JPH01202875A - Manufacture of superconductive material structure - 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] [Table of contents] Overview Industrial field of application Conventional technology Problems to be solved by the invention Means for solving the problems Example (1) First embodiment of the present invention (First embodiment) .2) (2) Second embodiment of the present invention (Figure 3) Effects of the invention [Summary] A method for manufacturing a ceramic-based superconducting material structure, in which a plurality of ceramic-based superconducting material layers and a The purpose of the present invention is to provide a method for manufacturing a superconducting material structure having excellent superconducting properties by suppressing interaction with a substance or a substrate. A method of manufacturing a superconducting material structure by interposing a layer includes the steps of: forming a first ceramic-based superconducting material layer having compositional components capable of becoming a superconductor; and adding oxygen to the first superconducting material layer. A step of introducing ions or fluorine ions, and interposing an intermediate layer made of a material other than a ceramic-based oxide superconducting material on the first superconducting material layer to introduce compositional components that can become a superconductor. forming a second ceramic-based superconducting material layer having;
and a step of introducing oxygen ions or fluorine ions into the second superconducting material layer.

[Industrial application field]

The present invention relates to a method for manufacturing a superconducting material structure, and more particularly to a method for manufacturing a multilayer superconducting material structure in which an intermediate layer is interposed between a plurality of ceramic-based superconducting material layers.

In recent years, the speed of computers has increased dramatically, and approaches to increase speed include multiplication of processors, improvement of switching speed of devices, and shortening of wiring distances by packaging these devices at high density.

In order to achieve high-density wiring, it is necessary to create circuits with fine wiring patterns, and while this miniaturization reduces the cross-sectional area of the conductor used for wiring, it also increases the electrical resistance of the wiring. do. As a result, the propagating electrical signal decreases and the waveform becomes distorted.

Therefore, if superconducting materials can be used as wiring materials in place of normal conductors such as copper, these problems will be greatly improved. Furthermore, if Josephson elements are constructed using superconducting materials and integrated, ultra-high-speed computer systems can be realized by utilizing high speed, low power consumption, and micro-mounting component technology.

Conventional superconductors have a low transition temperature to the superconducting state, requiring the use of liquid helium or liquid hydrogen for cooling. However, since these cooling media are difficult to handle and costly, it has been difficult to realize superconducting wiring materials.

However, in recent years, so-called high-temperature superconductors typified by Y-Ba-Cu-0 ceramics have appeared, and the possibilities for practical application of superconducting wiring are greatly expanding.

[Conventional technology]

Ceramic oxide high-temperature superconductors become superconductive at relatively high temperatures above the boiling point of liquid nitrogen (77°K), so they can be used in semiconductor devices such as ICs, parts of various devices,
It has a wide range of applications, such as wiring inside equipment, and the demands are large. In order to meet these demands, it is necessary to efficiently form thin films of good quality. For example, the constituent elements of semiconductors and integrated circuits, including Josephson junctions, have the characteristic of being all-thin-film integrated circuits consisting of thin-film elements. For this reason, the properties, uniformity, and reproducibility of thin films based on crystallinity such as crystal grain size and orientation of thin films are important in determining the yield of devices and ultimately of superconducting integrated circuits.
This is an important factor in reliability.

In order to apply ceramic-based high-temperature superconducting materials to packaging interconnects, it is first necessary to establish thin film technology, which also requires that the film can be formed at the lowest possible process temperature. Considering that the current density will also be miniaturized, it is necessary to have a current density of 10 hA/cIa or more.

Conventional methods for forming thin films of ceramic superconducting materials mainly include sputtering, EB evaporation, and the like. In the sputtering method, a target with a similar composition is used as a material for growth, and this is vaporized by ion sputtering and grown on a substrate. Furthermore, in the EB evaporation method, a substance (evaporation source) for forming a thin film is evaporated using an EB gun and deposited on a substrate.

[Problem to be solved by the invention]

However, in this conventional method of forming a ceramic superconducting material layer, high temperature and long-term heat treatment is required to control the oxygen composition of the superconducting material layer. There have been various problems, such as the interaction between substances (metal materials, semi-quadram materials, insulator materials, etc.) and ceramic materials, which blurs the interface and deteriorates superconducting properties.

Next, this problem will be explained in detail.

A typical example of the ceramic material layer that can serve as the above-mentioned high-temperature superconductor is one having a composition of, for example, Y13a2Cu, 0-r-x. This ceramic material layer does not exhibit superconductivity in the as-grown state, or the temperature at which it exhibits superconductivity is the boiling point of liquid nitrogen (7
The temperature is considerably lower than 7° K), and such super-low-temperature characteristics strongly depend on the oxygen composition ratio of the ceramic material layer. That is, 0. As is clear from -X, the proportion of oxygen is slightly less than 7 (for example, usually Oa, a), but unless enough oxygen enters, it will not become a high-temperature superconductor.

Therefore, in order to sufficiently increase the oxygen composition ratio, the grown ceramic material layer is placed in an oxygen atmosphere with a
Thermal diffusion was carried out for several hours at a temperature of 000 °C,
As a result, the temperature at which the four starting states can be achieved can be increased to 77° or more, and the superconducting current can be significantly increased.

However, as heat treatment is performed multiple times at high temperatures and for long periods of time, as mentioned above, the interface becomes blurred and the superconducting properties deteriorate, and in order to further reduce the deterioration of the properties, the type of interlayer material must be limited. (For example, metals and other low melting point substances cannot be used.) New problems arise.

Therefore, the present invention provides a method for manufacturing a multilayered ceramic-based super(left-door material structure) that suppresses the interaction between multiple superconducting material layers and a glabellar substance or a substrate and has excellent superconducting properties. It is intended to.

[Means to solve the problem]

In order to achieve the above object, the method for manufacturing a superconducting material structure according to the present invention includes a method for manufacturing a superconducting material structure by interposing an intermediate layer between at least two ceramic-based superconducting material layers. a step of forming a first ceramic-based superconducting material layer having a compositional component that can become a superconducting material; a step of introducing oxygen ions or fluorine ions into the first superconducting material layer; and a step of introducing the first superconducting material into the first superconducting material layer. forming a second ceramic-based superconducting material layer having compositional components capable of becoming a superconductor by interposing an intermediate layer made of a material other than the ceramic-based oxide superconducting material on the layer; , a step of introducing oxygen ions or fluorine ions into the second superconducting material layer.

[For production]

In the present invention, the first
After forming a ceramic superconducting material layer, oxygen ions or fluorine ions are introduced into this superconducting material layer, and an intermediate layer is interposed on top of the first superconducting material layer to form a superconductor. After forming the second ceramic-based superconducting material layer having the composition to be obtained, oxygen ions or fluorine ions are introduced into the superconducting material layer.

Therefore, the oxygen composition ratio in the superconducting material layer can be reliably increased, and the interaction between the superconducting material layer and the interlayer substance or substrate can be suppressed, even without oxygen diffusion through high-temperature and long-term heat treatment. Ru.

〔Example〕

Hereinafter, the present invention will be explained based on the drawings.

Figure 1.2 is a diagram showing a first embodiment of the method for manufacturing a superconducting material structure according to the present invention, and is an example in which the superconducting material structure of the present invention is manufactured on a substrate 1. .

FIG. 1 is a cross-sectional view showing the structure of a superconducting material, and in FIG. 1, 1 is a growth substrate. As the growth substrate l, for example, St, MgO, sapphire (Al203),
Spinel (MgO'A I203) or the like is used. The reason why such a material is used as the substrate 1 is that it does not contain magnetic impurities that are essential for realizing a superconducting integrated circuit made of thin film elements, and it is possible to obtain a substrate that is clean and has good flatness.

2 and 3 are ceramic-based superconducting material layers having the compositions YBa2 Cuz and 07-X, respectively, and an intermediate layer 4 is formed between the superconducting material layer 2 and the superconducting material layer 3. . The super-flattened '25+A material layer 2.3 is formed in the same manner. That is, first YB is placed on the substrate l.
A ceramic superconducting material layer 2 having a composition of az Cu307-X is formed by sputtering, EB evaporation, or CV.
The superconducting material layer 2 is formed by method D at a temperature of 300 to 1 Ooo'c, and then oxygen ions or oxygen ions and fluorine ions are introduced into this superconducting material layer 2 by, for example, an ion implantation method. As a result, the entry of oxygen is appropriately adjusted, and the superconducting material layer 2 becomes a high-temperature superconductor. After that, the superconducting material layer 2 is coated by sputtering, EB evaporation, or CVD.
The intermediate layer 4 is formed by a method at a temperature of 300-1000°C. Next, a superconducting material layer 3 is formed on the intermediate layer 4 using a process similar to that for forming the superconducting material layer 2, and then oxygen ions or fluorine ions are implanted.

Such a structure can be manufactured by any of the sputtering method, EB evaporation method, and CVD method, but the applicant has previously developed the CVD method, which provides a thin film with the best characteristics. An example of forming a superconducting material layer by this method will be explained with reference to FIG.

FIG. 2 is a schematic diagram of an apparatus (CVD apparatus) for carrying out chemical vapor deposition (CVD). In Figure 2,
11 is a cylindrical heat-resistant reaction tube made of quartz. There are four resistance heating furnaces 12a to 12 around the reaction tube 11.
d, and the resistance heating furnaces 12a to 12d generate heat by applying current to heat each part of the reaction tube 11. On the other hand, a source chamber 13 is provided inside the reaction tube 11, and three source ports 14a to 14c are arranged within the source chamber 13. Source po eye 4a = 1
4c has B a Cl z + Y Cls, respectively.
+ Cu Cl is contained, source port 143 ~
14C is BaCl and gas respectively when heated by the resistance heating furnaces 12a to 12d.

Generate YCl3 gas and CuCl gas. That is,
In this embodiment, since Y 2 and B a '-Cu are used as materials for the ceramic-based oxide high-temperature superconductor, these are gasified.

A small-diameter gas introduction part 13 is provided at one end of the source chamber 13.
A is provided, and a carrier gas H is supplied from the gas introduction part 13a.
In addition to e, CO□ and H2 are introduced as necessary. The other end of the source chamber 13 is open, and a substrate support 15 is placed on the side thereof at a predetermined distance. The substrate support 15 is made of heat-resistant graphite, quartz, or the like, and the growth substrate 1 is placed on its upper surface. on the other hand,
Similarly, a small diameter gas inlet 11a is provided at one end of the reaction tube 11.
is provided, and an exhaust port 11b is provided at the other end. The exhaust port 11b is connected to a vacuum pump (not shown) to exhaust the gas in the reaction tube 11.

In the above configuration, first, YBa, C and
The process of forming the ceramic-based oxide superconducting material layer 2 having the composition u=O, , l will be described.

The growth substrate 1 is placed on the substrate support 15, and the source ports 143 to 14c are filled with BaCl,...
Add YCl, CuC1. Next, the reaction tube 11 is heated by the resistance heating furnaces 12a-12d, and BaC1z gas, YC1, YC1, and
A gas, CuC1 gas, is generated, and a carrier gas He is introduced from the gas introduction section 13a, and the generated gas is sent onto the growth substrate l.

Further, a carrier gas He is introduced through the gas inlet 11a, and cot 2 and H2 are introduced, and these gases are sent through the outside of the source chamber 13 onto the growth substrate l. At this time, the growth substrate 1 is also heated by the resistance heating furnace 12a. As a result, an oxidation/reduction reaction occurs on the growth substrate 1 or around the growth substrate 1, and a chemical reaction shown by the formula (■) occurs on the growth substrate 1, resulting in YBaz Cu30? A thin film of high temperature superconductor -X is grown.

Y Cl 3 + 2 B a Cl z + 3 C
u C1+7CO□+58゜YB at, Cus 07-X + 7 Co +1
0HC1...■ The above growth conditions were performed within the following range.

Growth substrate temperature (Tsus)...850-120
0℃BaC1, temperature (TB,)...800~1
150℃YCl3 temperature (Ty) - 700
~1150℃CuC1 temperature (Tcu)・・・・・・・・・
・350~1100℃ coz? ffi degree (vs. He)...
......0. OI~10%HzfQ degree (vs. He)
・・・・・・・・・0.01~20% growth substrate・
...(100) S i , (100) M
g 0 (1102) Sapphire (At□03) (100
) Spinel (M g O-A 1 zOl) Growth film thickness: 0.2 to 5 μm Next, the substrate 1 is taken out from the CVD apparatus, and the superconducting material layer 2 formed on the substrate 1 is coated with the superconducting material layer 2 shown in FIG. Ion implantation of 016° is performed from the direction indicated by the middle arrow I. In the ion implantation, for example, oxygen atoms are ionized in a vacuum using a predetermined ion implantation device, accelerated by an electric field, and implanted into the superconducting material layer 2. At this time, the number of implanted oxygen atoms per unit area (dose amount) is 10'5-10''Cl11-'', and the voltage used for acceleration (acceleration voltage) is 50 to 400 Kev. As a result, even if there are unreacted metal atoms in the superconducting material layer 2, the metal atoms are actively oxidized by ion implantation, and the oxygen composition ratio becomes appropriate to exhibit superconducting characteristics.

Next, the substrate 1 on which the superconducting material layer 2 has been formed is transferred to the CVD apparatus shown in FIG. An intermediate layer 4 is formed on 2 by the CVD method. Furthermore, a superconducting material layer 3 is formed on this intermediate layer 4 in the same apparatus as the superconducting material layer 2, and the superconducting material layer 3 is formed under the same conditions as the superconducting material layer 2. Inject oxygen ions into the

In this way, a superconducting material structure is obtained in which the intermediate layer 4 is interposed between the two superconducting material layers 2.3 formed on the substrate 1.

Next, the effects of the superconducting material structure obtained by the above method will be discussed.

(I) In this example, the oxygen composition ratio of the superconducting material layer is increased by ion implantation at a low temperature without performing high temperature and long-term heat treatment. In this case, unlike doping by thermal diffusion, ion implantation is a technique that utilizes a physical process that does not undergo a thermal equilibrium state, and therefore has the following excellent advantages.

That is, first, the amount and depth of oxygen atoms can be precisely controlled. In ion implantation, the number of ions to be implanted into the superconducting material layer 2 can be measured while being implanted, so the accuracy of the implantation amount is extremely high. Furthermore, since ion implantation can be performed at room temperature, high-temperature heat treatment is not required. Therefore, by such ion implantation, a sufficient amount of oxygen enters the superconducting material layer 2, and the temperature at which the superconducting state becomes at least 77 degrees can be raised to at least 77 degrees, and this superconducting property can be made stable. It is possible to significantly increase the superconducting current.

(I[) Also, since there is no high-temperature, long-term heat treatment, the core interlayer material and the superconductor in the case where the circuit is multilayered by interposing the interlayer material mentioned above between the crystal of the substrate 1 and the superconducting materials N2 and 3. No interaction occurs with the conductive material layers 2 and 3, and these interfaces remain unblurred and clear, thus avoiding deterioration of the superconducting properties. Furthermore, the type of glabellar substance is not limited for the above reasons. Therefore, a low melting point substance such as a metal material can be selected as the interlayer substance, and superconducting materials and circuit elements configured by bonding with various substances can be easily realized.

1st tip darkness FIG. 3 is a diagram showing a second embodiment of the present invention.

In the first embodiment, an example was explained in which oxygen was introduced into the entire surface of the grown superconducting material layer by ion implantation, but in the second embodiment, oxygen was grown on the substrate 1 as shown in FIG. The superconducting material layer 22 is covered with a photoresist film 5 (
Region 2 covered and patterned using ion-implanted protective film)
Oxygen ions are implanted only into 2a under the same conditions as in the first embodiment. Therefore, only the region 22a becomes a high temperature superconductor. In this second embodiment as well, the same effects as in the first embodiment can be obtained, and the superconducting material layer 22 corresponding to the circuit pattern can be selectively formed only in necessary parts, facilitating device fabrication. can be done.

In addition, in the above example, an example of manufacturing a superconducting material structure by the CVD method was explained in detail, but such a superconducting material structure can also be manufactured by the above-mentioned sputtering method or E 73 Q deposition method, and this detailed example is omitted.

Furthermore, in each of the above embodiments, the case where only oxygen was used as an ion source in the ion implantation method was explained, but fluorine may be mixed with oxygen and used as an ion source, and fluorine has a high bonding energy with metal atoms. Because of the strong ion implantation, the effect of ion implantation is greater than that of oxygen alone.

Furthermore, in the above embodiment, an example was explained in which the number of superconducting material layers is two, but this is not limiting, and even if there are three, four, or more layers, the necessary portion between each layer can be adapted to the purpose. A similar effect can be obtained by interposing the intermediate layer 4.

Further, although the above embodiment is an example in which a superconducting material layer is formed on a substrate, the application of the present invention is not limited to this.

For example, a plurality of superconducting materials may be grown individually and the intermediate layer 4 may be interposed between them.

Furthermore, in the above embodiments, a case was explained in which a composition of YBaz Cus 07-X was used as the ceramic or Cu-based p superconducting material. Similar effects can be obtained using superconducting materials with other compositions, such as those in which Ba is replaced with other alkaline earth metals such as Sr, and those in which part of O is replaced with halogen. It will be done.

Next, an example of such a substitution is shown.

In the case of LnBaz Cu307-z (1,yIH lanthanum-based element), Ln is Nd (neodymium)
, Sm (samarium), Eu (europium), Gd
(gadolinium), Tb (terbium), Dy (dysprosium), Ho (holmium), Er (erbium)
, Tm (thulium), and Yb (interbium).

Furthermore, even if two or more of these oxides are grown as a mixture, a high-temperature superconductor can be obtained.

Note that chlorides, bromides, or iodides of these metals are used as the growth material.

Further, in the above embodiment, a case was explained in which aluminum (AI) was used as the interlayer material forming the intermediate layer 4, but such an interlayer material may be other than a ceramic-based oxide superconducting material. For example, C
u % A g SA Metal materials such as u, NiSi,
, Co51z, Mo5it.

Silicides such as WSi, CrSi2, FeSi, S
i, Ge, CaAs, GaAlAs5 Inp.

Semiconductor materials such as InAs, GaP, Sin, A 1
zO,, MgO, MgO・AlzOs, YzO
Examples include insulating materials such as l.

〔Effect of the invention〕

According to the present invention, after forming a first ceramic-based superconducting material layer having compositional components capable of becoming a superconductor, oxygen ions or fluorine ions are introduced into this superconducting material layer to form a first superconductor. With an intermediate layer interposed on the material layer,
After forming a second ceramic-based superconducting material layer having compositional components capable of becoming a superconductor, oxygen ions or fluorine ions are introduced into this superconducting material layer, which requires high-temperature and long-term heat treatment. Even without oxygen diffusion, the oxygen composition ratio in the superconducting material layer is reliably increased, the interaction between the superconducting material layer and the glabellar substance or the substrate is suppressed, and it has excellent superconducting properties. A superconducting material structure is obtained.

As a result, metal materials, semiconductor materials, silicides,
It is possible to introduce various glabellar materials made of insulating materials, etc., and it becomes possible to mix with semiconductor devices such as memory devices, logic devices, light receiving devices, light emitting devices, Josephson devices, and combine with superconducting wiring. .

[Brief explanation of the drawing]

Figure 1.2 is a diagram showing a first embodiment of the method for manufacturing a superconducting material structure according to the present invention, Figure 1 is a sectional view showing its configuration, and Figure 2 is a CVD process for carrying out the method. A schematic diagram of the apparatus, FIG. 3 is a sectional view showing the configuration of a second embodiment thereof. ■...Growth substrate, 2.3.22...Superconducting material layer, 4...
・Intermediate layer, 5... Photoresist film (ion implantation protective film),
22a...Patterned area. Patent Applicant: Fujitsu Limited, 1 Agent: Patent Attorney Sada Igeta ('5- Fig. 3 is a cross-sectional view showing the configuration of the second embodiment)

Claims (1)

[Claims] A method for manufacturing a superconducting material structure by interposing an intermediate layer between at least two ceramic-based superconducting material layers, comprising: a first ceramic having a composition that can become a superconductor; a step of forming a layer of a ceramic-based superconducting material; a step of introducing oxygen ions or fluorine ions into the first superconducting material layer; and forming a ceramic-based oxide superconducting material layer on the first superconducting material layer. By interposing an intermediate layer made of a material other than a conductive material,
It is characterized by comprising the steps of: forming a second ceramic-based superconducting material layer having a composition that can become a superconductor; and introducing oxygen ions or fluorine ions into the second superconducting material layer. A method for manufacturing a superconducting material structure.