JPH0666481B2 - Method for manufacturing superconducting thin film - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an improvement in a method for producing a superconducting thin film, and more specifically, to amorphization and / or microcrystallization without maintaining the substrate at an extremely low temperature. And a method for producing a beryllium-based alloy superconducting thin film.

<Technical Background of the Invention> A superconducting thin film is used as a superconducting electrode material for a Josephson device for high-speed computers, or as a superconducting quantum interference device (so-called SQUID, that is, Super-Conducting Quantum).
It is drawing attention as a material for thin film devices such as inter-ference devices.

Conventionally known lead superconducting thin film element materials, niobium superconducting thin film element materials, and beryllium superconducting thin film element materials are known as superconducting thin film element materials. However, the lead superconducting thin film element material is easily oxidized, its change over time is large, and its strength is low. In addition, the niobium superconducting thin film element material is easily oxidized and has the property that the oxidation proceeds to the inside. In addition, there is a drawback that the characteristics change with time.

Contrary to this, beryllium superconducting thin film element materials are less likely to be oxidized than the above-mentioned lead superconducting thin film element materials and niobium superconducting thin film element materials, have little change over time, and have a dielectric constant of only 1/5 that of niobium. Since it does not have a high speed switching operation, it has the potential of being widely used as a superconducting thin film element.

By the way, as a method for forming a beryllium thin film, beryllium is sputtered with an ion beam of an inactive element or a neutral particle beam, and a beryllium thin film is deposited on the surface of a substrate which is arranged oppositely, or by a chemical vapor deposition method (so-called CVD method). A method of depositing a beryllium thin film on the surface of the substrate is also conceivable, but there is a problem in that the thin film formation rate is slow and the economy and mass productivity are poor. For this reason, the low-temperature vacuum deposition method has been conventionally used when producing a beryllium superconducting thin film.

The conventional low-temperature vacuum evaporation method is based on the physical review published by the American Physical Society, “Physical Revie Letters”.
w Letters) ", Vol. 19, No. 3 (1967) pp.121-125, liquid helium heat-shielded with liquid nitrogen 2 in a vacuum chamber 1 using a low-temperature vacuum deposition apparatus. Three
The substrate to be attached 4 is cooled to the temperature of liquid helium, and the vapor deposition material 6 is heated and vaporized by the heater (filament) 5 arranged below the substrate 4, and the substrate is passed through the openings of the heat shield shutters 7 and 8. A thin film of the vapor deposition material 6 was formed on the lower surface of 4 (see FIGS. 3 and 4).

Regarding the properties of beryllium superconducting thin films prepared by such a low temperature vacuum deposition method, the 20th volume of the academic journal "Zeitschrift der Physik" published by the West German Physical Society (German name: Zeitschrift der Physik) 1975
, G. Grangvist et al., "Deposition-quenched beryllium and beryllium-based alloys (Original title: Superc
onduc-tivity of Vapour Quenched Beryllium and Bery
llium-based Alloys) ”, its superconducting transition temperature is 8 ° K-10 ° K. In addition, its superconducting property is that the deposited beryllium thin film cannot be crystal-grown because beryllium is vapor-deposited on the substrate kept at an extremely low temperature (-270 ° C), and the beryllium thin film is in an amorphous or microcrystallized state. It explains that it will be.

<Problems to be Solved by the Invention> However, the beryllium superconducting thin film prepared by the above-described low temperature vacuum deposition method has a drawback that the beryllium thin film changes to a hexagonal system at room temperature and loses its superconducting properties. It was

Further, when manufacturing, a low temperature vacuum deposition apparatus for cooling the substrate with liquid nitrogen, liquid helium or the like has to be used, which is disadvantageous in that the manufacturing cost and the manufacturing method are expensive and complicated.

This invention was made in order to eliminate the drawbacks of the conventional method for producing a beryllium superconducting thin film by the low temperature vacuum deposition method. The beryllium superconducting thin film deposited on the substrate surface was left at room temperature. Even so, it is an object of the present invention to provide a method for producing a beryllium superconducting thin film in which the crystal state does not change and superconducting properties can be obtained by lowering the temperature below the superconducting transition temperature.

(B) In addition to the beryllium superconducting thin film having the above-mentioned characteristics, the present invention aims to provide a method for producing a beryllium-based alloy having the above-mentioned characteristics.

Further, the present invention is capable of producing a beryllium superconducting thin film or a beryllium-based alloy superconducting thin film in an amorphized or microcrystalline state even when the substrate temperature is not kept at the liquid helium temperature during the production of the beryllium superconducting thin film. An object of the present invention is to provide a method for manufacturing a thin film and a beryllium-based alloy superconducting thin film.

<Means for Solving the Problems> In order to achieve the above object, the present invention heats and evaporates beryllium or a beryllium-based alloy in a vacuum when producing a beryllium superconducting thin film and a beryllium-based alloy superconducting thin film. Then, a beryllium thin film is deposited on the surfaces of the substrates arranged to face each other, and the beryllium thin film on the substrate surface is irradiated with an ion beam or a neutral particle beam to amorphize the beryllium or beryllium-based alloy thin film on the substrate surface and / or Alternatively, it is characterized by being crystallized.

In the method for producing a beryllium superconducting thin film and a beryllium-based alloy superconducting thin film of the present invention, the type of ion beam or neutral particle beam with which the beryllium thin film on the substrate surface is irradiated is argon (Ar), helium (He), or krypton (Kr). ), Xenon (Xe) and other beryllium and inactive Group 0 elements of the periodic table, the same beryllium (Be) or the above elements and carbon (C),
It may be an ion beam of a mixture with an element such as nitrogen (N) or oxygen, or a neutralized particle beam, that is, an atomic beam.

Also, the kinetic energy of the above-mentioned ions or neutral particles should be large enough to change the lattice position of beryllium atoms on the substrate surface by bombarding the beryllium thin film on the substrate surface, and at least 10 eV or more. It is thought that it is necessary to accelerate, and normally gives acceleration energy of about 1 KeV. In addition, in relation to the characteristics of the beryllium superconducting thin film to be produced and the ion beam or neutral particle beam to be irradiated for film formation, in addition to the above-mentioned conditions, the irradiation ion beam or neutral particle beam In some cases, the superconducting thin film produced by remaining may deteriorate the superconducting property. This is particularly remarkable when the particle beam to be irradiated, that is, the ion beam or the neutral particle beam uses the active element. For example, when the superconducting thin film contains 1 atomic% or more of oxygen, the superconducting transition temperature decreases as the oxygen concentration increases.

On the other hand, in the case of a Group 0 element of the periodic table such as a rare element, the probability of remaining in the thin film is low. Therefore, even if the ion beam or neutral particle beam irradiating the beryllium thin film remains in the superconducting thin film, an element that does not significantly deteriorate the superconducting property, such as carbon or nitrogen, is used, or It is better to use an ion beam or neutral particle beam of a Group 0 element having a low probability of remaining.

Further, in the present invention, when evaporating beryllium by heating, a known electron beam heating method or resistance heating method is applied.

Further, in the present invention, the substrate on which the beryllium thin film is deposited may be an insulating substrate such as silica (SiO ₂ ) or alumina (Al ₂ O ₃ ) or a substrate made of another conductive material.

Further, it goes without saying that the beryllium superconducting thin film and the beryllium-based alloy superconducting thin film of the present invention can be produced at room temperature, but the beryllium is kept by holding the substrate at a low temperature such as liquid nitrogen or liquid helium. It can also be deposited by heating vapor deposition.

The beryllium-based alloy thin film produced by the method for producing a beryllium-based alloy superconducting thin film of the present invention includes beryllium and a Group 0 element of the periodic table or beryllium and boron, carbon, nitrogen, oxygen, silicon, aluminum, and gold. It consists of an alloy with at least one substance.

<Operation> As described above, when beryllium is heated and evaporated in a vacuum, and a beryllium thin film is deposited on the surfaces of substrates facing each other, the film formation mechanism is not always clear. It is thought that it collides with the substrate surface with large kinetic energy, moves around while giving thermal energy to the substrate, forms atomic pairs and atomic groups with other vapor deposition particles, and is trapped at the trap center of the substrate surface to form a beryllium thin film.

However, at the same time, the high-speed ion beam or neutral particle beam irradiated on the beryllium thin film surface is incident on the beryllium thin film,
The beryllium thin film is considered to be amorphous or microcrystallized because it serves to suppress the crystal orientation of the beryllium thin film from being determined.

Therefore, the superconducting properties of beryllium superconducting thin films and beryllium-based alloys produced by adjusting the irradiation amount or acceleration energy of the ion beam or neutral particle beam irradiating the beryllium thin film deposited on the substrate surface, especially superconductivity The transition temperature can be controlled.

Further, the beryllium or beryllium-based alloy thin film deposited on the surface of the substrate is irradiated with a beam or neutral particle beam of an ionized gas of a mixture of a gas such as methane (CH ₄ ), nitrogen, oxygen and a rare gas. As a result, the elements of these mixed substances enter the atomic lattice of Be, and a beryllium-based alloy superconducting thin film with less change over time can be manufactured.

<Example> Next, the present invention will be specifically described based on Examples and Comparative Examples.

Example 1 FIG. 1 is a sectional view showing a schematic configuration of a vacuum vapor deposition apparatus 20 used for carrying out the method for producing a beryllium superconducting thin film of the present invention.

The illustrated vacuum deposition apparatus 20 includes an exhaust apparatus 12 for decompressing and evacuating the inside of the vacuum chamber 11 to a vacuum, a beryllium 14 for heating and evaporation contained in a crucible 13 in the vacuum chamber 11, and this beryllium.
A resistance heater 15 for heating 14, a substrate 17 arranged to deposit the beryllium particles 16 evaporated in the upper part of the vacuum chamber 11, and a gas supply cylinder arranged outside the vacuum chamber 11.
An ion beam generator 23 for generating an Ar ion beam 22 in the vacuum chamber 11 through the gas supply pipe 25 and directing it to the lower surface of the substrate 17, and a shutter 24 having beryllium vaporized particles openably and closably provided on the lower surface of the substrate 17 are provided. ing.

The flow rate of gas supplied from the gas supply cylinder 19 to the ion beam generator 23 can be adjusted by the valve 21.

When a beryllium superconducting thin film is formed on the surface of the substrate 17 by using the vacuum vapor deposition device 20, the exhaust device 12 is operated and the vacuum chamber 11 is activated.
After exhausting the inside to 10 ^-6 to 10 ^-7 Torr, the resistance heater 15
The beryllium 14 is heated and vaporized by means of the above to deposit the beryllium vaporized particles on the lower surface of the substrate 17, while operating the valve 21 to move the Ar gas in the gas supply cylinder 19 from the ion beam generator 23 to the high-speed Ar ion beam (or Ar atom). Line) to the lower surface of the substrate 17.

Next, by opening and closing the shutter 24 at an appropriate time interval, a beryllium superconducting thin film could be formed on the lower surface of the substrate 17.

In this embodiment, Ar gas having a purity of 99.9995% was used as the gas to be put into the gas supply cylinder 19.

As a concrete manufacturing procedure, the inside of the vacuum chamber 11 was evacuated to 1 × 10 ⁻⁷ Torr before introducing the gas, and then the ion beam generator was used.
Ar gas was introduced into 23. The pressure in the vacuum chamber 11 at this time was 5 × 10 ⁻⁵ Torr. The distance between the beryllium 14 and the substrate 17 was 25 cm, and the heating temperature of the heater 15 was adjusted so that the deposition rate of the beryllium film on the lower surface of the substrate 17 was about 3 Å / sec (3 angstroms per second). Furthermore, the substrate
The acceleration energy of Ar ions or atoms simultaneously irradiated to the lower surface of the substrate 17 was 1 KeV, and the irradiation amount of the Ar ion beam to the lower surface of the substrate 17 was 4 × 10 ¹³ / cm ² / sec. The substrate temperature was kept within the range of 25 ± 5 ° C. by water cooling the substrate with a jacket (denoted by reference symbol A in the figure). Shatter 24
Is opened for 5 minutes to allow a thickness of 900
A beryllium film of Å was formed. FIG. 2 shows the result of measurement using a known four-terminal electrical resistance measuring method for measuring the superconducting transition temperature of this beryllium thin film. The characteristic obtained was curve a. From this characteristic curve a, it was found that the beryllium thin film of the example had a superconducting transition temperature of 5.5K. Further, when the amount of argon (Ar) in the beryllium film was identified by AES, it was 0.3 atom%.

Example 2 Example 1 was repeated except that the gas supply cylinder 19 (see FIG. 1) of Example 1 was filled with Ar gas containing 0.1% oxygen gas instead of 99.9995% pure Ar gas. A beryllium thin film was produced according to the same vacuum evaporation apparatus and production method.

The content of oxygen in the obtained beryllium thin film was identified by Auger Electron Spectroscopy (hereinafter referred to as "AES").

The superconducting transition temperature measured by the four-terminal electrical resistance method is 5.
It was 1 ° K.

Example 3 The same vacuum as in Example 1 except that Ar gas containing 0.2% oxygen gas was used instead of 99.9995% pure Ar gas filled in the gas supply cylinder 19 (see FIG. 1) of Example 1. Vapor deposition equipment
20 was used to form a beryllium thin film on the lower surface of the substrate by the same manufacturing method. When the amount of oxygen in the obtained beryllium thin film was identified by AES, it was 0.9 atom%.

It was also found that the beryllium thin film had a superconducting transition temperature of 5.0 ° K when measured by a four-terminal electrical resistance method.

Example 4 Same as Example 1 except that Ar gas containing 0.4% oxygen gas was used in place of Ar gas having a purity of 99.9995% filled in the gas supply cylinder 19 (shown in FIG. 1) of Example 1. A beryllium thin film was formed on the lower surface of the substrate by the same manufacturing method using the vacuum vapor deposition device 20.

When the amount of oxygen in the obtained beryllium thin film was identified by AES, it was found to contain 1.5 atom%.
It was also found that the superconducting transition temperature measured by the four-terminal electrical resistance method was 3.6 ° K.

Example 5 Example 5 was carried out except that Ar gas containing 5% CH ₄ (methane) gas was used instead of Ar gas having a purity of 99.9995% filled in the gas supply cylinder 19 (shown in FIG. 1) of Example 1. A beryllium thin film was formed on the lower surface of the substrate by using the same vacuum deposition apparatus 20 as in Example 1 and the same manufacturing method.

When the amount of carbon in the obtained beryllium thin film was identified by AES, it was 9.0 atom%. The superconducting transition temperature was 5.7 ° K as measured by the four-terminal electrical resistance method.

Example 6 Example 6 except that Ar gas containing 5% N ₂ (nitrogen) gas was used instead of 99.5% pure Ar gas filled in the gas supply cylinder 19 (shown in FIG. 1) of Example 1. A beryllium thin film was formed on the lower surface of the substrate by using the same vacuum vapor deposition apparatus 20 as in No. 1 and the same manufacturing method. The nitrogen content in the obtained beryllium thin film was identified by AES and found to be 2.0 atomic%. The superconducting transition temperature was 6.2 ° K as measured by the four-terminal electrical resistance method.

Example 7 Example 1 is replaced with the beryllium-based alloy containing 10% lithium instead of the beryllium (raw material) 14 of Example 1.
The beryllium thin film was formed on the lower surface of the substrate by the same production method using the same vacuum vapor deposition device 20 as described above. The amount of lithium in the obtained beryllium thin film was identified by AES to be 9.0 atom%.
Met. The superconducting transition temperature was 7.5 ° K as measured by the four-terminal electrical resistance method.

Example 8 A beryllium thin film was formed on the lower surface of a substrate by the same production method as in Example 1 except that a beryllium-based alloy containing 10% boron was used instead of the beryllium (raw material) 14 in Example 1. Was formed. When the amount of boron in the obtained beryllium thin film was identified by AES, it was 10. atom%. The superconducting transition temperature was 7.3 ° K as measured by the four-terminal electrical resistance method.

Example 9 A beryllium thin film was formed on the lower surface of a substrate by the same production method as in Example 1 except that a beryllium-based alloy containing 8% silicon was used instead of beryllium (raw material) 14 in Example 1. Was formed. When the amount of silicon in the obtained beryllium thin film was identified by AES, it was 8 atom%. The superconducting transition temperature was 7.1 ° K as measured by the four-terminal electrical resistance method.

Example 10 A beryllium thin film was formed on the lower surface of a substrate by the same production method as in Example 1 except that a beryllium-based alloy containing 10% aluminum was used instead of beryllium (raw material) 14 in Example 1. Was formed. The amount of aluminum in the obtained beryllium thin film was identified by AES.
It was 8.0 atomic%. The superconducting transition temperature was 7.2 ° K as measured by the four-terminal electrical resistance method.

Example 11 A beryllium thin film was formed on the lower surface of a substrate by the same manufacturing method as in Example 1 except that a beryllium-based alloy containing 5% gold was used instead of the beryllium (raw material) 14 in Example 1. Was formed. When the amount of gold (Au) in the obtained beryllium thin film was identified by AES, it was 5.0 atom%. The superconducting transition temperature was 7.7 ° K as measured by the four-terminal electrical resistance method.

Comparative Example 1 Vacuum deposition apparatus used in the superconducting thin film manufacturing method of Example 1
Instead of 20, low temperature vacuum deposition equipment shown in FIGS. 3 and 4
10, the substrate 4 was cooled with liquid helium, and the beryllium raw material (purity 99.9%) in the evaporation crucible was heated and evaporated to deposit the beryllium thin film on the lower surface of the substrate 4. When the beryllium thin film thus obtained was kept at an extremely low temperature and measured by a four-terminal electrical resistance method, its superconducting transition temperature was 8.5 ° K.

Comparative Example 2 A beryllium alloy thin film containing 4% oxygen was used instead of the beryllium raw material 4 used in Comparative Example 1, and a beryllium-based alloy thin film was deposited on the lower surface of the substrate by the same manufacturing method. When the beryllium-based alloy thin film thus obtained was kept at an extremely low temperature and measured by a four-terminal electrical resistance method, its superconducting transition temperature was 5.0 ° K. The oxygen content in the beryllium-based alloy thin film identified by AES was 1.0 atom%.

Comparative Example 3 A beryllium alloy thin film containing 10% of carbon was used instead of the beryllium raw material 4 used in Comparative Example 1, and a beryllium-based alloy thin film was deposited on the lower surface of the substrate by the same manufacturing method. When the obtained beryllium-based alloy thin film was measured by a four-terminal electrical resistance method while keeping it at an extremely low temperature, its superconducting transition temperature was 7.1 ° K. The carbon content in the beryllium-based alloy thin film identified by AES was 9.0 atomic%.

Comparative Example 4 Instead of the beryllium raw material 4 used in Comparative Example 1, a beryllium alloy containing 5% nitrogen was used, and a beryllium-based alloy thin film was deposited on the lower surface of the substrate by the same manufacturing method. When the beryllium-based alloy thin film thus obtained was kept at an extremely low temperature and measured by a four-terminal electrical resistance method, its superconducting transition temperature was 6.8 ° K. The nitrogen content in the beryllium-based alloy thin film identified by AES was 1.5 atom%.

Comparative Example 5 A beryllium-based alloy thin film containing 20% lithium was used in place of the beryllium raw material 4 used in Comparative Example 1, and a beryllium-based alloy thin film was deposited on the lower surface of the substrate by the same manufacturing method. When the beryllium-based alloy thin film thus obtained was measured by a four-terminal electrical resistance method while being kept at an extremely low temperature, its superconducting transition temperature was 6.0 ° K. The amount of lithium in the beryllium-based alloy thin film identified by AES was 14 atom%.

Comparative Example 6 Instead of the beryllium raw material 4 used in Comparative Example 1, a beryllium alloy containing 10% boron was used, and a beryllium-based alloy thin film was deposited on the lower surface of the substrate by the same manufacturing method. While keeping the beryllium-based alloy thin film obtained at an extremely low temperature,
The superconducting transition temperature was 6.5 ° K as measured by the four-terminal electrical resistance method. The boron content in the beryllium-based alloy thin film identified by AES was 10 atom%.

Comparative Example 7 A beryllium-based alloy thin film was deposited on the lower surface of the substrate by the same manufacturing method using a beryllium alloy containing 8% silicon instead of the beryllium raw material 4 used in Comparative Example 1. While keeping the beryllium-based alloy thin film obtained at an extremely low temperature,
The superconducting transition temperature was 6.3 ° K as measured by the four-terminal electrical resistance method. The amount of silicon in the beryllium-based alloy thin film identified by AES was 8.0 atom%.

Comparative Example 8 A beryllium-based alloy thin film was deposited on the lower surface of a substrate by the same manufacturing method using a beryllium alloy containing 10% aluminum instead of the beryllium raw material 4 used in Comparative Example 1. When the obtained beryllium-based alloy thin film was kept at an extremely low temperature and measured by a four-terminal electrical resistance method, its superconducting transition temperature was 7.0 ° K. The amount of aluminum in the beryllium-based alloy thin film identified by AES was 8.0 atom%.

Comparative Example 9 Instead of the beryllium raw material 4 used in Comparative Example 1, a beryllium alloy containing 5% gold was used, and a beryllium-based alloy thin film was deposited on the lower surface of the substrate by the same manufacturing method. When the obtained beryllium-based alloy thin film was measured by a four-terminal electrical resistance method while keeping it at an extremely low temperature, its superconducting transition temperature was
It was 9.0 ° K. The amount of gold in the beryllium-based alloy thin film identified by AES was 5.0 atom%.

Regarding the beryllium thin film and the beryllium-based alloy thin film produced in Examples 1 to 11 and Comparative Examples 1 to 9 described above, the results of tracing the change in the superconducting transition temperature every one week after the completion of the production are shown in Table 1 below. It was shown to.

However, “transition temperature” in Table 1 is an abbreviation for superconducting transition temperature. Further, the transition temperature values in the bold frame in Table 1 (superconducting transition temperature values of Comparative Examples 1 to 9 after one week has elapsed) are values measured in an extremely low temperature state. All other transition temperature values are values after the lapse of the posting period at room temperature.

From Table-1, in the beryllium thin films obtained in Examples 1 to 5, the change with time of the superconducting transition temperature is about ±±.
It was not observed within the range of 0.1 ° K.

In the beryllium thin films obtained in Examples 6 to 11, the change in superconducting transition temperature with time remained within the range of about 1 ° K.

On the contrary, in the samples obtained in Comparative Examples 1 to 9, the superconducting properties were lost in most of the samples within 2 weeks of storage at room temperature (superconducting transition temperature was higher than the measurement limit of 1.5 ° K). Is also synonymous with the decline.) In addition, the superconducting transition temperature of the sample in which some superconductivity remained was lowered to about 2 ° K to 3 ° K.

<Effects of the Invention> As is clear from the above description, the superconducting thin film produced by the method for producing a superconducting thin film of the present invention has a substrate with a liquid helium temperature higher than that produced by the conventional low temperature vacuum deposition method. The superconducting thin film can be manufactured very easily without the need for complicated cooling or an expensive device.

Further, since the superconducting thin film produced by the manufacturing method of the present invention does not change in superconducting properties even when kept at room temperature,
It can be used as a material for various superconducting devices.

In addition, compared to other vapor deposition methods such as sputter vapor deposition and chemical vapor deposition, the structure of the superconducting thin film is extremely simple, the thin film formation rate is high, and it is practical. Very good.

[Brief description of drawings]

FIG. 1 is a sectional view showing a schematic structure of a vacuum vapor deposition apparatus used for carrying out the method for producing a superconducting thin film of the present invention, and FIG. 2 is a sample temperature of a superconducting thin film obtained by the apparatus of FIG. FIG. 3 is a characteristic diagram showing a relation of resistance, FIG. 3 is a sectional view showing a schematic configuration of a low temperature vacuum vapor deposition apparatus used for manufacturing a conventional superconducting thin film,
FIG. 4 is an enlarged perspective view showing a schematic configuration of a substrate device unit of the low temperature vacuum vapor deposition apparatus of FIG. In the drawings, 1, 11 ... Vacuum tank, 4, 17 ... Substrate, 5, 15 ... Heater, 6 ... Evaporating material, 10 ... Low temperature vacuum evaporator, 14 ... Beryllium, 16 ... Evaporating particles, 19 ... Gas supply cylinder, 20 ... Vacuum deposition apparatus used in the present invention, 22 ... Ion beam particles, 23 ... Ion beam generator, 24 ... Shutter.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takayuki Nakamura Tokai-mura, Ibaraki Prefecture Tokai-mura, Shirahoji 162 Shirane, Nippon Telegraph and Telephone Corporation Ibaraki Telecommunications Research Laboratories (72) Inventor Yasushi Maeda Naka-gun, Ibaraki Prefecture Tokai-mura, Oita, Shirahoji, Shirane 162, Nippon Telegraph and Telephone Corporation, Ibaraki Telecommunications Research Laboratories (56) References JP 61-39588 (JP, A) JP 60-25225 (JP, A) JP Sho 61-163265 (JP, A)

Claims (3)

[Claims] 1. A beryllium or beryllium-based alloy is heated and vaporized in a vacuum to deposit a beryllium thin film on the surface of a substrate facing each other, and the beryllium or beryllium-based alloy thin film is irradiated with an ion beam or a neutral particle beam. Then, a method for producing a superconducting thin film, which comprises amorphizing and / or microcrystallizing a beryllium or beryllium-based alloy thin film. 2. An ion beam or neutral particle beam for irradiating a beryllium or beryllium-based alloy thin film on a substrate surface with beryllium or a group 0 element of the periodic table or an ion of a mixture of nitrogen, oxygen and carbon. Or a beam of neutral particles.
The method for producing a superconducting thin film according to item (1). 3. The superconducting thin film produced by the method for producing a superconducting thin film comprises beryllium and a Group 0 element of the periodic table, or lithium and boron, carbon, nitrogen, oxygen, silicon, aluminum and gold. Claims characterized in that it is a superconducting thin film of an alloy consisting of
The method for producing a superconducting thin film according to item (1).