JPH06271393A - Thin-film laminate and oxide superconducting conductor and their production - Google Patents

Abstract

PURPOSE:To provide a thin film laminate having polycrystallinc thin films for orientation control having excellent crystal orientability and the oxide superconducting conductor formed by utilizing this laminate and to provide a process capable of producing the laminate and the conductor at a high film forming speed. CONSTITUTION:This thin film laminate has a base material A, the rapidly formed polycrystalling thin film B which is formed on the film forming surface of this base material A and is bonded with many crystal grains and the polycrystalling thin film C for orientation control which is formed in this rapidly formed polycrystalling thin film B, is formed thinner than the rapidly formed polycrystalling thin film B and has <=30 deg. grain boundary inclination. Since this laminate has the polycrystalling thin film C for orientation control having <=30 deg. grain boundary inclination on the base material, the crystalline structures of the thin films to be formed thereon are aligned. The oxide superconducting conductor having excellent superconducting characteristics is, therefore, obtd. Since the laminate has the rapidly formed polycrystalling thin film, the thick laminate is obtd. in a short film forming time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film laminate having an orientation-controlled polycrystalline thin film having excellent crystal orientation, an oxide superconducting conductor having an oxide superconducting layer having excellent superconducting properties, and a method for producing them.

[0002]

2. Description of the Related Art The oxide superconductor discovered in recent years is an excellent superconductor exhibiting a critical temperature exceeding the liquid nitrogen temperature. At present, this type of oxide superconductor is a practical superconductor. There are various problems to be solved for use as One of the problems is that the oxide superconductor has a low critical current density.

The problem that the critical current density of the oxide superconductor is low is largely due to the existence of electrical anisotropy in the crystal itself of the oxide superconductor. It is known that electricity easily flows in the a-axis direction and the b-axis direction of the crystal axis, but it hardly flows in the c-axis direction. From such a viewpoint, in order to form an oxide superconductor on a substrate and use it as a superconductor, an oxide superconductor in a good crystal orientation is formed on the substrate, and, It is necessary to orient the a-axis or b-axis of the crystal of the oxide superconductor in the direction in which electricity is intended to flow and the c-axis of the oxide superconductor in the other direction.

Conventionally, various means have been tried to form an oxide superconducting layer having a good crystal orientation on a substrate such as a substrate or a metal tape. One of the methods is MgO or SrT, which has a similar crystal structure to that of the oxide superconductor.
A method of forming an oxide superconducting layer on a single crystal substrate such as iO ₃ by a film forming method such as sputtering has been carried out. MgO and SrTi
When a film forming method such as sputtering is performed using an O ₃ single crystal substrate, the crystal of the oxide superconducting layer grows on the basis of the crystal of the single crystal substrate, so that the crystal orientation is improved. It is known that the oxide superconducting layer formed on these single crystal base materials exhibits a sufficiently high critical current density of about tens of thousands to several hundreds of thousands A / cm ² . .

[0005]

In order to use an oxide superconductor as a conductor, it is necessary to form an oxide superconducting layer having good crystal orientation on a long base material such as a tape. There is. 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, so that the oxide superconducting material with good crystal orientation is obtained. Layers cannot be formed at all. In addition, since the heat treatment performed when forming the oxide superconducting layer causes a diffusion reaction between the metal tape and the oxide superconducting layer, there is a problem that the crystal structure of the oxide superconducting layer is destroyed and the superconducting characteristics are deteriorated. .

Therefore, conventionally, on a base material such as a metal tape,
It has been practiced to coat an intermediate thin film of MgO, SrTiO ₃ or the like using a sputtering device and form an oxide superconducting layer on this intermediate thin film. However, the oxide superconducting layer formed on the intermediate thin film of this kind by a sputtering apparatus has a critical current density (for example, about several thousand A / cm ² ) which is considerably lower than that of the oxide superconducting layer formed on the single crystal substrate. There was a problem of not showing. This is considered to be due to the reason explained below.

In FIG. 12, a polycrystalline intermediate thin film 2 is formed on a substrate 1 such as a metal tape by a sputtering device, and an oxide superconducting layer 3 is formed on the polycrystalline intermediate thin film 2 by a sputtering device.
3 is a cross-sectional structure of an oxide superconducting conductor formed with. In the structure shown in FIG. 12, the oxide superconducting layer 3 is in a polycrystalline state, and a large number of crystal grains 4 are randomly bonded. Looking at each of these crystal grains 4 individually, the c-axis of the crystal of each crystal grain 4 is oriented perpendicular to the substrate surface, but the a-axis and the b-axis are oriented in a disordered direction. It is considered that

In this way, a is obtained for each crystal grain of the oxide superconducting layer.
When the orientations of the axis and the b-axis become disordered, the quantum coupling property of the superconducting state is lost at the grain boundaries where the crystal orientation is disturbed, and as a result, the superconducting properties, especially the critical current density, are likely to decrease. The oxide superconductor is in a polycrystalline state in which the a-axis and b-axis are not oriented when the polycrystalline intermediate thin film 2 formed thereunder is not in the a-axis and b-axis orientation. Therefore, it is considered that when the oxide superconducting layer 3 is formed, the oxide superconducting layer 3 grows so as to match the crystal of the polycrystalline intermediate thin film 2.

Therefore, the present inventors formed a polycrystalline intermediate thin film of YSZ or the like on a metal tape such as Hastelloy tape, and on this polycrystalline intermediate thin film, a YBaCuO-based material having excellent stability among oxide superconductors was formed. Various attempts have been made to manufacture a superconducting conductor having excellent superconducting properties by forming the superconducting layer of. From among these attempts, the present inventors firstly formed an intermediate thin film having excellent crystal orientation,
Alternatively, in order to obtain a superconducting tape having excellent superconducting properties, Japanese Patent Application No. 3-1286836 and Japanese Patent Application No. 3-12683
No. 7, Japanese Patent Application No. 3-2055551, Japanese Patent Application No. 4-1344
Patent applications have been filed in Japanese Patent Application No. 3 and Japanese Patent Application No. 4-293464.

According to the techniques described in these patent applications, when a polycrystalline intermediate thin film is formed on a base material of a metal tape such as Hastelloy tape by a sputtering device, the surface of the base material film is formed simultaneously with sputtering. By forming a polycrystalline rapid-deposited thin film while irradiating an ion beam from an oblique direction, a polycrystalline rapid-deposited thin film having excellent crystal orientation can be formed. According to this method, the grain boundary tilt angle formed by the a-axis or the b-axis of each crystal lattice of a large number of crystal grains forming the polycrystalline rapid-deposited thin film can be made equal to 30 degrees or less, and the crystal orientation is excellent. A polycrystalline rapid-deposited thin film can be formed. And further, if the oxide superconducting layer is formed on the intermediate thin film excellent in the orientation, the crystal orientation of the oxide superconducting layer will be excellent.
It is possible to form an oxide superconducting layer having excellent crystal orientation and high critical current density.

However, in the method according to the above patent application, when the sputtered particles are deposited to form a polycrystalline intermediate thin film, the sputtered particles are sputtered by obliquely sputtering a part of the deposited film with an ion beam. Since the deposition is performed, there is a problem that the film formation rate at the time of forming the polycrystalline intermediate thin film becomes slow, and the film formation rate becomes slower than the film formation by ordinary sputtering.

By the way, in addition to the field of application of the oxide superconductor, a technique for forming various alignment films on a substrate such as a polycrystal is used. For example, in the fields of optical thin films, fields of magneto-optical disks, fields of wiring boards, fields of high-frequency waveguides, high-frequency filters, cavity resonators, etc. The problem is to form a good polycrystalline thin film. That is, if the crystal orientation of the obtained polycrystalline thin film is good, an optical thin film, a magnetic thin film formed thereon,
Since the film quality of the wiring thin film and the like is improved, it is said that it is preferable to be able to form an optical thin film, a magnetic thin film, a wiring thin film and the like having good crystal orientation on the substrate.

As a core material of a magnetic head used in a high frequency band, a magnetic thin film such as permalloy or sendust having a high magnetic permeability and being thermally stable has been put into practical use. Conventionally, these magnetic thin films are formed on a predetermined substrate by vapor deposition or sputtering, but if the orientation of the crystal orientation of these magnetic thin films is low, it is difficult to control the magnetic anisotropy of the magnetic thin films. Therefore, there is a problem that the orientation of crystal grains becomes disordered in the film plane, and the high frequency characteristics of magnetic permeability are impaired. Further, if the crystallographic axis in the plane of the film is disordered, local fluctuations called skew and ripple occur in the in-plane magnetization, which impairs the high frequency characteristics of magnetic permeability as described above. Therefore, a magnetic thin film having excellent crystal orientation is desired.

The present invention has been made to solve the above-mentioned problems, and it is possible to orient the c-axis of the crystal axes of crystal grains at right angles to the film-forming surface of the base material, and at the same time, to form the film-forming surface. A thin film laminate having an orientation-controlled polycrystalline thin film excellent in crystal orientation, in which the a-axis and the b-axis of the crystal grains of the crystal grains can be aligned along a plane parallel to the plane, and an oxide superconducting conductor using the same And a method capable of producing the thin film laminate and the oxide superconducting conductor at a high film-forming rate.

[0015]

In order to solve the above-mentioned problems, the present invention provides a multi-layer structure comprising a base material and a large number of crystal grains formed on the film-forming surface of the base material. It comprises a crystallographically accelerated thin film, and an orientation-controlled polycrystalline thin film having a grain boundary tilt angle of 30 degrees or less, which is formed on the polycrystalline rapid-formed thin film and is thinner than the polycrystalline rapid-formed thin film.

In order to solve the above-mentioned problems, a second aspect of the present invention comprises a base material and a large number of crystal grains formed on the film-forming surface of the base material and bonded to each other. The present invention comprises an orientation-controlled polycrystalline thin film and a polycrystalline rapid-deposited thin film formed on the orientation-controlled polycrystalline thin film and formed thicker than the orientation-controlled polycrystalline thin film.

In order to solve the above-mentioned problems, a third aspect of the present invention includes a base material, and a polycrystalline rapid-deposited thin film formed on a film-forming surface of the base material and having a large number of crystal grains bonded to each other. An orientation-controlled polycrystalline thin film having a grain boundary tilt angle of 30 degrees or less formed on the polycrystalline rapidly-deposited thin film and thinner than the polycrystalline rapidly-deposited thin film, and an oxide superconducting layer formed on the orientation-controlled polycrystalline thin film. It is equipped with.

In order to solve the above-mentioned problems, a fourth aspect of the present invention comprises a base material and a large number of crystal grains formed on the film-forming surface of the base material and bonded to each other. Orientation-controlled polycrystalline thin film, polycrystalline quick-deposited thin film formed on the orientation-controlled polycrystalline thin film and thicker than the orientation-controlled polycrystalline thin film, and oxide superconducting layer formed on the polycrystalline fast-deposited thin film. It is equipped with.

In order to solve the above-mentioned problems, a fifth aspect of the present invention is to form a polycrystalline rapid-deposited thin film formed by bonding a large number of crystal grains on a film-forming surface of a substrate by a film-forming method such as sputtering. A film forming process is performed on the polycrystalline rapid-deposited thin film while irradiating an ion beam at an incident angle in a range of 50 to 60 degrees from an oblique direction with respect to the film forming surface, and a grain boundary tilt angle of crystal grains is set to 3.
An orientation-controlled polycrystalline thin film having a temperature of 0 degrees or less is formed.

In order to solve the above-mentioned problems, the invention according to claim 6 is 50 to 60 from an oblique direction with respect to the film forming surface of the base material.
Film formation processing is performed while irradiating the ion beam at an incident angle in the range of 10 degrees to form an orientation control polycrystalline thin film having a grain boundary tilt angle of 30 degrees or less in which a large number of crystal grains are bonded on the substrate film formation surface.
On this orientation-controlled polycrystalline thin film, a polycrystalline rapid-deposited thin film in which a large number of crystal grains are combined is formed by a film forming method such as sputtering.

In order to solve the above problems, the invention according to claim 7 is the method for manufacturing a thin film laminate according to claim 5 or 6, wherein the incident angle of the ion beam is set in the range of 55 to 60 degrees. The film is formed so that the grain boundary tilt angle of the crystal grains of the orientation-controlled polycrystalline thin film is within 25 degrees.

In order to solve the above-mentioned problems, the invention according to claim 8 is the method for producing a thin film laminate according to claim 5, 6 or 7, wherein a polycrystalline rapid-accelerating thin film is formed by a high frequency sputtering method, and orientation control is performed. The crystal thin film is formed by the ion beam sputtering method.

In order to solve the above problems, the invention according to claim 9 provides an oxide superconducting layer on the orientation-controlled polycrystalline thin film or intermediate thin film according to claim 5, 6, 7 or 8 by a film forming method. To form.

In order to solve the above-mentioned problems, the invention according to claim 10 forms the oxide superconducting layer according to claim 9 on an orientation-controlled polycrystalline thin film or a polycrystalline accelerated thin film,
The oxide superconducting layer is epitaxially grown.

[0025]

Since there is an orientation-controlled polycrystalline thin film having a grain boundary tilt angle of 30 degrees or less, when another thin film is formed on this orientation-controlled polycrystalline thin film by a film forming method, the crystal structure of the thin film is formed. Will be good. Therefore, the thin film laminate having this orientation-controlled polycrystalline thin film can be widely used as the structure of the basic portion of various thin film laminates whose crystal structures need to be aligned.

Since the oxide superconducting layer formed on the orientation-controlled polycrystalline thin film having the grain boundary tilt angle of 30 degrees or less has a good crystal orientation, it exhibits excellent superconducting properties. In addition, since the polycrystalline rapid-growth thin film formed on the orientation-controlled polycrystalline thin film has a good crystal orientation, the oxide superconducting layer formed on it also has a good crystal orientation, resulting in excellent superconducting properties. Indicates. Furthermore, if the orientation-controlled polycrystalline thin film is formed thinner than the polycrystalline rapid-deposited thin film, the portion of the orientation-controlled polycrystalline thin film, which takes a long time to form the film, is reduced, and the polycrystalline rapid-deposited thin film portion that can increase the film formation rate is increased. The film forming time is shortened. Also, high frequency sputtering can be used as a method for forming a polycrystalline rapid-deposited thin film, and ion beam sputtering can be used as a method for forming an orientation-controlled polycrystalline thin film.

On the other hand, when depositing the orientation-controlled polycrystalline thin film on the substrate film-forming surface or the polycrystalline rapid-deposited thin film by the film-forming method, the ion beam is applied from the range of 50 to 60 degrees in the oblique direction of the substrate film-forming surface. As a result, the polycrystalline thin film constituent particles deposited during film formation are efficiently activated, resulting in a-axis orientation and b-axis orientation in addition to the c-axis orientation with respect to the film formation surface of the substrate. An orientation-controlled polycrystalline thin film is formed so that the property is also improved. As a result, even with a polycrystalline thin film having a large number of grain boundaries,
All of the a-axis orientation, b-axis orientation, and c-axis orientation of each crystal grain were improved, and an orientation-controlled polycrystalline thin film with improved film quality was obtained, and formed on this orientation-controlled polycrystalline thin film. Since the oxide superconducting layer also has a good crystal orientation, an oxide superconducting conductor having excellent superconducting properties can be obtained.

When the incident angle of the ion beam at the time of forming the orientation-controlled polycrystalline thin film is set to 55 to 60 degrees with respect to the substrate film-forming surface, the grain boundary tilt angle of the crystal grains of the orientation-controlled polycrystalline thin film is 30. The orientation becomes even more uniform than the degree, and it becomes possible to obtain the one having excellent orientation which is equal to or less than 25 degrees. Further, when the polycrystalline rapid-deposited thin film is formed by the high frequency sputtering method and the orientation control polycrystalline thin film is formed by the ion beam sputtering method, the high-frequency sputtered method having a high film formation rate is effectively utilized to make the polycrystalline rapid-deposited thin film having a large thickness And a thin orientation-controlled polycrystalline thin film with excellent crystal orientation is obtained by a sputtering method using oblique ion beam irradiation and a slow film-forming rate, so that the film formation time of the entire thin film stack is shortened.

The inventors of the present invention assume the following as a factor for adjusting the crystal orientation of the polycrystalline thin film.
In the unit cell of the crystal of the cubic polycrystalline thin film formed on the substrate, the substrate normal direction is the <100> axis, and the other <010> axis and the <001> axis are both <100>.
> The direction is orthogonal to the axis. Considering an ion beam that is incident obliquely to the normal line of the substrate with respect to these directions, it is 54 when incident along the diagonal direction of the unit lattice, that is, along the <111> axis with respect to the origin of the unit lattice. .
The incident angle is 7 degrees. Here, as described above, good crystal orientation is exhibited in the ion beam incident angle range of 50 to 60 degrees, and particularly in the 55 to 60 degree range. This means that the ion beam incident angle is equal to 54.7 degrees. It is considered that the ion channeling occurs most effectively when these angles are matched or approximated, and it is considered that the crystal is deposited in the crystal deposited on the substrate. Only the atoms that have a positional relationship that matches the angle on the upper surface of the material tend to remain selectively, and other disordered atomic arrangements are sputtered and removed by the sputtering effect generated by the obliquely incident ion beam. As a result, it is presumed that only the crystals in which the atoms having a good orientation are gathered and selectively deposited, and this causes the crystal orientation to be adjusted.

Further, when an oxide superconducting layer is formed on the orientation-controlled polycrystalline thin film or on the polycrystalline rapid-deposited thin film on the orientation-controlled polycrystalline thin film, if the oxide superconducting layer is epitaxially grown, the oxide superconducting layer is formed. As a result of the crystal growth of the layer along the crystal of the orientation-controlled polycrystalline thin film or the polycrystalline rapid-deposited thin film, the oxide superconducting layer also has excellent a-axis orientation, b-axis orientation, and c-axis orientation.

[0031]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment of a thin film laminate 5 according to the present invention. In FIG. 1, A is a base material, B is a polycrystalline rapid-deposited thin film formed on this base material A, and C is this multi-layered film. The orientation-controlled polycrystalline thin films formed on the rapid-crystallized thin film B are shown. The base material A has a substrate shape in this example, but other various shapes such as a linear shape, a tape shape, and a disk shape can be used, and as the constituent material of the base material A, Various metal materials such as silver, platinum and copper, alloys such as stainless steel and copper alloys, materials such as glass and ceramics, and materials appropriately selected from clad plates and composite plates of various alloys and ceramics. Can be used.

The polycrystalline rapid-deposited thin film B is composed of a large number of fine crystal grains 6 in which crystals having a cubic crystal structure are aggregated and integrated with each other through crystal grain boundaries.
The a-axis and the b-axis are not specially oriented in the crystal axes of each crystal grain of the polycrystalline rapid-deposited thin film B, but the c-axis is oriented almost at right angles to the upper surface (deposition surface) of the base material A. Preferably.

The orientation-controlled polycrystalline thin film C is composed of a large number of fine crystal grains 7 in which crystals having a cubic crystal structure are aggregated and integrated with each other through crystal grain boundaries. The c-axis of the crystal axes of is oriented substantially at right angles to the upper surface (deposition surface) of the base material A, and the a-axis and the b-axis of the crystal axes of the respective crystal grains 7 are oriented in the same direction. It is in-plane oriented. Further, the a-axis (or the b-axis) of the crystals of the respective crystal grains 7 are joined and integrated by setting the angle (the grain boundary tilt angle K shown in FIG. 2) between them to be within 30 degrees.

Next, an apparatus and a manufacturing method for manufacturing the polycrystalline rapid-deposited thin film B and the orientation-controlled polycrystalline thin film C will be described. FIG. 2 shows an example of an apparatus for producing the polycrystalline rapid-deposited thin film B, and the apparatus of this example is a high frequency sputtering apparatus. The apparatus of this example is mainly configured by a base material holder 11 that holds a base material A, and a plate-shaped target 12 that is arranged above the base material holder 11 so as to face each other at a predetermined interval. In addition, reference numeral 13 in the drawing denotes a target 12
The target holder 13 holds the target holder 13. The target holder 13 is connected to the high frequency power source 14, and the high frequency power source 14 and the base material holder 11 are grounded.

The base material holder 11 and the target holder 13 are housed in a vacuum container (not shown) so that the surroundings of the base material holder 11 and the target holder 13 can be kept in a vacuum atmosphere. Further, an atmosphere gas supply source such as a gas cylinder is connected to the vacuum container, and if necessary, the inside of the vacuum container is in a low pressure state such as vacuum, and an argon gas or other inert gas atmosphere or oxygen is supplied. It can be made to contain an inert gas atmosphere. With the above structure, plasma can be generated in the space above the base material A by operating the high frequency power source 14 after depressurizing the inside of the vacuum container.
By the action of this plasma, the particles of the target 12 can be sputtered and blown toward the base material A side.

When a long metal tape (a tape made of Hastelloy or stainless steel) is used as the base material A, a metal tape feeding device and a winding device are provided inside the vacuum container, and the metal tape is continuously fed from the feeding device. It is preferable that the metal tape is sent out onto the base material holder 11 and then wound up by a winding device so that a continuous film can be formed on the metal tape.

The base material holder 11 is provided with a heater inside thereof, and the base material A is disposed on the base material holder 11.
Can be heated to a desired temperature as needed. The target 12 is for forming a desired polycrystalline rapid-deposited thin film B, and has the same composition as or similar composition to the polycrystalline thin film having a desired composition. Specific examples of the target 12 include zirconia (YSZ) stabilized with MgO or Y ₂ O ₃ , MgO, and S.
Although rTiO ₃ or the like can be used, it is not limited to these, and a target suitable for the polycrystalline rapid-deposited thin film B to be formed may be appropriately used.

Next, using the apparatus having the above-mentioned structure, Y is applied onto the base material A.
A case of forming a polycrystalline rapid-deposited thin film B of SZ will be described. To form the polycrystalline rapid-deposited thin film B on the substrate A, use YS
The inside of the vacuum container in which the base material A is stored is evacuated to a reduced pressure atmosphere while using the Z target. Then, the high frequency power supply 14 is operated. As a result, the constituent particles of the target 12 are sputtered and fly onto the base material A. If these particles are deposited for a required time, the polycrystalline rapid-deposited thin film B having a desired thickness can be formed on the base material A. The a-axis, the b-axis, and the c-axis of the crystal axes of a large number of crystal grains forming the polycrystalline rapid-deposited thin film B thus obtained may all be oriented in any direction or have orientation. But good.

Next, FIG. 4 shows the above-mentioned orientation control polycrystalline thin film C.
This is an example of an apparatus for manufacturing a. The apparatus of this example has a configuration in which an ion beam sputtering apparatus is provided with an ion gun for ion beam assist.

The apparatus of this embodiment comprises a base material holder 15 for holding the base material A, a plate-shaped target 16 diagonally above and facing the base material holder 15 at a predetermined interval, and the base material holder 15. Facing diagonally upward with a certain interval,
Further, the main components are an ion gun 17 arranged apart from the target 16 and a sputter beam irradiation device 18 arranged obliquely below the target 16 toward the lower surface of the target 16. Reference numeral 19 in the figure denotes a target holder that holds the target 16.

The apparatus of this embodiment is housed in a vacuum container (not shown) so that the periphery of the base material A can be maintained 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.

The base material holder 15 is provided with a heater inside so that the base material A located on the base material holder 15 can be heated to a desired temperature as needed. An angle adjusting mechanism D is attached to the bottom of the base material holder 15. The angle adjusting mechanism D includes an upper support plate 20 joined to the bottom of the base material holder 15 and the upper support plate 20.
A lower support plate 21 pin-coupled to the lower support plate 2
The base 22 which supports 1 is mainly constituted. The upper support plate 20 and the lower support plate 21 are configured to be rotatable relative to each other via a pin coupling portion, and the base material holder 1
The tilt angle of 5 can be adjusted. Although the apparatus of this example is provided with the angle adjusting mechanism D for adjusting the angle of the base material holder 15, the angle adjusting mechanism D is attached to the supporting portion of the ion gun 17 to adjust the inclination angle of the ion gun 17 to adjust the ion beam. The incident angle may be adjusted. 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.

The target 16 is for forming a target orientation-controlled polycrystalline thin film, and has the same composition as or similar composition to the orientation-controlled polycrystalline thin film having a desired composition. Specifically as the target 16, M
Zirconia stabilized with gO or Y ₂ O ₃ (YS
Z), MgO, SrTiO ₃ or the like is used, but the present invention is not limited to this, and a target suitable for the orientation-controlled polycrystalline thin film to be formed may be appropriately used.

The ion gun 17 is constructed so that an evaporation source is housed inside the container and an extraction electrode is provided 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 17 having the internal structure shown in FIG. 5 is used. The ion gun 17 is configured to include an extraction electrode 26, a filament 27, and an introduction tube 28 for Ar gas or the like inside a cylindrical container 25, and can ionically irradiate ions from the tip of the container 25 in a beam shape. Is.

As shown in FIG. 4, the ion gun 17 has its central axis S with respect to the upper surface (film-forming surface) of the base material A at an incident angle θ (the normal line (normal line) of the base material A and the center line S). The angle is made by the angle) and the two are opposed to each other. The incident angle θ is preferably in the range of 50 to 60 degrees, but most preferably in the range of 55 to 60 degrees. Therefore, the ion gun 17 is arranged so that it can irradiate the upper surface of the base material A with an ion beam at an incident angle θ. The ion gun 17
The ion beam for irradiating the base material A with He ⁺ , N
An ion beam of a rare gas such as e ⁺ , Ar ⁺ , Xe ⁺ , and Kr ⁺ , or a mixed ion beam of these and oxygen ions may be used. However, in order to adjust the crystal structure of the orientation-controlled polycrystalline thin film to be formed, a certain amount of atomic weight is required, and considering that the effect becomes thin with an ion that is too light, Ar ⁺ , Kr ^+, etc. It is preferable to use ions. The sputter beam irradiation device 18 is
The structure is the same as that of the ion gun 17, and the target 16 can be irradiated with an ion beam to knock out the constituent particles of the target 16 toward the base material A.

Next, the case of forming the YSZ orientation-controlled polycrystalline thin film C on the polycrystalline rapid-deposited thin film B using the apparatus having the above structure will be described. To form the orientation-controlled polycrystalline thin film C on the polycrystalline rapid-deposited thin film B, a YSZ target is used, and the angle adjusting mechanism D is adjusted so that the ion beam irradiated from the ion gun 17 is irradiated onto the upper surface of the polycrystalline rapid-deposited thin film B. It is possible to irradiate at an angle in the range of 50 to 60 degrees. Next, the inside of the container accommodating the base material A is evacuated to create a reduced pressure atmosphere. At this time, the pressure in the vacuum container is lower than the pressure in the vacuum container of the high frequency sputtering apparatus shown in FIG. 3 because of the use of the ion beam. Then, the ion gun 17 and the sputter beam irradiation device 18 are operated.

When the target 16 is irradiated with the ion beam from the sputter beam irradiation device 18, the constituent particles of the target 16 are knocked out and fly onto the base material A. And
On the polycrystalline rapid-deposited thin film B, the constituent particles knocked out from the target 16 are deposited and, at the same time, from the ion gun 17 to Ar.
Irradiation with a mixed ion beam of ions and oxygen ions forms an orientation-controlled polycrystalline thin film C. However, in this case, the film thickness of the orientation control polycrystalline thin film C is formed thinner than that of the polycrystalline rapid accelerating thin film B. The incident angle θ when irradiating the ions is 50
The range of 60 to 60 degrees is preferable, and the range of 55 to 60 degrees is the most preferable. Here, if θ is 90 degrees, c of the polycrystalline thin film is
Although the axis is oriented at right angles to the film-forming surface on the base material A (the upper surface of the polycrystalline rapid-deposited thin film B), the axis (11
1) It is not preferable because the surface is raised. When θ is 30 degrees, 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.

By carrying out sputtering while irradiating the ion beam at such an incident angle, the orientation-controlled polycrystalline thin film C of YSZ formed on the polycrystalline rapid-deposited thin film B is formed.
Although it is possible to orient the a-axis and the b-axis of the crystal axes of
This is probably because the sputtered particles being deposited were irradiated with the ion beam at an appropriate angle.

The inventors of the present invention assume the following as factors for adjusting the crystal orientation of the orientation-controlled polycrystalline thin film C. The unit cell of the crystal of the orientation-controlled polycrystalline thin film C of YSZ is a cubic system as shown in FIG. 6, and in this crystal lattice, the substrate normal direction is the <100> axis and the other <010> Both the axis and the <001> axis are in the directions shown in FIG. Considering an ion beam that is obliquely incident on these directions with respect to the substrate normal, in the case where the ion beam is incident on the origin O of FIG. 6 along the diagonal direction of the unit lattice, that is, along the <111> axis. The incident angle is 54.7 degrees.

Here, the incident angle is 50 to 60 as described above.
The best crystal orientation when irradiating with an ion beam within a range of degrees means that when the incident angle of the ion beam coincides with or is around 54.7 degrees,
Ion channeling occurs most effectively, and in the crystal that is being deposited on the polycrystalline rapid-deposited thin film B, only the atoms having the positional relationship on the upper surface of the polycrystalline rapid-deposited thin film B that is aligned with the angle tend to remain selectively. Other disordered atomic arrangements are removed by being sputtered by the ion beam sputtering effect from an oblique direction, and as a result, only the crystals of atoms with good orientation are selectively left and deposited. It is presumed to be due to this. However, among the crystals thus deposited, the ones with disordered atomic arrangement are removed while being deposited by the ion beam, so the deposition rate becomes worse and the deposition rate is slower than that of ordinary sputtering. Become slow.

FIG. 1 shows a thin film stack 5 in which a polycrystalline rapid-deposited thin film B of YSZ and an orientation-controlled polycrystalline thin film C are deposited on a substrate A by the above method. Although FIG. 1 shows a state in which only one layer of crystal grains 7 is formed, it goes without saying that the crystal grains 7 may have a multilayer structure. When the orientation-controlled polycrystalline thin film C is formed by sputtering while irradiating the ion beam from the oblique direction as described above, the film formation rate is such that the polycrystalline rapid-deposited thin film B is formed by ordinary ion beam sputtering or high frequency sputtering. It will be lower than in the case. For example, by high frequency sputtering, a film can be formed at a rate of about 0.5 μm / hour, but by sputtering while irradiating an ion beam from an oblique direction, a rate of about 0.1 μm / hour can be obtained. This is a film forming process.

Therefore, if the polycrystalline rapid-deposited thin film B is formed thick to reduce the film thickness, and the orientation-controlled polycrystalline thin film C having good crystal orientation is thinly formed thereon, the polycrystalline rapid-deposited thin film B is obtained. It becomes possible to perform the film forming process in a shorter time than the case where the entire film thickness including the orientation-controlled polycrystalline thin film C is used as the orientation-controlled polycrystalline thin film C. Further, when the polycrystalline rapid-deposited thin film B and the orientation control polycrystalline thin film C are made of the same material, the bondability between the two thin films B and C becomes good, and the bonding strength between them becomes sufficiently high.

The thin-film laminate 5 having the above-described structure is further provided with various thin films such as an oxide superconducting layer, a magnetic thin film, an optical thin film, and a wiring thin film for practical use. To be done. Further, since the orientation control polycrystalline thin film C is formed on the uppermost part of the thin film stack 5, all the various thin films formed thereon have excellent crystal orientation. The characteristics are improved.

Next, an apparatus for producing an oxide superconducting conductor by forming an oxide superconducting layer on the thin film laminate 5 and a method for producing the same will be described. FIG. 7 shows an example of an apparatus for forming an oxide superconducting layer by a film forming method, and FIG. 7 shows a laser vapor deposition apparatus. Laser vapor deposition apparatus 3 of this example
0 has a processing container 31, and the substrate A and the target 33 can be installed in the vapor deposition processing chamber 32 inside the processing container 31. That is, a base 34 is provided at the bottom of the vapor deposition processing chamber 32, the base material A can be installed on the upper surface of the base 34, and the base 34 is supported diagonally above the base 34 by a support holder 36. The target 33 is provided in an inclined state. Further, the processing container 31 is connected to a vacuum exhaust device 37 via an exhaust hole 37a so that the vapor deposition processing chamber 32 can be depressurized to a predetermined pressure.

The target 33 has the same or similar composition as 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. Therefore, the target 33 is Y ₁ Ba ₂ Cu ₃ Ox, Y ₂
Ba ₄ Cu ₈ Ox, Y ₃ Ba ₃ Cu ₆ Ox, (Bi, P
b) ₂ Ca ₂ Sr ₂ Cu ₃ Ox, (Bi, Pb) ₂ Ca ₂ Sr ₃
Cu ₄ Ox composition or Tl ₂ Ba ₂ Ca ₂ Cu ₃ O
x, Tl ₁ Ba ₂ Ca ₂ Cu ₃ Ox, Tl ₁ Ba ₂ Ca ₃ Cu ₄ O
Since it is used for forming an oxide superconducting layer having a high critical temperature represented by the composition x, etc., it is preferable to use the same composition or a similar composition.

The base 34 has a built-in heater so that the base material A can be heated to a desired temperature as needed. When a long metal tape (made of Hastelloy or stainless steel) is used as the base material A, the metal tape delivery device 45 and the winding device 45 are wound inside the vacuum container as shown by the chain double-dashed line in FIG. A device 46 is provided so that the metal tape 47 is continuously sent from the sending device 45 onto the base 34, and subsequently wound by the winding device 46 so that a continuous film can be formed on the metal tape. Is preferred.

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 provided. The target 33 can be focused and irradiated through the transparent window 42 attached to the side wall of the processing container 31. The laser emitting device 38 is the target 33.
If it is possible to knock out the constituent particles from
Any of AG laser, CO ₂ laser, excimer laser, etc. may be used.

Next, a method for forming the oxide superconducting layer E on the YSZ orientation control polycrystalline thin film C will be described. First, the base material A on which the orientation-controlled polycrystalline thin film C is formed is placed on the base 34 of the laser deposition apparatus 30 shown in FIG.
The pressure in the vapor deposition processing chamber 32 is reduced by the vacuum exhaust device 37. 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. Also, the base 34
The heater A may be 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 orientation-controlled polycrystalline thin film C. Here, since the orientation control polycrystalline thin film C is preliminarily c-axis oriented during the deposition of the constituent particles and is also oriented along the a-axis and the b-axis, the oxide superconducting layer E formed on the orientation control polycrystalline thin film C is formed. The c-axis, a-axis, and b-axis of the crystal are crystallized by epitaxial growth so as to match the orientation-controlled polycrystalline thin film C. As a result, the oxide superconducting layer E having good crystal orientation can be obtained. After the film formation, a heat treatment for adjusting the crystal structure of the oxide superconducting layer E may be performed if necessary.

FIG. 8 shows an oxide superconducting conductor 50 in which the oxide superconducting layer E is formed on the thin film laminate 5 by the method described above. The oxide superconducting layer E formed on the orientation control polycrystalline thin film C is in a polycrystalline state. In each of the crystal grains of the oxide superconducting layer E, the thickness direction of the base material A is increased. The c-axis, which is difficult to apply electricity to, is oriented, and the a-axis or the b-axis is oriented in the surface direction of the base material A.
Therefore, the obtained oxide superconducting layer E is excellent in the quantum bondability at the crystal grain boundaries and has little deterioration in 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. You can get what you want. Further, since the polycrystalline rapid-deposited thin film B is formed sufficiently thicker than the orientation-controlled polycrystalline thin film C, it has an effect of becoming a heat-resistant buffer layer during the heat treatment and is effective in eliminating thermal stress. .
Further, since the thick polycrystalline rapid-deposited thin film B is provided between the base material A and the oxide superconducting layer E, the elements of the oxide superconducting layer E are less likely to diffuse to the base material A side during the heat treatment. The composition of the oxide superconducting layer E is unlikely to collapse.

FIG. 9 shows another example of the oxide superconducting conductor according to the present invention. Oxide superconducting conductor 5 of this example
1 is one in which an oxide superconducting layer E is formed on a thin film laminate 52, and the thin film laminate 52 of this example is a substrate A and an orientation control polycrystalline thin film C formed on this substrate A. And a polycrystalline rapid-deposited thin film B ′ formed on this orientation-controlled polycrystalline thin film C. The orientation-controlled polycrystalline thin film C of this example has a grain boundary tilt angle of crystal grains of 30 degrees or less, similarly to the orientation-controlled polycrystalline thin film C of the above-described example, and a method equivalent to the method described above. However, the difference from the previous example is that the orientation control polycrystalline thin film C is formed directly on the base material A. Then, a polycrystalline rapid-deposited thin film B ′ is formed on this orientation-controlled polycrystalline thin film C, but this polycrystalline rapid-deposited thin film B ′ is different from the polycrystalline rapid-deposited thin film B described in the previous example. A characteristic feature is that the a-axis and the b-axis of the respective crystal axes of a large number of crystal grains constituting the rapid-deposited thin film B ′ are oriented with their grain boundary tilt angles reduced and the crystal orientation is excellent.

This is because when a polycrystalline accelerated thin film B'is formed on the orientation-controlled polycrystalline thin film C by sputtering, the crystals of the polycrystalline accelerated thin film B'are epitaxially grown so as to match the crystals of the orientation-controlled polycrystalline thin film C. This is because it is possible to adjust the crystal orientation of the polycrystalline rapid-deposited thin film B ′. Therefore, the oxide superconducting layer E formed on the polycrystalline rapid-deposited thin film B ′ can also be made to have excellent crystal orientation as in the case of the above-mentioned example, and the oxide superconducting conductor 51 having a high critical current density can be obtained. become able to. Also in this example, by forming the orientation-controlled polycrystalline thin film C thin and the polycrystalline rapid-deposited thin film B ′ thick, the processing time of the portion of the orientation-controlled polycrystalline thin film C where the film formation rate becomes slow is shortened. Therefore, the film formation time can be shortened as compared with the case where all of the polycrystalline rapid-deposited thin film B ′ and the orientation control polycrystalline thin film C are manufactured by ion beam sputtering with ion beam assist.

FIG. 10 shows still another example of the oxide superconducting conductor according to the present invention. The oxide superconducting conductor 53 of this example is obtained by forming an oxide superconducting layer E on a thin film laminate 54, and the thin film laminate 54 of this example has a base material A.
And the orientation control polycrystalline thin film C formed on the base material A.
And a polycrystalline accelerated thin film B ″ formed on the orientation-controlled polycrystalline thin film C. The orientation-controlled polycrystalline thin film C of this example is equivalent to the orientation-controlled polycrystalline thin film C of the example described above based on FIG. 9, and in-beam irradiation is performed from an oblique direction by using the apparatus shown in FIG. In the polycrystalline body formed by performing the above, each of a large number of crystal grains forming the orientation-controlled polycrystalline thin film C has excellent crystal orientation.

On the orientation-controlled polycrystalline thin film C,
A polycrystalline rapid-deposited thin film B ″ is formed, and this polycrystalline rapid-deposited thin film B ″ has an excellent crystal orientation similar to the polycrystalline rapid-deposited thin film B ′ of the example described above with reference to FIG. Is. However, it is the manufacturing method that the polycrystalline rapid-deposited thin film B ″ of this example is different from the polycrystalline rapid-deposited thin film B ′ of the previous example.

The polycrystalline rapid-deposited thin film B ″ of this example is not manufactured by using the high frequency sputtering apparatus shown in FIG. 3, but is manufactured by the ion beam irradiation type sputtering apparatus shown in FIG. That is, when the polycrystalline rapid-growth thin film B ″ is formed on the orientation-controlled polycrystalline thin film C, the apparatus shown in FIG. The device 18 is operated to perform the film forming process, but the ion gun 17 is not operated during the film forming process. As a result, the particles sputtered by the ion beam from the target 16 are oriented control polycrystalline thin film C
Deposit on top. If the ion gun 17 is not operated here, all of the sputtered particles flying to the side of the base material A can be deposited, so that the film formation rate is good and the film formation speed is higher than that when the ion gun 17 is operated. Will be faster.

In this case, however, the orientation control polycrystalline thin film C
Since the polycrystalline rapid-deposited thin film B ″ is formed on the upper surface by sputtering, the crystal of the polycrystalline rapid-deposited thin film B ″ can be epitaxially grown so as to match the crystal of the orientation-controlled polycrystalline thin-film C. The crystal orientation of the thin film B ″ can be adjusted. Therefore, the oxide superconducting layer E formed on the polycrystalline rapid-deposited thin film B ″ can also have excellent crystal orientation as in the case of the above-mentioned example, and the oxide superconducting conductor 53 having a high critical current density can be obtained. Will be able to. Also in this example, by forming the orientation-controlled polycrystalline thin film C thin and the polycrystalline rapid-deposited thin film B ″ thick, the processing time of the portion of the orientation-controlled polycrystalline thin film C where the film formation rate becomes slower is reduced. Since it can be shortened, the film formation time can be shortened.

On the other hand, FIG. 11 shows another example of an apparatus for producing the polycrystalline rapid-deposited thin film B and the orientation-controlled polycrystalline thin film C. In the apparatus of this example, the same components as those of the apparatus shown in FIG. 4 are designated by the same reference numerals and the description thereof will be omitted. The apparatus of this example is different from the apparatus shown in FIG. 4 in that three targets 16 are provided, three sputtering beam irradiation devices 18 are provided, and a high-frequency power source 14 is connected to the target 16.

In the apparatus of this example, three targets 1
By using 6, 16 and 16 as targets having different compositions, different kinds of particles can be ejected from the respective targets and deposited on the substrate A to form a polycrystalline thin film, which is more complicated. There is a feature that even a polycrystalline thin film having a composition can be manufactured. Further, the high frequency power source 14 is operated to perform sputtering from the target 16 to form a polycrystalline rapid-deposited thin film B, and then the high frequency power source 14 is stopped to adjust the pressure inside the vacuum container, and then sputtering by ion beam irradiation. It is also possible to form the orientation-controlled polycrystalline thin film C by performing ion beam assist with an ion beam gun. Also when the thin film laminate 5 is manufactured using the apparatus of this example, an orientation-controlled polycrystalline thin film having excellent orientation can be obtained as in the case of the above-described example.

In the above example, the polycrystalline rapid-deposited thin film B was formed by high frequency sputtering and ion beam sputtering, but other film forming methods such as CVD method, vacuum evaporation method,
It is needless to say that the polycrystalline rapid-deposited thin film may be formed by a commonly known film forming method such as an electron beam evaporation method.

(Manufacturing Example 1) Using the high frequency sputtering apparatus having the structure shown in FIG. 3, the inside of the vacuum container of this apparatus was evacuated by a vacuum pump to reduce the pressure to 1 × 10 ⁻³ Torr. As a base material, Hastelloy C276 tape having a width of 10 mm, a thickness of 0.5 mm and a length of 10 cm was used. Target is Y
Using SZ (stabilized zirconia), the sputtering voltage is set to 300 V and the sputtering current is set to 100 mA, and sputtering is performed for 1 hour to form a 0.5 μm-thick YSZ polycrystal thin film on the substrate. did.

Next, using the ion beam sputtering apparatus having the structure shown in FIG. 4, the inside of the vacuum container accommodating this apparatus was evacuated by a vacuum pump to reduce the pressure to 3.0 × 10 ⁻⁴ Torr. A target made of YSZ (stabilized zirconia) was used, and the sputtering voltage was 1000 V and the sputtering current was 10
0 mA, the incident angle of the beam of the ion source was set to 55 degrees, the assist voltage of the ion source was set to 300 V, and the current density of the ion beam was set to ²⁰ μA / cm ² , respectively, and the substrate was simultaneously irradiated with ions by sputtering. Then, a YSZ oriented polycrystalline thin film having a thickness of 0.1 μm was formed by performing a film forming process for 1 hour, and a thin film laminate was obtained. The current density of the ion beam is measured by a current density measuring device grounded near the sample. Here, the above-mentioned polycrystalline rapid-deposited thin film having a thickness of 0.5 μm was deposited in 1 hour, but the orientation-controlled polycrystalline thin film could be deposited at a thickness of 0.1 μm in 1 hour. It has been clarified that a polycrystalline rapid-deposited thin film can be formed at a rate of about 5 times higher than that of an orientation-controlled polycrystalline thin film formed by ion beam-assisted sputtering when a polycrystalline rapid-deposited thin film is formed by high-frequency sputtering.

An X-ray diffraction test of the surface portion of the obtained YSZ thin film laminate sample by the θ-2θ method using CuKα rays was conducted. FIG. 13 shows an ion beam incident angle of 5
It is a figure which shows the diffraction intensity of the sample which measured 5 degree, the ion beam voltage 300V, and the current density of an ion beam at 20 microA / cm < ² >. From the results shown in FIG. 13, (20
0) or (400) plane peaks are observed, and YS
It can be presumed that the (100) plane of the polycrystalline thin film of Z is oriented along a plane parallel to the surface of the base material.
It was found that the polycrystalline thin film of (1) was formed with its C-axis oriented perpendicular to the upper surface of the substrate. FIG. 14 shows a pole figure of the thin film laminate sample, but similar results were obtained.

FIG. 15 shows an ion beam voltage of 300 V and an ion beam current of 2 at an ion beam incident angle of 90 degrees.
It is a figure which shows the diffraction intensity of the comparative sample manufactured by setting to 0 and 40 microA / cm < ² >, respectively. From the results shown in FIG. 15, the YSZ (200) peak and (400) peak can be recognized even when the incident angle of the ion source is set to 90 °, and sufficient c-axis orientation is recognized. It was

Next, it was measured whether or not the a-axis or the b-axis of the YSZ polycrystalline thin film was oriented in each of the samples having the c-axis oriented as described above. For the measurement, see Figure 1.
As shown in FIG. 6, the YSZ thin film sample is irradiated with X-rays at an angle θ, and X-rays are positioned at an angle of 2θ (58.7 degrees) with respect to the incident X-rays in a vertical plane including the incident X-rays. A counter 60 is installed, and the value of the horizontal angle φ with respect to the vertical plane including the incident X-ray is appropriately changed, that is, the base material A is shown in FIG.
By measuring the diffraction intensity obtained by rotating by the rotation angle φ as indicated by the arrow in FIG. 1, the orientation of the a-axis or the b-axis of the orientation-controlled polycrystalline thin film was measured. The results are shown in FIGS. 17 and 18.

As shown in FIG. 17, in the case of the sample manufactured by setting the incident angle of the ion beam to 55 degrees, no diffraction peak appears when φ is 45 degrees, and φ is 90 degrees and 0 degrees. In other words, that is, YS every 90 degrees with respect to the rotation angle φ.
The peak of the (311) plane of Z appears. This corresponds to the (011) peak of YSZ in the substrate surface, and it was revealed that the a-axis or the b-axis of the YSZ polycrystalline thin film was oriented. On the other hand,
As shown in FIG. 8, in the case of the sample manufactured with the ion beam incident angle set to 90 degrees, no special peak was observed, and a
It was found that the directions of the axis and the b axis are disordered.

From the above results, it is clear that the orientation-controlled polycrystalline thin film of the sample obtained by the above apparatus and the above-mentioned manufacturing method is oriented not only in the c-axis orientation but also in the a-axis orientation and the b-axis orientation. Became. Therefore, it has been clarified that a polycrystalline thin film having excellent orientation can be manufactured.

On the other hand, FIG. 19 shows the result of measuring the crystal orientation of each crystal grain of the orientation-controlled polycrystalline thin film of this sample, using the orientation-controlled polycrystalline thin film sample used for the measurement of FIGS. 17 and 18. . In this measurement, when X-ray diffraction is performed by the method described above with reference to FIGS. 17 and 18, the angle φ is −
This is a measurement of the diffraction peak when the value is set in steps of 5 degrees from 10 degrees to 45 degrees. From the results shown in FIG. 19, the diffraction peak of the obtained YSZ orientation-controlled polycrystalline thin film was 3
It appears within 0 degree, that is, within 30 degrees of the grain boundary tilt angle,
It is clear that it disappears at 45 degrees. Therefore,
The grain boundary tilt angle of the crystal grains of the obtained polycrystalline thin film was found to be within 30 degrees, and it was revealed that the polycrystalline thin film had a good orientation.

Next, in FIG. 20, the ion beam voltage is set to 30
It was obtained when the orientation control polycrystalline thin film was manufactured by setting 0 V, the ion beam current density to 40 μA / cm ² , the ion beam energy to 300 eV, and changing the ion beam incident angle from 0 degree to 65 degrees. FIG. 3 shows the relationship between the ion beam incident angle and the full width at half maximum in the distribution of crystals in the orientation-controlled polycrystalline thin film in the (111) direction. Note that the above-mentioned full-width-half-maximum values are obtained by obtaining a pole figure as shown in FIG. 14 for each of the obtained samples and drawing auxiliary lines e and f as shown in FIG. 14 from the center of this pole figure. It was determined at an angle half the angle α formed by these auxiliary lines e and f, that is, at a peak ratio of half. From the results shown in FIG. 20, it has been clarified that the crystal orientation becomes good when the ion beam incidence angle is in the 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.

Next, an oxide superconducting layer was formed on the polycrystalline thin film by using a laser vapor deposition apparatus having the structure shown in FIG.
As the target, a target made of an oxide superconductor having a composition of Y _0.7 Ba _1.7 Cu _3.0 O _7-x was used. The inside of the vapor deposition processing chamber was depressurized to 1 × 10 ⁻⁶ Torr, and laser vapor deposition was performed at room temperature. An ArF laser with a wavelength of 193 nm was used as a laser for target evaporation. After this film formation, 4
The thin film was heat treated in an oxygen atmosphere at 00 ° C for 60 minutes. The oxide superconducting conductor obtained by the above treatment has a width of 0.5 mm and a length of 10 cm.

The oxide superconducting conductor was cooled, and the critical temperature and the critical current density were measured. As a result, the critical temperature = 90.
K, showing critical current density = 200000 A / cm ² ,
It was confirmed that it exhibited extremely excellent superconducting properties.
Therefore, it was revealed that the obtained oxide superconducting layer has excellent crystal orientation. On the other hand, in a sample in which a polycrystalline rapid-deposited thin film of YSZ was formed on the same base material as the above by the same method as the above, and the oxide superconducting layer equivalent to the above was directly formed on the sample, the critical Current density is 20000
A / cm ² was shown.

(Manufacturing Example 2) As a base material, a Hastelloy C276 tape having the same size as in the above manufacturing example was used.
This substrate was attached to the ion beam sputtering apparatus having the structure shown in FIG. 4, and the inside of the vacuum container of this apparatus was evacuated by a vacuum pump to reduce the pressure to 3.0 × 10 ⁻⁴ Torr. A target made of YSZ is used, the sputtering voltage is 1000V,
Sputtering current 100 mA, ion beam incident angle 5
The angle is set to 5 degrees, the assist voltage of the ion source is set to 300 V, the current density of the ion beam is set to 100 μA / cm ² , and the ion beam irradiation is performed simultaneously with the sputtering on the substrate to perform YSZ orientation of 0.1 μm thickness. A control polycrystalline thin film was formed over 1 hour to obtain an orientation controlled polycrystalline thin film.

Next, sputtering was performed with the ion gun stopped to form a YSZ orientation control polycrystalline thin film having a thickness of 0.4 μm for 2 hours to obtain a thin film laminate.
Here, the above-mentioned polycrystalline rapid-deposited thin film having a thickness of 0.1 μm was formed in 1 hour, whereas the orientation-controlled polycrystalline thin film having a thickness of 0.4 μm could be formed in 2 hours. It has been clarified that forming a polycrystalline rapid-deposited thin film without operating the ion gun can form a film at about twice as fast as forming an orientation-controlled polycrystalline thin film by sputtering using an ion beam gun.

Subsequently, an oxide superconducting layer equivalent to that in the above-mentioned production example was formed on the above-mentioned thin film laminated body by the laser deposition method equivalent to that in the above-mentioned production example to obtain an oxide superconducting conductor. The oxide superconducting conductor was cooled, and the critical temperature and the critical current density were measured. As a result, the critical temperature = 90K, the critical current density =
It was 200,000 A / cm ^2, and it was confirmed that it exhibited extremely excellent superconducting properties.

(Manufacturing Example 3) As a base material, a Hastelloy C276 tape having the same size as that of the above manufacturing example was used, and on this base material, orientation control of a thickness of 0.1 μm was performed under the same conditions as in Manufacturing Example 2. A polycrystalline thin film was formed. Next, a 0.4 μm-thick polycrystalline rapid-deposited thin film was formed on this orientation-controlled polycrystalline thin film by using the same high-frequency sputtering device as that used in Production Example 1 to obtain a thin film laminate. Subsequently, an oxide superconducting layer equivalent to that in the above-mentioned production example was formed on this thin film laminated body by the laser deposition method equivalent to that in the above-mentioned production example to obtain an oxide superconducting conductor. The oxide superconducting conductor was cooled and the critical temperature and critical current density were measured. As a result, it was confirmed that the critical temperature was 90K and the critical current density was 200,000A / cm ^{2 and} that it exhibited extremely excellent superconducting properties. It was

[0085]

As described above, according to the present invention, a polycrystalline rapid-deposited thin film and a grain boundary tilt angle 30 thinner than that are formed on a substrate.
Since the following orientation-controlled polycrystalline thin film is provided, the crystal structure of the thin film formed thereon can be easily arranged. Therefore, when the oxide superconducting layer is formed on the orientation-controlled polycrystalline thin film, the crystal structure of the oxide superconducting layer is improved, and an oxide superconducting conductor having excellent superconducting properties can be obtained. Also,
When what is formed on the orientation-controlled polycrystalline thin film is a magnetic thin film, an optical thin film, or a wiring thin film, the crystal structure of these thin films can be adjusted. Furthermore, since the orientation-controlled polycrystalline thin film is formed thinner than the polycrystalline rapid-deposited thin film, and the polycrystalline rapid-deposited thin film that is easier and faster to manufacture than the orientation-controlled polycrystalline thin film is formed thicker, the total film formation time is reduced. There is an effect that can be shortened.

Further, in the case where the thick polycrystalline rapid-deposited thin film is formed on the orientation-controlled polycrystalline thin film having the grain boundary tilt angle of 30 degrees or less, the crystal orientation of the polycrystalline rapid-deposited thin film can be easily adjusted. Therefore, when the oxide superconducting layer is formed on the polycrystalline rapid-deposited thin film, the crystal structure of the oxide superconducting layer is improved, and the oxide superconducting conductor having excellent superconducting properties can be obtained. Also,
When what is formed on the orientation-controlled polycrystalline thin film is a magnetic thin film, an optical thin film, or a wiring thin film, the crystal structure of these thin films can be adjusted. Furthermore, since the orientation-controlled polycrystalline thin film is formed thinner than the polycrystalline rapid-deposited thin film, and the polycrystalline rapid-deposited thin film that is easier and faster to manufacture than the orientation-controlled polycrystalline thin film is formed thicker, the total film formation time is reduced. There is an effect that can be shortened.

On the other hand, after the polycrystalline rapid-deposited thin film is formed on the substrate, the grain boundary inclination angle of the crystal grains is changed by performing the film forming process while irradiating the ion beam at an incident angle of 50 to 60 degrees from the oblique direction. It is possible to form an orientation-controlled polycrystalline thin film having a degree of 30 ° or less, whereby a thin film laminate having a polycrystalline thin film having stable film quality and excellent crystal orientation can be obtained. Furthermore, by forming the orientation-controlled polycrystalline thin film on the substrate and then forming the polycrystalline accelerated thin film, the crystals of the polycrystalline accelerated thin film can be easily aligned with the orientation-controlled polycrystalline thin film. If an oxide superconducting layer is formed in the thin film laminate obtained by the above method, with respect to the crystal of the orientation-controlled polycrystalline thin film, or with respect to the crystal of the polycrystalline quick-deposited thin film having good crystal orientation, Since it is possible to form a high quality one while matching the crystals of the oxide superconducting layer, it is possible to obtain an oxide superconducting conductor having excellent superconducting properties.

On the other hand, the incident angle of the ion beam is 55 to 6
If it is set to 0 degree, the grain boundary tilt angle of the orientation-controlled polycrystalline thin film can be made uniform within 25 degrees, and a polycrystalline thin film having more excellent orientation can be obtained. Further, by forming the polycrystalline quick-deposited thin film by high-frequency sputtering and the orientation-controlled polycrystalline thin film by ion beam sputtering, it is possible to perform a film forming process efficiently at a high film forming rate. Furthermore,
When forming the oxide superconducting layer on the thin film laminate, the crystal orientation can be improved by making the oxide superconducting layer grow epitaxially, and an oxide superconducting conductor having excellent superconducting properties can be obtained. Like

[Brief description of drawings]

FIG. 1 is a constitutional view showing a thin film laminate formed by the method of the present invention.

FIG. 2 is an enlarged plan view showing crystal grains of the thin film laminate shown in FIG. 1, crystal axis directions thereof, and grain boundary tilt angles.

FIG. 3 is a block diagram showing an example of a high-frequency sputtering apparatus for carrying out the method of the present invention to produce a polycrystalline rapid-deposited thin film on a substrate.

FIG. 4 is a configuration diagram showing an example of an ion beam sputtering apparatus for carrying out the method of the present invention to produce an orientation-controlled polycrystalline thin film on a substrate.

5 is a cross-sectional view showing an example of an ion gun used in the device shown in FIG.

FIG. 6 is an explanatory diagram showing an angular relationship between an incident angle of an ion beam and a cubic crystal lattice when a film forming process is performed together with ion beam irradiation.

FIG. 7 is a configuration diagram showing an example of an apparatus for forming an oxide superconducting layer on an orientation-controlled polycrystalline thin film.

FIG. 8 is a sectional view showing a first example of an oxide superconducting conductor according to the present invention.

FIG. 9 is a sectional view showing a second example of an oxide superconducting conductor according to the present invention.

FIG. 10 is a sectional view showing a third example of an oxide superconducting conductor according to the present invention.

FIG. 11 is a constitutional view showing another example of the sputtering apparatus used for manufacturing the polycrystalline rapid-deposited thin film and the orientation-controlled polycrystalline thin film by carrying out the method of the present invention.

FIG. 12 is a structural diagram showing the crystal orientation of each crystal grain of a polycrystalline rapid-deposited thin film manufactured by a conventional method.

FIG. 13 shows an ion beam incident angle of 55 degrees, an ion beam voltage of 300 V, and an ion beam current density of 20 μA.
3 is a graph showing an X-ray diffraction result of an orientation-controlled polycrystalline thin film manufactured at a film thickness of / cm ² .

FIG. 14 is an ion beam incident angle of 55 degrees, an ion beam voltage of 300 V, and an ion beam current density of 20 μA.
FIG. 4 is a pole figure of a polycrystalline thin film manufactured at a rate of / cm ² .

FIG. 15 shows an ion beam incident angle of 90 degrees, an ion beam voltage of 300 V, and an ion beam current of 20 μA.
It is a graph which shows the X-ray-diffraction result of the polycrystalline thin film manufactured by 0 microampere.

FIG. 16 is a-axis and b-axis of an orientation-controlled polycrystalline thin film.
It is a block diagram for demonstrating the test performed in order to measure axial orientation.

FIG. 17 is a graph showing diffraction peaks of the (311) plane of an orientation-controlled polycrystalline thin film sample manufactured at an ion beam incident angle of 55 degrees.

FIG. 18 is a graph showing a diffraction peak of a (311) plane of an orientation-controlled polycrystalline thin film sample manufactured at an ion beam incident angle of 90 degrees.

FIG. 19 is a graph showing diffraction peaks at every rotation angle of 5 ° of an orientation-controlled polycrystalline thin film sample manufactured at an ion beam incident angle of 55 °.

FIG. 20 is a graph showing the relationship between the incident angle of the ion beam and the full width at half maximum of the obtained orientation-controlled polycrystalline thin film sample.

[Explanation of symbols]

A ... Substrate, B, B ', B''... Polycrystalline rapid deposition thin film, C ... Orientation control polycrystalline thin film, E ... Oxide superconducting layer, K ... Grain boundary tilt angle, θ ... Incident angle, φ
... Rotation angle, 5 ... Thin film laminate, 6, 7 ... Crystal grains, 11, 15 ... Base material holder, 12, 16 ... Target, 14 ... High frequency power supply, 17 ... Ion gun, 1
8 ... Ion beam irradiation device, 30 ... Laser vapor deposition device,
33 ... Target, 50, 51, 53 ... Oxide superconducting conductor, 52, 54 ... Thin film laminate,

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location C30B 29/22 501 M 8216-4G

Claims (10)

[Claims] 1. A substrate, a polycrystalline rapid-deposited thin film formed on the film-forming surface of the substrate and having a large number of crystal grains bonded to each other, and a polycrystalline rapid-deposited thin film formed on the polycrystalline rapid-deposited thin film. A thin film laminate comprising an orientation-controlled polycrystalline thin film having a grain boundary tilt angle of 30 degrees or less formed thinner than the thin film. 2. An orientation-controlled polycrystalline thin film having a grain boundary tilt angle of 30 degrees or less formed by a substrate, a large number of crystal grains bonded to each other on a film-forming surface of the substrate, and the orientation-controlled polycrystalline thin film. A thin film laminate, comprising a polycrystalline rapid-deposited thin film formed above and thicker than the orientation-controlled polycrystalline thin film. 3. A substrate, a polycrystalline rapid-deposited thin film formed on a film-forming surface of the substrate and having a large number of crystal grains bonded to each other, and the polycrystalline rapid-deposited formed on the polycrystalline rapid-deposited thin film. An oxide superconducting conductor comprising an orientation-controlled polycrystalline thin film having a grain boundary tilt angle of 30 degrees or less formed thinner than the thin film, and an oxide superconducting layer formed on the orientation-controlled polycrystalline thin film. . 4. An orientation-controlled polycrystalline thin film having a grain boundary tilt angle of 30 degrees or less, which is formed of a substrate, a large number of crystal grains bonded to each other on the film-forming surface of the substrate, and the orientation-controlled polycrystalline thin film. An oxide superconducting film, comprising: a polycrystalline rapid-deposited thin film formed above the orientation-controlled polycrystalline thin film; and an oxide superconducting layer formed on the polycrystalline rapid-deposited thin film. conductor. 5. A polycrystalline rapid-deposited thin film formed by combining a large number of crystal grains by a film-forming method such as sputtering is formed on the film-forming surface of a base material, and the polycrystalline rapid-deposited thin film is formed on the polycrystalline film And forming an orientation-controlled polycrystalline thin film having a grain boundary tilt angle of crystal grains of 30 degrees or less by performing a film formation process while irradiating an ion beam at an incident angle of 50 to 60 degrees from an oblique direction. Method for manufacturing thin film laminate. 6. An oblique direction 50 from the film forming surface of the base material.
Film formation is performed while irradiating an ion beam at an incident angle in the range of up to 60 degrees to form an orientation-controlled polycrystalline thin film with a grain boundary tilt angle of 30 degrees or less in which a large number of crystal grains are bonded on the substrate film formation surface. Then, a method for producing a thin film laminated body is characterized in that a polycrystalline rapid-growth thin film in which a large number of crystal grains are bonded is formed on the orientation-controlled polycrystalline thin film by a film forming method such as sputtering. 7. The method of manufacturing a thin film laminate according to claim 5, wherein the ion beam incident angle is 55 to 60.
A method for producing a thin film laminate, wherein the film thickness is set in a range of degrees, and the grain boundary tilt angle of the crystal grains of the orientation-controlled polycrystalline thin film is within 25 degrees. 8. The method for producing a thin film laminate according to claim 5, 6 or 7, wherein the polycrystalline rapid-deposited thin film is formed by a high frequency sputtering method, and the orientation-controlled polycrystalline thin film is formed by an ion beam sputtering method. And a method for producing a thin film laminate. 9. An oxide superconducting layer is formed by a film forming method on the orientation-controlled polycrystalline thin film or the intermediate thin film obtained by the manufacturing method according to claim 5, 6, 7 or 8. Method for manufacturing oxide superconducting conductor. 10. When the oxide superconducting layer according to claim 9 is formed on an orientation-controlled polycrystalline thin film or a polycrystalline rapid-deposited thin film, the oxide superconducting layer is epitaxially grown. Production method.