JPH02200774A - Production of sputtering target for forming superconducting ceramic film - Google Patents

Abstract

PURPOSE:To produce the target for forming a film excellent in superconductivity by mixing Ba carbonate powder and an excess of Cu oxide powder over the specified amt. to be mixed, calcining the mixture under specified conditions, crushing the calcined material and hot-pressing the crushed material. CONSTITUTION:The Ba carbonate powder and Cu oxide powder or the Sr carbonate powder, Ca carbonate powder, and Cu oxide powder or the Ba carbonate powder, Ca carbonate powder and Cu oxide powder are mixed. In this case, an excess of the Cu oxide powder over the carbonate powder by 0.1-10wt.% with respect to the equimolar ratio is added. The obtained mixture is held at 750-980 deg.C for 8-40hr, and calcined. Consequently, the multicomponent oxide of Ba, etc., and Cu free of residual carbonate ion is obtained. The oxide is crushed, and the powder is hot-pressed to obtain a sputtering target. By using this target, a superconducting ceramic film free of C as the impurities and excellent in superconductivity is obtained.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for manufacturing a sputtering target for forming a superconducting ceramic film, and more specifically, a method for manufacturing a sputtering target for forming a superconducting ceramic film on a substrate surface. The present invention relates to a method for manufacturing a target for use.

[Conventional technology]

In recent years, attempts have been made to form a superconducting ceramic film on a substrate surface using a multi-source sputtering method.

At present, Y-B2 is the superconducting ceramic mentioned above.
-Cu -0-based superconducting ceramics, BI Sr Ca
CU-O superconducting ceramics, and Tl-Ba,
-Ca-Cu-0 system superconducting ceramics are generally known, and methods for forming these superconducting ceramic films on the substrate surface by multi-dimensional sputtering include: (1) metal CU target, Y2O3 target;
and a target made of a complex oxide of Ba and Cu,
These targets are transferred to a ternary sputtering device.
(2) A metal Cu target,
A target made of metal B1 and a target made of a composite oxide of Sr, Ca, and Cu are prepared, these targets are simultaneously charged and set in a ternary sputtering apparatus, and sputtering is performed to form B1Sr -Ca on the substrate surface.
-Cu -0 system superconducting ceramic film forming method, (3) metallic Cu target, and Ba, Ca, and Cu
Prepare composite oxide targets, set these targets in a binary sputtering device at 161 o'clock,
Perform sputtering and apply T to the thin film after sputtering.
A method is known in which a TJ-Ba-Ca-Cu-0 based superconducting ceramic film is formed on a substrate surface by annealing in an atmosphere containing β vapor.

In order to produce the target made of a composite oxide of Ba and Cu, first, Ba carbonate powder and Cu oxide powder each having an average particle size of 101 F or more are prepared.

These powders were mixed into Ba carbonate powder:Cu oxide powder-1.
1 (mol It) 5, using a ball mill with hexane as a solvent for 4 to 6 hours, average particle size: 2 to 5.
The mixture is mixed and pulverized 12 times until it reaches 3 Bra, dried, and then fired and pulverized at a temperature of 750 to 980° C. and held for 10 to 15 hours. The above-mentioned pulverization is carried out by first crushing in a mortar and then finely pulverizing in a ball mill. 1-
The calcination and pulverization were repeated 5 times in step 4, and further dried to produce a composite oxide powder of Ba and C[j] with an average particle size of 4 to 5 m.

The above composite oxide powder of Ba and Cu has a temperature of 750 to 8
50℃, press pressure: 100-300kg/cd, 2
A target made of a composite oxide of Ba and Cu is formed by vacuum hot pressing under conditions of holding for ~5 hours.

The method for producing a target made of a composite oxide of IBa and [:l] has been described in detail below, but in order to produce the target made of a composite oxide of Sr, Ca, and Cu, Sr carbonate powder, C
Prepare a carbonate powder and C11 oxide powder, and mix these powders with Sr carbonate powder: Ca, carbonate powder: CIJ
Oxide powder-1: To prepare the Ba, Ca, and Cu composite oxide target, mix Ba carbonate powder, Ca, carbonate powder, and Prepare Cu oxide powder, and mix these powders into Ba carbonate powder: Ca carbonate powder: Cu oxide powder in a ratio of 1:2 (
These blended powders were mixed in the same manner as in the manufacturing method of the Ba and Cu composite oxide target described above in step 17 to prepare a target made of a composite oxide of Sr, Ca, and Cu. A target made of a composite oxide of Ca and Cu was manufactured.

Hereinafter, what is the "predetermined blending amount" of the raw material powder necessary to produce a composite oxide of Ba and Cu, a composite oxide of Sr, Ca, and Cu, and a composite oxide of Ba, Ca, and Cu, respectively? , Ba carbonate powder: Cu oxide powder -1=1 (molar ratio)
, Sr carbonate powder + Ca carbonate powder: Cu oxide powder-1
81,: 2 (molar ratio), Ba carbonate powder: Ca carbonate powder: Cu oxide powder-1
,: 1:2 (molar ratio).

[Problem to be solved by the invention]

The above Ba and Cu composite oxide target, Sr and Ca
and Cu composite oxide target, and B, a and Ca
Both targets made of composite oxides of Cu and Cu use carbonate powder as the raw material powder, but the carbonate ions (Co') of this carbonate remain unreacted as carbonate even after the firing and pot pressing process. When a superconducting ceramic film is formed on a substrate surface by a multi-source sputtering method using a composite oxide target containing carbonate ions (Co3) remaining in the composite oxide target, impurities are added to the formed superconducting ceramic film. As a result, C is mixed in, and the superconducting ceramic film containing C has a problem in that its superconducting properties are significantly deteriorated.

[Means to solve the problem]

Therefore, the present inventors conducted research to solve this problem, and found that a mixed powder containing an excess amount of Cu oxide powder with respect to a prescribed carbonate powder was used as a raw material powder, and was then fired and pulverized. The composite oxide powder obtained by this method has extremely little residual C as an impurity, and the C content of the target obtained by hot pressing this composite oxide powder with extremely low residual C is also extremely low. Therefore, the C content of the superconducting ceramic film formed on the substrate by the multi-source sputtering method using a complex oxide target/nod with an extremely low C content is also extremely low, which deteriorates the superconducting properties of the superconducting ceramic film. We have learned that there is no need to do so.

The present invention was made based on this knowledge, and involves baking a mixed powder in which Cu oxide powder is added to carbonate powder in an amount of 0.1 to 10% by weight in excess of a predetermined amount. The present invention is characterized by a method for manufacturing a sputtering target for forming a superconducting ceramic film, in which a composite oxide powder obtained by grinding and pulverizing is pressed.

The above Cu oxide powder is added in an amount of 0°1 to 1
．． The reason for blending the Cu oxide powder in excess of 0ffl% is that if the Cu oxide powder is added in an excess amount of less than 0.1% by weight than the predetermined blending amount, the amount of C remaining in the composite oxide powder will not decrease;
Excessive blending exceeding 10% by weight is also undesirable because segregation will occur. Therefore, the excess amount of Cu oxide powder was set at 0.1 to 10% by weight.

The firing temperature of the mixed powder of Cu oxide powder with an excess of 1 to 10% by weight and a predetermined amount of carbonate powder is 750 to 98% by weight.
Preferably, the temperature is within the range of 0°C. The above firing temperature is 7
If the temperature is less than 50°C, calcination will hardly proceed due to the low temperature, and carbonate will remain, which is undesirable.
If the temperature exceeds 980°C, the fired body will partially melt, which is not preferable.

〔Example〕

First, the present invention will be specifically explained based on examples.

Example 1 As raw material powder, barium carbonate (hereinafter referred to as B a COa) powder with an average particle size of 5 μs and an average particle size of 3t
Cupric oxide (hereinafter referred to as CuO) of I3 was prepared, and each of these powders was weighed using a ball mill so that the composition had an excess of CuO than the predetermined blending amount shown in Table 1. n~6 each using hexane as a solvent
(The proportion of excess CuO contained in the mixed powder is also shown in Table 1). After drying these mixed powders, they were placed in an aluminum baking dish and were primarily fired in a Matsufuru furnace in an air atmosphere at the firing temperature and firing time shown in Table 1. The temperature increase rate at this time is 150℃
/ hour, and the temperature was lowered by furnace cooling. This fired body was crushed in an agate mortar, further crushed in a wet ball mill for 6 hours, dried, and then secondary fired again in a Matsufuru furnace at the firing temperature and firing time shown in Table 1. This secondary fired body was crushed again in an agate mortar, crushed in a wet ball mill for 8 hours, dried and subjected to f5.
(denoted as O2) powder.

In this way, the B a Cu O2 powder obtained by
A vacuum pot press was performed at a temperature of 850° C. for 4 hours to obtain a hot pressed body having a diameter of 50×thickness of 0.7e+n. After processing this, the present invention target 1 in Table 1 is obtained.
-15, comparative targets 1 to 12 and conventional target 1 were produced. These targera!・The analysis sample cut out from the inside after removing the surface layer was analyzed by high-frequency furnace combustion infrared absorption method 1.7, and the C content was measured, and the results were used in the first
Shown in the table.

Next, the above-mentioned targets 1 to 5 of the present invention, comparative targets 1 to 2, and conventional target 1 were each made of metal Cu.
A target made of Y2O3 and a target made of Y2O3 were charged and set in a Mimoto sputtering apparatus, and sputtering was performed under the following conditions.

The total pressure of the atmosphere is 10' to 10 Torr, the atmosphere is Ar or 02 containing 5 to 5096, and the power supplied to Ar1 is 100 to 800 W.

Substrate material: MgO single crystal with a planar dimension of 300 mm, substrate heating: 050'C or no heating, substrate-target distance iv: 50 to 130 mm.

The Y-Ba-6-O thread hora ceramics 4 film formed on the substrate surface under the conditions listed below was heated twice in the air at 910°C.
, annealing treatment was performed for 1 hour, and the critical temperature Te ('K) was measured in this state by a four-terminal method, and the results are also shown in Table 1.

From the results in Table 1, it can be seen that the amount of CuO powder
The target prepared by hot pressing the BaCuO2 powder obtained by blending 1 to 10% excess of . It can be seen that the critical temperature of the Y Ba-Cu-O thread conductive ceramic film formed using this target does not decrease.

Example 2 As raw material powders, strontium carbonate (hereinafter referred to as S r COa) powder, calcium carbonate (hereinafter referred to as Ca COa) powder, and C
UO powder was prepared, and these powders were blended so as to have a composition with an excess of Cu and O compared to the predetermined blending amounts shown in Table 2.Using a ball mill, using special grade n-hexane as a solvent, (The proportion of excess CuQ contained in the mixed powder is also shown in Table 1). After drying these mixed powders, place them in an alumina baking dish.
．． Primary firing was performed in a Matsufuru furnace in a general atmosphere at the firing temperature and firing time shown in Table 2. The temperature increase rate and temperature decrease rate at this time were exactly the same as in Example 1.

The primary fired body thus obtained was crushed in an agate mortar, further crushed in a wet ball mill for 6 hours, dried, and fired again in a Matsufuru furnace under the secondary firing conditions shown in Table 2. did. This secondary fired body is crushed again in an agate mortar, crushed in a wet ball mill for 8 hours, and dried. The resulting product is a composite oxide of Sr, Ca, and Cu (hereinafter referred to as S
r Ca Cu 204) powder.

Thus obtained S r Ca CLJ 204
The powder was vacuum pot-pressed at a temperature of 850° C. for 4 hours to obtain a hot-pressed body having a diameter of 5 em and a thickness of 0.7 c+n. This was processed to produce targets 16 to 30 of the present invention, comparative targets 3 to 4, and conventional target 2 shown in Table 2. Analytical samples cut from the inside of these targets with their surfaces removed were analyzed by high-frequency furnace combustion infrared absorption method to measure the carbon content (km), and the results are shown in Table 2.

Next, the above-mentioned targets 16 to 30 of the present invention. Comparison targets 3 to 4 and conventional target 2 were charged and set in a ternary sputtering apparatus together with a metal Cu target and a metal Bi target, respectively, and sputtering was performed under exactly the same sputtering conditions as in Example 1. and the formed B1. -3r -Ca -
A Cu-0 based superconducting ceramic film was deposited in the atmosphere at a temperature of
The material was annealed at 850° C. for 30 hours, and the critical temperature Te ('K) was measured in this state by a four-probe method. The results are shown in Table 2.

Example 3 As raw material powder, B a C with average particle size: 54, respectively
OCa CO3 and CuO powders were prepared, and these powders were blended so as to have a composition with an excess of CuO than the predetermined blending amounts shown in Table 3, and special grade n-hexane was added using a ball mill. Each was mixed as a solvent for 6 hours (the proportion of excess CuO contained in the mixed powder is also shown in Table 1). After drying these mixed powders, they were primarily fired in an alumina firing chamber in a Matsufuru furnace in an atmospheric atmosphere under the conditions shown in Table 3. The temperature increase and temperature decrease rates at this time were exactly the same as in Example 1. The primary fired body thus obtained was crushed in an agate mortar, further crushed in a wet ball mill for 6 hours, dried, and secondary fired again in a Matsufuru furnace under the conditions shown in Table 3. This secondary fired body was crushed again in an agate mortar, crushed in a wet ball mill for 8 hours, and dried. The resulting product was a complex oxide of Ba, Ca, and Cu (hereinafter referred to as
It was powder (denoted as BaCaCu204).

The thus obtained BaCaCu204 powder was vacuum hot-pressed at a temperature of 850°C for 4 hours to obtain a hot-pressed body with a diameter of 5c+n and a thickness of 0.7J. Target 31 of the present invention in Table 3
~45, comparative targets 5-6 and conventional target 3
was created. Analytical samples cut from the inside of these targets with their surfaces removed were analyzed by high-frequency furnace combustion infrared absorption method to measure the C content, and the results are shown in Table 3.

Next, the above-mentioned targets 31 to 45 of the present invention, comparative targets 3 to 4, and conventional target 3 were respectively charged and set together with a metal Cu target into a binary sputtering apparatus, and sputtering was performed under exactly the same conditions as in Example 1. Sputtering was carried out under the following conditions, and the sputtered thin film was heated to 2840℃ in an atmosphere containing TΩ vapor.
℃ and held for 50 hours, and in this state, the critical temperature '1' e ('K) was measured by the four-probe method,
These results are shown in Table 3.

〔Effect of the invention〕

From the results shown in Tables 1 to 3, targets 1 to 45 of the present invention containing CuO in excess of 0.1 to 10% by weight over the predetermined amount were all compared to conventional targets 1 to 3 containing a predetermined fXtcuo content. The C content is lower than that of the target, and therefore, the superconducting ceramic film formed using this target also has excellent superconducting properties. In addition, as seen in Comparative Targets 1 to 6), if the excess CuO content falls outside the range of this invention, the resulting target's C
It can be seen that if the content does not decrease and, on the other hand, the content deviates to the high side, partial melting occurs and a target cannot be formed.

Furthermore, by blending an appropriate amount of excess CuO, it acts as a binder between the composite oxide particles, and therefore a target with excellent strength can be obtained, and there are also effects such as ease of handling.

Claims (1)

[Claims] (1) Mixed powder obtained by blending and mixing Ba carbonate powder and Cu oxide powder, temperature: 750-980°C, 8-980°C.
By firing under conditions of holding for 40 hours to form a composite oxide of Ba and Cu, and then pulverizing the composite oxide of Ba and Cu and hot pressing the resulting composite oxide powder of Ba and Cu. A method for manufacturing a sputtering target made of a composite oxide of Ba and Cu, characterized in that the Cu oxide powder is added in an amount of 0.1 to 10% by weight in excess of a predetermined blending amount. Target manufacturing method. (2) Mixed powder obtained by blending and mixing Sr carbonate powder, Ca carbonate powder, and Cu oxide powder at a temperature of 7
S is fired under the conditions of 50-980℃ and held for 8-40 hours.
A composite oxide of r, Ca, and Cu is formed, and then this Sr
and Sr and C obtained by pulverizing a composite oxide of Ca and Cu.
In a method for manufacturing a sputtering target made of a composite oxide of Sr, Ca, and Cu by hot pressing a composite oxide powder of a and Cu, the amount of the Cu oxide powder is 0.1 to 10 A method for producing a sputtering target for forming a superconducting ceramic film, characterized by adding an excess amount by weight. (3) Mixed powder obtained by blending and mixing Ba carbonate powder, Ca carbonate powder, and Cu oxide powder at a temperature of 7
B is baked under the conditions of 50-980℃ and held for 8-40 hours.
A, a complex oxide of Ca and Cu is formed, and then this Ba
Ba and C obtained by pulverizing a composite oxide of Ca and Cu
In a method for manufacturing a sputtering target made of a composite oxide of Sr, Ca, and Cu by hot pressing a composite oxide powder of a and Cu, the amount of the Cu oxide powder is 0.1 to 10 A method for producing a sputtering target for forming a superconducting ceramic film, characterized by adding an excess amount by weight.