JPH02156075A - Production of thin superconductor film - Google Patents

Abstract

PURPOSE:To increase the efficiency of capture of vapor phase superconductor ceramics on a body for deposition by irradiating the ceramics with laser beam to ionize the atoms of the ceramics and by impressing voltage whose polarity is reverse to that of the ionized atoms on the body. CONSTITUTION:A target 31 is irradiated with laser beam 32 for generating clusters to generate clustery sputtered particles 34a from the target 31. The particles 34a are ionized by irradiation with laser beam 33 for ionization and the ionized particles are decomposed to generate positively ionized atoms 34. Negative voltage is impressed on a body 35 for deposition and the ionized atoms 34 are attracted to the body 34 and deposited. By this method, a high quality thin superconductor film can be formed at a high rate in a high yield of the starting material.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention generates an electric field between a vapor phase superconductor ceramic and an adherend, thereby actively moving the vapor phase superconductor ceramic onto the adherend. A method for producing superconductor thin films deposited on

<Prior Art> Techniques for forming superconductor thin films using RF sputtering and laser beam sputtering have been known. According to the laser beam sputtering method, as shown in FIG. 4, a superconducting ceramic target 21 is irradiated with a laser beam 22 to generate cluster-shaped vapor phase superconducting ceramics 23, and the cluster-shaped sputtered particles are 23 is deposited on the substrate 24 to form the thin film 2.
form 5. In this laser beam sputtering method, since the sputter particles generated from the target are in the form of clusters, sputter particles of atomic units are generated.
This method has the advantage that the film formation rate is faster than the F sputtering method.

<Problems to be Solved by the Invention> However, in the above method, sputtered particles scattered from the target, that is, vapor-phase superconducting ceramics, are deposited on an adherend (substrate) placed opposite the target. As a result, sputtered particles with a large scattering angle tend to come off the substrate, resulting in a problem that the sputtered particles generated from the target are captured on the substrate with poor efficiency.

Incidentally, when the vapor phase particles are allowed to move freely and deposited on the adherend, the above-mentioned situation is the same even in methods other than the sputtering method.

The present invention was made in view of the above-mentioned conventional circumstances, and an object of the present invention is to provide a method capable of forming a superconducting thin film with high raw material yield by increasing the trapping efficiency of vapor phase superconducting ceramics on an adherend. shall be.

<Means for Solving the Problems> The invention of the present application to solve the above problems irradiates vapor phase superconducting ceramics with a laser beam to ionize the constituent atoms of the superconducting ceramics, and at the same time ionizes the constituent atoms of the superconducting ceramics into an adherend. This is a method for producing a superconductor thin film characterized by applying a voltage of opposite polarity and depositing a vapor phase superconductor ceramic on an adherend.

<Operation> In the present invention, the vapor phase superconducting ceramics generated by a laser beam scattering method or the like is ionized by irradiating the vapor phase superconducting ceramics with a laser beam having an energy greater than the ionization voltage of the constituent atoms. A voltage of opposite polarity to the vapor phase superconductor ceramic is applied to the adherend, and the vapor phase superconductor ceramic is positively attracted and deposited on the adherend to form a thin film. That is, by increasing the σ trapping efficiency on the adherend of vapor-phase superconductor ceramics, a superconductor thin film is formed in good yield and at high speed.

For example, in a method to which the present invention is applied to a laser beam scattering method, as shown in FIG.
A superconductor thin film 36 is formed on a substrate 35 to which a voltage of opposite polarity is applied by a power source 37.
First, as shown in FIG. 2(a), a process of generating cluster-shaped sputtered particles 34a from the target 31 by irradiating the target 31 with a laser beam 32 for cluster generation, and an ionization process as shown in second ffi(b). Clustered sputtered particles 3 generated by laser beam 33
4a is irradiated to ionize and decompose it into positive electrode ionized atoms 34, and the positive electrode ionized atoms 34 are attracted and deposited on a substrate 35 to which a negative electrode voltage is applied. In particular, as mentioned above, the initial state is a cluster state in which the kinetic energy per unit of atom is small, and this cluster is ionized and decomposed by a laser beam before reaching the adherend, and the polarity is reversed. According to the method of forming a thin film on an adherend to which a voltage of Can be done.

Incidentally, the above-mentioned invention of the present application is not particularly limited in the method of generating vapor phase superconducting ceramics, and in addition to the above-mentioned laser beam irradiation, raw material elements can be turned into plasma with a high frequency electric field to produce cluster-shaped vapor phase superconducting ceramics. Various methods can be used, such as forming.

In addition, the ionizing laser beam may be applied to the sputtered particles from the target to the adherend.
It is preferable to irradiate near the target because the generated sputtered particles can be scattered and spread to efficiently irradiate the bamboo shoots with the laser light.

<Example> First, as shown in FIG. 3, in an apparatus for carrying out the manufacturing method of the present invention, a target 4, a substrate 5, and a heating material are placed in a container 3 to which an oxygen supply pipe 1 and an exhaust pipe 2 are connected. Equipped with a heater 6,
It is equipped with a laser oscillator 9.10 facing a glass window 7.8 provided in the container 3, and further equipped with a power source 11 connected to the substrate 5.

Oxygen is supplied into the container 3 through an oxygen supply pipe 1 connected to an oxygen supply source (not shown), and the inside of the container 3 is exhausted through an exhaust pipe 2 connected to an exhaust device (not shown). Ru.

Further, the target 4 is supported by a holder having a rotation mechanism, and is configured to rotate at a constant speed. Further, a substrate 5 facing the target 4 is heated by a heater 6. Further, the laser oscillator 9 is for cluster generation, the laser oscillator 10 is for ionization, and the laser oscillators 9 and 10 are configured to irradiate laser beams to positions eccentric from the rotation center of the target 4, respectively. Further, a voltage is applied to the substrate 5 by a power source 11.

Next, the results of manufacturing a superconductor thin film using the above-mentioned apparatus will be explained below.

First, the distance between the substrate 5 and the target 4 is 40 mm, and the composition of the target 4 is Bi: Sr: Ca: Cu: 0=2.
: 2: 2: 3: X, substrate 5 is MgO single crystal,
The temperature of the substrate 5 is set to 650°C, and a Nd YAG laser beam (wavelength 1.0
64μm, pulse width 15ns, output 0. 8J/cm2
) to the target 4, and the laser oscillator 1
ArF excimer laser light for ionization (wavelength 0
．． 193 μm, pulse width 10 ns, output 2 x 10 J/
cm2) near the target 4, and the vapor pressure is 3.
OX 1 (15 Torr:, oxygen gas flow: 115
A thin film was formed on the substrate S using SCCM. As a result, a superconductor thin film with Tc=85 was obtained at a deposition rate of 0.05 persons/pulse.

Next, when a voltage of -32V was applied to the substrate 5 to the particles whose clusters were decomposed and ionized to the positive electrode, the film formation rate increased to 0.46 people/bars, and the M weave was formed several times. The critical temperature was also improved to Tc=94K.

Effect> As explained above, according to the invention of the present application, since the vapor phase superconductor ceramic and the adherend are charged with opposite polarities, the yield of the vapor phase superconductor ceramic to the adherend is increased. It can be deposited well and a high quality superconductor thin film can be formed at high speed.

In addition, especially when the present invention is applied to a laser beam scattering method, cluster-like particles having relatively small energy per atomic unit are decomposed into atoms and ionized by a laser beam on the way to the adherend. Since this will be deposited on the adherend to which polarity is applied in the opposite direction, 1. Ionized atoms can be efficiently captured on the adherend, and re-sputtering on the adherend can be prevented, and a homogeneous superconductor thin film can be efficiently formed several times. Also,
Since cluster-shaped sputtered particles are generated from the target using a laser beam for cluster generation, and these are decomposed by a laser beam for cluster decomposition and deposited on the adherend, in addition to the above effects, a composition close to that of the target can be obtained. superconductor thin films can be easily obtained. Furthermore, the excited state of the cluster can be easily controlled by the type of laser light, and fine control can be achieved depending on the superconductor composition, etc.

2(a) and 2(b) are conceptual diagrams of the manufacturing process of a superconductor thin film, FIG. 3 is a block diagram of an example of the manufacturing apparatus used in the present invention, and FIG. 4 is a conventional FIG. 2 is a conceptual diagram of a method for manufacturing an electromotive conductor thin film.

4.21.31 is the target, 5.24.35 is the adherend (substrate), 9.10 is a laser oscillator, 22.32.33 is a laser beam.

Patent applicant Mitsubishi Metals Co., Ltd. agent Patent attorney Kiyoshi Kuwai - (1 other person)

[Brief explanation of the drawing]

FIG. 1 shows a first superconductor thin film according to an embodiment of the present invention. figure Figure 3 Figure 2 Figure 2 (nothing) (b) Figure 4 122) 21

Claims (1)

[Claims] While ionizing the constituent atoms of the superconducting ceramic by irradiating the gas phase superconducting ceramic with laser light,
A method for producing a superconductor thin film, which comprises applying a voltage having a polarity opposite to that of the ions to an adherend to deposit vapor phase superconductor ceramics on the adherend.