JP7280075B2 - Sputtering target material, manufacturing method thereof, and thin film - Google Patents

Description

The present invention relates to a sputtering target material and its manufacturing method. The present invention also relates to a thin film formed by a sputtering method.

Materials obtained by doping lanthanum to strontium tin oxide are useful as oxide semiconductors and transparent conductors. Conventionally, oxide semiconductors and transparent conductors made of this material have been formed by a pulsed laser deposition (PLD) method. For example, Patent Document 1 describes that an SrSnO ₃ film containing 3 atomic % of La is deposited on a SrTiO ₃ substrate containing Nb by the PLD method. In this document, this film is used as a cathode of a photochemical electrode, and hydrogen gas is generated by using a nitrite electrolyte, a sulfurous acid electrolyte, or a carbonic acid electrolyte containing hydrogen ions as a raw material.

Non-Patent Document 1 describes the epitaxial growth of a La-doped SrSnO ₃ thin film by the PLD method. The document states that this thin film is transparent in the wavelength region from 390 nm to 1600 nm.

JP 2018-24913 A

Journal of Physics D: Applied Physics 48 (2015) 455106

Thus, La-doped _SrSnO3 thin films are useful materials in various fields. As described above, the PLD method was adopted for the production of this thin film. However, the PLD method is not industrially suitable in that it is unsuitable for manufacturing large-area thin films and that the film formation rate is low.

It is therefore an object of the present invention to provide materials suitable for the industrial production of La-doped SrSnO ₃ thin films.

As a result of intensive studies to solve the above-mentioned problems, the inventors of the present invention have focused on the fact that the sputtering method is suitable for large-area film formation and high-rate film formation. The invention has been completed. That is, the present invention comprises an oxide represented by Sr _1-x La _x SnO ₃ (where x represents a number of 0.0010 or more and 0.10 or less), has a perovskite structure, and has a bulk density of 6.00 g/ The above problem is solved by providing a sputtering target material having a weight of cm ³ or more and 6.50 g/cm ³ or less.

In addition, the present invention provides a suitable method for producing the sputtering target material,
Provided is a method for producing a sputtering target material, comprising the step of hot-pressing a temporary molded body containing a strontium source, a lanthanum source and a tin source while covering the surface of the temporary molded body with a foil made of tantalum. .

Further, the present invention provides a thin film made of an amorphous oxide containing strontium, lanthanum and tin, which can be crystallized by heating at 800° C. or higher.

According to the present invention, a sputtering target material in which generation of particles is suppressed is provided.

FIG. 1 is a graph showing the temperature dependence of the volume resistance of the sputtering target material obtained in each example. 2 is a scanning electron microscope image of the surface of a thin film produced using the target materials obtained in Comparative Examples 5 and 6. FIG.

The present invention will be described below based on its preferred embodiments. The sputtering target material of the present invention (hereinafter also simply referred to as “target material”) is composed of an oxide represented by Sr _1-x La _x SnO ₃ . The numerical range of x in the formula is 0.0010 or more and 0.10 or less. That is, the target material of the present invention contains strontium, tin, lanthanum and oxygen as main constituent elements. The target material of the present invention is mainly composed of strontium tin oxide and has a structure in which strontium is partially substituted with lanthanum. The amount of strontium replaced by lanthanum is represented by x. By adjusting the value of x within the above range, the properties of the thin film produced from the target material of the present invention can be controlled. Especially when the value of x is more than 0.020 and less than or equal to 0.10, the properties of thin films produced from the target material of the present invention are more desirable.

The amounts of strontium, tin and lanthanum contained in the target material of the present invention can be measured by, for example, an inductively coupled plasma atomic emission spectrometer. The amount of oxygen can be measured by, for example, an oxygen/nitrogen analyzer (PS3520UVDD manufactured by Hitachi High-Technologies Corporation).

It is preferable that the target material of the present invention contains each of the elements described above and does not contain other elements. However, as long as the effects of the present invention are not impaired, unintended inclusion of unavoidable impurities in the target material is not prevented.

The target material of the present invention has a perovskite structure. Due to this crystal structure, a thin film having desired properties can be produced by sputtering using the target material of the present invention. The crystal structure of the target material of the present invention can be confirmed by, for example, a powder X-ray diffraction method, a surface X-ray diffraction method, or the like.

By forming the target material from the oxide represented by Sr _1-x La _x SnO ₃ , it becomes possible to form the target thin film over a large area at a high deposition rate. As a result of investigations by the present inventors, it was found that a large amount of particles are generated when sputtering is performed using a target material composed of an oxide represented by Sr _1-x La _x SnO ₃ . As a result of various investigations by the inventors of the present invention on means for suppressing the generation of particles, it was found that the generation of particles can be suppressed by adjusting the density of the target material. Specifically, by setting the density of the target material to preferably 6.00 g/cm ³ or more and 6.50 g/cm ³ or less, generation of particles during sputtering is effectively suppressed. More specifically, since the target material becomes denser and the number of pores (holes) is reduced, discharge is stabilized during sputtering, and generation of particles due to arcing is suppressed. From the viewpoint of making this effect more remarkable, the density of the target material is more preferably 6.20 g/cm ³ or more and 6.50 g/cm 3 or less, and still more preferably 6.30 g/cm ^{3 or} more and 6.50 g/cm 3 or more. Set to ³ or less. In order to set the bulk density of the target material within this range, the target material may be manufactured, for example, by the method described later.

The density of the target material referred to in the present invention does not mean the density of the material itself constituting the target material, ie, the true density, but the bulk density of the target material. Bulk density is the density that takes into account the volume occupied by the solid, open pores, and internal voids. The bulk density is measured by the Archimedes method, and the bulk density (g/cm ³ ) is calculated by the following formula.
d ₁ =[(C ₁ )/(C ₂ −C ₃ )]×d ₂
d ₁ : bulk density (g/cm ³ ) C ₁ : dry weight (g) C ₂ : saturated water weight (g)
C ₃ : Weight in water (g) d ₂ : Density of water during test (g/cm ³ )
The true density of the oxide represented by Sr _1-x La _x SnO ₃ depends on the value of x, but theoretically ranges from 6.433 g/cm ³ to 6.437 g/cm ³ .

In relation to the bulk density, it is also preferable that the target material of the present invention has a low open porosity from the viewpoint of suppressing particle generation. Specifically, the target material of the present invention preferably has an open porosity of 2.00% or less, more preferably 0.50% or less, and even more preferably 0.25% or less. . The lower limit of the open porosity is not particularly limited, and is ideally 0%.

The open porosity (%) of the target material is measured by the Archimedes method and calculated by the following formula.
P = [( _C2 - _C1 )/( _C2 - _C3 )] x 100
P: open porosity (%) _C1 : dry weight (g) _C2 : saturated water weight (g)
C ₃ : weight in water (g)

The target material of the present invention preferably has high conductivity from the viewpoint of facilitating film formation during sputtering and increasing the film formation rate. It is also preferable from the viewpoint of enhancing the electrical conductivity of the manufactured thin film and exhibiting desired semiconductor characteristics. Specifically, the target material of the present invention preferably has a volume resistance of 40.0 Ω cm or less, more preferably 4.0 Ω cm or less, and 1.0 Ω cm or less. is more preferred. There is no lower limit to the value of volume resistance, and the lower the better. The volume resistivity of the target material is the value measured at room temperature, typically 27°C. To adjust the volume resistivity of the target, for example, the value of x in Sr _1−x La _x SnO ₃ may be adjusted within the above range. As the x value increases, that is, as the doping amount of lanthanum increases, the volume resistance tends to decrease. The volume resistivity of the target material was calculated from the following formula using HL5500PC (Hall effect measuring device) manufactured by Nanometrics Japan Co., Ltd.
ρ=(πt/ln2)(V _M /I _S )
ρ: Volume resistance (Ω cm)
t: sample thickness (cm)
V _M : voltage to be measured (V)
I _S : applied current (A)

The target material of the present invention preferably has the property that the volume resistivity decreases as the temperature rises. Materials that have the property that their volume resistivity decreases with increasing temperature generally exhibit semiconductor-like behavior. Obtainable. For example, when the volume resistance at a temperature of 27°C is 3.2Ω·cm, the volume resistance at a temperature of 227°C is preferably 1.4Ω·cm. In order to impart such properties to the target material, for example, the value of x in Sr _1-x La _x SnO ₃ may be adjusted.

The shape and dimensions of the target material of the present invention are not particularly limited, and conventional shapes and dimensions can be adopted. As for the shape, for example, a flat plate shape or a cylindrical shape can be adopted. When it is in the form of a flat plate, it can be in the form of a disc having a diameter of 10 mm or more, particularly 20 mm or more, especially 50 mm or more. Although there is no particular upper limit, the diameter is preferably 500 mm or less because a large press device or the like is required.

Next, a suitable method for producing the sputtering target material of the present invention will be described. The sputtering target material of the present invention has a step of hot-pressing a temporary compact containing a strontium source, a lanthanum source, and a tin source while covering the surface of the temporary compact with a foil made of tantalum. This manufacturing method will be described in detail below.

First, a strontium source, a lanthanum source and a tin source, which are raw material powders, are prepared. As a strontium source, for example, strontium carbonate or oxide can be used. If carbonate is used as a raw material here, carbon dioxide is generated in the sintering process, which will be described later, and this may cause cracks in the target material. Therefore, it is more desirable to use oxides than carbonates. On the other hand, since strontium oxides tend to react with water in the atmosphere to produce hydroxides, it is disadvantageous in that it requires careful attention to process control. Considering both, it is preferable to use strontium carbonate because of its high stability in the atmosphere.

Carbonates and oxides can also be used as lanthanum and tin sources. Since lanthanum and tin oxides are more stable in the atmosphere than strontium oxides, strict process control is not required. Therefore, there is no need to use carbonates, which may cause cracks in the target material, and oxides may be used.

The raw material powders described above are mixed so as to obtain the target composition of the target material, that is, Sr _1-x La _x SnO ₃ . For mixing, various mixing and stirring devices such as a ball mill can be used. When mixing using a ball mill, wet mixing is preferred. It is preferable to use an organic solvent such as ethanol as the liquid medium for wet mixing.

The mixed powder thus obtained is used to produce a temporary compact. In the present invention, the term "temporary compact" refers to a compact formed into a specific shape by applying only pressure to the mixed powder without heating. This molding method is called "temporary molding". The pressurizing force for the temporary molding is preferably 5 MPa or more and 100 MPa or less, particularly 10 MPa or more and 100 MPa or less, particularly 20 MPa or more and 100 MPa or less, in order to successfully obtain a target material having the desired bulk density.

When strontium carbonate is used as the strontium source, it is preferable to perform a calcining step prior to performing the above-described temporary molding. Specifically, a powder raw material containing a carbonate as a strontium source, a lanthanum source and a tin source is calcined. This decarboxylates the strontium carbonate in the raw material powder. Along with this, strontium is reacted with tin and/or lanthanum to form a complex oxide stable in the air. By performing decarboxylation by calcination, it is possible to effectively suppress cracks in the target material obtained by sintering, which will be described later.

The calcination is preferably performed at 950° C. or higher and 1200° C. or lower, more preferably 1000° C. or higher and 1200° C. or lower, and even more preferably 1000° C. or higher and 1100° C. or lower. By calcining within this temperature range, strontium carbonate, which is a carbonate of strontium, can be sufficiently decarboxylated without causing sintering of the raw material powder. The calcination time is preferably 1 hour or more and 10 hours or less, more preferably 1 hour or more and 5 hours or less, and 2 hours or more, provided that the calcination temperature is within the above range. It is more preferable to set the time to 4 hours or less. The calcined material is calcined under these conditions, and the calcined material obtained thereby is pulverized and subjected to the above calcination.

The temporary compact obtained by the above method is subjected to a sintering step to obtain the desired target material. It is preferable to use a hot press method for sintering from the viewpoint of successfully obtaining a target material having the desired bulk density. Prior to the hot press method, the surface of the temporary molded body is covered with a foil made of tantalum. The reason for covering with tantalum foil is as follows. Molds used for hot pressing are generally made of carbon. When hot pressing is performed using such a mold, the tin oxide contained in the temporary compact is partially reduced by the carbon in contact with the tin oxide during the hot pressing to form metallic tin. Since this metallic tin has a low melting point, it adheres to the inner surface of the mold. Due to the metallic tin adhering to the inner surface, cracks may occur in the target material when the temperature is lowered after hot pressing. Therefore, in order to prevent reduction of tin oxide, the surface of the temporary compact is covered with tantalum foil to prevent contact between tin oxide and carbon. For this purpose, it is most desirable that the entire surface of the temporary molded body is covered with tantalum foil. Of course, a part of the temporary compact may be exposed within a range that can prevent contact between tin oxide and carbon.

The reason why tantalum is used as the foil covering the surface of the temporary compact is that tantalum has a higher melting point than the sintering temperature of the temporary compact and that the tantalum foil has high plasticity. Any metal foil other than tantalum foil may be used as long as it has similar properties. In particular, it is preferable to use a metal foil having a melting point higher than the sintering temperature of the temporary compact by 600° C. or more. The thickness of the tantalum foil is generally about 5 μm to 100 μm.

The temporary compact whose surface is coated with tantalum foil is subjected to a sintering process by hot pressing. As a result of investigations by the present inventors, it was found that it is advantageous to appropriately set the heating rate, sintering temperature, and press pressure in the sintering step in order to obtain a target material having the desired bulk density. .

It is advantageous from the viewpoint of obtaining a target material having the desired bulk density that the heating rate in the sintering step is higher than the general heating rate employed when sintering the oxide powder. It has been found. Specifically, the temperature increase rate is preferably set to 200° C./h or more and 600° C./h or less, more preferably 250° C./h or more and 600° C./h or less, and 300° C./h or more to 600° C./h or more. C./h or less is more preferable.

The sintering temperature is preferably set at 1050°C or higher and 1300°C or lower, more preferably 1100°C or higher and 1300°C or lower, and even more preferably 1150°C or higher and 1250°C or lower. The sintering time is preferably set to 1 hour or more and 10 hours or less, more preferably 1.5 hours or more and 7 hours or less, on the condition that the sintering temperature is within this range, and 2 hours. It is more preferable to set the time to 5 hours or less.

Regarding the press pressure, it is preferably set to 20 MPa or more and 100 MPa or less, more preferably 25 MPa or more and 100 MPa or less, and is set to 35 MPa or more and 100 MPa or less, provided that the sintering temperature is within the above range. is more preferable. The sintering atmosphere is preferably an inert gas atmosphere such as nitrogen gas or argon gas.

After completion of sintering, the heating is stopped and the temperature of the sintered body is lowered. At the same time, the pressure is released so that the sintered body is not subjected to press pressure. The reason for releasing the pressurization is that if the press pressure is maintained while the temperature is lowered, cracks are likely to occur when the sintered body shrinks.

By adopting the above sintering conditions, a target material, which is a sintered compact of an oxide semiconductor having a desired bulk density, can be obtained. After the target material is obtained in this manner, the surface thereof is ground and smoothed, and then attached to the backing plate. Grinding is performed so that the surface roughness Ra (JIS B0601) is preferably 3 μm or less, more preferably 1 μm or less, and still more preferably 0.5 μm or less, from the viewpoint of suppressing the occurrence of arcing. A bonding material such as indium can be used for attachment to the backing plate. Oxygen-free copper, for example, can be used as the backing plate. In the present invention, the target material also includes a state before target material finishing processes such as surface grinding and bonding. Moreover, the shape of the target material is not limited to a flat plate, and includes a cylindrical shape. In the present invention, a sputtering target means a product obtained by bonding one or more of these target materials to a backing plate or the like and used for sputtering. When sputtering is performed using this target, generation of particles is suppressed more than conventionally.

The target thus obtained is suitably used as a target for DC sputtering or RF sputtering, for example. By performing sputtering using a target having the target material of the present invention, for example, a thin oxide semiconductor or a transparent conductor can be successfully formed. This thin film is made of an oxide containing strontium, lanthanum and tin, preferably an oxide represented by Sr _1-x La _x SnO ₃ (where x represents a number of 0.0010 or more and 0.10 or less). Become. In order to use this thin film as an oxide semiconductor or a transparent conductor, the thickness is preferably set to 300 nm or less, more preferably 50 nm or more and 300 nm or less, particularly 110 nm or more and 280 nm or less. is preferred.

The oxide immediately after sputtering is generally in an amorphous state. Crystallization is possible by subjecting this oxide to heat treatment. By crystallization, the function as an oxide semiconductor or a transparent conductor is exhibited. The heat treatment is preferably performed at 800° C. or higher from the viewpoint of sufficient crystallization, more preferably from 800° C. to 900° C., still more preferably from 800° C. to 850° C. from the viewpoint of more reliable crystallization. Heat treatment. The heating time is preferably set to 0.5 hours or more and 10 hours or less, more preferably 1 hour or more and 7 hours or less, provided that the heating temperature is within this range, and 1 hour or more and 5 hours. It is more preferable to set the time to an hour or less. The atmosphere of the heat treatment is preferably a vacuum atmosphere of ^{10 -6} Pa or less, more preferably 10 Pa or less and 10 ^-6 Pa or more, and still more preferably 10 ^-2 Pa or less and 10 ^-6 Pa or more. .

In particular, the thin film formed by sputtering on a single-crystal SrTiO ₃ substrate using the target material of the present invention can be single-crystallized by the heat treatment described above. Single-crystallization of a thin film improves conductivity as an oxide semiconductor or a transparent conductor, and thus the thin film becomes more useful as an oxide semiconductor. In this case, it is preferable from the viewpoint of crystal orientation to form a thin film by sputtering the (001) plane of the single crystal SrTiO ₃ substrate. The substrate is not limited to single-crystal SrTiO ₃ and other single-crystal materials may be used as long as the thin film can be single-crystallized. Examples of such materials include single crystal NdScO ₃ , single crystal NdGaO ₃ and single crystal MgO.

EXAMPLES The present invention will be described in more detail below with reference to examples. However, the scope of the invention is not limited to such examples.

[Example 1]
<Raw material powder>
_SrCO3 powder was used as the strontium source. _SnO2 powder was used as the tin source. La ₂ O ₃ was used as the lanthanum source.
<Weighing of raw material powder>
In this example, the raw material powders were weighed by an electronic balance so that the atomic ratio was Sr _1-x La _x SnO ₃ (x=0.0010). 494.3 g of SrCO ₃ powder, 505.2 g of SnO ₂ powder, and 0.5 g of La ₂ O ₃ powder were used (also Sr _1−x La _x SnO ₃ (x = 0.0010 to 0.10)).
<Mixing of raw material powder>
Each raw material powder was mixed using a ball mill. SrCO ₃ powder, SnO ₂ powder, La ₂ O ₃ powder, ethanol, and Φ10 mm zirconia balls were put into a polypropylene pot and mixed for 15 hours.
<Filtration and drying of raw material powder>
The slurry was taken out from the pot and filtered using filter paper to separate the raw material powder. This raw material powder was dried with a dryer.
<calcination>
The dried raw material powder was placed in a high-temperature furnace and calcined at 1050° C. for 3 hours to decarbonate.
<Temporary molding>
A disk-shaped temporary compact was obtained by pressing the raw material powder using a cemented carbide die. The press pressure was 20 MPa.
<Hot press>
The upper and lower surfaces and side surfaces of the temporary molded body were covered with a tantalum foil having a thickness of 10 μm. The temporary compact after coating was hot-pressed using a carbon die. The press conditions were set to a temperature increase rate of 400° C./h, a sintering temperature of 1200° C., a sintering time of 3 hours, and a press pressure of 35 MPa in a nitrogen atmosphere. Thus, a sintered compact of an intended oxide semiconductor, that is, a target material was obtained.
<Temperature drop>
When the sintering was completed, the heating and pressure applied to the sintered body were stopped and the sintered body was allowed to cool. After the surface of the target material thus obtained was ground to a surface roughness of 0.5 μm, it was bonded to a backing plate made of oxygen-free copper using indium solder to obtain a sputtering target. Identification by XRD confirmed that this target material had a perovskite structure (the same was true for the examples described below).

[Examples 2 to 11]
A target material and a sputtering target were obtained in the same manner as in Example 1, except that the conditions shown in Table 1 below were used.

[Comparative Example 1]
This comparative example is an example in which La ₂ O ₃ was not used as the raw material powder. A target material and a sputtering target were obtained in the same manner as in Example 1 except for this.

[Comparative Example 2]
In this comparative example, calcination was not performed, the surface of the temporary compact was not covered with a tantalum foil in the hot press, the temperature increase rate in the hot press was lower than in Example 1, and pressure was applied during cooling. be. Also, the amount of La ₂ O ₃ powder was as shown in Table 1. A target material and a sputtering target were obtained in the same manner as in Example 1 except for these.

[Comparative Example 3]
This comparative example is an example in which sintering was performed without pressurization. Also, the amount of La ₂ O ₃ powder was as shown in Table 1. A target material and a sputtering target were obtained in the same manner as in Example 1 except for these.

[Comparative Example 4]
This comparative example is an example in which the sintering temperature of the hot press is lower than that of Example 1 and the sintering time is shorter than that of the example. Also, the amount of La ₂ O ₃ powder was as shown in Table 1. A target material and a sputtering target were obtained in the same manner as in Example 1 except for these.

[Comparative Example 5]
This comparative example is an example in which the sintering temperature of the hot press is lower than that of the first example. Also, the amount of La ₂ O ₃ powder was as shown in Table 1. A target material and a sputtering target were obtained in the same manner as in Example 1 except for these.

[Evaluation 1]
The bulk density, open porosity, and volume resistance at 27° C. of the target materials obtained in Examples and Comparative Examples were measured, and appearance was evaluated. Table 1 shows the results. FIG. 1 shows changes in the volume resistivity of the target material with respect to temperature changes. Appearance quality was evaluated according to the following criteria.
A: Sintering is sufficient and cracks are not observed.
B: Insufficient sintering or cracking observed, bulk density less than 6.00 g/cm ³ .

As shown in Table 1, when Examples 1, 3, 5, 7, 8 and 10 are compared, it is found that the volume resistance of the sintered body decreases according to the doping amount of lanthanum. Since the calcining and hot pressing conditions were the same in these examples, it is believed that the decrease in volume resistivity is due to the addition of lanthanum.
Further, when comparing Example 3 with a hot press temperature of 1200° C. and Comparative Example 4 with a hot press temperature of 1000° C., Example 3 has a higher bulk density. From this, it was found that the hot press temperature affects the density of the target material.
In Comparative Example 2, metal Sn was generated and the target material was broken into a large number of fragments, and the target material was fragmented instead of disc-shaped, and therefore could not be used in subsequent steps and evaluations.
In Comparative Example 3, since the gauge pressure during hot pressing was 0 MPa and no pressure was applied, the target material was not sintered sufficiently, and the target material was crushed during the Archimedes density measurement, and could not be used for the subsequent steps and evaluation. I didn't.
In Comparative Example 4, the sintering temperature was as low as 1000° C. and the sintering time was as short as 1 hour, resulting in a low bulk density and insufficient sintering.
Comparative Example 5 has a sufficient sintering time of 3 hours, but the sintering temperature is as low as 900 ° C., so the bulk density is low and sintering is insufficient. In FIG. , 0.020, 0.035, 0.050, and 0.100, all of the sintered bodies of Sr _1-x La _x SnO ₃ show a tendency that the volume resistivity decreases with increasing temperature. , it can be seen that the material is not metallic in that the volume resistivity increases with temperature rise, but is semiconducting in nature.

[Evaluation 2]
The target materials obtained in Examples 4 and 11 and Comparative Examples 4 and 5 were sputtered to form a thin film having a thickness of 200 nm on a glass substrate. The film formation conditions were as shown below.
・Power: 1.53 W/cm ²
・ Pressure: 0.4 Pa
・Substrate temperature: Room temperature ・Oxygen partial pressure: 0%
Particles generated during sputtering were observed with a scanning electron microscope. Three fields of view were photographed at a magnification of 1000 times. The number of particles was measured from the scanning electron microscope image, classified according to the following criteria, and the average number of particles in three fields of view was calculated. Table 2 shows the results. 2 shows enlarged images of the surfaces of the thin films obtained in Comparative Examples 4 and 5, which were observed with a scanning electron microscope.
A: The maximum diameter of particles is 3 μm or more B: The maximum diameter of particles is 5 μm or more C: The maximum diameter of particles is 10 μm or more

As is clear from the results shown in Table 2 and FIG. 2, the high-density sputtering target having a bulk density of 6.356 g/cm ³ obtained in Example 4 and the bulk density of 6.334 g/cm 3 obtained in Example 11 The high-density sputtering targets of ^{No. 3} are the low-density sputtering target with a bulk density of 5.646 g/cm ³ obtained in Comparative Example 4 and the low-density sputtering target with a bulk density of 5.085 g/cm ³ obtained in Comparative Example 5. It can be seen that the number of generated particles is suppressed compared to the target.

Claims (11)

represented by Sr _1-x La _x SnO ₃ (x represents a number of 0.0010 or more and 0.10 or less), made of an oxide having a perovskite structure, and having a bulk density of 6.00 g/cm ³ or more6. A sputtering target material of 50 g/cm ³ or less. The sputtering target material according to claim 1, wherein x is a number exceeding 0.050 and 0.10 or less. The sputtering target material according to claim 1 or 2, which has a volume resistance of 40.0 Ω·cm or less at 27°C. 4. The sputtering target material according to any one of claims 1 to 3, wherein the volume resistance decreases as the temperature rises. The sputtering target material according to any one of claims 1 to 4, which is disk-shaped with a diameter of 10 mm or more. A method for producing a sputtering target material according to claim 1,
A step of hot-pressing a temporary molded body containing a strontium source, a lanthanum source and a tin source in a state where the surface of the temporary molded body is covered with a foil made of tantalum ,
A method for producing a sputtering target material, wherein the hot pressing is performed by setting a heating rate to 200° C./h or more and 400° C./h or less and setting a sintering temperature to 1050° C. or more and 1300° C. or less. Using strontium carbonate as the strontium source,
calcining a powder raw material containing the strontium source, the lanthanum source and the tin source to decarboxylate the strontium source;
7. The manufacturing method according to claim 6, wherein the powder raw material after decarboxylation is temporarily molded to obtain the temporary compact. 8. The manufacturing method according to claim 6 or 7 , wherein after the sintering is completed, the temperature is lowered while the pressure is released. Sr _1-x La _x SnO ₃ (x represents a number of 0.0010 or more and 0.10 or less), is made of an oxide having a perovskite structure, and has a bulk density of 6.00 g/cm ³ 6.50 g/cm or more ³ A method for producing a thin film consisting of amorphous oxides containing strontium, lanthanum and tin, which can be crystallized by heating at 800° C. or above, by sputtering the following oxides. Single crystal SrTiO ₃ 10. The method for producing a thin film according to claim 9, which is formed on a substrate and can be single-crystallized by heating at 800[deg.] C. or higher. 11. The method for producing a thin film according to claim 9, wherein the thickness is 300 nm or less.

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