or Y
Y-based oxide superconductors such as Ba ₂ Cu ₄ O _y , Ba _1-x K _x Bi
Such Ba-based oxide superconductor O _3, Nd _2-x Ce such Nd-based oxide superconductor _{x CuO y, Bi 2 Sr 2} CaCu 2 O y, Bi 2-x
Examples thereof include Bi-based oxide superconductors such as Pb _x Sr ₂ Ca ₂ Cu ₃ O _y , La-based oxide superconductors, Tl-based oxide superconductors, Pb-based oxide superconductors, and the like. Further, there may be mentioned those obtained by substituting the above-mentioned components such as Y with other rare earth elements and those obtained by substituting the above-mentioned components such as Ba with other alkaline earth metals.

[0017]

According to the present invention, it is possible to prevent the raw material gas from depositing on the inner wall of the reactor to be made into fine powder, and to change the composition of the oxide superconducting film formed by floating the fine powder. It is possible to prevent the deterioration. Therefore,
It is possible to obtain a cold wall type MOCVD reactor in which an oxide superconducting film having excellent composition uniformity and stable superconducting properties is formed.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional side view of an embodiment.

FIG. 2 is a partial cross-sectional side view of another embodiment.

[Explanation of symbols]

 1: Reactor 11: Source gas supply port 16: Residual gas exhaust port 2: Reaction substrate 3: Electric resistance type heating means 4: High frequency heating coil

Claims (1)

Claim: What is claimed is: 1. A high-frequency heating coil is provided on the outer periphery of a reactor having a supply port for a raw material gas for forming an oxide superconducting film and an exhaust port for a residual gas, and an oxide superconducting film is attached to the reactor. A MOCVD reaction characterized in that an electric resistance type heating means is arranged in a portion which is partially arranged corresponding to a reaction substrate to be received and in which a high frequency heating coil is not arranged on the outer periphery of the reactor. vessel.