JPH0586464A - Target for sputtering and its manufacture - Google Patents

Abstract

PURPOSE:To prevent the peeling of a target layer from a substrate, to improve the mechanical strength of the target layer as well as to reduce the concn. of Al on the outer surface layer of the target layer and thereby to extremely reduce the influence of Al at the time of sputtering. CONSTITUTION:The subject target 11 is formed of a columnar substrate 12, intermediate layers 13 and 14 formed on the outer circumferential face of the substrate 12 and a target layer 15 formed on the outer circumferential face of the intermediate layer 14 and essentially consisting of an Si alloy at least contg. Al, and the concn. of Al in the region R separated by a certain distance from the boundary face 16 with the intermediate layer 14 of the target layer 15 is regulated to a one higher than that in the part S other than the region R. Furthermore, as for its manufacturing method, the intermediate layers 13 and 14 are formed on the outer circumferential face 12a of the columnar substrate 12 by a thermal-spraying method, and the target layer 15 is formed on the outer circumferential face of the intermediate layers 13 and 14 by a thermal- spraying method.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sputtering target in which a target layer containing Si alloy or Si as a main component is formed on the outer peripheral surface of a substrate by a thermal spraying method, and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, a D alloy has a target layer of Si alloy.
As a target for C sputtering (hereinafter, simply referred to as a target), a planar type (disk-shaped or rectangular plate-shaped) target is widely used. However, since this target has a very low material usage efficiency of 20% or less and is incapable of continuous sputtering or sputtering of long objects, a cylindrical target is being used recently.

FIG. 5 is a sectional view showing an example of a cylindrical target. This target 1 is one in which a target layer 3 of a Si alloy is uniformly formed on an outer peripheral surface 2a of a cylindrical stainless backing tube (base) 2 by a thermal spraying method.

This target 1 has a material use efficiency of 8
It is a target of 0 to 90%, which is very high, and can be uniformly sputtered on a wide portion such as a glass surface or a mirror surface, so that the field of application may be expanded more and more in the future.

[0005]

By the way, when the target 1 is manufactured, the target layer 3 is likely to be cracked when the target layer 3 is sprayed onto the backing tube 2, and the target layer 3 is easily cracked. There was a problem of easy peeling. This is because the backing tube 2 made of stainless steel and the target layer 3 made of Si alloy are not well compatible with each other, so that the bonding strength between them is weak and the target layer 3 is easily cracked due to thermal stress at the time of thermal spraying. This is because.

As described above, when sputtering is performed using the target 1 having a weak bonding strength between the backing tube 2 and the target layer 3, there is a problem that the target layer 3 is separated from the backing tube 2 during the sputtering. This is because the target layer 3 and the backing tube 2 have different thermal expansion coefficients, so that the target layer 3 and the backing tube 2 repeat expansion and contraction for each sputtering, and the target layer 3 and the backing tube 2 respectively.
The joint strength between the target layer 3 and the backing tube 2 is further reduced, and the target layer 3 may be peeled off from the backing tube 2 or the like, which adversely affects the quality of the product.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a sputtering target of a Si alloy and a method for manufacturing the same, which can effectively solve the above problems.

[0008]

In order to solve the above problems, the present invention employs the following sputtering target and its manufacturing method.

That is, the sputtering target according to the first aspect is mainly composed of a columnar substrate, an intermediate layer formed on the outer peripheral surface of the substrate, and a Si alloy containing at least Al formed on the outer peripheral surface of the intermediate layer. It is characterized in that the Al concentration in a region which is composed of a target layer as a component and is separated from the boundary surface of the target layer with the intermediate layer by a predetermined distance is higher than that in a region other than the region.

A sputtering target according to a second aspect is mainly composed of a columnar substrate, an intermediate layer formed on the outer peripheral surface of the substrate, and a Si alloy containing at least Al formed on the outer peripheral surface of the intermediate layer. The target layer as a component, and the Al concentration in a region of the target layer that is separated from the boundary surface with the intermediate layer by a predetermined distance is gradually decreased from the boundary surface toward the outer surface of the target layer. Is characterized by.

A sputtering target according to a third aspect is the sputtering target according to the first or second aspect, wherein the portion of the target layer other than the region is made by adding one of B and P. It is characterized by consisting of.

A sputtering target according to a fourth aspect of the present invention is the sputtering target according to the first, second or third aspects, wherein the base body contains at least one selected from stainless steel and Cu alloy as a main component. It is characterized by

The sputtering target according to a fifth aspect is the sputtering target according to the first, second or third aspect, wherein the intermediate layer is Mo, Ti,
It is characterized in that at least one selected from W and Ni is the main component.

A sputtering target according to a sixth aspect is the sputtering target according to the first, second, third, fourth or fifth aspect, characterized in that the intermediate layer is composed of a plurality of layers.

Further, a sputtering target according to a seventh aspect is the sputtering target according to the sixth aspect, characterized in that the outermost layer of the intermediate layer contains Ni as a main component.

A sputtering target according to an eighth aspect is the sputtering target according to the first, second or third aspect, characterized in that the base is cylindrical.

In the method for producing a sputtering target according to a ninth aspect, an intermediate layer is formed on the outer peripheral surface of a columnar substrate by a thermal spraying method, and at least Al is formed on the outer peripheral surface of the intermediate layer by a thermal spraying method. It is characterized in that the target layer containing a Si alloy containing as a main component is formed so that the concentration of Al in a region distant from the boundary surface with the intermediate layer by a predetermined distance is higher than that in the region other than the region.

In the method for producing a sputtering target according to a tenth aspect of the present invention, an intermediate layer is formed on the outer peripheral surface of the columnar substrate by a thermal spraying method, and at least Al is formed on the outer peripheral surface of the intermediate layer by a thermal spraying method. A target layer containing a Si alloy as a main component is formed such that the Al concentration in a region separated from the boundary surface with the intermediate layer by a predetermined distance gradually decreases from the boundary surface toward the outer surface of the target layer. It is characterized by

The method for manufacturing a sputtering target according to claim 11 is the method for manufacturing a sputtering target according to claim 9 or 10, wherein the target layer is separated from the boundary surface with at least the intermediate layer by a predetermined distance. The feature is that Si to which one of B and P is added is formed in a portion other than the above region.

The method of manufacturing a sputtering target according to claim 12 is the method of manufacturing a sputtering target according to claim 9, 10 or 11,
The base is characterized by a tubular shape.

The present invention will be described in more detail below. As the substrate, a material having the following properties, that is, nonmagnetic properties, high mechanical strength, good thermal conductivity, good corrosion resistance, good heat resistance, and small coefficient of thermal expansion is preferable. Further, the intermediate layer has the following properties, that is, non-magnetic property, good compatibility with the substrate, small thermal expansion coefficient (similar to Si-based alloy), and difficult reaction with other layers. Materials are preferred.

Here, the main component of the substrate is at least one selected from stainless steel and Cu alloy because these materials are hard to corrode in an oxidizing or reducing atmosphere, and The reason is that the good thermal conductivity can enhance the cooling efficiency.

Further, the main component of the target layer is a Si alloy containing at least Al because Si alone is high in electrical resistance and DC sputtering cannot be performed because Si is an intrinsic semiconductor, but a Si alloy containing at least Al. This is because the electrical resistance of the target layer can be reduced and the electrical conductivity of the target layer can be ensured. Further, by adding Al, the mechanical strength and heat resistance of the Si alloy are increased, and problems such as cracking of the target layer and easy peeling from the backing tube are eliminated.

The reason why the Al concentration in the region separated from the boundary surface of the target layer with the intermediate layer by a predetermined distance is higher than that in the other regions is that the target layer and the intermediate layer have the same concentration. This is to increase the bonding strength, and also
The portion other than the above region is made of a Si alloy having a low concentration of Al, or Si containing one of B and P added,
This is to reduce the influence of Al on the sputtered product as much as possible.

The main components of the intermediate layer are Mo, Ti, W,
At least one selected from Ni is used because these elements are difficult to react with both the substrate and the target layer.

When the intermediate layer is composed of a plurality of layers, for example, the layer bonded to the substrate is nonmagnetic, has good compatibility with the substrate, has a small coefficient of thermal expansion (similar to Si alloy), and reacts with other layers. It is preferable to have characteristics such as being difficult to do (not forming a brittle intermetallic compound). In addition, the layer that is joined to the target layer is non-magnetic, has resistance to oxidation, has a small coefficient of thermal expansion (similar to Si alloy), does not easily react with other layers (does not react with Si and does not form brittle intermetallic compounds), etc. It is preferable to have the characteristics of

A plasma spraying method is preferably used as the spraying method. This plasma spraying method is a method of uniformly spraying the melted target material onto the outer peripheral surface of the substrate using plasma generated in an inert gas atmosphere or in the atmosphere.

For example, when an intermediate layer containing any one of Mo, Ti, W, and Ni is formed, a predetermined amount of fine particles of the above elements are supplied and the fine particles are added to the plasma generated by the plasma generation torch. Introduce and melt. The molten element is sprayed onto the surface of the substrate by plasma and solidified on the surface to form a uniform layer of the element on the surface.

When the target layer is formed on the outer peripheral surface of the intermediate layer, the fine particles of Si and the fine particles of Al are contained in the plasma generated by the plasma generation torch at a predetermined ratio. Supply while adjusting the amount of. Plasma softens Si and at the same time Al
To melt. The softened Si and the melted Al are sprayed onto the surface of the substrate by the flow of plasma and solidified on the surface to form an alloy phase in which Si and Al are uniformly mixed at a predetermined ratio. For example, the above Si particles and A
If the ratio of the fine particles of 1 is continuously adjusted, an alloy phase in which the ratio of Si and Al continuously changes in the thickness direction is formed, and the ratio of the fine particles of Si and Al is adjusted stepwise. Then, an alloy phase in which the ratio of Si and Al changes stepwise in the thickness direction is formed.

Further, when the thermal spraying method is used, after forming a Si alloy containing Al in a region separated from the boundary surface of the target layer with the intermediate layer by a predetermined distance, one of B and P is further added. It is also easy to form the added Si.

[0031]

In the sputtering target according to the first aspect of the present invention, between the substrate and the target layer containing Si alloy containing at least Al as a main component, both materials are well compatible with each other and the bonding strength is large. By forming the layer, the target layer is firmly bonded to the substrate via the intermediate layer, and the target layer is prevented from peeling from the substrate. Further, by increasing the Al concentration in a region distant from the boundary surface of the target layer with the intermediate layer by a certain distance, the Al concentration is higher than that in a region other than the region, thereby improving the mechanical strength of the target layer and the outer surface. By lowering the Al concentration of, it is possible to reduce the influence of Al during sputtering as much as possible.

Further, in the sputtering target according to the present invention, the Al concentration in the region of the target layer, which is separated from the boundary surface with the intermediate layer by a predetermined distance, has the Al concentration from the boundary surface toward the outer surface of the target layer. By gradually lowering, it becomes possible to further improve the mechanical strength in the target layer and reduce the Al concentration on the outer surface to minimize the influence of Al at the time of sputtering.

Further, in the sputtering target according to the third aspect of the present invention, the conductivity of the target layer is not affected by Al by making the portion other than the region of the target layer Si containing one of B and P. A thin film can be formed.

Further, in the sputtering target according to the fourth aspect, the corrosion resistance and the cooling efficiency are enhanced by using the main component of the substrate as at least one selected from stainless steel and Cu alloy.

In the sputtering target according to the present invention, the main component of the intermediate layer is Mo, Ti,
By using at least one selected from W and Ni, the familiarity with the substrate is improved and the risk of peeling of the target layer is eliminated.

Further, in the sputtering target according to the sixth aspect, by forming the intermediate layer into a plurality of layers, each layer can be composed of a material having a function required for the layer.

In the sputtering target according to the seventh aspect, since the outermost layer of the intermediate layer contains Ni as a main component, it becomes difficult for the outermost layer and the target layer to react with each other, and a brittle intermetallic compound is formed. There is nothing to do.

Further, in the sputtering target according to the eighth aspect, by making the base body cylindrical, the mechanical strength of the base body is enhanced.

Further, in the method for manufacturing a sputtering target according to the ninth aspect, the concentration of Al in a region in which a target layer containing a Si alloy containing at least Al as a main component is separated from the boundary surface with the intermediate layer by a predetermined distance. Is formed so as to have a higher concentration than the portion other than the region,
The joint strength between the layers is improved, and the cooling efficiency is also improved. Further, it is not necessary to machine the target layer, and it is not necessary to align the target layer with the substrate. Therefore, it becomes possible to easily and promptly manufacture a long cylindrical target.

Further, in the method for manufacturing a sputtering target according to claim 10, Si containing at least Al is used.
By forming a target layer containing an alloy as a main component so that the concentration of Al in a region separated from the boundary surface with the intermediate layer by a certain distance gradually decreases from the boundary surface toward the outer surface of the target layer. The joint strength between the layers is improved, and the cooling efficiency is also improved. Further, it is not necessary to machine the target layer, and it is not necessary to align the target layer with the substrate. Therefore, it becomes possible to easily and promptly manufacture a long cylindrical target.

In the method for producing a sputtering target according to claim 11, the target for semiconductor is formed by forming Si to which one of B and P is added in a portion other than the region of the target layer. Can be manufactured.

In the method of manufacturing a sputtering target according to the twelfth aspect of the present invention, the step of processing the base into a cylindrical shape can be omitted by forming the base into a cylindrical shape.

[0043]

EXAMPLE An example of the present invention will be described below.
FIG. 1 is a sectional view of a cylindrical target 11. In this target 11, a first intermediate layer 13, a second intermediate layer 14, and a target layer 15 are sequentially laminated on an outer peripheral surface 12 a of a cylindrical backing tube (base) 12.

Here, the backing tube 12 is mainly composed of stainless steel, the first intermediate layer 13 is mainly composed of Mo, and the second intermediate layer 14 is mainly composed of Ni. Further, the target layer 15 is a target layer containing a Si alloy containing Al as a main component, and as shown in FIG. 2, the Al concentration in the region R separated from the boundary surface 16 with the intermediate layer 14 by a predetermined distance is the region. It gradually decreases from the boundary surface 16 to the outside in R, and in the portion S other than the region R, Al
The concentration of is constant.

Next, a method of manufacturing the target 11 will be described. First, a backing tube 12 made of stainless steel having an outer diameter of 150 mm, an inner diameter of 120 mm and a length of 1000 mm is prepared.
On the outer peripheral surface 12a of No. 2, a first intermediate layer 13 made of Mo and a second intermediate layer 14 made of Ni were sequentially laminated by a plasma spraying method in an amount of about 30 μm and about 20 μm, respectively, and thereafter, Si fine particles and Al fine particles were formed. Si while adjusting the ratio continuously
A target layer 15 made of a Si alloy in which the ratios of Al and Al continuously change in the thickness direction is laminated by about 5 mm.

The conditions of the plasma spraying method are as follows. (A) Thermal spraying conditions of the intermediate layer (Mo, Ti, W, Ni) Gas: Ar, H2 Plasma arc voltage: 50 V Arc current: 500 A Gas amount: 50 l / min (b) Thermal spraying conditions of Si alloy Gas: Ar, H2 plasma arc voltage: 60 V arc current: 600 A gas amount: 55 l / min

As described above, the first intermediate layer 1 is formed on the outer peripheral surface 12a of the backing tube 12 by the plasma spraying method.
It is possible to manufacture the target 11 in which 3, the second intermediate layer 14, and the target layer 15 are sequentially stacked.

Table 1 compares the characteristics of the target of the present invention and the conventional target (comparative example). Here, the backing tube 12 is made of stainless steel (SUS), Cu-0.02% Zr-0.5% Cr (O.
MC), oxygen-free copper (OFC), copper alloy (Cu-2% C
r) four alloys, the first intermediate layer 13 and the second intermediate layer 14 include four metals Mo, Ti, W, and Ni, and the target layer 15 includes Al in the region R. The Si alloy containing the S and the portion S other than the region R have S with a constant Al concentration.
i alloy.

[0049]

[Table 1]

As is clear from Table 1, in the target of the present invention, the degree of cracking of the target layer during thermal spraying and the degree of cracking of the target layer during sputtering are significantly higher than those of the conventional one (comparative example). You can see that it is improving. Therefore, it can be seen that the mechanical strength of the target layer is increased, the defects are reduced, and the bonding strength between the substrate and the target layer is also improved.

As described above, in this target 11, the outer peripheral surface 12a of the cylindrical backing tube 12 is used.
In addition, since the first intermediate layer 13, the second intermediate layer 14, and the target layer 15 are sequentially laminated by the plasma spraying method, the mechanical strength of the target layer 15 itself is significantly improved and the target layer 15 itself is significantly improved. By forming the intermediate layers 14 and 15 that are well compatible with both the layer 15 and the backing tube 12 and have a large bonding strength, the bonding strength between the target layer 15 and the backing tube 12 can be significantly improved, and therefore, The various properties of the target layer 15 can be significantly improved as compared with the conventional ones, and the target layer 15 can be prevented from peeling from the backing tube 12. Further, the mechanical strength of the target layer 15 is improved and the A of the outer surface 17 is
By reducing the l concentration, the influence of Al during sputtering can be reduced as much as possible. Moreover, the thickness of the target layer 15 is not restricted.

Further, according to the method of manufacturing the target 11, since the bonding strength between the backing tube 12 and the target layer 15 can be greatly improved, the cooling efficiency can be greatly improved. Moreover, since the cylindrical backing tube 12 is used, the step of processing into a cylindrical shape can be omitted.

A target 21 shown in FIG. 3 shows another embodiment of the present invention, in which the target layer 15 of the target 11 described above is changed to a target layer 22.
Only points different from the target 11 will be described.

The target layer 22 gradually reduces the Al concentration in the region R, which is separated from the boundary surface 16 with the intermediate layer 14 by a predetermined distance, outward from the boundary surface 16 in the region R, and In the portion S other than R, the Al concentration is set to 0. The portion S other than the region R is formed of Si to which one of B and P is added.

The target layer 22 is continuously sprayed onto the outer peripheral surface 16 of the second intermediate layer 14 by a plasma spraying method while continuously adjusting the ratio of Si fine particles and Al fine particles. About 0.5m of Si alloy that changes to
m, and then about 5 mm of Si to which one of B and P is added is sequentially formed.

In the target 21, in a portion S other than the region R of the target layer 22, either B or P
By forming the seed-added Si, it is possible to provide a target capable of forming a conductive thin film that is not affected by Al.

Table 2 is a comparison of the characteristics of the target of the present invention and the conventional target (comparative example). Here, the backing tube 12 is made of stainless steel (SUS), Cu-0.02% Zr-0.5% Cr (O.
MC), oxygen-free copper (OFC), copper alloy (Cu-2% C
r) four alloys, the first intermediate layer 13 and the second intermediate layer 14 include four metals Mo, Ti, W, and Ni, and the target layer 15 includes Al in the region R. The contained Si alloy and the portion S other than the region R were made of Si to which any one of B and P was added.

[0058]

[Table 2]

As is clear from Table 2, in the target of the present invention, the degree of cracking of the target layer during thermal spraying and the degree of cracking of the target layer during sputtering are significantly larger than those of the conventional one (comparative example). You can see that it is improving. Therefore, it can be seen that the mechanical strength of the target layer is increased, the defects are reduced, and the bonding strength between the substrate and the target layer is also improved.

[0060]

As described above, according to claim 1 of the present invention.
According to the sputtering target described above, a columnar base body, an intermediate layer formed on the outer peripheral surface of the base body, and a target layer mainly formed of a Si alloy containing at least Al formed on the outer peripheral surface of the intermediate layer. A of a region that is separated from the boundary surface of the target layer with the intermediate layer by a certain distance.
Since the concentration of l is higher than that of the portion other than the region, the target layer is firmly bonded to the substrate through the intermediate layer which is well compatible with the materials of the substrate and the target layer and has high bonding strength. Therefore, the target layer can be prevented from peeling from the substrate. In addition, by increasing the mechanical strength of the target layer and decreasing the Al concentration on the outer surface, Al during sputtering can be reduced.
It becomes possible to reduce the influence of.

Further, according to the sputtering target of the second aspect, the columnar substrate, the intermediate layer formed on the outer peripheral surface of the substrate, and the Si alloy containing at least Al formed on the outer peripheral surface of the intermediate layer. And a concentration of Al in a region separated from the boundary surface of the target layer with the intermediate layer by a certain distance from the boundary surface toward the outer surface of the target layer. As a result, the target layer is firmly bonded to the substrate through the intermediate layer that has good compatibility with the materials of the substrate and the target layer and has high bonding strength, and prevents the target layer from peeling from the substrate. can do. Further, by further improving the mechanical strength in the target layer and lowering the Al concentration on the outer surface, the influence of Al during sputtering can be reduced as much as possible.

According to the sputtering target of claim 3, in the sputtering target of claim 1 or 2, either B or P is added to the portion of the target layer other than the region. Since it is made of Si, it is possible to provide a target capable of forming a conductive thin film that is not affected by Al.

According to the sputtering target of the fourth aspect, in the sputtering target of the first, second or third aspect, the base body contains at least one selected from stainless steel and Cu alloy as a main component. Therefore, the corrosion resistance and cooling efficiency of the substrate can be improved.

According to the sputtering target of the fifth aspect, in the sputtering target of the first, second or third aspect, the intermediate layer is Mo,
Since the main component is at least one selected from Ti, W, and Ni, the familiarity with the substrate can be improved, and the risk of peeling of the target layer can be eliminated.

According to the sputtering target of the sixth aspect, in the sputtering target of the first, second, third, fourth or fifth aspect, the intermediate layer is composed of a plurality of layers. Each layer can be composed of a material having the required function for that layer.

According to the sputtering target of the seventh aspect, in the sputtering target of the sixth aspect, since the outermost layer of the intermediate layer has Ni as a main component, the outermost layer is The reaction with the target layer can be made difficult, and a brittle intermetallic compound is not formed.

According to the sputtering target of the eighth aspect, in the sputtering target of the first, second or third aspect, since the base body is cylindrical, the mechanical strength of the base body is improved. Can be increased.

According to the method of manufacturing a sputtering target according to claim 9, the outer peripheral surface of the columnar substrate is
An intermediate layer is formed by a thermal spraying method, and a target layer mainly composed of a Si alloy containing at least Al is formed on the outer peripheral surface of the intermediate layer by a certain distance from a boundary surface with the intermediate layer. Since the Al concentration is set to be higher than that of the portion other than the region, the bonding strength between the layers can be improved and the cooling efficiency can also be improved. Further, it is not necessary to machine the target layer, and it is not necessary to align the target layer with the substrate. Therefore, it becomes possible to easily and promptly manufacture a long cylindrical target.

According to the method of manufacturing a sputtering target according to claim 10, an intermediate layer is formed on the outer peripheral surface of the columnar substrate by a thermal spraying method, and at least the intermediate layer is formed on the outer peripheral surface of the intermediate layer by a thermal spraying method. In the target layer containing a Si alloy containing Al as a main component, the Al concentration in a region separated from the boundary surface with the intermediate layer by a certain distance is gradually decreased from the boundary surface toward the outer surface of the target layer. Since they are formed, the bonding strength between the layers can be improved, and the cooling efficiency can also be improved. Further, it is not necessary to machine the target layer, and it is not necessary to align the target layer with the substrate. Therefore, it becomes possible to easily and promptly manufacture a long cylindrical target.

According to the method of manufacturing a sputtering target according to claim 11, in the method of manufacturing a sputtering target according to claim 9 or 10,
Since Si containing one of B and P added is formed in at least a portion of the target layer other than a region that is separated from the boundary surface with the intermediate layer by a certain distance. It will be possible.

According to the method for producing a sputtering target according to claim 12, in the method for producing a sputtering target according to claim 9, 10 or 11, the substrate is tubular. The step of processing the substrate into a cylindrical shape is reduced.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a sputtering target according to an embodiment of the present invention.

FIG. 2 is a graph showing Al concentration in a cross section of a sputtering target according to an example of the present invention.

FIG. 3 is a cross-sectional view of a sputtering target according to another embodiment of the present invention.

FIG. 4 is a graph showing Al concentration in a cross section of a sputtering target according to another example of the present invention.

FIG. 5 is a cross-sectional view of a conventional sputtering target.

[Explanation of symbols]

 Reference Signs List 11 sputtering target 12 backing tube (cylindrical base) 12a outer peripheral surface 13 first intermediate layer 14 second intermediate layer 15 target layer 16 boundary surface 17 outer surface R area other than S area 21 sputtering target 22 target layer

Claims (12)

[Claims] 1. A columnar substrate, an intermediate layer formed on an outer peripheral surface of the substrate, and a target layer formed on an outer peripheral surface of the intermediate layer and containing a Si alloy containing at least Al as a main component. A sputtering target, wherein the concentration of Al in a region separated from the boundary surface of the target layer with the intermediate layer by a predetermined distance is higher than that of a region other than the region. 2. A columnar substrate, an intermediate layer formed on an outer peripheral surface of the substrate, and a target layer formed on an outer peripheral surface of the intermediate layer and containing a Si alloy containing at least Al as a main component. A sputtering target characterized in that the Al concentration in a region of the target layer that is separated from the boundary surface with the intermediate layer by a certain distance is gradually reduced from the boundary surface toward the outer surface of the target layer. 3. The sputtering target according to claim 1, wherein a portion of the target layer other than the region is made of Si to which one of B and P is added. 4. The sputtering target according to claim 1, wherein the substrate is mainly composed of at least one selected from stainless steel and Cu alloy. 5. The sputtering target according to claim 1, wherein the intermediate layer contains at least one selected from Mo, Ti, W, and Ni as a main component. 6. The sputtering target according to claim 1, wherein the intermediate layer comprises a plurality of layers. 7. The sputtering target according to claim 6, wherein the outermost layer of the intermediate layer contains Ni as a main component. 8. The sputtering target according to claim 1, wherein the substrate has a cylindrical shape. 9. An intermediate layer is formed on the outer peripheral surface of a columnar substrate by a thermal spraying method, and a target layer containing a Si alloy containing at least Al as a main component is formed on the outer peripheral surface of the intermediate layer by a thermal spraying method. A method for manufacturing a sputtering target, which is characterized in that the Al concentration in a region separated from the boundary surface with the intermediate layer by a predetermined distance is higher than that in the region other than the region. 10. An intermediate layer is formed on the outer peripheral surface of a columnar substrate by a thermal spraying method, and a target layer mainly containing a Si alloy containing at least Al is formed on the outer peripheral surface of the intermediate layer by a thermal spraying method. A method of manufacturing a sputtering target, characterized in that the Al concentration in a region spaced apart from the boundary surface with the intermediate layer by a certain distance is gradually decreased from the boundary surface toward the outer surface of the target layer. 11. Sputtering, characterized in that at least a portion of the target layer other than a region separated from the boundary surface with the intermediate layer by a certain distance is formed with Si containing one of B and P added thereto. Of manufacturing target for automobile. 12. The method for manufacturing a sputtering target according to claim 9, 10 or 11, wherein the substrate has a tubular shape.