JP3415888B2 - Apparatus and method for producing polycrystalline thin film and method for producing oxide superconducting conductor - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and a method for producing a polycrystalline thin film having a uniform crystal orientation and a method for producing an oxide superconducting conductor having a uniform crystal orientation.

[0002]

2. Description of the Related Art Conventionally, various methods have been tried for forming an oxide superconducting layer having a good crystal orientation on a substrate such as a substrate or a metal tape. As one of the methods, MgO or SrTiO ₃ having a crystal structure similar to that of the oxide superconductor is used.
There is a method of forming an oxide superconducting layer on the single crystal substrate by a film forming method such as sputtering. If a film forming method such as sputtering is performed using the single crystal base material of MgO or SrTiO ₃ ,
Since the crystal of the oxide superconducting layer grows on the basis of the crystal of the single crystal base material, it is possible to improve the a-axis or b-axis orientation of the crystal. It is known that the formed oxide superconducting layer exhibits a sufficiently high critical current density of about tens of thousands to 100,000 A / cm ² .

In order to use an oxide superconductor as a conductor, it is necessary to form an oxide superconducting layer having a good crystal orientation on a long base material such as a tape.
However, when an oxide superconducting layer is directly formed on a base material such as a metal tape, the metal tape itself is a polycrystal and its crystal structure is significantly different from that of the oxide superconductor. There is a problem that the superconducting layer cannot be formed. Therefore, conventionally, an intermediate layer made of a polycrystalline thin film such as MgO or SrTiO ₃ is coated on a base material such as a metal tape by using a sputtering device, and an oxide superconducting layer is formed on the intermediate layer. ing. However, the oxide superconducting layer formed on the intermediate layer of this type by a sputtering apparatus has a critical current density (e.g., several thousand to 1,000) which is considerably lower than that of the oxide superconducting layer formed on the single crystal substrate.
There was a problem that it showed only 0 A / cm ² ).
This is considered to be due to the reason explained below.

First, as shown in FIG. 11, an intermediate layer 2 of a polycrystalline thin film is formed on a substrate 1 made of a polycrystalline material such as a metal tape by a film forming method such as sputtering, and the intermediate layer 2 is formed on the intermediate layer 2. When the oxide superconducting layer 3 is formed to produce the superconducting conductor A ′, both the intermediate layer 2 and the oxide superconducting layer 3 are in a polycrystalline state, and the oxide superconducting layer 3 has a large number of crystal grains 4.
Are disordered, and the intermediate layer 2 has many crystal grains 5
Are in a chaotically coupled state. Looking at each of the crystal grains 5 of the oxide superconducting layer 3 individually, although the c-axis of the crystal of each crystal grain 5 is oriented to be perpendicular to the substrate surface to some extent, The b-axis is considered to be in a chaotic direction. However, the oxide superconductor has electric anisotropy in the crystal itself, and it is particularly easy for electricity to flow in the a-axis direction and the b-axis direction of the crystal axis, but in the c-axis direction. It has electrical anisotropy depending on the specific direction of the crystal axis, such as difficulty in flowing.

Therefore, if the directions of the a-axis and the b-axis are disordered for each crystal grain of the oxide superconducting layer as described above, the quantum coupling property of the superconducting state is lost at the crystal grain boundary where the crystal orientation is disturbed. As a result, it seems that superconducting characteristics, especially critical current density, are reduced. The oxide superconductor is in a polycrystalline state in which the a-axis and the b-axis are not oriented because the intermediate layer 2 formed thereunder is in the polycrystalline state in which the a-axis and the b-axis are not oriented. This is probably because the oxide superconducting layer 3 grows so as to match the crystal of the intermediate layer 2 when the oxide superconducting layer 3 is formed.

[0006]

Therefore, the present inventors have found that
By forming a polycrystalline thin film such as yttrium-stabilized zirconia (hereinafter, abbreviated as YSZ) having good crystal orientation on the base material of the metal tape, and forming an oxide superconducting layer on the polycrystalline thin film, Various attempts have been made to manufacture oxide superconducting conductors with excellent superconducting properties. Then, from such an attempt, the inventors of the present invention first disclosed Japanese Patent Application No. 3-1268.
No. 36, Japanese Patent Application No. 3-126837, Japanese Patent Application No. 2-205
No. 551, Japanese Patent Application No. 4-13443, Japanese Patent Application No. 4-293.
No. 464, etc., have filed patent applications for a polycrystalline thin film having excellent crystal orientation and an oxide superconducting conductor using the polycrystalline thin film.

According to the techniques described in these patent applications, when YSZ particles are deposited on a substrate by a film-forming method such as sputtering or laser deposition, the YSZ particles are deposited with respect to the normal line of the film-forming surface of the substrate. By irradiating an ion beam at an incident angle of 50 to 60 degrees from an oblique direction, it is possible to form a polycrystalline thin film having excellent crystal orientation, and to form an oxide superconducting layer on this polycrystalline thin film. Thus, an oxide superconducting conductor having excellent superconducting properties can be obtained. Then, the present inventors presume the following factors, as described in Japanese Patent Application No. 4-293464, as a factor for adjusting the crystal orientation of the YSZ polycrystalline thin film on the base material.

The unit cell of the crystal of the YSZ intermediate layer 2 is a cubic crystal as shown in FIG. 12, and in this crystal lattice, the substrate normal direction is the <100> axis and the other <010>.
The> axis and the <001> axis are both in the directions shown in FIG. Considering an ion beam that is incident on these directions obliquely with respect to the substrate normal, when incident on the origin O of FIG. 12 in the diagonal direction of the unit lattice, that is, along the <111> axis, , The incident angle is 54.7 degrees.

Here, as described above, good crystal orientation in the incident angle range of 50 to 60 degrees means that the incident angle θ of the ion beam coincides with the above-mentioned 54.7 degrees or before and after that. , Ion channeling occurs most effectively, and in the crystal deposited on the base material A, only the atoms having a positional relationship matching the angle on the base material A tend to remain selectively. It is presumed that the disordered atomic arrangement of atoms is removed by being sputtered by the ion beam sputtering effect, so that only the crystals of the atoms with good orientation are selectively left and deposited.

From such a background, the present inventors have carried out the laser deposition method to deposit the YSZ particles on the base material while performing the above-mentioned ion beam irradiation to thereby deposit the YSZ particles on the base material. An intermediate layer was formed, and the crystal orientation of this intermediate layer was measured. The result is shown in FIG. FIG.
Is a Hastelloy C-27 with a thickness of 0.1 mm and a width of 5.0 mm.
The inside of the vacuum chamber is a metal tape substrate consisting of 6
It is moved at a rate of 20 to 30 cm per hour, and Kr- is applied to the YSZ target provided in the vacuum chamber.
The (111) pole figure of the intermediate layer obtained by carrying out the laser vapor deposition method of irradiating the F excimer laser and depositing the particles generated from this YSZ target on the substrate to form the intermediate layer is shown. is there. In carrying out this laser vapor deposition method, the incident angle with respect to the normal line of the base material film-forming surface was set to 5
Particles are deposited by setting the angle to 5 degrees and irradiating a Kr ⁺ + O ₂ mixed ion beam from an oblique direction of the substrate.

[0011]

From the analysis results shown in FIG. 13, this YSZ intermediate layer is <1 perpendicular to the film forming surface of the substrate.
00> orientation and one <1 in the direction of ion beam incidence.
It was found that the 11> axis was oriented and the crystal axes were ordered in a plane parallel to the film forming surface of the substrate. Also, in FIG.
From the results shown in, <11 along the incident direction of the ion beam
It was found that the orientation of the 1> axis was excellent, but the orientation of the axis in the direction perpendicular to the incident direction of the ion beam was somewhat disturbed.

The present inventors assume that the cause of such disorder of crystal orientation is as follows. First of all, with a suitable assist energy, YSZ
When depositing the above crystal on the substrate, it is the most stable and highly probable that the crystal grows with the <100> axis direction of the YSZ crystal facing the normal to the substrate film formation surface in terms of free energy. Will be higher. In addition to that, the effect of the oblique irradiation of the ion beam as described above causes
When the <111> axis shown in FIG. 2 is fixed, the YSZ crystal may disturb the orientation when the YSZ crystal is rotated around the <111> axis in FIG. 12 to shift the position. Even if the <100> axis is insufficiently fixed by energy, similar crystal orientation disorder may occur,
It is considered that these factors individually or individually affect each other to cause some alignment disorder as shown in FIG. Based on the above, the present inventor arrived at the present invention with the aim of further improving the crystal orientation of the intermediate layer based on the results of this analysis.

The present invention has been made to solve the above-mentioned problems, and the crystal axis c is perpendicular to the film forming surface of the substrate.
The axes can be oriented, and at the same time, the a-axis and the b-axis of the crystal axes of the crystal grains can be aligned along a plane parallel to the film formation surface, and a polycrystalline thin film having excellent crystal orientation can be manufactured. An oxide superconducting conductor provided with an oxide superconducting layer excellent in crystal orientation, and providing an apparatus and a manufacturing method, and having a wide range of choices in synthesis conditions and constituent materials at this time. The purpose is to provide.

[0014]

In order to solve the above-mentioned problems, in order to solve the above-mentioned problems, particles generated from a target are deposited on a substrate, and a polycrystalline thin film made of the particles is formed on the substrate. In a manufacturing apparatus, a base material holder that supports the base material, a target that is arranged opposite to the base material holder, and energy is applied to the target to eject constituent particles of the target toward the base material. The apparatus and the method of forming the film-forming surface while irradiating the substrate with an ion beam at an incident angle of 50 to 60 degrees from an oblique direction with respect to the normal line of the film-forming surface of the substrate supported by the substrate holder. It is provided with a plurality of ion guns arranged at intervals of 90 degrees or 180 degrees around the line.

In order to solve the above-mentioned problems, the invention described in claim 2 is an apparatus for depositing particles generated from a target on a base material to produce a polycrystalline thin film comprising the particles on the base material. A base material holder for supporting the material, a target arranged opposite to the base material holder, a generator for applying energy to the target to eject the constituent particles of the target toward the base material, and the base material holder 5 from an oblique direction with respect to the normal to the film-forming surface of the substrate supported by
The substrate is irradiated with the ion beam at an incident angle of 0 to 60 degrees, and 90 degrees or 180 degrees around the normal to the film formation surface.
It is provided with a plurality of ion guns arranged at intervals.

In order to solve the above-mentioned problems, the invention as set forth in claim 3 deposits particles generated from a target on a base material to form a polycrystalline thin film comprising the particles on the base material.
In a method for producing an oxide superconducting conductor by forming an oxide superconducting layer thereon, when depositing the particles on a substrate, an ion beam generated by an ion source is applied to a normal line of a substrate deposition surface. The particles are deposited on the base material while being irradiated with an incident angle in the range of 50 to 60 degrees from the oblique direction, and the ion beam with which the base material is irradiated is surrounded by the normal line as the central axis. Irradiation is performed from a plurality of directions at intervals of 90 degrees or 180 degrees.

In order to solve the above-mentioned problems, a second aspect of the present invention is a method for depositing particles generated from a target on a base material to produce a polycrystalline thin film made of the particles on the base material. When depositing the particles on the substrate, the particles are irradiated with the ion beam generated by the ion source at an incident angle in the range of 50 to 60 degrees from the oblique direction with respect to the normal line of the substrate film formation surface. While being deposited on the base material, the ion beam for irradiating the base material is irradiated around the normal line as the central axis from a plurality of directions at intervals of 90 degrees or 180 degrees, while the ion beam is formed on the polycrystalline thin film. The oxide superconducting layer is formed by a film method.

[0018]

In the cubic unit cell of a polycrystalline thin film such as YSZ deposited on the substrate, the substrate normal direction is <100.
> Axis indicating the height direction of the unit cell, and other <001
The> axis and the <010> axis both indicate a direction orthogonal to the <100> axis, for example, the width direction or the depth direction of the unit lattice. Here, in the YSZ polycrystalline thin film under a certain condition, the <100> axis is made to be orthogonal to the base material film-forming surface to deposit atoms, which results in stable growth in terms of free energy. Further, in consideration of an ion beam that is incident obliquely to the substrate normal, there are 5 cases where the ion beam is incident along the diagonal direction of the unit lattice, that is, along the <111> axis.
The incident angle is 4.7 degrees.

The incident angle of the ion beam is 50-60.
The range of degrees means that ion channeling occurs most effectively when the incident angle θ of the ion beam coincides with or is about 54.7 degrees, and the crystals deposited on the substrate. In the above, only the atoms having a positional relationship matching the angle on the base material are likely to remain selectively, and other disordered atomic arrangements are removed by being sputtered by the ion beam sputtering effect. It is presumed that only the crystals, in which the atoms with good orientation are assembled, selectively remain and are deposited. Even if channeling does not occur, it is considered that the selective sputtering effect occurs due to convergent collision, anisotropy of ejection energy, and the like.

However, in this case, with only the ion beam in one direction, there is a possibility that the unit cell may rotate around the ion beam in one direction to cause a shift in which atoms try to be deposited. In addition, due to the free energy. There is a possibility that the atoms may try to deposit by shifting the direction of the unit cell against the stability. Therefore, in order to irradiate a plurality of ion beams onto the substrate film-forming surface at the above-mentioned incident angle and to irradiate the ion beam every 90 degrees or 180 degrees around the normal line of the substrate film-forming surface, For example, at least two axial directions of the unit cell of the polycrystalline thin film can be fixed. As a result, the probability that the unit cell of the crystal being deposited will be displaced is extremely small, and a polycrystalline thin film with improved crystal orientation can be obtained. At this time, it is not always necessary that (100) is stable in the direction of the substrate normal in terms of free energy. This is because if the <111> axis is determined to be biaxial, the growth will be uniquely determined in the cubic crystal.

Therefore, in the manufacturing apparatus, the ion gun is provided so that the ion beam can be emitted from the plurality of predetermined directions at the predetermined incident angle with respect to the surface of the substrate on which the film is formed, so that the orientation can be improved. A crystalline thin film can be manufactured. Further, in the manufacturing method, a polycrystalline thin film having a good orientation can be formed by irradiating the surface of the base material film with the ion beam from a plurality of predetermined directions at a predetermined incident angle. Furthermore, if an oxidation-conducting superconducting layer is formed on the polycrystalline thin film having excellent orientation, an oxide superconducting conductor having an oxide superconducting layer having excellent orientation can be manufactured.

[0022]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment in which the polycrystalline thin film of the present invention is formed on a substrate. In FIG. 1, A is a tape-shaped substrate and B is a polycrystalline thin film formed on the upper surface of the substrate A. Is shown. In this example, the tape-shaped base material is used as the base material A, but various shapes such as a plate material, a wire material, and a strip can be used, and the base material A is made of silver, platinum, or stainless steel. It is made of various metal materials such as steel, copper, nickel alloys such as Hastelloy, or various glasses or various ceramics.

The polycrystalline thin film B is YSZ (yttrium-stabilized zirconia), M having a cubic crystal structure.
The polycrystalline thin film B is made of gO or the like and is provided so as to cover the entire upper surface of the substrate A. As shown in FIG. The c-axis of the crystal axis of each crystal grain 20 is oriented at right angles to the upper surface (deposition surface) of the substrate B, and the a-axis and the b-axis of the crystal axis of each crystal grain 20 are mutually They are oriented in the same direction and are in-plane oriented. The polycrystalline thin film B is
It is necessary to be crystalline cubic, and hexagonal and orthorhombic are not preferred, and compounds may be used as long as they are cubic. Further, the c-axis of each crystal grain 20 is oriented at right angles to the (upper surface) film formation surface of the base material A. The a-axis (or the b-axis) of each crystal grain 20 is joined and integrated by making the angle (the grain boundary tilt angle K shown in FIG. 2) between them within 30 degrees.

Next, an apparatus for manufacturing the polycrystalline thin film B will be described. FIG. 3 shows an example of an apparatus for forming the polycrystalline thin film B. In this example, the laser vapor deposition apparatus is provided with an ion gun for ion beam assist. This apparatus includes a base material holder 11 for holding a base material A, and plate-shaped targets 12 that are arranged diagonally below the base material holder 11 so as to face each other at a predetermined interval.
An ion gun 13A, which is arranged to face the base material holder 11 so as to sandwich the base material holder 11 at a predetermined interval,
13B and a laser emitting device (generation device) 14 provided on the side of the target 12 for irradiating a laser beam toward the upper surface of the target 12.

The main part of the apparatus of this example is the vacuum container 1.
5, the base material holder 11 and the target 12 are stored.
Around the circumference of the vacuum container 15 can be maintained in a vacuum atmosphere, and the ion guns 13A and 13B are attached to the peripheral wall of the vacuum container 15.
Is attached. Furthermore, in the vacuum container 15,
An atmosphere gas supply source such as a gas cylinder (not shown) is connected to the inside of the vacuum container 15 in a low pressure state such as vacuum,
At the same time, the atmosphere can be adjusted to an argon gas or other inert gas atmosphere or an inert gas atmosphere containing oxygen. The laser light emitting device 1
The laser beam emitted from the target 4 passes through the first reflecting mirror 14a, the second reflecting mirror 14b, the condensing lens 14c, and the window 15a attached to the side wall of the vacuum container 15 to the target 1
The upper surface of 2 is focused and irradiated.

On the other hand, in this example, as the base material 2, a long metal tape (a tape made of Hastelloy or stainless steel) in the form of a base material A is used. A winding device 9 is provided, and the tape-shaped base material 2 is continuously fed from the delivery device 8 to the base material holder 11 and then wound by the winding device 9 to form a polycrystalline thin film on the tape-shaped base material A. It is configured so that B can be continuously formed. The base material holder 11 has a heater inside so that the base material A supplied from the delivery device 8 to the base material holder 11 can be heated to a desired temperature. Specific examples of the target 12 include zirconia (YSZ) stabilized with MgO or Y ₂ O ₃ , and Mg.
O, SrTiO ₃ or the like is used, but the present invention is not limited to this, and a target suitable for the polycrystalline thin film to be formed may be used.

Each of the ion guns 13A and 13B has an evaporation source housed inside a container and is provided with an extraction electrode near the evaporation source. Then, a part of atoms or molecules generated from the evaporation source is ionized, and the ionized particles are controlled by an electric field generated by an extraction electrode to irradiate as an ion beam. There are various methods for ionizing particles, such as a DC discharge method, a high frequency excitation method, a filament method, and a cluster ion beam method. The filament type is a method in which a tungsten filament is electrically heated to generate thermoelectrons, which are collided with evaporated particles in a high vacuum to be ionized. The cluster ion beam method is a method of bombarding clusters of aggregate molecules that come out in a vacuum from a nozzle provided at an opening of a crucible containing a raw material, bombarded with thermal electrons, ionized, and radiated.
In this embodiment, the ion gun 13 having the internal structure shown in FIG. 4 is used. The ion gun 13 includes an extraction electrode 17, a filament 18 and an Ar inside a cylindrical container 16.
It is configured to include a gas introduction tube 19 and the like, and can ionically irradiate ions from the tip of the container 16 in a beam shape.

In each of the ion guns 13A and 13B, as shown in FIG. 3, the central axis S ₁ or S ₂ of the ion guns 13A and 13B with respect to the upper surface (deposition surface) of the substrate 2 is an incident angle θ (perpendicular to the substrate A). They are opposed to each other with an inclination of (normal line) H and an angle formed by the center line S. These incident angles θ are 50-60
The range of degrees is preferred, but the range of 55-60 degrees is most preferred. Therefore, the ion guns 13A and 13B are
The ion guns 13A and 13B are arranged so that the ion beam can be incident at an incident angle θ with respect to the normal line of the film forming surface of the base material A, and the ion guns 13A and 13B are arranged around the normal line of the film forming surface of the base material A 18
They are arranged at 0 degree intervals. The ion gun 13A,
The incident angles of the ion beams by 13B are preferably the same, but they may be slightly different.

The ion beam applied to the substrate A by the ion guns 13A and 13B is He ⁺ , Ne ⁺ , Ar ⁺ ,
Ion beam of rare gas such as Xe ⁺ , Kr ⁺ , or
A mixed ion beam of them and oxygen ions is used.
However, in order to arrange the crystal structure of the polycrystalline thin film B, a certain amount of atomic weight is required, and considering that the effect becomes too thin with an ion that is too light, it is preferable to use an ion such as Ar ⁺ or Kr ^+. More preferable. The laser emitting device 14 condenses and irradiates a laser beam onto the target 12 through a transparent window 15a attached to the side wall of the vacuum container 15, and scoops out the constituent particles of the target 12 to eject the target 12 toward the substrate A side. Is something that can be done. The laser emitting device 14 may be any one of YAG laser, CO ₂ laser, excimer laser, etc. as long as it can emit particles from the target 12.

Next, using the above-mentioned apparatus, Y
A case of forming the polycrystalline thin film B of SZ will be described.
In order to form the polycrystalline thin film B on the base material A, a YSZ target is used, the inside of the vacuum container 15 accommodating the base material A is decompressed, and the delivery device 8 transfers the base material holder 11 to the base material holder 11. The base material A is sent out at a predetermined speed, and the ion guns 13A and 13B and the laser emitting device 14 are operated.

When the target 12 is irradiated with the laser beam from the laser emitting device 14, the constituent particles of the target 12 are dug out and fly to the base material A side. Then, the particles generated from the target 12 are deposited on the base material A, and at the same time, from the ion guns 13A and 13B, for example, Kr
Irradiation is performed with a mixed ion beam of ⁺ ions and oxygen ions or an ion beam of Kr ⁺ ions. The incident angle θ when irradiating the ion beam is most preferably in the range of 50 to 60 degrees. By performing the above processing, the YSZ polycrystalline thin film B having excellent crystal orientation can be formed on the base material A.

Here, when the incident angle θ is 30 degrees, the c-axis of the polycrystalline thin film is oriented at right angles to the film forming surface of the substrate A, but the in-plane orientation is insufficient. Also, the incident angle θ is 9
At 0 degree, the polycrystalline thin film does not even have c-axis orientation. If the ion beam irradiation is carried out at an angle within the above-mentioned preferable range, the (100) plane of the crystal of the polycrystalline thin film will stand.

As a factor for adjusting the crystal orientation of the polycrystalline thin film B, the inventors of the present invention, as described above with reference to FIG. 12, have an incident angle of an appropriate angle for producing the ion channeling effect on the atoms during deposition. It is estimated that this is because the ion beam irradiation was performed at an angle. Here in the present invention,
As shown in FIG. 3, since the ion beams are irradiated from the two ion guns 13A and 13B arranged at intervals of 180 degrees at an incident angle θ in the range of 50 to 60 degrees, atoms being deposited on the base material A are formed. In the cubic crystal lattice
The two <111> axes of the crystal lattice can be fixed. That is, in the crystal lattice shown in FIG.
If the 1> axis is fixed with the ion gun 13A, this <
It is possible to fix the axis in the g direction in FIG. 12, which is oriented in a direction obtained by rotating the unit cell by 180 degrees with respect to the 111> axis. Therefore, as described above with reference to FIG. 12, it is possible to suppress the misalignment of the crystal lattice that tends to occur around the <111> axis. For this reason, the polycrystalline thin film B having excellent crystal orientation can be formed.

Various thin films can be laminated on the polycrystalline thin film B formed as described above according to the purpose. For example, if the oxide superconducting layer is formed on the polycrystalline thin film B having excellent orientation by the film forming method, the oxide superconducting layer can be epitaxially grown and the crystal orientation of the oxide superconducting layer can be improved. Therefore, an oxide superconductor having excellent superconducting properties can be obtained. If a magnetic thin film is formed on the polycrystalline thin film B having excellent orientation, a magnetic thin film having excellent magnetic properties can be obtained. Similarly, an optical thin film, a wiring thin film, etc. can be formed on the polycrystalline thin film B. If it is formed, a high-performance thin film suitable for those purposes can be obtained.

By the way, in the above embodiment, the ion guns 13A and 13B are arranged on both sides of the base material A at intervals of 180 degrees, but the number of ion guns arranged is not limited to this, and as shown in FIG. By arranging the ion gun 13C at an angle of 90 degrees in addition to 13A and 13B, a total of three ion guns may be arranged. Further, although not shown in the drawings, the ion gun 13C is 90 degrees around the base material A. You may arrange four ion guns at intervals.

Next, the case where an oxide superconducting layer is formed on the polycrystalline thin film B to manufacture an oxide superconducting conductor will be described. FIG. 6 shows an example of an apparatus for forming an oxide superconducting layer by a film forming method, and FIG. 6 shows a laser vapor deposition apparatus. The laser deposition apparatus 30 of this example includes a processing container 31.
The base material A and the target 33 can be installed in the vapor deposition processing chamber 32 inside the processing container 31.
That is, the base 34 is provided at the bottom of the vapor deposition processing chamber 32, and the base material A can be installed in a horizontal state on the upper surface of the base 34, and the support holder 36 is provided diagonally above the base 34. The supported target 33 is provided in an inclined state. Further, a feeding device 8 ′ for the base material A and a winding device 9 ′ for the base material A are provided on both sides of the base 34. The feeding device 8 ′ sends the base material A onto the base 34, and then the winding device 8 ′. The substrate A can be wound by the device 9 '. The processing container 31 is connected to a vacuum exhaust device 37 via an exhaust hole 37a so that the inside of the processing container 31 can be depressurized to a predetermined pressure.

The target 33 has a composition similar to or close to that of the oxide superconducting layer to be formed, or
It is composed of a sintered body of a complex oxide or a plate body such as an oxide superconductor containing a large amount of components that easily escape during film formation. The base 34 has a built-in heater so that the base material A can be heated to a desired temperature. On the other hand, a laser emitting device 38, a first reflecting mirror 39, a condenser lens 40, and a second reflecting mirror 41 are provided on the side of the processing container 31, and the laser beam generated by the laser emitting device 38 is supplied to the processing container. The target 33 can be focused and irradiated through a transparent window 42 attached to the side wall of 31. The laser emitting device 38 may be a YAG laser, if it can eject the constituent particles from the target 33.
Any one such as CO ₂ laser and excimer laser may be used.

Next, the case of forming the oxide superconducting layer C on the polycrystalline thin film B will be described. Polycrystalline thin film B
The substrate A on which is formed is supplied from the delivery device 8 ′ onto the base 34 of the laser vapor deposition device 30 shown in FIG.
Is depressurized with a vacuum pump. Here, if necessary, an oxygen gas may be introduced into the vapor deposition processing chamber 32 so that the vapor deposition processing chamber 32 has an oxygen atmosphere. Further, the base material A is sent from the delivery device 8 ′ onto the base 34, and the heater of the base 34 is operated to heat the base material A to a desired temperature.

Next, the laser beam generated from the laser emitting device 38 is focused and irradiated on the target 33 in the vapor deposition processing chamber 32. As a result, the constituent particles of the target 33 are scooped out or evaporated, and the particles are deposited on the polycrystalline thin film B. Here, since the polycrystalline thin film B is preliminarily oriented along the c-axis and is also oriented along the a-axis and the b-axis during the deposition of the constituent particles, the crystal c of the oxide superconducting layer C formed on the polycrystalline thin film B is c. Crystallization is performed by epitaxial growth so that the axis, the a axis, and the b axis are aligned with the polycrystalline thin film B. As a result, the oxide superconducting layer C having good crystal orientation can be obtained.

The oxide superconducting layer C is coated on the upper surface of the polycrystalline thin film B as shown in FIG. 7, and the c axis of the crystal grain 23 is perpendicular to the upper surface of the polycrystalline thin film B. The a-axis and the b-axis of the crystal grains 23 are oriented in-plane along a plane parallel to the upper surface of the base material as in the polycrystalline thin film B described above, and as shown in FIG. The grain boundary tilt angle K ′ formed between them is a value close to the grain boundary tilt angle K of the polycrystalline thin film B,
For example, it is set within 30 degrees. The oxide superconductor that constitutes the oxide superconducting layer C is Y ₁ Ba ₂ Cu ₃ Ox,
_{Y 2 Ba 4 Cu 8 Ox,} Y 3 Ba 3 Cu 6 Ox a composition, or _{(Bi, Pb) 2 Ca 2} Sr 2 Cu 3 Ox, (Bi, Pb) 2 C
a ₂ Sr ₃ Cu ₄ Ox composition or Tl ₂ Ba ₂ Ca
₂ Cu ₃ Ox, Tl ₁ Ba ₂ Ca ₂ Cu ₃ Ox, Tl ₁ Ba ₂ Ca
It is an oxide superconductor with a high critical temperature represented by a composition such as ₃ Cu ₄ Ox.

The oxide superconducting layer C formed on the polycrystalline thin film B is in a polycrystalline state, and each of the crystal grains of the oxide superconducting layer C is as shown in FIG. In the thickness direction of the base material A, the c-axis, which is hard to pass electricity, is oriented, and in the longitudinal direction of the base material A, the a-axis or the b-axis is oriented. Therefore, the obtained oxide superconducting layer has excellent quantum bondability at the crystal grain boundaries and little deterioration of the superconducting properties at the crystal grain boundaries. Therefore, it is easy to pass electricity in the plane direction of the base material A and the critical current density is excellent. Things are obtained.

Next, another example of the apparatus for producing the polycrystalline thin film B will be described. FIG. 9 shows another example of the apparatus for producing the polycrystalline thin film B. The apparatus of this example is
The sputtering system is provided with two ion guns for ion beam assist. The apparatus of this example includes a base material holder 51 for holding the base material A horizontally, and the base material holder 51.
A plate-shaped target 52 diagonally above and opposed to the target holder 52 at a predetermined interval, and ion guns 53A and 53B facing diagonally above the base material holder 51 at a predetermined interval and spaced from the target 52. A sputter beam irradiation device 54 arranged below the target 52 and facing the lower surface of the target 52 is mainly configured. Further, reference numeral 55 in the figure denotes a target 52.
It shows a target holder holding. The ion guns 53A and 53B are both the base holder 5
50 with respect to the normal line H of the film forming surface of the base material A supplied onto
The ion guns 53A and 53A are arranged so that they can be irradiated with an ion beam at an incident angle of -60 degrees, and are arranged at 90-degree intervals around the normal line.

The apparatus of this embodiment is housed in a vacuum container (not shown) so that the periphery of the base material A can be kept in a vacuum atmosphere. Further, an atmosphere gas supply source such as a gas cylinder is connected to the vacuum container, the inside of the vacuum container is in a low pressure state such as vacuum, and argon gas or another inert gas atmosphere or an inert gas containing oxygen. It can be made into an atmosphere.

Since the base material A is a metal tape,
A feeding device and a winding device, which are omitted in the drawing, are provided on the front side and the rear side of the base material holder 51 shown in FIG. 9, and the base material A is continuously fed from the sending device to the base material holder 51, and then the winding device is wound. The device is configured so that it can be wound up. An angle adjusting mechanism D is attached to the bottom of the base material holder 51. The angle adjusting mechanism D includes an upper support plate 55 joined to the bottom of the base material holder 51 and the upper support plate 55.
A lower support plate 56 pin-connected to the lower support plate 5 and the lower support plate 5
The base 57 which supports 6 is mainly constituted. The upper support plate 55 and the lower support plate 56 are configured to be rotatable relative to each other via a pin coupling portion, and the base material holder 5
The tilt angle of 1 can be adjusted. In this example, the angle adjusting mechanism D for adjusting the angle of the base material holder 51.
Although the angle adjusting mechanism D is provided with the ion guns 53A, 53
You may make it attach to B and adjust these inclination angles and adjust the incident angle of an ion beam. Further, the angle adjusting mechanism is not limited to the configuration of this embodiment, and it goes without saying that various configurations can be adopted.

Sputter beam irradiation device (generation device)
Reference numeral 54 has a configuration similar to that of the ion gun 53, and irradiates the target 52 with an ion beam to target 52.
The constituent particles of can be knocked out. In addition,
In the device used in the present invention, it is important to be able to knock out the constituent particles of the target 53. Therefore, a voltage is applied to the target 52 with a high frequency coil or the like so that the constituent particles of the target 52 can be knocked out. The sputter beam irradiation device 54 may be omitted.

In order to form the polycrystalline thin film B on the base material A with the apparatus of this example, a target such as YSZ is used and the angle adjusting mechanism D is adjusted to adjust the ion guns 53A, 53.
The ion beam emitted from B is irradiated at an angle in the range of 50 to 60 degrees with respect to the normal line of the film formation surface of the base material holder 51. Next, the inside of the container accommodating the base material A is evacuated to create a reduced pressure atmosphere. Then, the substrate A is sent to the base 51 side and the ion gun 13 and the sputter beam irradiation device 54 are operated.

By the above-mentioned processing, it becomes possible to manufacture a polycrystalline thin film having a good orientation as in the case of the laser vapor deposition method described above. Here, if the laser vapor deposition method as shown in the previous example is applied, a polycrystalline thin film can be manufactured at a higher film formation rate as compared with the oblique ion beam irradiation method applying the sputtering method. Specifically, in the sputtering method of oblique ion beam irradiation, 0.002
In the laser deposition method, it is possible to form a film at a high rate of about 0.05 to 0.07 μm / min by a laser deposition method of irradiating an oblique ion beam in a film deposition rate of about −0.003 μm / min. it can. However, if the film forming rate may be slowed down, instead of the laser vapor deposition method, sputtering as in this example may be performed and oblique ion beam irradiation may be performed during sputtering.

(Manufacturing Example) Using the apparatus having the structure shown in FIG. 9, the inside of the container accommodating this apparatus was evacuated by a vacuum pump to reduce the pressure to 3.0 × 10 ⁻⁴ Torr. Base material is width 1
Hastelloy C with 0 mm, thickness 0.5 mm and length 10 cm
276 tape was used. A target made of YSZ (stabilized zirconia: Y ₂ O ₃ 3 mol%) is used, the sputtering voltage is 1000 V, the sputtering current is 100 mA, and the incident angles of the beams of the two ion sources are set to 0 to 65 degrees. The ion beam energy was set to 200 eV and ion irradiation was performed simultaneously with sputtering on the substrate to form a film-like YSZ layer having a thickness of 0.3 μm.

FIG. 10 shows the relationship between the incident angle and the full width at half maximum in the distribution of crystals in the (111) direction of the polycrystalline thin film obtained by the above method. The full value at half maximum was determined for each of the obtained samples by the angle of the spread state from the center of the pole figure in the figure drawn in the pole figure, that is, the peak ratio half. From the results shown in FIG. 10, it has been clarified that the crystal orientation becomes good in the ion beam incident angle range of 50 to 60 degrees. Further, it was also revealed that the grain boundary tilt angle can be minimized to about 25 degrees by setting the angle of incidence of the ion beam to 55 to 60 degrees.

[0050]

As described above, according to the present invention, the ions are incident at an angle of 50 to 60 degrees with respect to the normal line of the substrate film-forming surface, and the ions are separated by 90 degrees or 180 degrees around the normal line. Since an ion gun is installed to irradiate the beam,
When the target particles are deposited on the substrate, the particles can be deposited while fixing at least two <111> axes of the crystal lattice of the cubic polycrystalline thin film. Therefore, a polycrystalline thin film having a good crystal orientation can be formed on the substrate. Various thin films can be stacked on the polycrystalline thin film thus formed according to the purpose. For example, if the oxide superconducting layer is formed on the polycrystalline thin film with excellent orientation by the film forming method, the oxide superconducting layer can be epitaxially grown and the crystal orientation of the oxide superconducting layer can be improved. An oxide superconductor having excellent superconducting properties can be obtained. If a magnetic thin film is formed on a polycrystalline thin film with excellent orientation, a magnetic thin film with excellent magnetic properties can be obtained. Similarly, an optical thin film, wiring thin film, etc. can be formed on the polycrystalline thin film. If so, a high-performance thin film suitable for those purposes can be obtained.

If the method of forming the oxide superconducting layer on the polycrystalline thin film having excellent crystal orientation is carried out by the film forming method, the crystal structure of the oxide superconducting layer can be adjusted, so that the superconducting characteristics can be improved. It is possible to obtain an excellent oxide superconducting conductor.

[Brief description of drawings]

FIG. 1 is a sectional view showing an example of a polycrystalline thin film obtained by carrying out the method of the present invention.

FIG. 2 is an explanatory diagram showing a grain boundary tilt angle of crystal grains of the polycrystalline thin film shown in FIG.

FIG. 3 is a block diagram showing an example of an apparatus used for carrying out the method of the present invention to form a polycrystalline thin film.

4 is a configuration diagram showing an example of an ion gun provided in the device shown in FIG.

FIG. 5 is a plan view showing a preferred example of the positional relationship between the base material and the ion gun.

FIG. 6 is a configuration diagram showing an example of a laser vapor deposition apparatus used for carrying out the method of the present invention to form an oxide superconducting layer on a polycrystalline thin film.

FIG. 7 is a cross-sectional view showing an example of an oxide superconducting conductor obtained by carrying out the method of the present invention.

8 is an explanatory view showing a grain boundary tilt angle of crystal grains of the oxide superconducting layer shown in FIG. 7.

FIG. 9 is a configuration diagram showing another example of an apparatus used when carrying out the method of the present invention.

FIG. 10 is a diagram showing the relationship between the ion beam incident angle and the full width at half maximum of a polycrystalline thin film obtained by carrying out the method of the present invention.

FIG. 11 is a configuration diagram showing a conventional oxide superconducting conductor in which an oxide superconducting layer is formed on a polycrystalline thin film on a base material.

FIG. 12 is a perspective view showing a cubic crystal lattice and an incident direction of an ion beam.

FIG. 13 is a (100) pole figure of a polycrystalline thin film previously experimentally manufactured by the present inventors.

[Explanation of symbols]

A ... Base material, B ... Polycrystalline thin film,
C ... Oxide superconducting layer, K, K '... Grain boundary tilt angle, θ ... Incident angle, H ... Normal line, 11, 51 ... Substrate holder, 12, 55 ... Target, 13A, 13B, 13C
... ion gun, 53A, 53B ... ion gun, 14 ... laser emission device (generation device), 20 ... crystal grain, 2
2 ... Oxide superconducting conductor, 23 ... Crystal grains, 54 ... Sputter beam irradiation device (generation device),

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) C23C 14/48 H01B 12/00-13/00

Claims (3)

(57) [Claims] 1. An apparatus for depositing particles generated from a target on a base material to manufacture a polycrystalline thin film comprising the particles on the base material, and a base material holder for supporting the base material, and the base material holder. A target arranged opposite to the holder, a generator for applying energy to the target to eject the constituent particles of the target toward the base material, and a method for forming a film on a base material supported by the base material holder. The substrate is irradiated with an ion beam at an incident angle of 50 to 60 degrees obliquely to the line, and a plurality of ion guns arranged at 90 or 180 degree intervals around the normal to the film-forming surface are provided. An apparatus for producing a polycrystalline thin film, which is characterized in that 2. A method of depositing particles generated from a target on a substrate to produce a polycrystalline thin film comprising the particles on a substrate, wherein an ion source is used when depositing the particles on the substrate. While irradiating the generated ion beam with an incident angle in the range of 50 to 60 degrees from an oblique direction with respect to the normal line of the base material film-forming surface, the particles are deposited on the base material and A method for producing a polycrystalline thin film, which comprises irradiating an ion beam for irradiation from a plurality of directions at 90 ° or 180 ° intervals around the normal line as a central axis. 3. Particles generated from a target are deposited on a substrate, a polycrystalline thin film made of the particles is formed on the substrate, and an oxide superconducting layer is formed on the polycrystalline thin film to form an oxide superconducting conductor. In the method of manufacturing, when depositing the particles on a substrate, an ion beam generated by an ion source is incident at an incident angle in a range of 50 to 60 degrees from an oblique direction with respect to a normal line of a substrate film formation surface. While the particles are deposited on the base material while being irradiated, the ion beam for irradiating the base material is irradiated around the normal line as a central axis at 90 ° or 180 ° intervals from a plurality of directions while being formed. A method for producing an oxide superconducting conductor, comprising forming an oxide superconducting layer on the formed polycrystalline thin film by a film forming method.