JPH0282585A - Superconducting wiring - Google Patents

Abstract

PURPOSE:To facilitate epitaxial growth of a high temperature superconducting film on an Si substrate by a method wherein, after a (Y2O3)x(ZrO2)1-x film (x<1) is builtup on the Si substrate by epitaxial growth, the high temperature superconducting film is builtup by epitaxial growth and formed into an electrode pattern. CONSTITUTION:A (Y2O3)x(ZrO2)1-x film (YSZ film) can be formed on an Si substrate by epitaxial growth performed by an electron beam evaporation method, a sol-gel method or the like. Moreover, a high temperature superconducting film can be builtup on the YSZ film by epitaxial growth. (x) of the (Y2O3)x(ZrO2)1-x YSZ film may be a value within a range of 0-1, more preferably 0-0.3. In order to form the electrode pattern, in the case of, for instance, SOI, the YSZ film is builtup on the Si substrate by epitaxial growth and an active device such as a transistor and the electrode pattern composed of the high temperature superconducting film can be formed on the YSZ film.

Description

[Detailed description of the invention] (Technical field) The present invention relates to superconducting wiring.

More specifically, the present invention relates to a superconducting wiring on a Si substrate useful for an ultra-LSI operating at liquid nitrogen temperature, a method for forming the same, and an ultra-LSI having the same.

(Background Art) In recent years, the development of Si[LSI] has been remarkable, and along with this, it has become increasingly difficult to form electrodes for highly densely integrated VLSIs. For example, MO prototyped with 16MDRAM
The design rule for S is 0.5 μm, and there is a trend toward further miniaturization in the future, and electrode patterns are also becoming significantly finer.

This trend has led to the problem of electrode resistance, and as the electrode pattern becomes thinner, this resistance increases, causing a drop in applied voltage and a delay in signal propagation speed, which has become a major problem. There is. Therefore, reducing the resistance of electrode materials has become an important technical issue.

On the other hand, as a huge number of semiconductors are integrated into a single chip, heat dissipation has become an important factor in determining the operating speed of VLSIs. Furthermore, due to the inherent mobility of Si materials, the operating speed of MOS or bipolar transistors has reached its limit at room temperature, and even though studies are underway on Si ultra-LSIs that can operate at liquid nitrogen temperatures of 77 degrees, including cooling effects. There is. In fact, St of liquid nitrogen temperature operation
-The operating speed (gate delay time) of a MOS transistor can be increased by about 10 @ compared to room temperature, and it is attracting attention as one of the next generation ultra-high speed LSIs.

However, the problem is that an electrode material that is stable and has low resistance at a liquid nitrogen temperature of 77°C has not been found, yet the technology for actually manufacturing it has not been established.

There are superconducting materials that have been attracting attention in recent years as a solution to these problems.

Bat-y yF CuO7-a, B i 5rCa
High-temperature superconductors such as CuO1TISrCaCuO have a critical temperature at which electrical resistance becomes zero, as high as 100 to 125°C, and some have been developed that have a sufficient margin for use at liquid nitrogen temperatures of 77°C.

However, in these superconducting materials, even if a thin film is not formed on a Si substrate, Sl diffuses into the superconducting film,
The major defect was that it did not exhibit superconductivity. For example, as a method for forming a high-temperature superconducting film on a Si substrate, S
3102 or P in the barrier layer to suppress the diffusion of l.
Although interposition of tM has been considered, the reality is that sufficient characteristics of a high-temperature superconducting film have not yet been obtained.

Furthermore, although it has been discovered that epitaxial growth is essential for achieving good superconductivity and characteristics, the technology for actually epitaxially growing a single crystal has not yet been established.

(Purpose of the Invention) This invention was made in view of the above-mentioned circumstances, and provides a new superconducting wiring and its superconducting wiring that makes it possible to epitaxially grow a conductive film on a Si substrate at a high temperature, which was previously impossible. The purpose of the present invention is to provide a fabrication method, and furthermore, to provide an r4LSI having this wiring and operating at liquid nitrogen temperature.

(Disclosure of the Invention) To achieve the above object, the present invention provides a super LSI that operates at liquid nitrogen temperature.
20s), (ZrO2), -3 film (x<1>) is epitaxially grown, then a high temperature superconducting film is epitaxially grown and processed into an electrode pattern shape, or a superconducting wiring that operates at liquid nitrogen temperature. In the VLSI, active elements of the LSI are formed on a Si substrate, and (Y20s) K (ZrOt) r-
t Jli (x<1) is grown epitaxially,
The present invention provides a superconducting wiring characterized by forming a hole in an electrode connection portion, then epitaxially growing a high-temperature superconducting film and processing it into a 4&pole pattern shape.

(Y20s)-(Zro, ), -3 film 1% (YSZI) on the Si substrate in this invention.
jI) can be formed by epitaxial growth using an electron beam evaporation method, a sol-gel method, or the like. Furthermore, it is possible to epitaxially grow a high temperature superconducting film on this YSZp.

The Y of (Y20s) x (Z r 02 ) t-* used here
For the B2 film, X can be set to a value of O to 1 or less, and particularly preferably, x=O to 0.3.

? liC [The method for forming one pattern is film v4
Depending on the structure, publicly known procedures can be adopted.

For example, in the case of Sol, a YB2 film can be epitaxially grown on a Sl substrate, and an electrode pattern made of active elements such as transistors and a high temperature superconducting film can be formed thereon.

In addition, when applied to normal VLSI, an epitaxially grown YB2 film is used as a glabella insulating film, and after drilling holes only in the electrode connection part, a high temperature superconducting film is epitaxially grown on top of it, and the electrode pattern shape is It is also possible to realize multilayer wiring that can be processed to

The high temperature superconductors used include Ba-YCu-0, B
1-8r-Ca-Cu-0, Tl5r-Ca-Cu-0
It can be set as appropriate.

In the following examples, the formation of a YB2 film and a high temperature superconducting film will be mainly explained. Of course, this invention is not limited in any way by the following examples.

Example 1 On a St substrate with <100) orientation, the substrate temperature s o
(Y2
0s ) x (Z r 02 ) YSZ in l-
llfi was grown for 100-200 rv.

Here, the crystallinity of the YB2 film was evaluated by varying X from 0 to 0.4. FIG. 1 shows the X-ray diffraction patterns of the obtained YSZM, respectively, for (a) x=0.04 and (b) x=0.09. In (a), the peak of orthorhombic system YSZ (200) plane appears strongly, but orthorhombic system YSZ (002) plane is slightly present. (b
), only the peak of the cubic YSz (200) plane is obscured.

Table 1 shows the lattice constant and S of the YSz film when X is changed.
It shows the mismatch rate with the lattice constant of the t-substrate. When X is in the range of 0 to 0.3, the lattice constant mismatch rate with the Si substrate is 1% or less.

This shows that YSZM with x=O~0.3 achieves good epitaxial growth.

Table 1 Lattice constant Mismatch rate factor 1-11 Process a 5. x -0.2 c 5.16 0.8 9 (cubic crystal) 5.13 0.220
()t) 5.16
0.830 ()t)
5.18 1.2 (Note) 5.43 (S i lattice constant) Xr "/1.5=5
．． 12 (A) Y2O, content rate - on uLX - 4 (orthorhombic) Example 2 In the same manner as in Example 1, (
Y20s) x (Z r O2) +−x x=
An O1 or ZrO2 film was epitaxially grown to a thickness of 100r+n+.

Next, using a target of Baz yc us 07-a, 0.0.
67~4, OPa pressure, substrate temperature 600~700℃
Sputtering was performed to form a high-temperature superconducting film.

Target size is 3 inches φ and rf power 15
0W and a film forming rate of 2 nl/n+in.

The thickness of the obtained superconducting film was 100 to 300 n1M. FIG. 2 shows the XR diffraction pattern of the obtained film. Only the peak of (OOJ) was observed. This results in an orthorhombic system B at with the C axis oriented perpendicular to the plane.
YCus 07-#! Epitaxial growth of IA can be confirmed.

FIG. 3 shows the critical temperature (Tc) characteristics of this superconducting film. At 88, the electrical resistance begins to decrease, and at 82
It showed good superconducting properties with completely zero electrical resistance.

Example 3 A superconducting film of B t 5rCaCuO is formed in the same manner as in Example 2, and a superconducting critical temperature characteristic of T c =98 to 80 is obtained.

Example 4 An epitaxial film with x = 0.05 was formed as the YSZ film of Example 1, and Ba2Y Cu was formed in the same manner as Example 2.
107-# Form a superconducting film.

Good characteristics can be obtained in the same manner.

Example 5 According to Example 1 or 2, a YSZ film is epitaxially grown on a Sl substrate, and thereon, operating elements such as transistors and electrode patterns made of high temperature superconducting films are formed.

As a result, flLsI of Sol structure is obtained.

[Brief explanation of the drawing]

FIG. 1 is a diffraction diagram showing an X-ray diffraction pattern of a YSZ film on a Sl (100) substrate in the present invention. FIG. 2 is a diffraction diagram showing an X-ray diffraction pattern of a B as YCu s 07-a film formed on S l <100)/Zr0t. FIG. 3 is a correlation diagram showing this critical temperature characteristic.

Claims (8)

[Claims] (1) In a VLSI that operates at liquid nitrogen temperature, Si
A (Y_2O_3)_x(ZrO_2)_1_-_x film (
A superconducting wiring characterized in that it is formed by epitaxially growing a high temperature superconducting film ( (2) A method for forming superconducting wiring comprising the method according to claim (1). (3) In VLSI operating at liquid nitrogen temperature, Si
Form an LSI active element on the substrate, (Y_2O_3)
A superconducting wiring characterized by epitaxially growing a _x(ZrO_2)_1_-_x film (x<1), drilling a hole in an electrode connection part, and then epitaxially growing a high temperature superconducting film and processing it into an electrode pattern shape. (4) A method for forming a superconducting interconnection comprising the method according to claim (3). (5) A VLSI operating at liquid nitrogen temperature having claim (1) or (3). (6) High temperature superconducting film is Ba-Y-Cu, Bi-Sr-C
Claims (1), (2), (3), (4) or (5) which are a-Cu or Ti-Sr-Ca-Cu based oxides.
), the superconducting wiring, the method for forming the same, or the super LSI. (7) (Y_2O_3)_x(ZrO_2)_1_-_x film (
A laminate formed by epitaxially growing X<1). (8) A multilayer film obtained by epitaxially growing a high temperature superconducting film on the (Y_2O_3)_x(ZrO_2)_1_-_x film of the laminate according to claim (7).