JP4059963B2 - Manufacturing method of oxide superconductor - Google Patents

Description

【００６１】
この結果から、４００℃以上の成膜温度では多結晶薄膜が[１１１]配向となってしまい、超電導層の臨界電流密度として良好な値が得られなかった。更に、３００℃以下において成膜するならば、多結晶薄膜の結晶配向性も良好になり、臨界電流密度も高いものが得られた。そしてこの傾向は、成膜温度が低くなるほど顕著になり、このデータから、１８００００Ａ／ｃｍ²以上の臨界電流密度を得るためには２００℃以下の温度とすることが好ましく、５５００００Ａ／ｃｍ²以上の臨界電流密度を得るためには１００℃以下の温度とすることが好ましいことも判明した。以上のことから、高い臨界電流密度を得るための成膜温度範囲は、３００℃〜−１５０℃の範囲内であっても、１００℃〜−１５０℃の範囲がより好ましい。
【００６２】
次に図１３は、基材テープ上に形成した多結晶薄膜の半値全幅に対する膜厚依存性を示すものである。図１３は１００℃に基材テープを保持して前記と同じ条件で成膜した場合の結果である。
この結果から[１００]軸の配向は、２００ｎｍを超える膜厚から安定し始めている。このことから、イオンビームを５０〜６０度の入射角度で斜め方向から照射しながら成膜する場合に、膜が堆積する初期の段階では結晶配向性が整っていない結晶が多少生じても、厚さが増加するにつれて結晶配向性が良好となり、[１００]軸の配向状態から見て２００ｎｍ以上の膜厚であれば結晶配向性に優れたものを得ることができることが明らかである。
【００６３】
次に、図１６は前述と同じ条件で製造したＹＳＺの多結晶薄膜の蒸着時間と半値全幅の関係において、成膜温度１００℃と２００℃での値の比較を示し、図１７は同ＹＳＺの多結晶薄膜の膜厚と半値全幅の関係において、成膜温度１００℃と２００℃での値の比較を示す。
いずれの図においても、２００℃よりも低温の１００℃で成膜した方が優秀な結晶配向性を示す多結晶薄膜を得られていることが示されている。
これらの試験結果から、より低い温度で成膜した方がより結晶配向性に優れた多結晶薄膜を得られることが明らかになった。
また、いずれの成膜温度においても、蒸着時間がある程度長くなくては、換言すると、膜厚がある程度厚くならなくては、良好な結晶配向性の多結晶薄膜を得にくいことも判明した。
【００６４】
【発明の効果】
以上説明したように本発明方法によれば、ターゲットから発生させた粒子を基材に堆積させる際に、基材成膜面の法線に対して５０度〜６０度の入射角度でイオンビームを照射し、成膜温度を３００℃以下にするので、基材の成膜面に対してｃ軸配向性に加えてａ軸配向性とｂ軸配向性をも向上させた粒界傾角３５度以下のＹＳＺの多結晶薄膜を確実に得ることができる。
これは、基材上に堆積する構成原子において、規定の向きから外れた向きに配置された不安定な原子をイオンビームのイオンがスパッタ効果を発揮させて除去するので、規定の位置に配置された安定性の高い原子のみが選択的に残り易くなり、この結果として配向性の良好な粒子の堆積が主体的になされて配向性の良好な多結晶薄膜が得られたものと思われる。
また、成膜時の温度を３００℃以下に制御することで、結晶を構成する原子の振動や運動を少なくすることができ、これらの影響力よりもイオンビームによる結晶配向性制御効果を大きくすることができる結果として配向性の良好な多結晶薄膜を得ることができる。また、イオンビームによる配向制御効果は、多結晶薄膜の特定の面を基材成膜面に垂直に正確に立てる作用を促進するものでもあるので、特定の面を基材成膜面に対して正確に位置決めできる結果として他の面の方向制御効果も向上させることができ、結果として膜全体としての結晶配向性に優れた結晶粒の集合体としての多結晶薄膜を得ることができる。
【００６５】
そして、前述の温度で形成した配向性の良好な多結晶薄膜上に酸化物超電導層を形成するならば、結晶配向性の良好な酸化物超電導層を生成させることができ、これにより臨界電流密度の高い超電導特性の良好な酸化物超電導導体を得ることができる。
また、ターゲットから発生させて基材上に堆積させるものとして具体的にイットリウム安定化ジルコニアを用いることができ、結晶配向性に優れたイットリウム安定化ジルコニアの多結晶薄膜を得ることができる。
更に、得られる多結晶薄膜の厚さを２００ｎｍ以上とするならば、十分に結晶配向性に優れた多結晶薄膜を確実に得ることができる。
【図面の簡単な説明】
【図１】 図１は、本発明方法により形成されたＹＳＺの多結晶薄膜を示す断面図である。
【図２】 図２は、図１に示すＹＳＺ多結晶薄膜の結晶粒とその結晶軸方向および粒界傾角を示す拡大平面図である。
【図３】 図３は、本発明方法を実施して基材上に多結晶薄膜を製造するための装置の一例を示す構成図である。
【図４】 図４は、図３に示す装置に設けられるイオンガンの一例を示す断面図である。
【図５】 図５は、図３に示す装置に設けられる冷却装置の一例を示す断面図である。
【図６】 図６は、図１に示すＹＳＺ多結晶薄膜の上に形成された酸化物超電導層を示す断面図である。
【図７】 図７は、多結晶薄膜の結晶配向性を測定するためのＸ線装置の配置図である。
【図８】 図８は、イオンビーム入射角度５５度、イオンビームエネルギー３００ｅｖで１００℃で成膜した多結晶薄膜の極点図である。
【図９】 図９は、イオンビーム入射角度５５度、イオンビームエネルギー３００ｅｖで２００℃で成膜した多結晶薄膜の極点図である。
【図１０】 図１０は、イオンビーム入射角度５５度、イオンビームエネルギー３００ｅｖで３００℃で成膜した多結晶薄膜の極点図である。
【図１１】 図１１は、イオンビーム入射角度５５度、イオンビームエネルギー３００ｅｖで４００℃で成膜した多結晶薄膜の極点図である。
【図１２】 図１２は、イオンビーム入射角度５５度、イオン ビームエネルギー３００ｅｖで５００℃で成膜した多結晶薄膜の極点図である。
【図１３】 基材上に形成した多結晶薄膜の厚さと半値全幅の関係を示す図である。
【図１４】 図１４は、イオンビームの入射角度と得られた多結晶薄膜の半値全幅との関係を示すグラフである。
【図１５】 図１５は、従来方法で基材上に成膜された多結晶薄膜と酸化物超電導層を示す構成図である。
【図１６】 図１６は、本発明方法で得られた多結晶薄膜の半値全幅と蒸着時間の関係を示す図である。
【図１７】 図１７は、本発明方法で得られた多結晶薄膜の半値全幅と膜厚の関係を示す図である。
【図１８】 図１８は、イオンビーム入射角度５５度、イオンビ ームエネルギー３００ｅｖで０℃で成膜した多結晶薄膜の極点図である。
【符号の説明】
Ａ…基材、Ｂ…多結晶薄膜、Ｃ…酸化物超電導層、Ｋ…粒界傾角、θ…入射角度、φ…回転角、２０、２１…結晶粒、２２…酸化物超電導導体、２３…基材ホルダ、２４・・・基材送出ボビン(送出装置)、２５・・・基材巻取ボビン(巻取装置)、３６…ターゲット、３８…イオンガン、３９・・・イオンソース、４０…成膜処理容器、Ｒ・・・冷却装置、６０・・・基台、６１・・・冷媒導入管、６２・・・往管、６３・・・戻管。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a polycrystalline thin film having a uniform crystal orientation and a method for producing an oxide superconducting conductor.
[0002]
[Prior art]
The oxide superconductor discovered in recent years is an excellent superconductor exhibiting a critical temperature exceeding the liquid nitrogen temperature, but at present, to use this kind of oxide superconductor as a practical superconductor. There are various problems to be solved. One of the problems is that the critical current density of the oxide superconductor is low.
[0003]
The problem that the critical current density of the oxide superconductor is low is largely due to the presence of electrical anisotropy in the oxide superconductor crystal itself. In particular, the oxide superconductor has its crystal axis. It is known that electricity can easily flow in the a-axis direction and b-axis direction, but it is difficult to flow electricity in the c-axis direction. From this point of view, in order to form an oxide superconductor on a substrate and use it as a superconducting conductor, an oxide superconducting layer having a good crystal orientation is formed on the substrate, It is necessary to orient the a-axis or b-axis of the crystal of the oxide superconducting layer in the direction in which electricity flows, and to orient the c-axis of the oxide superconductor in the other direction.
[0004]
Conventionally, various means have been tried to form an oxide superconducting layer with good crystal orientation on a substrate such as a substrate or a metal tape. As one of the methods, MgO or SrTiO having a crystal structure similar to that of the oxide superconductor is used._ThreeA method of forming an oxide superconducting layer on such a single crystal substrate by a film forming method such as sputtering is performed.
MgO or SrTiO_ThreeWhen a film formation method such as sputtering is performed using a single crystal substrate, the crystal of the oxide superconducting layer grows based on the crystal of the single crystal substrate, so that the crystal orientation can be improved. The oxide superconducting layer formed on these single crystal substrates has several hundred thousand A / cm.²It is known to exhibit a sufficiently high critical current density.
[0005]
[Problems to be solved by the invention]
By the way, in order to use an oxide superconductor as a conductor, it is necessary to form an oxide superconducting layer with good crystal orientation on a long substrate such as a tape. However, when an oxide superconducting layer is formed directly on a base material such as a metal tape, the metal tape itself is polycrystalline and its crystal structure is significantly different from that of an oxide superconductor. The layer cannot be formed at all. Moreover, there is a problem that a diffusion reaction occurs between the metal tape and the oxide superconducting layer due to the heat treatment performed when forming the oxide superconducting layer, the crystal structure of the oxide superconducting layer is destroyed, and the superconducting characteristics are deteriorated.
[0006]
Therefore, conventionally, MgO or SrTiO is used on a base material such as a metal tape by using a sputtering apparatus._ThreeAn oxide superconducting layer is formed on this intermediate layer. However, the oxide superconducting layer formed on this kind of intermediate layer by a sputtering apparatus has a significantly lower critical current density (for example, several thousand to 10,000 A / cm) than the oxide superconducting layer formed on the single crystal substrate.²There was a problem that it only showed. This is considered to be due to the reason explained below.
[0007]
FIG. 14 shows a cross-sectional structure of an oxide superconducting conductor in which an intermediate layer 2 is formed on a base material 1 such as a metal tape by a sputtering apparatus, and an oxide superconducting layer 3 is formed on the intermediate layer 2 by a sputtering apparatus. Is. In the structure shown in FIG. 14, the oxide superconducting layer 3 is in a polycrystalline state, and a large number of crystal grains 4 are randomly coupled. 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 b-axis are in random directions. It is thought that.
[0008]
Thus, when the orientation of the a-axis and b-axis becomes disordered for each crystal grain of the oxide superconducting layer, the quantum conductivity of the superconducting state is lost at the grain boundary where the crystal orientation is disordered. In particular, it seems to cause a decrease in critical current density.
The reason why the oxide superconductor is in a polycrystalline state in which the a-axis and b-axis are not oriented is that the intermediate layer 2 formed thereunder is in a polycrystalline state in which the a-axis and b-axis are not oriented. In addition, when the oxide superconducting layer 3 is formed, it is considered that the oxide superconducting layer 3 grows so as to match the crystal of the intermediate layer 2.
[0009]
By the way, other than the application field of the oxide superconductor, techniques for forming various alignment films on a polycrystalline base material are used. For example, the field of optical thin film, the field of magneto-optical disk, the field of wiring board, the field of high-frequency waveguides, high-frequency filters, and cavity resonators. The formation of a good polycrystalline thin film is a problem. In other words, if the crystal orientation of the polycrystalline thin film is good, the quality of the optical thin film, magnetic thin film, thin film for wiring, etc. formed on the polycrystalline thin film is improved. It is more preferable if a good optical thin film, magnetic thin film, wiring thin film, etc. can be directly formed.
[0010]
Therefore, the present inventors formed a polycrystalline thin film of yttrium-stabilized zirconia (hereinafter abbreviated as YSZ) on the base material of the metal tape, and formed an oxide superconducting layer on the polycrystalline thin film. Various attempts have been made to produce oxide superconductors with excellent superconducting properties.
From such attempts, the present inventors have first disclosed Japanese Patent Application Laid-Open No. 4-329865 (Japanese Patent Application No. 3-126636), Japanese Patent Application Laid-Open No. 4-331957 (Japanese Patent Application No. 3-126937), In Kaihei 4-90025 (Japanese Patent Application No. 2-205551), Japanese Patent Application Laid-Open No. 6-39368 (Japanese Patent Application No. 4-13443), Japanese Patent Application Laid-Open No. 6-145777 (Japanese Patent Application No. 4-293464), etc. A patent application has been filed for a polycrystalline thin film excellent in orientation and an oxide superconducting conductor using the same.
[0011]
According to the techniques described in these patent applications, when depositing YSZ particles on a substrate, a polycrystalline thin film having excellent crystal orientation is formed by irradiating an ion beam from an oblique direction of the substrate. It is something that can be done.
In parallel with the above-mentioned patent application, the present inventors have conducted research for producing a long or large-area polycrystalline thin film and an oxide superconducting conductor. As a result of research on a method for producing a crystalline thin film and obtaining superconducting properties even better than conventional methods when a superconducting layer is formed on a polycrystalline thin film, the present invention has been achieved.
[0012]
The present invention has been made in order to develop the technology of the above-mentioned patent application and to effectively solve the above problems based on the above background. The c-axis of the crystal axis is perpendicular to the film-forming surface of the substrate. A polycrystalline thin film having excellent crystal orientation, in which the a-axis and b-axis of the crystal grains can be aligned along a plane parallel to the film-forming surface. Another object of the present invention is to provide an oxide superconducting conductor having an oxide superconducting layer having an excellent crystal orientation and a high critical current density.
Another object of the present invention is to provide an apparatus for producing a polycrystalline thin film having excellent crystal orientation.
[0013]
[Means for Solving the Problems]
  In order to solve the above-mentioned problems, the present invention deposits particles generated from a target on a base material, and forms a polycrystalline thin film composed of constituent elements of the target on the base material.And then forming an oxide superconducting layer on the polycrystalline thin film.In order to deposit the target particles on the substrate, the ion beam generated by the ion source is irradiated from an oblique direction at an incident angle in the range of 50 to 60 degrees with respect to the normal of the film formation surface of the substrate. While depositing the particles to form a polycrystalline thin film, the temperature during film formation is 300 ° C. or lower.And after forming the polycrystalline thin film, an oxide superconducting layer is formed thereon.
[0015]
  In order to solve the above problems, the present inventionSaid1 uses a yttrium-stabilized zirconia target. In order to solve the above problems, the present inventionSaidThe thickness of the polycrystalline thin film formed on the substrate is 200 nm or more.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 shows an example of a structure in which a polycrystalline thin film of YSZ (yttrium stabilized zirconia) is formed on a substrate by carrying out the method of the present invention. In FIG. 1, A is a tape-shaped substrate, B shows a polycrystalline thin film formed on the upper surface of the substrate A.
The base material A is in the form of a tape in this example, 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, stainless steel, or the like. It consists of various metal materials such as nickel alloys such as steel, copper and hastelloy, or various glasses or various ceramics.
[0019]
The polycrystalline thin film B is made of YSZ having a cubic crystal structure or CeO.₂A large number of such fine crystal grains 20 are joined and integrated with each other via crystal grain boundaries, and the c-axis of the crystal axis of each crystal grain 20 is relative to the upper surface (film formation surface) of the substrate A. The a-axis and the b-axis of the crystal axes of each crystal grain 20 are oriented in a right angle and are oriented in the same direction in the same direction. The a-axes (or b-axes) of the crystal grains 20 are joined and integrated with an angle formed between them (grain boundary inclination angle K shown in FIG. 2) within 35 degrees. Note that the value of the grain boundary tilt angle K can be adjusted by controlling the temperature during film formation in the method of manufacturing the polycrystalline thin film B described later, and is smaller than 35 degrees by controlling the temperature during film formation. Can be adjusted up to the value.
[0020]
FIG. 3 is a diagram showing an example of an apparatus for manufacturing a polycrystalline thin film suitably used for carrying out the method for manufacturing a polycrystalline thin film of the present invention.
In this example, the polycrystalline thin film manufacturing apparatus supports a tape-shaped substrate A and can be heated or cooled to a desired temperature, and a block-shaped substrate holder 23 on the substrate holder 23. A substrate delivery bobbin (delivery device) 24 for delivering the material A, a substrate take-up bobbin (winding device) 25 for winding up the tape-like substrate A on which the polycrystalline thin film is formed, and the base A plate-like target 36 disposed diagonally above the material holder 23 with a predetermined interval; a sputtering beam irradiation device (sputtering means) 38 disposed toward the lower surface of the target 36 diagonally above the target 36; An ion source 39 facing the side of the substrate holder 23 with a predetermined interval and spaced apart from the target 36, and the cooling device R can be evacuated. It has a configuration provided (film deposition process chamber) 40.
[0021]
The base material holder 23 includes a heater 23a made of a metal wire or the like that generates resistance when energized, and a tape-shaped base material A fed onto the base material holder 23 is formed as desired. It can be heated to temperature. Such a substrate holder 23 is disposed in an optimum irradiation region of the ion beam irradiated from the ion source 39 in the film formation processing container 40. Further, the base material holder 23 is provided by being mounted on a side triangular base 60, and the base 60 is formed by a refrigerant introduction pipe 61 provided through the outer wall 40 a of the film formation processing container 40. A cooling device R is configured by being mainly supported by a base 60 and a refrigerant introduction pipe 61 supported by the central portion of the container 40.
[0022]
The base 60 in this form is made of a hollow metal block having a triangular cross section as shown in FIG. 5, and its upper surface 60a can make the incident angle of the ion beam with respect to the base material to be described later in the range of 50 to 60 degrees. The surface is inclined. In addition, a refrigerant introduction pipe 61 is connected to the back surface 60b of the base 60, and the refrigerant introduction pipe 61 has a double structure including an internal forward pipe 62 and a return pipe 63 covering the outside. Both the pipe 62 and the return pipe 63 communicate with the internal space of the base 60 inside the chamber, and both of them extend substantially horizontally and pass through the outer wall 40a of the film formation processing vessel 40 to the outside. Both pipes are led out and are curved upward, and an injection part 64 is formed at the distal end of the forward pipe 62 so as to protrude slightly above the distal end of the return pipe 63. A funnel-shaped injection member 65 is mounted.
[0023]
The distal end portion of the outgoing pipe 62 on the base 60 side and the distal end portion of the return pipe 63 on the base 60 side are both hermetically joined to the connection holes on the back surface 60b of the base 60, so that the film forming process container Even when the inside of the base 40 is depressurized, the inside of the base 60 can be brought into an atmospheric pressure state outside the film formation processing container, and a liquid refrigerant such as liquid nitrogen or cooling air can be placed inside the above-described injection member 65. A gas refrigerant or the like is fed in so that the interior of the base 60 can be filled with the refrigerant.
[0024]
Further, when the forward pipe 62 and the return pipe 63 are provided, if the refrigerant introduction pipe 61 is constituted only by the forward pipe 62, liquid nitrogen is introduced into the injection member 65 and liquid nitrogen is fed from the forward pipe 62 into the base 60. This is to prevent liquid nitrogen or vaporized nitrogen gas that has been previously fed from staying inside the base 60 and preventing new liquid nitrogen from being supplied to the base 60 even if trying to do so. If the return pipe 63 is provided at this point, the old liquid nitrogen or vaporized nitrogen gas staying in the base 60 can be easily discharged into the atmosphere through the return pipe 63. The base 60 can be sufficiently cooled by always supplying fresh liquid nitrogen to the base 60, and the cooling capacity can be increased. Further, if a double structure in which the outside of the forward pipe 62 is covered with the return pipe 63 is adopted, the forward pipe 62 can be covered with the refrigerant or nitrogen gas passing through the return pipe 63. The outgoing pipe 62 can be cooled by the refrigerant inside 63, and the temperature of the refrigerant can be prevented from being unnecessarily increased inside the outgoing pipe 62.
[0025]
Further, the refrigerant supply pipe 61 is provided through the flange plate 66, and the flange plate 66 closes the mounting hole 40b formed in the outer wall 40a of the film formation processing container 40, and is fixed to the outer wall 40a by screws or the like. It is detachably fixed. In addition, a temperature measuring device 67 for measuring the temperature of the base 60 is mounted on the flange plate 66 so as to be adjacent to the refrigerant supply pipe 61, and a substrate holder is mounted by a temperature sensor 68 connected to the temperature measuring device 67. It is comprised so that the temperature of 23 can be measured. That is, when the base material holder 23 is set on the upper surface 60a of the base 60 as shown by a two-dot chain line in FIG. 5, the temperature of the base material holder 23 is controlled by keeping the temperature sensor 68 in contact with the base material holder 23. It is configured so that it can be measured.
[0026]
From the above, the base material A is desired by heating the base material holder 23 by heating the base material holder 23 to a temperature higher than normal temperature by the heater 23a or by cooling the base material A by the base 60. For example, a temperature in the range of + 500 ° C. to −196 ° C. That is, the heating can be easily adjusted from room temperature to about 500 ° C. by heating the heater, and further, the heater is stopped and a cooling medium such as liquid nitrogen is used as a cooling medium, and the above cooling device is used for 77K (about It can be easily cooled to about −196 ° C.).
[0027]
Since the cooling device R used here is not limited to the one shown in FIG. 5, it is a cooling device using fluorine gas such as chlorofluorocarbon or ammonia used in a normal cooling device such as a cooler, and is about −30 ° C. Of course, an apparatus capable of cooling may be provided. Further, since the substrate is naturally heated by the arrival of hot particles from the target during film formation, for example, the substrate is 100 when the film is formed at room temperature and the substrate holder is not heated or cooled at all. It will be heated to about ℃. Moreover, when forming into a film, cooling with liquid nitrogen, the capability to cool the base material A from the base 60 can be adjusted by adjusting the material and thickness of the base material holder 23 which supplies a base material. For example, when the substrate holder 23 that is thin and excellent in thermal conductivity is used and the supply amount of liquid nitrogen from the refrigerant introduction pipe 61 is sufficiently secured, it can be easily reduced to about −150 ° C. even if the heat generated during film formation is subtracted. In contrast, by forming the substrate holder 23 with a thick metal material, the cooling capacity from the base 60 can be kept low. In this case, even if liquid nitrogen refrigerant is used, The temperature of the material A can be easily adjusted to about −150 to −50 ° C.
[0028]
In the manufacturing apparatus for the polycrystalline thin film B of this example, the tape-like base material A is continuously sent out from the base material delivery bobbin 24 onto the base material holder 23, and after passing through the optimum irradiation region, the base material A The polycrystalline thin film B can be continuously formed on the substrate A by winding the substrate with the substrate winding bobbin 25.
[0029]
The target 36 is used to form a target polycrystalline thin film, and a target having the same or approximate composition as the polycrystalline thin film having the target composition can be used. Specifically, the target 36 is MgO or Y₂O_ThreeStabilized zirconia (YSZ), CeO₂, MgO, SrTiO_ThreeHowever, the present invention is not limited to this, and a target suitable for the polycrystalline thin film to be formed may be used as appropriate. Such a target 36 is rotatably attached to the target support 36a by a pin or the like so that the inclination angle can be adjusted.
The sputtering beam irradiation device (sputtering means) 38 is configured to contain an evaporation source in a container and a grid for applying a drawing voltage in the vicinity of the evaporation source. By irradiating the ion beam, the constituent particles of the target 36 can be knocked out toward the base material A.
[0030]
The ion source 39 has substantially the same configuration as that of the sputter beam irradiation device 38, and includes a grid for storing an evaporation source in the container and applying a drawing voltage in the vicinity of the evaporation source. . And it is an apparatus which ionizes the atom or a part of molecule | numerator generated from the said evaporation source, and irradiates it as an ion beam by controlling the ionized particle | grain with the electric field generated in the grid. There are various types of ionization of particles such as a direct current 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 energized and heated to generate thermoelectrons and collide with evaporated particles in a high vacuum to be ionized. In the cluster ion beam system, clusters of aggregate molecules coming out in a vacuum from a nozzle provided in an opening of a crucible containing raw materials are bombarded with thermal electrons and ionized to be emitted.
[0031]
In the polycrystalline thin film manufacturing apparatus of this embodiment, the ion source 39 having the internal structure shown in FIG. 4 is used. The ion source 39 includes a cylindrical ion chamber 45 having a grid 46, a filament 47, and an introduction tube 48 such as Ar gas. The ion source 39 forms a beam from a beam port 49 at the tip of the ion chamber 45. It can radiate substantially in parallel. The installation position of the ion source 39 can be changed, and the diameter d of the beam port 49 can also be changed.
[0032]
As shown in FIG. 3, the ion source 39 has its central axis S with respect to the film-forming surface of the substrate A and an incident angle θ (an angle formed between the normal (normal) H of the substrate A and the center line S). So they are inclined and face each other. The incident angle θ is preferably in the range of 50 to 60 degrees, more preferably in the range of 55 to 60 degrees, and most preferably 55 degrees. Therefore, the ion source 39 is arranged so that the ion beam can be irradiated at a certain incident angle θ with respect to the normal H of the film formation surface of the substrate A.
[0033]
In addition, the ion source 39 has a spread angle Δθ of an ion beam radiated from the following formula (I)
Δθ ≦ 2tan^-1(D / 2L) (I)
(Where Δθ is the divergence angle of the ion beam, d is the beam aperture (cm) of the ion source 39, and L is the distance between the beam aperture 49 of the ion source 39 and the substrate A (cm). Therefore, the ion beam transport distance L and the beam aperture d are set according to the crystal orientation of the target polycrystalline thin film. The ion beam spread angle Δθ is preferably 5 degrees or less, and more preferably 3 degrees or less. For example, in the case of L = 40 cm, Δθ ≦ 5 ° can be controlled when d ≦ 3.49 cm, and Δθ ≦ 3 ° can be controlled when d ≦ 2.09 cm.
[0034]
The ion beam applied to the substrate A by the ion source 39 is He when an intermediate layer of YSZ is formed.⁺, Ne⁺, Ar⁺, Xe⁺, Kr⁺An ion beam of a rare gas such as, or a mixed ion beam of these and oxygen ions may be used.₂In the case of forming an intermediate layer of⁺Ion beam or Kr⁺And Xe⁺The mixed ion beam is used.
[0035]
In addition, the film forming container 40 is connected to a rotary pump 51 and a cryopump 52 for bringing the inside of the film forming container 40 into a low pressure state such as a vacuum, and an atmospheric gas supply source such as a gas cylinder. In addition, the inside of the film formation processing vessel 40 can be in a low pressure state such as a vacuum and an argon gas or other inert gas atmosphere or an inert gas atmosphere containing oxygen.
Further, the film forming container 40 includes a current density measuring device 54 for measuring the current density of the ion beam in the film forming container 40 and a pressure gauge 55 for measuring the pressure in the container 40. Is attached.
In the polycrystalline thin film manufacturing apparatus of this embodiment, an angle adjustment mechanism may be attached to the support portion of the ion source 39 to adjust the tilt angle of the ion source 39, thereby adjusting the incident angle of the ion beam. Needless to say, the angle adjusting mechanism may have various configurations. Further, the ion beam transport distance L can be changed by changing the installation position of the ion source 39. However, the ion beam transport can be performed by adjusting the length of the support 23a of the substrate holder 23. The distance L may be changed.
[0036]
Next, the case where a polycrystalline thin film of YSZ is formed on the tape-shaped substrate A using the manufacturing apparatus having the above-described configuration will be described.
To form a polycrystalline thin film on a tape-shaped substrate A, YSZ or CeO₂Using a target 36 made of the like, the inside of the film formation processing container 40 containing the base material A is evacuated to form a reduced-pressure atmosphere, and the base material A is transferred from the base material delivery bobbin 24 to the base material holder 23. Then, the ion source 39 and the sputter beam irradiation device 38 are operated.
[0037]
Moreover, the temperature of the base material A in contact with the base material holder 23 is adjusted to a desired temperature of 300 ° C. or less by operating a heater or a cooling device attached to the base material holder 23. The set temperature of the substrate A is preferably set as low as possible even within a range of 300 ° C. or less, based on the result of the crystal orientation of YSZ described later and the data on the critical current density of the superconducting layer described later. When the film forming temperature is set to 300 ° C. or lower, a temperature range of 100 ° C. or lower, which indicates the substrate temperature when the substrate A is not particularly heated by the substrate holder 23 at normal temperature, is preferable, and liquid nitrogen that can be widely used as a refrigerant at low cost A temperature range of −150 ° C. or higher that can be easily cooled is a more preferable set temperature.
[0038]
By the way, when liquid nitrogen is introduced into the injection member 65 and liquid nitrogen is filled into the internal space of the base 60 through the outgoing pipe 62 from here, the heated state by the deposited particles or the other provided in the film formation processing container 40 Even if a substrate holder that is as thin as possible using liquid nitrogen is adopted due to thermal radiation from the above apparatus, the temperature of the substrate A is limited to cooling to about −150 ° C., so it is further cooled to a lower temperature. In this case, other refrigerant such as liquid helium is used.
[0039]
When the target 36 is irradiated with an ion beam from the sputtering beam irradiation device 38, the constituent particles of the target 36 are knocked out and fly onto the base material A.
Then, the constituent particles knocked out from the target 36 are deposited on the base material A sent out onto the base material holder 23, and at the same time, from the ion source 39, for example, Ar⁺A polycrystalline thin film B having a desired thickness is formed by irradiation with a mixed ion beam of ions and oxygen ions, and the tape-shaped substrate A after the film formation is wound around the substrate take-up bobbin 25.
[0040]
Here, the incident angle θ when irradiating the ion beam is preferably in the range of 50 to 60 degrees, more preferably in the range of 55 to 60 degrees, and most preferably 55 degrees. Here, when θ is 90 degrees, the c-axis of the polycrystalline thin film is preferably oriented because the (111) plane stands on the film-forming surface of the substrate A, although it is oriented at right angles to the film-forming surface on the substrate A. Absent.
When θ is 30 degrees, the polycrystalline thin film does not even have c-axis orientation. If the ion beam is irradiated at an incident angle in a preferable range as described above, the (100) plane of the polycrystalline thin film will stand. By performing sputtering while irradiating an ion beam at such an incident angle, the a-axis and the b-axis of the polycrystalline thin film of YSZ formed on the substrate A are directed in the same direction. In-plane orientation is performed along a plane parallel to the upper surface (film formation surface) of the substrate A.
[0041]
In the method for producing a polycrystalline thin film according to this embodiment, the constituent particles of the target 36 provided in the film-forming treatment container 40 that can be evacuated as described above are knocked out by sputtering and deposited on the substrate A. At this time, an ion beam generated from the ion source 39 is deposited while being irradiated at an incident angle of 50 to 60 degrees with respect to the normal line H of the film formation surface of the substrate A to form a polycrystalline thin film on the substrate A. In the film forming method, by controlling the temperature of the substrate A to a desired temperature, a material having better crystal orientation can be obtained. The adjustment of the ion beam incident angle can be realized by preparing a plurality of materials having different inclination angles of the upper surface 60a of the base 60, and performing film formation after appropriately replacing the ones having the desired angles.
[0042]
Here, as will be clarified in Examples described later, a polycrystalline thin film of YSZ having a grain boundary tilt angle of 35 degrees can be obtained by setting the substrate temperature to 300 ° C., and by setting it to 200 ° C. A YSZ polycrystalline thin film with a field inclination angle of 25 degrees can be obtained, and a YSZ polycrystalline thin film with a grain boundary inclination angle of 18 degrees can be obtained by setting to 100 ° C., and a grain boundary inclination angle by setting to 0 ° C. A 13 degree YSZ polycrystalline thin film can be obtained. By setting the temperature to −100 ° C., a YSZ polycrystalline thin film having a grain boundary tilt angle of 10 degrees can be obtained. A polycrystalline thin film of YSZ having a field inclination angle of 8 degrees can be obtained.
[0043]
Then, the oxide superconducting layer 22 having the structure shown in FIG. 5 is obtained by laminating the oxide superconducting layer C on the polycrystalline thin film formed as described above by a film forming method such as sputtering or laser deposition. Can do.
The oxide superconducting layer C is coated on the upper surface of the polycrystalline thin film B, and the c-axis of the crystal grain 23 is oriented at right angles to the upper surface of the polycrystalline thin film B. The a-axis and b-axis are in-plane oriented along a plane parallel to the upper surface of the base material in the same manner as the polycrystalline thin film B described above, and the grain boundary inclination angle formed between the crystal grains 23 is formed to a small value. .
[0044]
The oxide superconductor constituting this oxide superconducting layer is Y₁Ba₂Cu_ThreeO_7-x, Y₂Ba_FourCu₈O_y, Y_ThreeBa_ThreeCu₆O_yOr (Bi, Pb)₂Ca₂Sr₂Cu_ThreeO_y, (Bi, Pb)₂Ca₂Sr_ThreeCu_FourO_yThe composition or Tl₂Ba₂Ca₂Cu_ThreeO_y, Tl₁Ba₂Ca₂Cu_ThreeO_y, Tl₁Ba₂Ca_ThreeCu_FourO_yIt is an oxide superconductor with a high critical temperature typified by such a composition.
[0045]
Here, if the oxide superconducting layer C is formed by a film forming method such as sputtering or laser vapor deposition on a polycrystalline thin film in which the grain boundary inclination angle is accurately aligned to about 35 to 8 degrees as described above, The oxide superconducting layer C laminated on the polycrystalline thin film is also epitaxially grown and crystallized so as to match the orientation of the polycrystalline thin film.
Therefore, the oxide superconducting layer C formed on the polycrystalline thin film B is hardly disturbed in crystal orientation, and in each of the crystal grains constituting the oxide superconducting layer C, the base material A In the thickness direction, the c-axis that hardly allows electricity to flow is oriented, and in the length direction of the substrate A, the a-axes or the b-axes are oriented. Therefore, the obtained oxide superconducting layer C is excellent in quantum connectivity at the grain boundaries and has almost no deterioration of the superconducting characteristics at the grain boundaries. And SrTO_ThreeA sufficiently high critical current density of the same level as that of the oxide superconducting layer obtained on the single crystal substrate can be obtained.
[0046]
In addition, in the case where the substrate temperature was set to 300 ° C. and a polycrystalline thin film of YSZ having a grain boundary tilt angle of 35 degrees was obtained, the critical current density of the oxide superconducting layer was 55000 A / cm.²A YSZ polycrystalline thin film having a substrate temperature of 200 ° C. and a grain boundary tilt angle of 25 ° is obtained as a critical current density of an oxide superconducting layer of 180000 A / cm.²A YSZ polycrystalline thin film having a substrate temperature of 100 ° C. and a grain boundary tilt angle of 18 degrees is obtained as the critical current density of the oxide superconducting layer is 550000 A / cm.²Can be obtained. Further, in the case of obtaining a YSZ polycrystalline thin film having a substrate temperature of 0 ° C. and a grain boundary tilt angle of 13 degrees, the critical current density of the oxide superconducting layer is 800000 A / cm.²In the case of obtaining a YSZ polycrystalline thin film having a substrate temperature of −100 ° C. and a grain boundary tilt angle of 10 °, the critical current density of the oxide superconducting layer is 1300000 A / cm.²In the case of obtaining a YSZ polycrystalline thin film having a substrate temperature of −150 ° C. and a grain boundary tilt angle of 8 degrees, the critical current density of the oxide superconducting layer is 2500000 A / cm.²Can be obtained.
[0047]
As described above, film formation is performed by ion beam irradiation while maintaining the substrate temperature at an appropriate temperature of 300 ° C. or less, so that the YSZ polycrystalline thin film B has excellent crystal orientation and excellent critical current characteristics. The physical superconductor 22 can be obtained.
In addition, the oxide superconducting conductor obtained in this example can be easily formed into a long tape having excellent flexibility, and application to a winding of a superconducting magnet can be expected.
[0048]
Note that the present inventors assume the following as a factor for adjusting the crystal orientation of the polycrystalline thin film B described above.
The unit lattice of the crystal of the YSZ polycrystalline thin film B is a cubic crystal. In this crystal lattice, the substrate normal direction is the <100> axis, and the other <010> axis and the <001> axis are both The other direction. Considering an ion beam incident from an oblique direction with respect to the substrate normal with respect to these directions, when entering the diagonal direction of the unit cell relative to the origin of the unit cell, that is, along the <111> axis, The incident angle with respect to the substrate normal is 54.7 degrees.
[0049]
According to the technology previously filed by the inventors of the present application, as shown in FIG. 14, the value of the full width at half maximum indicating the crystal orientation of the polycrystalline thin film of YSZ obtained according to the incident angle of the ion beam is The minimum value is shown when the beam incident angle is in the range of 55 to 60 degrees.
Here, as described above, good crystal orientation is exhibited in the incident angle range of 50 to 60 degrees. When the incident angle of the ion beam coincides with or is around 54.7 degrees, the ion channeling is performed. In the crystal deposited on the base material A, only the atoms in the arrangement relationship corresponding to the angle on the upper surface of the base material A are likely to remain selectively, and other disordered atoms It is presumed that the arrayed elements are removed by being sputtered by the sputtering effect of the ion beam, so that only crystals with a good orientation of atoms are selectively left and deposited.
[0050]
At this time, the irradiation effect of the ion beam on YSZ has two effects, that is, the effect of raising the (100) plane of YSZ perpendicular to the substrate and the effect of adjusting the in-plane orientation. It is presumed that the effect of raising the (100) plane perpendicularly to the main is the main. This is because if the effect of raising YSZ (100) perpendicular to the substrate is insufficient, the in-plane orientation is inevitably disturbed.
[0051]
Next, when film formation is performed while irradiating an ion beam at an incident angle of 50 to 60 degrees with respect to the normal of the film formation surface, the value of the grain boundary tilt angle K of the polycrystalline thin film B is improved when temperature control is performed. The inventor of the present application presumes the reason why the crystal orientation of the polycrystalline thin film B is improved as follows.
In order to obtain a thin film with good crystallinity in a film formation method such as normal sputtering or laser vapor deposition, film formation is performed while heating the film formation atmosphere to a high temperature, for example, about 400 to 600 ° C. or higher. That is common knowledge. Obtaining a film with high crystallinity by forming a film while heating to such a high temperature means that there is a close relationship between the film formation temperature and crystallization, In the field of thin film production, it is understood that when the film formation temperature is low, a film rich in amorphousness is easily generated.
[0052]
However, in the case of using a film forming technique accompanying ion beam irradiation, which is a technique related to the present invention, the film forming temperature is preferably as low as possible because the effect of adjusting the crystal by the ion beam is extremely large. This is because the lower the temperature, the less the movement and vibration of the atoms that make up the crystal, and the more effective the effect of aligning the crystal with ion beam irradiation is. It is estimated that the thin film B is easily generated.
[0053]
That is, according to the technique of the present invention, a polycrystalline thin film having a stable [100] axis can be obtained as the temperature is lowered, and the angle of the [111] axis is uniquely determined accordingly, and the crystal is formed. The crystal orientation is improved because dechanneeling does not occur due to the thermal vibration of the atoms and the collision cross section of ions along the [111] axis is reduced to enable effective orientation control. Seem.
Note that the polycrystalline thin film B having higher crystal orientation can be obtained as the film forming temperature is lowered, and the polycrystalline thin film B having better crystal orientation is obtained when the polycrystalline thin film B is formed at a temperature of 100 ° C. or lower. The fact that the film can be obtained is contrary to the knowledge that it is difficult to obtain a film with high crystallinity without film formation while heating at a high temperature in general film formation technology. It is possible to know the peculiarity of the technology for forming a film while irradiating the film obliquely.
[0054]
【Example】
Example 1
3 to 5 was used to perform sputtering with ion beam irradiation to form a YSZ polycrystalline thin film on a metal tape. The inside of the vacuum vessel containing the apparatus shown in FIG. 3 is evacuated with a vacuum pump to 3.0 × 10^-FourWhile reducing the pressure to Torr, Ar + O in the vacuum vessel₂The gas of Ar is 16.0 sccm, O₂The gas was supplied at a rate of 8.0 sccm.
As the substrate, Hastelloy C276 tape having a mirror-finished surface of 10 mm in width, 0.5 mm in thickness, and several m in length was used. The target is YSZ (Y₂O_Three: 8 mol%), Ar⁺The target is irradiated with ions from the ion gun and sputtered, and the incident angle of the ion beam from the ion gun is set to an incident angle of 55 degrees with respect to the normal of the film forming surface of the base tape on the base holder.⁺+ O₂The ion beam energy is 300 eV and the ion current density is 100 μA / cm.²Then, ion beam irradiation was performed simultaneously with laser deposition on the substrate, and a YSZ layer having a thickness of 1100 nm was formed on the substrate tape while moving the substrate tape along the substrate holder at a constant speed.
[0055]
During the film formation, the heater of the base material holder was operated, and the temperatures of the base material and the polycrystalline thin film during film formation were controlled to 500 ° C., 400 ° C., 300 ° C., and 200 ° C., respectively. Further, when the film was formed at room temperature without operating the heater, the temperature of the base material and the polycrystalline thin film was maintained at a temperature of 100 ° C. due to the ion beam irradiation effect and heat generation from other parts inside the apparatus. For further comparison, the substrate is cooled with liquid nitrogen using the cooling device shown in FIG. 5, and the substrate holder and the polycrystalline thin film are cooled at temperatures of 0 ° C. and −100 by changing the thickness of the substrate holder used. A polycrystalline thin film was formed on a tape-shaped substrate by controlling the temperature at ℃ and −150 ℃, respectively.
[0056]
The results of obtaining the (111) pole figure and the (100) pole figure by X-ray in each of the obtained samples are shown in FIGS. From the results shown in FIG. 8 to FIG. 12 and FIG. 18, when the film is formed, it is in a state in which the orientation is excellent ([100] orientation state) when the film forming temperature is set to a lower temperature of 300 ° C. or lower. I was able to confirm that. Conversely, it was confirmed that when the temperature was higher than 300 ° C. (400 ° C. or 500 ° C.), the [100] orientation was lost and the [111] orientation was obtained.
[0057]
Next, whether or not the a-axis or b-axis of the YSZ polycrystalline thin film was oriented in each c-axis oriented sample as described above was measured.
For the measurement, as shown in FIG. 7, the YSZ polycrystalline thin film formed on the substrate A is irradiated with X-rays at an angle θ, and incident X-rays are incident on a vertical plane including incident X-rays. The X-ray counter 58 is installed at an angle of 2θ (58.7 degrees) with respect to the vertical angle, and the value of the horizontal angle φ with respect to the vertical plane including the incident X-rays is appropriately changed. The orientation of the a-axis or b-axis of the polycrystalline thin film B was measured by measuring the diffraction intensity obtained by rotating it by the rotation angle φ as indicated by the arrows in FIG.
[0058]
Furthermore, the crystal orientation in each crystal grain of the obtained YSZ polycrystalline thin film was tested. In this test, when performing X-ray diffraction by the method described above with reference to FIG. 7, the diffraction peak was measured when the angle of φ was set to a value in increments of 1 degree from −20 degrees to 20 degrees. And the in-plane orientation was calculated | required by whether the peak value appeared in the range of ± times, and disappeared in the range of ± times.
[0059]
Further, an oxide superconducting layer was formed on these polycrystalline thin films using an ion beam sputtering apparatus. Y as target_0.7Ba_1.7Cu_3.0O_7-xA target made of an oxide superconductor having the following composition was used. The inside of the vapor deposition chamber is 1 × 10^-6The pressure was reduced to tall and sputtering was performed. Thereafter, heat treatment was performed at 400 ° C. for 60 minutes in an oxygen atmosphere. The obtained oxide superconducting tape conductor has a width of 10.0 mm and a length of 1 m.
The oxide superconducting tape conductor was cooled with liquid nitrogen, and the results of measuring the critical temperature and the critical current density by a four-terminal method for the central portion having a width of 10 mm and a length of 10 mm were obtained.
In the above measurement results, the relationship between the film formation temperature, the in-plane orientation, and the critical current density is shown below.
[0060]

[0061]
From this result, the polycrystalline thin film was [111] oriented at a deposition temperature of 400 ° C. or higher, and a good value was not obtained as the critical current density of the superconducting layer. Furthermore, if the film was formed at 300 ° C. or lower, the polycrystalline thin film had good crystal orientation and a high critical current density. This tendency becomes more prominent as the film formation temperature becomes lower. From this data, 180000 A / cm²In order to obtain the above critical current density, the temperature is preferably 200 ° C. or lower, preferably 550000 A / cm.²It has also been found that a temperature of 100 ° C. or lower is preferable in order to obtain the above critical current density. From the above, the film forming temperature range for obtaining a high critical current density is more preferably in the range of 100 ° C. to −150 ° C. even in the range of 300 ° C. to −150 ° C.
[0062]
Next, FIG. 13 shows the film thickness dependence with respect to the full width at half maximum of the polycrystalline thin film formed on the base tape. FIG. 13 shows the results when the base tape was held at 100 ° C. and the film was formed under the same conditions as described above.
From this result, the orientation of the [100] axis starts to stabilize from a film thickness exceeding 200 nm. Therefore, in the case of forming a film while irradiating an ion beam with an incident angle of 50 to 60 degrees from an oblique direction, even if a crystal with poor crystal orientation is formed at the initial stage of film deposition, As the thickness increases, the crystal orientation becomes better, and it is clear that a film having an excellent crystal orientation can be obtained if the film thickness is 200 nm or more when viewed from the [100] axis orientation state.
[0063]
Next, FIG. 16 shows a comparison of values at deposition temperatures of 100 ° C. and 200 ° C. in the relationship between the deposition time and full width at half maximum of the YSZ polycrystalline thin film manufactured under the same conditions as described above, and FIG. In the relationship between the film thickness of the polycrystalline thin film and the full width at half maximum, a comparison of values at film forming temperatures of 100 ° C. and 200 ° C. is shown.
In any of the figures, it is shown that a polycrystalline thin film exhibiting excellent crystal orientation is obtained when the film is formed at 100 ° C. lower than 200 ° C.
From these test results, it was found that a polycrystalline thin film having better crystal orientation can be obtained by forming a film at a lower temperature.
It has also been found that at any film formation temperature, it is difficult to obtain a polycrystalline thin film with good crystal orientation unless the vapor deposition time is long, in other words, the film thickness must be somewhat thick.
[0064]
【The invention's effect】
As described above, according to the method of the present invention, when particles generated from a target are deposited on a base material, an ion beam is applied at an incident angle of 50 degrees to 60 degrees with respect to the normal of the base film forming surface. Irradiation makes the film forming temperature 300 ° C. or lower, so that the grain boundary inclination angle is 35 ° or lower which improves the a-axis orientation and the b-axis orientation in addition to the c-axis orientation with respect to the film forming surface of the substrate. A YSZ polycrystalline thin film can be obtained reliably.
This is because, in the constituent atoms deposited on the substrate, the ions in the ion beam remove the unstable atoms arranged in a direction deviating from the specified direction by exerting the sputtering effect, so that they are arranged in the specified position. It is likely that only highly stable atoms are likely to remain selectively, and as a result, particles having good orientation are mainly deposited, and a polycrystalline thin film having good orientation is obtained.
In addition, by controlling the temperature during film formation to 300 ° C. or less, the vibration and movement of atoms constituting the crystal can be reduced, and the crystal orientation control effect by the ion beam is made larger than these influences. As a result, a polycrystalline thin film having good orientation can be obtained. In addition, the orientation control effect by the ion beam also promotes the action of accurately setting a specific surface of the polycrystalline thin film perpendicularly to the substrate film formation surface. As a result of accurate positioning, the direction control effect of other surfaces can also be improved, and as a result, a polycrystalline thin film as an aggregate of crystal grains excellent in crystal orientation as the whole film can be obtained.
[0065]
  Then, if an oxide superconducting layer is formed on the polycrystalline thin film having good orientation formed at the above-mentioned temperature, an oxide superconducting layer having good crystalline orientation can be formed, and thereby the critical current density can be generated. An oxide superconducting conductor having a high superconducting property can be obtained.
  Further, yttrium-stabilized zirconia can be specifically used as a material generated from a target and deposited on a substrate, and a polycrystalline thin film of yttrium-stabilized zirconia having excellent crystal orientation can be obtained.
  Furthermore, if the thickness of the obtained polycrystalline thin film is 200 nm or more, a polycrystalline thin film having sufficiently excellent crystal orientation can be obtained with certainty.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a polycrystalline thin film of YSZ formed by the method of the present invention.
FIG. 2 is an enlarged plan view showing crystal grains of the YSZ polycrystalline thin film shown in FIG. 1, its crystal axis direction, and grain boundary tilt angle.
FIG. 3 is a block diagram showing an example of an apparatus for producing a polycrystalline thin film on a substrate by carrying out the method of the present invention.
FIG. 4 is a cross-sectional view showing an example of an ion gun provided in the apparatus shown in FIG.
FIG. 5 is a cross-sectional view showing an example of a cooling device provided in the apparatus shown in FIG. 3;
FIG. 6 is a cross-sectional view showing an oxide superconducting layer formed on the YSZ polycrystalline thin film shown in FIG.
FIG. 7 is a layout diagram of an X-ray apparatus for measuring the crystal orientation of a polycrystalline thin film.
FIG. 8 is a pole figure of a polycrystalline thin film formed at 100 ° C. with an ion beam incident angle of 55 degrees and an ion beam energy of 300 ev.
FIG. 9 is a pole figure of a polycrystalline thin film formed at 200 ° C. with an ion beam incident angle of 55 degrees and an ion beam energy of 300 ev.
FIG. 10 is a pole figure of a polycrystalline thin film formed at 300 ° C. with an ion beam incident angle of 55 degrees and an ion beam energy of 300 ev.
FIG. 11 is a pole figure of a polycrystalline thin film formed at 400 ° C. with an ion beam incident angle of 55 degrees and an ion beam energy of 300 ev.
FIG. 12 is a pole figure of a polycrystalline thin film formed at 500 ° C. with an ion beam incident angle of 55 degrees and an ion beam energy of 300 ev.
FIG. 13 is a diagram showing the relationship between the thickness of a polycrystalline thin film formed on a substrate and the full width at half maximum.
FIG. 14 is a graph showing the relationship between the incident angle of an ion beam and the full width at half maximum of the obtained polycrystalline thin film.
FIG. 15 is a configuration diagram showing a polycrystalline thin film and an oxide superconducting layer formed on a substrate by a conventional method.
FIG. 16 is a diagram showing the relationship between the full width at half maximum of a polycrystalline thin film obtained by the method of the present invention and the deposition time.
FIG. 17 is a diagram showing the relationship between the full width at half maximum and the film thickness of a polycrystalline thin film obtained by the method of the present invention.
FIG. 18 is a pole figure of a polycrystalline thin film formed at 0 ° C. with an ion beam incident angle of 55 degrees and an ion beam energy of 300 ev.
[Explanation of symbols]
A ... Base material, B ... Polycrystalline thin film, C ... Oxide superconducting layer, K ... Grain boundary tilt angle, θ ... Incident angle, φ ... Rotation angle, 20, 21 ... Crystal grain, 22 ... Oxide superconducting conductor, 23 ... Substrate holder, 24 ... Substrate delivery bobbin (delivery device), 25 ... Substrate take-up bobbin (take-up device), 36 ... Target, 38 ... Ion gun, 39 ... Ion source, 40 ... Make Membrane processing vessel, R ... cooling device, 60 ... base, 61 ... refrigerant introduction pipe, 62 ... outward pipe, 63 ... return pipe.

Claims (3)

Particles generated from a target are deposited on a base material, a polycrystalline thin film made of constituent elements of the target is formed on the base material , and then an oxide superconducting layer is formed on the polycrystalline thin film. In the manufacturing method, when depositing the target particles on the substrate, the ion beam generated by the ion source is obliquely incident at an incident angle in the range of 50 to 60 degrees with respect to the normal of the film formation surface of the substrate. The polycrystalline thin film is formed by depositing the particles on the base material while irradiating from above, and the temperature during the film formation is set to 300 ° C. or lower , and after forming the polycrystalline thin film, an oxide superconducting layer is formed thereon A method for producing an oxide superconducting conductor. The method for producing an oxide superconducting conductor according to claim 1 , wherein a target of yttrium-stabilized zirconia is used. Method of manufacturing an oxide superconductor according to claim 1 or 2, wherein the setting the thickness of the polycrystalline thin film to be produced on the substrate and above 200 nm.

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