JP2003229610A - Method for manufacturing oxide superconducting junction substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method which reduces the number of manufacturing processes and obtains an oxide superconducting junction substrate showing high reproducibility. <P>SOLUTION: An oxide superconducting film 2 for a lower part electrode of c-axis orientation is formed on a surface of a substrate 1. After patterning, an interlayer insulating film 5 is formed. By etching a part of the interlayer insulating film 5 on the superconducting film 2, an aperture part 6 of the interlayer insulating film 5 is formed. After that, a thin film 3 for a barrier layer and an oxide superconducting film 4 for an upper part electrode of c-axis orientation are formed, and a junction 8 is formed. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used, for example, in analog / digital converters and ultra-small magnetic field detection.
The present invention relates to a method for manufacturing an oxide superconducting junction substrate.

[0002]

2. Description of the Related Art FIG. 3 and FIG.
N APPLIED SUPERCONDUCTIVITY, VOL.9, No.2, (1999-6),
FIG. 3 is a schematic view showing a method for manufacturing a conventional oxide superconducting junction substrate referred to as a laminated type described on page 3450, where 1 is a substrate, 2 is a c-axis oriented oxide superconducting film for a lower electrode, and 3 is a barrier. Layer thin film, 4 is a c-axis oriented oxide superconducting film for an upper electrode, 5 is an interlayer insulating film, 6 is a perforated portion of the interlayer insulating film, 7
Is an oxide superconducting film for a wiring layer, and 8 is a junction.

A method of manufacturing the oxide superconducting junction substrate shown in FIGS. 3 and 4 will be described. On the surface of the substrate 1, a c-axis-oriented oxide superconducting film 2 for the lower electrode, for example, a c-axis-oriented YBaCuO film, a barrier layer thin film 3, for example PrB.
The aCuO film and the c-axis oriented oxide superconducting film 4 for the upper electrode are continuously deposited by a sputtering method, a laser deposition method or the like (3- (1)). After that, a partial region of the oxide superconducting film 4 for the upper electrode, the thin film 3 for the barrier layer, and the oxide superconducting film 2 for the lower electrode is removed by etching to determine the position of the lower electrode (3- (2)). . Further, a partial region of the oxide superconducting film 4 for the upper electrode and the thin film 3 for the barrier layer is removed by etching to determine the position of the junction 8 (3- (3)). afterwards,
An interlayer insulating film 5 is deposited in order to prevent the oxide superconducting film 2 for the lower electrode from being electrically short-circuited with the oxide superconducting film 4 for the upper electrode except at the bonding portion 8 (3- (4)). Next, by removing a partial region of the interlayer insulating film 5 by etching,
A perforated portion 6 of the interlayer insulating film 5 for electrically connecting the oxide superconducting film 4 for the upper electrode and the oxide superconducting film 7 for the wiring layer is formed (3- (5)). Next, the surface of the oxide superconducting film 4 for the upper electrode under the perforated portion 6 is cleaned by heating in vacuum or the like, and then the oxide superconducting film 7 for the wiring layer is deposited to form 3- (6). The junction structure shown is manufactured.

The superconducting junction having the above structure is composed of a c-axis oriented oxide superconducting film 2 for the lower electrode / thin film 3 for the barrier layer /
The junction portion 8 having the three-layer structure of the c-axis oriented oxide superconducting film 4 for the upper electrode serves as an oxide superconducting junction substrate that causes the Josephson effect, and the oxide for the wiring layer is formed through the perforated portion 6 of the interlayer insulating film. It is connected to the superconducting film 7 and is used as a superconducting quantum interference device or a single magnetic flux quantum device. The reason why the c-axis oriented oxide superconducting film is used as the superconducting thin film is as follows. In order to manufacture a practical electronic element or electronic circuit, it is necessary to pass a current in the oxide superconducting film in the wiring portion in parallel with the substrate surface. Therefore, the oxide superconducting film in that portion is a c-axis oriented film. Because it must be.

[0005]

However, in the oxide superconducting substrate thus manufactured, the c-axis oriented oxide superconducting film 2 for the lower electrode / thin film for barrier layer 3 / the upper electrode for the c-axis orientation is used. Since the wiring layer is connected by forming the perforated portion 6 of the interlayer insulating film after forming the junction portion 8 having the three-layer structure of the oxide superconducting film 4, the manufacturing process is complicated, and the oxide for wiring layer is complicated. In the process of laminating the superconducting film 7, there is a problem that the joint portion 8 is damaged due to high temperature heating. As described above, in the production of the conventional oxide superconducting bonded substrate, there are many steps, and since the oxide superconducting film is laminated again after the bonding portion 8 is formed, there is a problem that the bonding characteristics are deteriorated or the yield is deteriorated. It was The present invention is
Oxide superconducting film 7 for wiring layer after formation of the above-mentioned joint portion 8
The present invention has been made in order to solve the problems associated with the stacking of oxides, and an object thereof is to obtain an oxide superconducting junction substrate showing a high reproducibility of superconducting junction characteristics by reducing the number of manufacturing steps.

[0006]

The method for manufacturing an oxide superconducting junction substrate of the present invention is characterized in that the junction 8 is formed in the perforated portion 6 of the interlayer insulating film. That is, according to the present invention, the c-axis-oriented oxide superconducting film 2 for the lower electrode is formed on the surface of the substrate 1, and the interlayer insulating film 5 is formed after patterning. Partly etched to form a hole 6 in the interlayer insulating film
Then, the barrier layer thin film 3 and the c-axis oriented oxide superconducting film 4 for the upper electrode are formed, and the bonding portion 8 is formed on the substrate.
Is a method for manufacturing an oxide superconducting junction substrate for forming a. When forming the perforated portion 6 of the interlayer insulating film, the surface of the lower electrode oxide superconducting film 2 may be etched and heat-treated to form the barrier layer thin film 3.

[0007]

In the oxide superconducting junction substrate of the present invention, the junction 8 is formed in the perforated portion 6 of the interlayer insulating film, and the oxide superconducting film 4 for the upper electrode simultaneously functions as the oxide superconducting film 7 for the wiring layer. The formation of the wiring layer oxide superconducting film 7 is not necessary, the manufacturing process is simplified, and the deterioration of the bonding characteristics due to the formation of the wiring layer superconducting film 7 can be eliminated.

[0008]

EXAMPLES Example 1 (Embodiment 1) Hereinafter, the present invention will be described with reference to Examples. FIG. 1 is a schematic diagram showing an example of a method for manufacturing an oxide superconducting junction substrate of the present invention. In FIG. 1, each number from 1 to 8 is shown in FIGS.
It is the same as or equivalent to the conventional method shown in FIG.

First, a c-axis oriented oxide superconducting film 2 for a lower electrode, for example, a c-axis oriented YBaCuO film is formed on a substrate 1 by a sputtering method or a laser deposition method (1-
(1)). After that, a part of the lower electrode oxide superconducting film 2 is removed by etching to determine the position of the lower electrode (1- (2)). In order to prevent an electrical short circuit with the oxide superconducting film 4 for the upper electrode, an interlayer insulating film 5 is laminated (1-
(3)). Next, a part of the inter-layer insulating film 5 is removed by etching to form a perforated portion 6 of the inter-layer insulating film (1- (4)). After that, after cleaning the surface of the oxide superconducting film 2 for the lower electrode under the perforated portion 6 by heat treatment in vacuum or the like, the thin film 3 for the barrier layer, for example PrBaC.
uO film and oxide superconducting film 4 for c-axis oriented upper electrode
1-by stacking the
The junction structure shown in (5) is formed. According to the present invention, since the bonding portion 8 is formed in the perforated portion 6 of the interlayer insulating film as described above, it is not necessary to stack the oxide superconducting film 7 for wiring layer, and the number of manufacturing steps is reduced, and The deterioration of the superconducting junction characteristics due to the wiring layer manufacturing process after the formation of the junction is eliminated, so that it is possible to manufacture a junction substrate with high reproducibility of the superconducting junction characteristics.

Embodiment 2 (Embodiment 2) Another embodiment of the present invention will be described. FIG. 2 is a schematic view showing a method of manufacturing a superconducting bonded substrate according to another embodiment of the present invention.
Is the same as or equivalent to. In Example 1,
After forming the perforated portion 6 of the interlayer insulating film, the surface of the oxide superconducting film 2 for the lower electrode is cleaned by heat treatment in vacuum or the like, and then the thin film 3 for the barrier layer and the oxide superconducting oxide for the c-axis oriented upper electrode. Although the film 4 was formed, in Example 2, the surface of the oxide superconducting film 2 for the lower electrode was intentionally etched to form an amorphous surface when the perforated portion 6 of the interlayer insulating layer was formed by etching. Then, the barrier layer thin film 3 called an interface modified type was formed by heat treatment in vacuum or the like, and then the upper electrode oxide superconducting film 4 was formed by a sputtering method, a laser deposition method or the like.

[0011]

As described above, according to the first aspect of the present invention, since the joint portion 8 is formed in the perforated portion 6 of the interlayer insulating film, the manufacturing process is simplified and deterioration of the joint characteristics is prevented. Therefore, it is possible to manufacture an oxide superconducting junction substrate having high reproducibility of characteristics. According to the second aspect of the present invention, since the barrier layer thin film 3 is formed when forming the perforated portion 6 of the interlayer insulating layer, the manufacturing process can be further simplified.

[Brief description of drawings]

FIG. 1 is a schematic view showing a manufacturing process of an oxide superconducting junction substrate of Example 1.

FIG. 2 is a schematic view showing a manufacturing process of an oxide superconducting junction substrate of Example 2.

FIG. 3 is a schematic view showing a manufacturing process of a conventional oxide superconducting junction substrate.

FIG. 4 is a schematic view showing a manufacturing process of a conventional oxide superconducting junction substrate.

[Explanation of symbols]

1 substrate, 2 oxide superconducting film for lower electrode, 3 thin film for barrier layer, 4 oxide superconducting film for upper electrode, 5 interlayer insulating film, 6 perforated portion of interlayer insulating film, 7 oxide superconducting film for wiring layer, 8 joints.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Kenichi Kuroda             2-3 2-3 Marunouchi, Chiyoda-ku, Tokyo             Inside Ryo Electric Co., Ltd. (72) Inventor Tetsuya Takami             2-3 2-3 Marunouchi, Chiyoda-ku, Tokyo             Inside Ryo Electric Co., Ltd. (72) Inventor Kazuhisa Nishi             2-3 2-3 Marunouchi, Chiyoda-ku, Tokyo             Inside Ryo Electric Co., Ltd. (72) Inventor Yukihiko Wada             2-3 2-3 Marunouchi, Chiyoda-ku, Tokyo             Inside Ryo Electric Co., Ltd. F term (reference) 4M113 AA06 AA16 AA25 AD62 BA04                       BB07 BC07 BC15 CA34

Claims (2)

[Claims] 1. A c-axis oriented oxide superconducting film for a lower electrode is formed on a surface of a substrate, an interlayer insulating film is formed after patterning, and a part of the interlayer insulating film on the oxide superconducting film for a lower electrode is formed. Etching to form the perforated part of the interlayer insulating film,
After that, a method for manufacturing an oxide superconducting bonded substrate, in which a barrier layer thin film and a c-axis oriented oxide superconducting film for an upper electrode are formed to form a bonding portion on the substrate. 2. The surface of the lower electrode oxide superconducting film is etched when forming a hole in the interlayer insulating film,
The method for manufacturing an oxide superconducting junction substrate according to claim 1, wherein the thin film for a barrier layer is formed by heat treatment.