Semiconductor wafer manufacturing method and semiconductor wafer

Abstract

The present invention is a method for manufacturing a semiconductor wafer, comprising: a step (1) for forming a carbon-doped silicon film on a silicon substrate at a first temperature; a step (2) for obtaining a laminated wafer by forming a carbon-undoped silicon film on the carbon-doped silicon film at the first temperature; and a step (3) for obtaining a semiconductor wafer by annealing the laminated wafer at a second temperature higher than the first temperature or by further forming a film on the laminated wafer at the second temperature. As a result, provided is a method for producing a semiconductor wafer including a silicon layer containing carbon in which SiC is not deposited on the wafer surface and other defects are suppressed.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a semiconductor wafer including a silicon layer containing carbon. Background Art

[0002] In silicon (Si) doped with carbon (C), properties such as metal gettering ability and oxygen capture effect that cannot be seen in non-doped Si are confirmed. Although various applications for devices can be expected based on the above properties, there is a problem that high-concentration C-doped Si will cause SiC to precipitate to the surface due to heat treatment. When applied to devices, there are many cases where thermal stability is required, such as high-temperature film formation for annealing or lamination with Si layers, so the technical problem lies in the thermal instability of C-doped Si.

[0003] In the conventional film formation of a silicon layer containing carbon, a method for forming an epitaxial film stack has been proposed, wherein, when an epitaxial layer stack is formed on a substrate, a carbon layer containing atoms having a target carbon concentration of 200 ppm to 5% is formed at a temperature below 700°C, a cap layer containing no carbon is formed at a temperature below 700°C, and then etching is performed using an etching gas (Patent Document 1). However, there are situations where the number of steps increases due to the need for an additional step such as etching, resulting in a situation where costs rise, or where the influence of defects on film quality is not discussed.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent No. 5090451 Summary of the invention

[0007] 1. Technical issues to be resolved

[0008] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for manufacturing a semiconductor wafer including a silicon layer containing carbon, wherein SiC is not precipitated on the wafer surface and other defects are suppressed.

[0009] (II) Technical solution

[0010] In order to solve the above-mentioned problems, the present invention provides a semiconductor manufacturing method, which has the following steps: step (1), forming a carbon-doped silicon film on a silicon substrate at a first temperature; step (2), forming a carbon-undoped silicon film on the carbon-doped silicon film at the first temperature, thereby obtaining a stacked wafer; and step (3), annealing the stacked wafer at a second temperature higher than the first temperature, or further forming a film on the stacked wafer at the second temperature, thereby obtaining a semiconductor wafer.

[0011] In this manner, by forming the carbon-undoped silicon film at the first temperature, a semiconductor wafer including a silicon layer containing carbon can be manufactured, in which SiC is not precipitated on the surface and other defects are suppressed.

[0012] Furthermore, it is preferable that the first temperature be set to 400°C to 1000°C.

[0013] At this time, it is more preferable to set the first temperature to 600°C to 800°C.

[0014] It is ideal to form a carbon-doped silicon film and a carbon-undoped silicon film at such a temperature.

[0015] Furthermore, it is preferred that the carbon-undoped silicon film has a thickness of 5 nm to 200 nm.

[0016] At this time, it is more preferable that the thickness of the carbon-undoped silicon film be 5 nm to 50 nm.

[0017] If the thickness of the carbon-undoped silicon film is set to such a thickness, the effect of the present invention can be more reliably exerted.

[0018] In addition, it is preferred that the carbon atom concentration of the carbon-doped silicon film be set to 1.0E+17 atoms / cm 3 Above and 4.5E+22 atoms / cm 3 (atoms / cm 3 )the following.

[0019] At this time, it is more preferable to set the carbon atom concentration of the carbon-doped silicon film to 1.0E+18 atoms / cm 3 Above and 2.0E+22 atoms / cm 3 the following.

[0020] At this time, it is further preferred that the carbon atom concentration of the carbon-doped silicon film be set to 1.0E+19 atoms / cm 3 Above and 5.0E+21 atoms / cm 3 the following.

[0021] It is practically preferable to set the carbon atom concentration of the carbon-doped silicon film to such a range.

[0022] In addition, the present invention provides a semiconductor wafer, wherein the semiconductor wafer has at least: a silicon substrate having an upper surface and a lower surface; a carbon-doped silicon film formed on the upper surface of the silicon substrate; and a carbon-undoped silicon film formed on the carbon-doped silicon film, and the semiconductor wafer has no SiC precipitated on the surface of the silicon substrate opposite to the lower surface.

[0023] According to the method for manufacturing a semiconductor wafer of the present invention, a semiconductor wafer can be manufactured which includes a silicon layer containing carbon and is free from such thermal degradation, and also has a good film quality of a silicon film not doped with carbon on the surface.

[0024] Furthermore, it is preferred that the carbon-undoped silicon film has a thickness of 5 nm to 200 nm.

[0025] In this case, it is more preferable that the carbon-undoped silicon film has a thickness of 5 nm to 50 nm.

[0026] If the thickness of the carbon-undoped silicon film is such a thickness, the effect of the present invention can be more reliably exerted.

[0027] In addition, it is preferred that the carbon atom concentration of the carbon-doped silicon film is 1.0E+17 atoms / cm 3 Above and 4.5E+22 atoms / cm 3 the following.

[0028] At this time, it is more preferable that the carbon atom concentration of the carbon-doped silicon film is 1.0E+18 atoms / cm 3 Above and 2.0E+22 atoms / cm 3 the following.

[0029] At this time, it is further preferred that the carbon atom concentration of the carbon-doped silicon film is 1.0E+19 atoms / cm 3 Above and 5.0E+21 atoms / cm 3 the following.

[0030] If the carbon atom concentration of the carbon-doped silicon film is within such a range, it is preferable in practical use.

[0031] (III) Beneficial effects

[0032] According to the present invention, after forming a carbon-doped silicon film, a carbon-undoped silicon film is formed on the carbon-doped silicon film at the same temperature, thereby manufacturing a semiconductor wafer which prevents the heat-induced degradation of the carbon-doped silicon film caused by subsequent high-temperature heat treatment and contains a high-quality carbon-doped silicon layer, while the film quality of the carbon-undoped silicon film on the surface is also good. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a flowchart showing an example of the first embodiment of the method for manufacturing a semiconductor wafer according to the present invention.

[0034] Figure 2 This is a flowchart showing an example of the second embodiment of the method for manufacturing a semiconductor wafer according to the present invention.

[0035] Figure 3This is a flow chart of film formation on a semiconductor wafer in the embodiment and the comparative example. DETAILED DESCRIPTION

[0036] As described above, there is a need to develop a method for manufacturing a semiconductor wafer including a silicon layer containing carbon while preventing degradation due to heat.

[0037] The inventors of the present application have repeatedly studied the above problem and found that in epitaxial wafers with a gettering effect, the carbon concentration is 1.0E+17 atoms / cm2 when formed at 700°C and a pressure of 1 to 80 Torr. 3 Above and 4.5E+22 atoms / cm 3 After the doped silicon epitaxial layer and the silicon epitaxial layer not doped with the above carbon are formed in the following manner, the silicon epitaxial layer to be the device active layer is formed at 1080°C, thereby reducing the defects from the carbon-doped epitaxial layer on the surface of the epitaxial layer, thereby completing the present invention.

[0038] That is, the present invention is a method for manufacturing a semiconductor wafer, comprising the following steps: step (1), forming a carbon-doped silicon film on a silicon substrate at a first temperature; step (2), forming a carbon-undoped silicon film on the carbon-doped silicon film at the first temperature, thereby obtaining a stacked wafer; and step (3), annealing the stacked wafer at a second temperature higher than the first temperature, or further forming a film on the stacked wafer at the second temperature, thereby obtaining a semiconductor wafer.

[0039] Hereinafter, the present invention will be described in detail, but the present invention is not limited thereto.

[0040] [Method for manufacturing semiconductor wafer]

[0041] The manufacturing method of the semiconductor wafer of the present invention includes a first mode and a second mode. The first mode is the following mode: through steps (1) and (2), a silicon film doped with carbon and a silicon film not doped with carbon formed thereon are formed on a silicon substrate at a first temperature to obtain a stacked wafer, and then a film is further formed on the stacked wafer at a second temperature higher than the first temperature through step (3). The second mode is the following mode: after the stacked wafer is obtained by performing steps (1) and (2) in the same manner as the first mode, the stacked wafer is annealed at a second temperature higher than the first temperature through step (3). Hereinafter, each mode is described in detail with reference to the accompanying drawings.

[0042] [First method]

[0043] Figure 1 The flowchart of one example of the first embodiment of the method for manufacturing a semiconductor wafer of the present invention is shown. In the first embodiment, a semiconductor wafer is obtained by performing the following steps (1) to (3). Figure 1 The first method will be described.

[0044] <Step (1)>

[0045] like Figure 1 As shown, step (1) is a step of forming a carbon-doped silicon film 2 on a silicon substrate 1 at a first temperature.

[0046] The silicon substrate 1 is not particularly limited, and is preferably a single crystal silicon substrate. The single crystal silicon substrate is not particularly limited, and may be a CZ substrate or a FZ substrate. In addition, it may be undoped or doped. In the case of doping, it may be n-type or p-type. In the case of n-type, for example, P, Sb or As may be doped. In the case of p-type, for example, B, Al or Ga may be doped. In addition, the orientation, diameter, resistivity, etc. of the substrate are not particularly limited.

[0047] On such a silicon substrate 1, a silicon film (silicon epitaxial layer) 2 doped with carbon is formed at a first temperature, for example, by CVD (chemical vapor growth), preferably by RP-CVD (reduced pressure CVD). The raw gas used at this time can use, for example, monomethylsilane or trimethylsilane as a carbon source, and dichlorosilane or monosilane as a silicon source. However, the raw gas is not limited to this. The film formation temperature at this time is the "first temperature", for example, it can be 400 to 1000°C, preferably 600 to 800°C, but not limited to this. The concentration of carbon atoms doped in the silicon layer can be adjusted according to the flow rate of the raw gas or the film formation temperature. In addition, the pressure during CVD can be set to 1 to 80 Torr (133 to 10640 Pa).

[0048] The carbon atom concentration of the carbon-doped silicon film 2 is preferably 1.0E+17 atoms / cm 3 Above and 4.5E+22 atoms / cm 3 Below, more preferably 1.0E+18 atoms / cm 3 Above and 2.0E+22 atoms / cm 3 Below, more preferably 1.0E+19 atoms / cm 3 Above and 5.0E+21 atoms / cm 3 The carbon atom concentration can be confirmed by SIMS (Secondary Ion Mass Spectroscopy).

[0049] The film thickness of the carbon-doped silicon film 2 is not particularly limited, and can be, for example, 10 to 1000 nm, preferably 20 to 500 nm, and more preferably 30 to 200 nm.

[0050] <Step (2)>

[0051] like Figure 1 As shown, step (2) is a step of forming a carbon-undoped silicon film 3 on the carbon-doped silicon film 2 at a first temperature to obtain a stacked wafer 10 .

[0052] The silicon film (silicon epitaxial layer) 3 not doped with carbon can also be formed, for example, by CVD, preferably by RP-CVD (reduced pressure CVD). The raw material gas used at this time is, for example, dichlorosilane or monosilane. However, the raw material gas is not limited to this gas. In addition, the pressure during CVD can be set to 1 to 80 Torr. Among them, the silicon film 3 not doped with carbon is formed at the same temperature (i.e., the first temperature) as the film formation temperature of the silicon film 2 doped with carbon.

[0053] In addition, step (1) and step (2) may be performed using the same CVD apparatus or may be performed using separate CVD apparatuses.

[0054] The carbon-doped silicon film formed at the first temperature functions as a silicon cap (Si-Cap) layer. When the film is further formed at a second temperature higher than the first temperature in the later-described step (3), diffusion of carbon from the carbon-doped silicon film 2 to the upper layer due to the high temperature can be suppressed.

[0055] The film thickness of the carbon-undoped silicon film 3 can be, for example, 5 nm to 200 nm, preferably 5 nm to 50 nm. With such a film thickness, diffusion of carbon from the carbon-doped silicon film 2 to the semiconductor wafer surface can be more reliably suppressed.

[0056] <Step (3)>

[0057] like Figure 1 As shown, step (3) is a step of further forming a film on the stacked wafer 10 at a second temperature higher than the first temperature, thereby obtaining the semiconductor wafer 100. Figure 1 In the above, an example is given in which the silicon film 4 to be the device active layer is further formed on the laminated wafer 10 , but the layer to be further formed in this step is not limited to this.

[0058] The silicon film (silicon epitaxial layer) 4 to be the active layer of the device can also be formed by, for example, CVD, preferably by RP-CVD (reduced pressure CVD). The raw material gas used at this time is, for example, dichlorosilane or monosilane. However, the raw material gas is not limited thereto. In addition, the pressure during CVD can be set to 1 to 80 Torr. Among them, the film formation in this process is performed at a second temperature higher than the first temperature.

[0059] The second temperature is not particularly limited as long as it is a temperature higher than the first temperature, and can be, for example, 800°C or higher, and is preferably 1000 to 1200°C.

[0060] The film thickness of the silicon film 4 to be formed into a device active layer in this step is not particularly limited, and may be set to an appropriate film thickness depending on the application.

[0061] In addition, step (3) may be performed using the same CVD apparatus as step (2) or using another CVD apparatus.

[0062] In the present invention, the film formation based on high temperature (second temperature) in step (3) is not performed directly above the silicon film 2 doped with carbon, but on the silicon film (Si-Cap layer) 3 not doped with carbon formed on the silicon film 2 at a low temperature (first temperature). Thus, it is possible to suppress the diffusion of carbon from the silicon film 2 doped with carbon to the upper layer. Therefore, the carbon of the semiconductor wafer 100 manufactured by the present invention is not diffused into the silicon film 4 to be the active layer of the device, that is, there is no precipitation of SiC on the surface of the epitaxial layer.

[0063] [Second method]

[0064] Figure 2 A flowchart showing an example of a second method for manufacturing a semiconductor wafer of the present invention is shown. In the second method for manufacturing a semiconductor wafer of the present invention, a semiconductor wafer is obtained by performing the following steps (1) to (3). Figure 2 The second method will be described.

[0065] <Step (1)>

[0066] like Figure 2 As shown, step (1) is a step of forming a carbon-doped silicon film 2 at a first temperature on a silicon substrate 1. Step (1) is the same as that described in the first embodiment.

[0067] <Step (2)>

[0068] like Figure 2 As shown, step (2) is a step of forming a carbon-undoped silicon film 3 on the carbon-doped silicon film 2 at a first temperature to obtain a stacked wafer 10. Step (2) is also the same as that described in the first embodiment.

[0069] <Step (3)>

[0070] like Figure 2 As shown, step (3) is a step of performing annealing on the stacked wafer 10 at a second temperature higher than the first temperature to obtain the semiconductor wafer 100 .

[0071] The second temperature during annealing is not particularly limited as long as it is a temperature higher than the first temperature, and can be, for example, 800°C or higher, and is preferably 1000 to 1200°C.

[0072] In the second embodiment, the annealing at a high temperature (second temperature) in step (3) is performed after the carbon-undoped silicon film (Si-Cap layer) 3 is formed at a low temperature (first temperature). Therefore, as in the first embodiment, the diffusion of carbon from the carbon-doped silicon film 2 to the upper layer at a high temperature can be suppressed. The semiconductor wafer 100 manufactured by the second embodiment of the present invention also does not have SiC precipitation on the surface of the epitaxial layer.

[0073] [Semiconductor Wafer]

[0074] In addition, the present invention provides a semiconductor wafer, which at least comprises: a silicon substrate having an upper surface and a lower surface; a carbon-doped silicon film formed on the upper surface of the silicon substrate; and a carbon-undoped silicon film formed on the carbon-doped silicon film, and no SiC is precipitated on the surface of the silicon substrate opposite to the lower surface.

[0075] The semiconductor wafer of the present invention may further form another epitaxial layer on the carbon-undoped silicon film, for example, a silicon film to be used as a device active layer.

[0076] The semiconductor wafer of the present invention can be manufactured by the semiconductor wafer manufacturing method of the present invention. Therefore, diffusion of carbon from the carbon-doped silicon film is suppressed by the carbon-undoped silicon film formed thereon, so SiC is not precipitated on the surface of the epitaxial layer.

[0077] Therefore, the semiconductor wafer of the present invention has metal absorption capability or oxygen capture effect, and the effect of improving RF (radio frequency) characteristics. At the same time, the silicon film not doped with carbon on the surface is also of high quality, so it can be applied to various devices (RF devices or CIS).

[0078] Example

[0079] The present invention is specifically described below using examples and comparative examples, but the present invention is not limited thereto. In addition, in the following examples and comparative examples, the defect evaluation of the semiconductor wafer surface was performed by measuring the number of LLS (local light scattering) defects using SP3 manufactured by KLA Tencor.

[0080] In the following Examples 1 to 8, Figure 3 As shown in the flow chart of FIG. 1 , steps (1) to (3) in the method for manufacturing a semiconductor wafer of the present invention are performed. On the other hand, in the following comparative examples 1 to 7, as Figure 3 As shown in the process flow, only steps (1) and (3) are performed in the method for manufacturing a semiconductor wafer of the present invention, and step (2) is not performed.

[0081] (Example 1)

[0082] Using RP-CVD at 700°C and 5 Torr, a SiH4 With SiH(CH 3 ) 3 A 100nm thick C-doped Si layer (carbon atom concentration: 1.0E+20 atoms / cm) was grown on a silicon substrate in a mixed gas atmosphere. 3 ). Then, a 30nm C non-doped Si layer (Si-cap layer) is grown at 700°C. After that, the temperature is raised to 1080°C to grow a Si layer to manufacture a semiconductor wafer. At this time, there are 16 LLS in 32nmup.

[0083] (Example 2)

[0084] As a semiconductor wafer to be evaluated, a semiconductor wafer was manufactured under the same conditions as in Example 1 except that the thickness of the C non-doped Si layer (Si-cap layer) was set to 10 nm. At this time, the number of LLSs in 32 nmup was 25.

[0085] (Example 3)

[0086] As the semiconductor wafer to be evaluated, in addition to setting the carbon atom concentration to 3.0E+21 atoms / cm 3 In addition, the semiconductor wafer was manufactured under the same conditions as in Example 1, and the number of LLSs in this case was 15 in 32nmup.

[0087] (Example 4)

[0088] As the semiconductor wafer to be evaluated, in addition to setting the carbon atom concentration to 8.0E+21 atoms / cm 3 In addition, the semiconductor wafer was manufactured under the same conditions as in Example 1, and the number of LLSs in 32nmup was 165.

[0089] (Example 5)

[0090] As the semiconductor wafer to be evaluated, in addition to setting the carbon atom concentration to 2.5E+22 atoms / cm 3 In addition, the semiconductor wafer was manufactured under the same conditions as in Example 1, and the number of LLSs in 32nmup was 861.

[0091] (Example 6)

[0092] Using RP-CVD at 850°C and 5 Torr, a SiH 4 With SiH 3 (CH 3 ) mixed gas atmosphere, a 100nm C-doped Si layer (carbon atom concentration: 2.0E+19 atoms / cm 3). Then, a 30nm C non-doped Si layer (Si-cap layer) is grown at 850°C. After that, the temperature is raised to 1080°C to grow a Si layer to manufacture a semiconductor wafer. At this time, there are 6 LLS in 32nmup.

[0093] (Example 7)

[0094] As the semiconductor wafer to be evaluated, in addition to setting the carbon atom concentration to 2.0E+18 atoms / cm 3 In addition, the semiconductor wafer is manufactured under the same conditions as in Example 6, and the number of LLSs in this case is 26 in 32nmup.

[0095] (Example 8)

[0096] As the semiconductor wafer to be evaluated, in addition to setting the carbon atom concentration to 4.0E+17 atoms / cm 3 In addition, a semiconductor wafer was manufactured under the same conditions as in Example 6, and at this time, the number of LLSs in 32nmup was 12.

[0097] (Comparative Example 1)

[0098] Using RP-CVD at 700°C and 5 Torr, a SiH 4 With SiH(CH 3 ) 3 A 100nm thick C-doped Si layer (carbon atom concentration: 1.0E+20 atoms / cm) was grown on a silicon substrate in a mixed gas atmosphere. 3 ). Then, the temperature is raised to 1080°C to grow the Si layer to manufacture a semiconductor wafer. At this time, the LLS is overloaded in 32nmup. In addition, overload means that the LLS is about 30,000 or more per wafer.

[0099] (Comparative Example 2)

[0100] As the semiconductor wafer to be evaluated, in addition to setting the carbon atom concentration to 3.0E+21 atoms / cm 3 In addition, a semiconductor wafer was manufactured under the same conditions as in Comparative Example 1, and at this time, LLS was overloaded in 32nmup.

[0101] (Comparative Example 3)

[0102] As the semiconductor wafer to be evaluated, in addition to setting the carbon atom concentration to 8.0E+21 atoms / cm 3 In addition, a semiconductor wafer was manufactured under the same conditions as in Comparative Example 1, and at this time, LLS was overloaded in 32nmup.

[0103] (Comparative Example 4)

[0104] As the semiconductor wafer to be evaluated, in addition to setting the carbon atom concentration to 2.5E+22 atoms / cm 3 In addition, a semiconductor wafer was manufactured under the same conditions as in Comparative Example 1, and at this time, LLS was overloaded in 32nmup.

[0105] (Comparative Example 5)

[0106] Using RP-CVD at 850°C and 5 Torr, a SiH 4 With SiH 3 (CH 3 ) mixed gas atmosphere, a 100nm C-doped Si layer (carbon atom concentration: 2.0E+19 atoms / cm 3 ). Then, the temperature is raised to 1080°C to grow a Si layer to manufacture a semiconductor wafer. At this time, LLS is overloaded in 32nmup.

[0107] (Comparative Example 6)

[0108] As the semiconductor wafer to be evaluated, in addition to setting the carbon atom concentration to 2.0E+18 atoms / cm 3 In addition, a semiconductor wafer was manufactured under the same conditions as in Comparative Example 5, and at this time, LLS was overloaded in 32nmup.

[0109] (Comparative Example 7)

[0110] As the semiconductor wafer to be evaluated, in addition to setting the carbon atom concentration to 4.0E+17 atoms / cm 3 In addition, a semiconductor wafer was manufactured under the same conditions as in Comparative Example 5, and at this time, LLS was overloaded in 32nmup.

[0111] Table 1 summarizes the results of Examples 1 to 8 and Comparative Examples 1 to 7.

[0112] [Table 1]

[0113]

[0114] As shown in Table 1, the semiconductor wafers manufactured by the semiconductor wafer manufacturing method of the present invention as in Examples 1 to 8 have no SiC precipitation on the surface of the epitaxial layer and very little LLS, and the diffusion of carbon is suppressed by the silicon cap layer. In particular, the carbon concentration in the C-doped Si layer is 3.0E21 atoms / cm 3 On the other hand, in Comparative Examples 1 to 7, the step (2) of the present invention was not implemented, but the device active layer was directly formed on the C-doped Si layer at a high temperature, so carbon diffused from the C-doped Si layer and SiC was precipitated on the surface of the device active layer, resulting in a very large number of LLS (overload).

[0115] This specification includes the following inventions.

[0116] [1]: A method for manufacturing a semiconductor wafer, comprising the following steps: step (1), forming a carbon-doped silicon film on a silicon substrate at a first temperature; step (2), forming a carbon-undoped silicon film on the carbon-doped silicon film at the first temperature, thereby obtaining a stacked wafer; and step (3), annealing the stacked wafer at a second temperature higher than the first temperature, or further forming a film on the stacked wafer at the second temperature, thereby obtaining a semiconductor wafer.

[0117] [2]: The method for manufacturing a semiconductor wafer as described in [1] above, wherein the first temperature is set to 400°C to 1000°C.

[0118] [3]: The method for manufacturing a semiconductor wafer as described in [1] or [2] above, wherein the first temperature is set to 600°C to 800°C.

[0119] [4]: The method for manufacturing a semiconductor wafer as described in [1], [2] or [3] above, wherein the thickness of the carbon-undoped silicon film is 5 nm to 200 nm.

[0120] [5]: The method for manufacturing a semiconductor wafer as described in [1], [2], [3] or [4] above, wherein the thickness of the carbon-undoped silicon film is 5 nm to 50 nm.

[0121] [6]: A method for manufacturing a semiconductor wafer as described in [1], [2], [3], [4] or [5] above, wherein the carbon atom concentration of the carbon-doped silicon film is set to 1.0E+17 atoms / cm 3 Above and 4.5E+22 atoms / cm 3 the following.

[0122] [7]: A method for manufacturing a semiconductor wafer as described in [1], [2], [3], [4], [5] or [6] above, wherein the carbon atom concentration of the carbon-doped silicon film is set to 1.0E+18 atoms / cm 3 Above and 2.0E+22 atoms / cm 3 the following.

[0123] [8]: A method for manufacturing a semiconductor wafer as described in [1], [2], [3], [4], [5], [6] or [7] above, wherein the carbon atom concentration of the carbon-doped silicon film is set to 1.0E+19 atoms / cm 3Above and 5.0E+21 atoms / cm 3 the following.

[0124] [9]: A semiconductor wafer, wherein the semiconductor wafer comprises at least: a silicon substrate having an upper surface and a lower surface; a carbon-doped silicon film formed on the upper surface of the silicon substrate; and a carbon-undoped silicon film formed on the carbon-doped silicon film; and the semiconductor wafer has no SiC precipitated on the surface of the silicon substrate opposite to the lower surface.

[0125]

[10] : The semiconductor wafer as described in [9] above, wherein the thickness of the carbon-undoped silicon film is 5 nm to 200 nm.

[0126]

[11] : The semiconductor wafer as described in [9] or

[10] above, wherein the thickness of the carbon-undoped silicon film is 5 nm to 50 nm.

[0127]

[12] : A semiconductor wafer as described in [9],

[10] or

[11] above, wherein the carbon atom concentration of the carbon-doped silicon film is 1.0E+17 atoms / cm 3 Above and 4.5E+22 atoms / cm 3 the following.

[0128]

[13] : A semiconductor wafer as described in [9],

[10] ,

[11] or

[12] above, wherein the carbon atom concentration of the carbon-doped silicon film is 1.0E+18 atoms / cm 3 Above and 2.0E+22 atoms / cm 3 the following.

[0129]

[14] : A semiconductor wafer as described in [9],

[10] ,

[11] ,

[12] or

[13] above, wherein the carbon atom concentration of the carbon-doped silicon film is 1.0E+19 atoms / cm 3 Above and 5.0E+21 atoms / cm 3 the following.

[0130] The present invention is not limited to the above-mentioned embodiments. The above-mentioned embodiments are merely examples, and any technical solution having substantially the same configuration as the technical concept described in the claims of the present invention and having the same function and effect is included in the technical scope of the present invention.

Claims

1. A method for manufacturing a semiconductor wafer, characterized in that: It has the following processes: Step (1), forming a carbon-doped silicon film on a silicon substrate at a first temperature; Step (2), forming a carbon-undoped silicon film on the carbon-doped silicon film at the first temperature, thereby obtaining a stacked wafer; and In step (3), the stacked wafer is annealed at a second temperature higher than the first temperature, or a film is further formed on the stacked wafer at the second temperature, thereby obtaining a semiconductor wafer.

2. The method for manufacturing a semiconductor wafer according to claim 1, wherein: The first temperature is set to 400°C to 1000°C.

3. The method for manufacturing a semiconductor wafer according to claim 2, wherein: The first temperature is set to 600°C to 800°C.

4. The method for manufacturing a semiconductor wafer according to claim 1, wherein: The carbon-undoped silicon film has a thickness of 5 nm to 200 nm.

5. The method for manufacturing a semiconductor wafer according to claim 4, characterized in that: The carbon-undoped silicon film has a thickness of 5 nm to 50 nm.

6. The method for manufacturing a semiconductor wafer according to claim 1, wherein: The carbon atom concentration of the carbon-doped silicon film is set to 1.0E+17 atoms / cm 3 Above and 4.5E+22 atoms / cm 3 the following.

7. The method for manufacturing a semiconductor wafer according to claim 6, wherein: The carbon atom concentration of the carbon-doped silicon film is set to 1.0E+18 atoms / cm 3 Above and 2.0E+22 atoms / cm 3 the following.

8. The method for manufacturing a semiconductor wafer according to claim 7, wherein: The carbon atom concentration of the carbon-doped silicon film is set to 1.0E+19 atoms / cm 3 Above and 5.0E+21 atoms / cm 3 the following.

9. A semiconductor wafer, characterized in that: The semiconductor wafer at least comprises: a silicon substrate having an upper surface and a lower surface; a carbon-doped silicon film formed on the upper surface of the silicon substrate; and, a carbon-undoped silicon film formed on the carbon-doped silicon film, and The semiconductor wafer has no SiC deposited on a surface of the silicon substrate opposite to the lower surface.

10. The semiconductor wafer according to claim 9, characterized in that The carbon-undoped silicon film has a thickness of 5 nm to 200 nm.

11. The semiconductor wafer according to claim 10, characterized in that The carbon-undoped silicon film has a thickness of 5 nm to 50 nm.

12. The semiconductor wafer according to claim 9, characterized in that The carbon atom concentration of the carbon-doped silicon film is 1.0E+17 atoms / cm 3 Above and 4.5E+22 atoms / cm 3 the following.

13. The semiconductor wafer according to claim 12, characterized in that The carbon atom concentration of the carbon-doped silicon film is 1.0E+18 atoms / cm 3 Above and 2.0E+22 atoms / cm 3 the following.

14. The semiconductor wafer according to claim 13, characterized in that The carbon atom concentration of the carbon-doped silicon film is 1.0E+19 atoms / cm 3 Above and 5.0E+21 atoms / cm 3 the following.

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