JPH013001A - Method for manufacturing superconducting ceramic thin films - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Graduation Field of Application] This invention relates to a method for producing a superconducting ceramic thin film. [Prior art and its problems] In recent years, superconducting ceramics such as Y-Ba-Cu-0 have been in the spotlight as having a high superconducting transition temperature. The high superconducting transition temperature of such superconducting ceramics is reflected in the layered crystal structure called perovskite type, and it is thought that electrons flow along the layers.

Therefore, it is desirable that the crystal structure of superconducting ceramics be uniaxially oriented; if the orientation is poor, the movement of electrons flowing along the layer will be hindered by grain boundaries, etc.
There is a problem that sufficient current capacity cannot be obtained.

By the way, conventionally, when a thin film of superconducting ceramic is produced on a substrate by a sputtering method or the like, the orientation of the crystals is not aligned, resulting in poor orientation.

Therefore, the present invention aims to provide a method for manufacturing a superconducting ceramic thin film with good crystal orientation.

Means for Solving Problem c] The present invention provides a method for producing a superconducting ceramic thin film in which a superconducting ceramic is grown in the form of a thin film on a substrate and then heat-treated. An electric field is applied to the substrate surface during the growth of ceramics and during heat treatment after growth.

[Effect]

In this invention, a perovskite material whose lattice constant is relatively close to the crystal lattice constant of superconducting ceramic crystals and has a similar crystal structure is used as the substrate. easy to form,
In addition, by applying an electric field during the thin film growth,
Polarization is induced in the crystals being deposited on the substrate, and the orientation of the crystals is aligned in the direction of the applied force, which improves the orientation of the crystals in the produced thin film.

Furthermore, by performing heat treatment while applying an electric field after forming the thin film, the orientation direction, which was incomplete at the time of forming the thin film, is further aligned.

〔Example〕

Next, as an example of the present invention, a method for manufacturing a superconducting ceramic thin film using a sputtering apparatus as shown in FIG. 1 will be described.

First, a strontium titanate substrate 1 is set as shown in FIG. An electric field is applied to this substrate 1 by an electrode 2 . For example, Y2O2, BaCO3,
Three pieces, a sintered body of CuO and a sintered body of Y2O3 and CuO alone, are prepared and placed at the target position.

Next, the target 3.4.5 is irradiated with an argon ion beam from the argon ion beam source 6, and Y, Ba,
Spat Cu.

These scattered atoms, molecules, etc. are partially ionized through the ionization section 7, drift in a space to which an electric field is applied, and are deposited on the substrate 1 in an oxygen atmosphere to form a thin film 8. At this time, the electric force of the ions effectively promotes orientation.

In the thin film 8 crystals grown on the substrate 1 in this way,
Since there are oxygen vacancies, further heat treatment is performed in an oxygen atmosphere to eliminate oxygen vacancies in the crystal.

The heat treatment is performed, for example, in a heat treatment furnace 9 as shown in FIG.

First, the substrate 1 on which the thin film 8 has been deposited is introduced into the reaction tube 10, and after the substrate 1 on which the thin film 8 has been deposited is sandwiched between electrode plates 11.12 made of tungsten or the like, oxygen is introduced, and the electrode plates 11. Heat treatment is performed while applying a high voltage between 12 and 12 to promote crystallization and orientation.

The direction in which the electric field is applied is either perpendicular or horizontal to the substrate 1, both during growth and during heat treatment.

Further, the applied electric field is 1 to IOKν/c3. 10
If it exceeds KV/ru+, discharge or dielectric breakdown may occur.

When the crystal structure of the thin film 8 thus obtained was examined, it was found that the crystal orientation was aligned in the direction of application of the electric field.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to manufacture a Cusco film, which is a super-transconducting ceramic with good crystal orientation and uniform crystal orientation. It also makes it possible to flow easily, which is very effective when manufacturing a Josephson junction with a multilayer structure.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an example of a thin film forming apparatus. FIG. 2 is a schematic diagram showing an example of a heat treatment apparatus. 1...Substrate, 8...Thin film. Patent applicant: Sumitomo Electric Industries, Ltd.

Claims (3)

[Claims] (1) In a method for manufacturing a superconducting ceramic thin film in which a superconducting ceramic is grown in the form of a thin film on a substrate and then heat-treated, a perovskite-based substrate is used as the substrate, and the substrate is A method for producing a superconducting ceramic thin film, characterized by applying an electric field to a surface. (2) The method for producing a superconducting ceramic thin film according to claim 1, wherein a sputtering method or an ionized vapor deposition method is used as the thin film producing means. (3) The method for producing a superconducting ceramic thin film according to claim 1, wherein the heat treatment is performed in an oxygen atmosphere.