Method for manufacturing epitaxial wafers and epitaxial wafers

Abstract

The objective is to provide a method for manufacturing an epitaxial wafer having an epitaxial film with controlled oxygen or nitrogen gettering ability. [Solution] A method for manufacturing an epitaxial wafer, comprising forming an epitaxial film on a substrate with a different lattice constant from that of the substrate, wherein the degree of lattice mismatch between the substrate and the epitaxial film is selected, and an epitaxial film with a lattice constant that satisfies the selected degree of lattice mismatch is formed on the substrate, thereby manufacturing an epitaxial wafer in which the oxygen or nitrogen gettering ability of the epitaxial film is controlled.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing an epitaxial wafer and an epitaxial wafer.

Background Art

[0002] It is known that oxygen dissolved in an epitaxial wafer causes afterimage characteristics of a CMOS image sensor (Non-Patent Document 1). In addition, it has been reported that nitrogen dissolved in an epitaxial wafer forms oxygen precipitates that function as gettering sites (Non-Patent Document 2). Thus, a technique for controlling the positions of oxygen, nitrogen, etc. dissolved in an epitaxial wafer is required.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Non-Patent Documents

[0004]

Non-Patent Document 1

Non-Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] Epitaxial wafers are manufactured using dislocations due to lattice mismatch as gettering sites for heavy metals (Patent Document 1). However, there are no reports of a technology that controls the oxygen and nitrogen gettering ability of an epitaxial wafer by the degree of lattice mismatch during film formation.

[0006] The present invention has been made to solve the above problems and aims to provide an epitaxial wafer having an epitaxial film (hereinafter also referred to as a "gettering epitaxial film") in which the ability to getter oxygen or nitrogen is controlled, and a method for manufacturing the same. [Means for solving the problem]

[0007] The present invention has been made to achieve the above objective, and provides a method for manufacturing an epitaxial wafer, which involves forming an epitaxial film on a substrate with a different lattice constant from that of the substrate to produce an epitaxial wafer, wherein the degree of lattice mismatch between the substrate and the epitaxial film is selected, and an epitaxial film with a lattice constant that satisfies the selected degree of lattice mismatch is formed on the substrate, thereby producing an epitaxial wafer in which the oxygen or nitrogen gettering ability of the epitaxial film is controlled.

[0008] This method for manufacturing epitaxial wafers allows for the production of epitaxial wafers by controlling the concentration of oxygen or nitrogen accumulated at the interface between the gettering epitaxial film and the substrate.

[0009] In this case, the method for manufacturing an epitaxial wafer can be used to produce an epitaxial wafer in which the oxygen gettering ability of the epitaxial film is controlled.

[0010] This allows for the manufacturing of epitaxial wafers by controlling the concentration of oxygen accumulated at the interface between the gettering epitaxial film and the substrate.

[0011] At this time, a relationship formula is obtained between the degree of lattice mismatch between the substrate and the epitaxial film and the concentration of oxygen or nitrogen accumulated at the interface between the substrate and the epitaxial film. By selecting the degree of lattice mismatch between the substrate and the epitaxial film based on this relationship formula, an epitaxial wafer can be manufactured in which the concentration of oxygen or nitrogen accumulated at the interface between the substrate and the epitaxial film is controlled.

[0012] This allows for more reliable control of the oxygen or nitrogen concentration accumulating at the interface between the gettering epitaxial film and the substrate, making it possible to manufacture epitaxial wafers.

[0013] At this time, a relationship formula is obtained between the degree of lattice mismatch between the substrate and the epitaxial film and the concentration of oxygen accumulated at the interface between the substrate and the epitaxial film. Based on this relationship formula, an epitaxial wafer can be fabricated in which the concentration of oxygen accumulated at the interface between the substrate and the epitaxial film is controlled.

[0014] This allows for more reliable control of the oxygen concentration accumulating at the interface between the gettering epitaxial film and the substrate, enabling the manufacture of epitaxial wafers.

[0015] In this case, the lattice mismatch can be selected from the range of 0.00005 to 0.13.

[0016] This allows for a more stable acquisition of the oxygen or nitrogen gettering ability of the gettering epitaxial film.

[0017] In this case, the lattice mismatch can be selected from the range of 0.0023 to 0.13.

[0018] This makes it possible to obtain a more stable ability of the gettering epitaxial film to get oxygen or nitrogen.

[0019] At this time, the epitaxial film can be formed under a pressure of 133 Pa to 10666 Pa.

[0020] Thereby, the film thickness and doping of the gettering epitaxial film can be easily made uniform.

[0021] At this time, the epitaxial film can be formed under a pressure of 667 Pa to 2666 Pa.

[0022] Thereby, the film thickness and doping of the gettering epitaxial film can be easily made more uniform.

[0023] At this time, the film thickness of the epitaxial film can be set to 0.005 μm to 3.0 μm.

[0024] Thereby, sufficient gettering ability can be obtained, and the epitaxial wafer can be manufactured at a low cost without forming the gettering epitaxial film to a thickness greater than necessary.

[0025] At this time, the film thickness of the epitaxial film can be set to 0.025 μm to 1.0 μm.

[0026] Thereby, sufficient gettering ability can be obtained, and the epitaxial wafer can be manufactured at a lower cost without forming the gettering epitaxial film to a thickness greater than necessary.

[0027] At this time, the epitaxial film can be formed at a temperature of 600 °C to 800 °C.

[0028] Thereby, the formation and doping of the gettering epitaxial film can be efficiently performed.

[0029] In this case, using a silicon substrate as the substrate, the epitaxial film made of carbon or germanium-doped silicon can be formed in a mixed gas atmosphere containing silicon and carbon or germanium.

[0030] This allows for the formation of epitaxial films at a lower cost and with reduced contamination compared to doping using ion implantation devices. Furthermore, it enables more uniform in-plane gettering of the epitaxial film.

[0031] In this case, using a silicon substrate as the substrate, the epitaxial film made of carbon-doped silicon can be formed in a mixed gas atmosphere containing silicon and carbon.

[0032] Carbon is commonly used, and the present invention is suitable for it.

[0033] In this case, the lattice constant of the epitaxial film can be controlled by changing the carbon concentration or germanium concentration of the epitaxial film.

[0034] This makes it possible to more reliably form epitaxial films with lattice constants that satisfy the selected degree of lattice mismatch.

[0035] In this case, the lattice constant of the epitaxial film can be controlled by changing the carbon concentration of the epitaxial film.

[0036] This makes it possible to more reliably form epitaxial films with lattice constants that satisfy the selected lattice mismatch using a carbon-containing mixed gas atmosphere suitable for the present invention.

[0037] In this case, the carbon concentration can be in the range of 0.0004 to 0.02 mol%.

[0038] This makes it possible to manufacture epitaxial wafers with sufficient gettering capability.

[0039] In this case, the carbon concentration can be in the range of 0.006 to 0.02 mol%.

[0040] This makes it possible to manufacture epitaxial wafers with even greater gettering capability.

[0041] In this case, the germanium concentration can be in the range of 0.15 to 100 mol%.

[0042] This makes it possible to manufacture epitaxial wafers with sufficient gettering capability.

[0043] In this case, the germanium concentration can be in the range of 1 to 35 mol%.

[0044] This makes it possible to manufacture epitaxial wafers with even greater gettering capability.

[0045] In this case, SiH4, SiH2Cl2, SiHCl3, Si2H6, or SiCl4 can be used as the silicon source for the mixed gas containing silicon and carbon or germanium.

[0046] Such gases are commonly used as silicon sources, are readily available, and are therefore suitable.

[0047] In this case, SiH(CH3)3, CH3SiH3, and C3H8 can be used as the carbon source for the mixed gas containing silicon and carbon or germanium.

[0048] Such gases are commonly used as carbon sources, are readily available, and are therefore suitable.

[0049] In this case, GeH4 can be used as the germanium source for the mixed gas containing silicon and carbon or germanium.

[0050] GeH4 is commonly used as a germanium source, is readily available, and is therefore a suitable choice.

[0051] The present invention has also been made to achieve the above objective, and provides an epitaxial wafer having a substrate and an epitaxial film on the substrate having a different lattice constant from the substrate, wherein the degree of lattice mismatch between the substrate and the epitaxial film is in the range of 0.00005 to 0.13.

[0052] Such an epitaxial wafer results in an epitaxial wafer in which the concentration of oxygen or nitrogen accumulated at the interface between the gettering epitaxial film and the substrate is controlled.

[0053] In this case, the lattice mismatch can be in the range of 0.0023 to 0.13.

[0054] This results in an epitaxial wafer in which the concentration of oxygen or nitrogen accumulated at the interface between the gettering epitaxial film and the substrate is more stably controlled.

[0055] In this case, the substrate can be a silicon substrate, and the epitaxial film can be a silicon epitaxial film gas-doped with carbon or germanium, thus forming an epitaxial wafer.

[0056] This results in an epitaxial wafer with a more uniform gettering capability across the plane and an epitaxial film with suppressed contamination. [Effects of the Invention]

[0057] As described above, the epitaxial wafer manufacturing method of the present invention makes it possible to manufacture an epitaxial wafer by controlling the concentration of oxygen or nitrogen accumulated at the interface between the gettering epitaxial film and the substrate. Furthermore, the epitaxial wafer of the present invention provides an epitaxial wafer in which the concentration of oxygen or nitrogen accumulated at the interface between the gettering epitaxial film and the substrate is controlled. [Brief explanation of the drawing]

[0058] [Figure 1] This graph shows the correlation between the oxygen concentration accumulated at the interface between the gettering epitaxial film and the substrate, and the degree of lattice mismatch between the gettering epitaxial film and the substrate. [Figure 2] A schematic side view of an example of the epitaxial wafer of the present invention is shown. [Figure 3] This graph shows the correlation between the nitrogen concentration accumulated at the interface between the gettering epitaxial film and the substrate, and the degree of lattice mismatch between the gettering epitaxial film and the substrate. [Figure 4] The evaluation results for Example 3 are shown (lattice mismatch in the range of 0 to -0.15). [Figure 5] The evaluation results for Example 3 are shown (lattice mismatch in the range of 0 to -0.0003). [Modes for carrying out the invention]

[0059] The present invention will be described in detail below, but the present invention is not limited to these descriptions.

[0060] As described above, there was a need for epitaxial wafers having an epitaxial film with controlled oxygen or nitrogen gettering ability, and for a method of manufacturing the same.

[0061] As a result of diligent research into the above-mentioned problems, the present inventors have discovered a method for manufacturing an epitaxial wafer, which involves forming an epitaxial film on a substrate with a different lattice constant from that of the substrate. This method involves selecting a degree of lattice mismatch between the substrate and the epitaxial film, and forming an epitaxial film on the substrate with a lattice constant that satisfies the selected degree of lattice mismatch. By doing so, the inventors have found that it is possible to manufacture an epitaxial wafer by controlling the concentration of oxygen or nitrogen accumulated at the interface between the gettering epitaxial film and the substrate. This has led to the completion of the present invention.

[0062] The inventors have also conducted extensive research on the above-mentioned problems and have found that an epitaxial wafer having a substrate and an epitaxial film on the substrate having a different lattice constant from the substrate, wherein the degree of lattice mismatch between the substrate and the epitaxial film is in the range of 0.00005 to 0.13, results in an epitaxial wafer in which the concentration of oxygen or nitrogen accumulated at the interface between the gettering epitaxial film and the substrate is controlled, thus completing the present invention.

[0063] In this invention, the "ability to get oxygen or nitrogen" of an epitaxial wafer refers to the accumulation of oxygen or nitrogen at the interface between the substrate and the epitaxial film during the manufacturing of the epitaxial wafer. In other words, the higher the concentration of oxygen or nitrogen accumulated at the interface, the higher the ability to get oxygen or nitrogen.

[0064] (Epitaxial wafer) Figure 2 shows a schematic side view of an example of the epitaxial wafer of the present invention. As shown in Figure 2, the epitaxial wafer 1 of the present invention has a substrate 2 and an epitaxial film (gettering epitaxial film) 3 on the substrate 2, which has a different lattice constant from the substrate 2.

[0065] The lattice mismatch between the substrate 2 and the epitaxial film 3 is in the range of 0.00005 to 0.13, preferably in the range of 0.0023 to 0.13. The value of the lattice mismatch is expressed as an absolute value.

[0066] With such an epitaxial wafer 1, the concentration of oxygen or nitrogen accumulated at the interface 4 between the gettering epitaxial film 3 and the substrate 2 is controlled.

[0067] The substrate 2 is not particularly limited, but may be, for example, a silicon substrate, with a diameter of 200 to 300 mm, or even larger, and can be a silicon single crystal substrate manufactured using conventional single crystal manufacturing equipment and procedures. There are no particular restrictions on the surface orientation, but it can be appropriately selected depending on the material of the desired epitaxial film 3.

[0068] The epitaxial film 3 can be a silicon epitaxial film gas-doped with carbon or germanium. This results in an epitaxial wafer with a more uniform gettering capability across the plane and an epitaxial film with suppressed contamination.

[0069] (Method for manufacturing epitaxial wafers) Next, the method for manufacturing the epitaxial wafer of the present invention will be described with reference to Figures 1 and 2.

[0070] The present invention provides a method for manufacturing an epitaxial wafer, which involves forming an epitaxial film 3 on a substrate 2 having a different lattice constant from the substrate 2 to produce an epitaxial wafer 1. The method involves selecting a degree of lattice mismatch between the substrate 2 and the epitaxial film 3, and forming an epitaxial film 3 on the substrate 2 with a lattice constant that satisfies the selected degree of lattice mismatch, thereby producing an epitaxial wafer 1 in which the oxygen or nitrogen gettering ability of the epitaxial film 3 is controlled.

[0071] According to this method for manufacturing epitaxial wafers, the concentration of oxygen or nitrogen accumulated at the interface 4 between the gettering epitaxial film 3 and the substrate 2 can be controlled to manufacture the epitaxial wafer 1.

[0072] In particular, it is preferable to use a method for manufacturing epitaxial wafers that produces an epitaxial wafer 1 in which the oxygen gettering ability of the epitaxial film 3 is controlled. Oxygen is a cause of afterimage characteristics in CMOS image sensors, so it is desirable to focus more on gettering.

[0073] As one embodiment of the present invention for manufacturing an epitaxial wafer, for example, a relationship between the degree of lattice mismatch between the substrate 2 and the epitaxial film 3 and the concentration of oxygen or nitrogen accumulated at the interface 4 between the substrate 2 and the epitaxial film 3 can be determined, and based on this relationship, the degree of lattice mismatch between the substrate 2 and the epitaxial film 3 can be selected to produce an epitaxial wafer 1 in which the concentration of oxygen or nitrogen accumulated at the interface 4 between the substrate 2 and the epitaxial film 3 is controlled.

[0074] This makes it possible to manufacture an epitaxial wafer 1 by more reliably controlling the concentration of oxygen or nitrogen accumulated at the interface 4 between the gettering epitaxial film 3 and the substrate 2.

[0075] In particular, it is preferable to determine a relationship between the degree of lattice mismatch between the substrate 2 and the epitaxial film 3 and the concentration of oxygen accumulated at the interface 4 between the substrate 2 and the epitaxial film 3, and then, based on this relationship, select the degree of lattice mismatch between the substrate 2 and the epitaxial film 3 to fabricate an epitaxial wafer 1 in which the concentration of oxygen accumulated at the interface 4 between the substrate 2 and the epitaxial film 3 is controlled.

[0076] This makes it possible to manufacture the epitaxial wafer 1 by more reliably controlling the concentration of oxygen accumulated at the interface 4 between the gettering epitaxial film 3 and the substrate 2.

[0077] This embodiment will now be described in more detail. First, multiple epitaxial wafers 1 are fabricated by varying the degree of lattice mismatch between the gettering epitaxial film 3 and the substrate 2. The concentration of oxygen or nitrogen accumulated at the interface between the substrate 2 and the gettering epitaxial film 3 of the fabricated epitaxial wafers 1 is evaluated using SIMS (Secondary Ion Mass Spectrometry).

[0078] A relational expression is calculated from the correlation between the lattice mismatch and the measured oxygen or nitrogen concentration. In this embodiment, with respect to oxygen, the following relational expression (1) was obtained, where A is the lattice mismatch and B is the oxygen concentration. Relational expression (1) is shown as a straight line (calculated value) in Figure 1. B = -1.85 × 10 21 A ···(1)

[0079] Furthermore, with respect to nitrogen, the following relationship (2) was obtained, where C is the degree of lattice mismatch and D is the nitrogen concentration. Relationship (2) is shown as a straight line (calculated value) in Figure 3. D = -1.98 × 10 21 C ···(2)

[0080] Based on the obtained relational equation, it becomes possible to select the degree of lattice mismatch between the gettering epitaxial film 3 and the substrate 2, and to control the concentration of oxygen or nitrogen accumulated at the interface 4 between the gettering epitaxial film 3 and the substrate 2, thereby enabling the fabrication of an epitaxial wafer.

[0081] The lattice mismatch can be selected from the range of 0.00005 to 0.13, preferably from the range of 0.0023 to 0.13. This makes it possible to obtain a more stable ability of the gettering epitaxial film 3 to get oxygen or nitrogen.

[0082] The substrate 2 is not particularly limited, but for example, a silicon substrate can be used. Furthermore, the epitaxial film 3 can be formed in a mixed gas atmosphere containing silicon and carbon or germanium, using carbon or germanium-doped silicon. In particular, carbon is commonly used and suitable for the present invention; therefore, it is preferable to form the epitaxial film 3 using carbon-doped silicon.

[0083] This allows for the formation of epitaxial films at a lower cost and with reduced contamination compared to doping using ion implantation devices. Furthermore, it enables more uniform gettering ability within the plane of the epitaxial film.

[0084] In this case, the lattice constant of the epitaxial film 3 can be controlled by changing the carbon concentration or germanium concentration of the epitaxial film 3. In particular, the lattice constant of the epitaxial film 3 can be controlled by changing the carbon concentration suitable for the present invention. This makes it possible to more reliably form epitaxial films with lattice constants that satisfy the selected degree of lattice mismatch.

[0085] The carbon concentration can be in the range of 0.0004 to 0.02 mol% (0.00034 to 0.017 mass%), preferably in the range of 0.006 to 0.02 mol%. This makes it possible to manufacture epitaxial wafers with sufficient gettering capability.

[0086] Furthermore, the germanium concentration can be in the range of 0.15 to 100 mol% (0.34 to 100 mass%), preferably in the range of 1 to 35 mol%. This makes it possible to manufacture epitaxial wafers with sufficient gettering capability.

[0087] The above-mentioned mixed gas containing silicon and carbon or germanium can, for example, use SiH4, SiH2Cl2, SiHCl3, Si2H6, or SiCl4 as the silicon source, SiH(CH3)3, CH3SiH3, or C3H8 as the carbon source, and GeH4 as the germanium source. These gases are commonly used, readily available, and therefore preferable.

[0088] The pressure during the formation of the epitaxial film 3 is not particularly limited as long as it is under reduced pressure, but it can be formed under a pressure of, for example, 133 Pa to 10666 Pa, preferably 667 Pa to 2666 Pa. This makes it possible to easily and uniformly control the film thickness and doping of the gettering epitaxial film 3.

[0089] Furthermore, the epitaxial film 3 can be formed at a temperature of 600°C to 800°C. This allows for efficient formation and doping of the gettering epitaxial film 3.

[0090] The thickness of the epitaxial film 3 can be 0.005 μm to 3.0 μm, preferably 0.025 μm to 1.0 μm. This allows for sufficient gettering capability and enables the low-cost manufacturing of epitaxial wafers without forming the gettering epitaxial film 3 to an unnecessarily thicker layer. [Examples]

[0091] The present invention will be described in detail below with reference to examples, but this is not intended to limit the present invention.

[0092] (Example 1) On a 300 mm diameter silicon substrate, a gettering epitaxial film containing silicon and carbon was fabricated using an RP-CVD apparatus at 740°C, 667 Pa (5 Torr) under reduced pressure, and in a mixed gas atmosphere containing SiH4 and SiH3 (CH3).

[0093] We selected lattice mismatch degrees of -0.0023, -0.004, and -0.005 for the silicon substrate and the gettering epitaxial film. By changing the carbon concentration, we formed gettering epitaxial films with lattice constants that satisfied the selected lattice mismatch, and fabricated epitaxial wafers.

[0094] The oxygen concentration accumulated at the interface between the gettering epitaxial film and the silicon substrate of the fabricated epitaxial wafer was evaluated using SIMS.

[0095] The evaluation results are shown in Figure 1. As shown in Figure 1, the selected lattice mismatch and the measured oxygen concentration were in approximate agreement with the relationship (1) above.

[0096] (Example 2) An epitaxial wafer was fabricated under the same conditions as in Example 1, and the nitrogen concentration accumulated at the interface between the gettering epitaxial film and the silicon substrate of the fabricated epitaxial wafer was evaluated using SIMS.

[0097] The evaluation results are shown in Figure 3. As shown in Figure 3, the selected lattice mismatch and the measured nitrogen concentration were in approximate agreement with the relationship (2) above.

[0098] (Example 3) Epitaxial wafers were fabricated under the same conditions as in Example 1, except that the lattice mismatch between the silicon substrate and the gettering epitaxial film was selected to be -0.00003, -0.00005, -0.0001, -0.0002, -0.001, -0.01, -0.08, and -0.13. The oxygen concentration accumulated at the interface between the gettering epitaxial film and the silicon substrate of the fabricated epitaxial wafers was evaluated using SIMS.

[0099] Figures 4 and 5 show the measurement results of oxygen concentration and their approximate linear relationships. Figure 4 plots the results for a lattice mismatch range of 0 to -0.15, and Figure 5 plots the results for a lattice mismatch range of 0 to -0.0003.

[0100] As shown in Figures 4 and 5, we confirmed that the correlation between lattice mismatch and oxygen concentration is linear in the range of -0.00005 to -0.13. As shown in Figure 5, the oxygen concentration value when the lattice mismatch is -0.00003 (i.e., in the region where the absolute value is lower than 0.00005) falls outside the linear region. Furthermore, in the region where the absolute value of the lattice mismatch is greater than 0.13, it was difficult to fabricate single-crystal epitaxial layers due to the high lattice mismatch. Based on these results, it is preferable to set the lattice mismatch to a range of 0.00005 to 0.13 (absolute value).

[0101] As described above, according to the embodiment of the present invention, based on relational equation (1), it was possible to select the degree of lattice mismatch between the gettering epitaxial film and the substrate, and to control the concentration of oxygen accumulated at the interface between the gettering epitaxial film and the substrate, thereby fabricating an epitaxial wafer.

[0102] This specification includes the following embodiments: [1]: A method for manufacturing an epitaxial wafer, comprising forming an epitaxial film on a substrate having a different lattice constant from the substrate, wherein the degree of lattice mismatch between the substrate and the epitaxial film is selected, and an epitaxial film having a lattice constant that satisfies the selected degree of lattice mismatch is formed on the substrate, thereby manufacturing an epitaxial wafer in which the oxygen or nitrogen gettering ability of the epitaxial film is controlled. [2]: A method for manufacturing an epitaxial wafer according to [1], comprising manufacturing an epitaxial wafer in which the oxygen gettering ability of the epitaxial film is controlled. [3]: A method for manufacturing an epitaxial wafer according to [1] or [2] above, comprising determining a relationship between the degree of lattice mismatch between the substrate and the epitaxial film and the concentration of oxygen or nitrogen accumulated at the interface between the substrate and the epitaxial film, and selecting the degree of lattice mismatch between the substrate and the epitaxial film based on the relationship, thereby manufacturing an epitaxial wafer in which the concentration of oxygen or nitrogen accumulated at the interface between the substrate and the epitaxial film is controlled. [4]: A method for manufacturing an epitaxial wafer according to [1], [2], or [3], comprising determining a relationship between the degree of lattice mismatch between the substrate and the epitaxial film and the concentration of oxygen accumulated at the interface between the substrate and the epitaxial film, and selecting the degree of lattice mismatch between the substrate and the epitaxial film based on the relationship, thereby manufacturing an epitaxial wafer in which the concentration of oxygen accumulated at the interface between the substrate and the epitaxial film is controlled. [5]: A method for manufacturing an epitaxial wafer according to [1], [2], [3], or [4], comprising selecting the lattice mismatch from the range of 0.00005 to 0.13. [6]: A method for manufacturing an epitaxial wafer according to [1], [2], [3], [4], or [5], comprising selecting the lattice mismatch from the range of 0.0023 to 0.13. [7]: A method for manufacturing an epitaxial wafer according to [1], [2], [3], [4], [5], or [6], comprising forming the epitaxial film under a pressure of 133 Pa to 10666 Pa. [8]: A method for manufacturing an epitaxial wafer according to [1], [2], [3], [4], [5], [6] or [7], comprising forming the epitaxial film under a pressure of 667 Pa to 2666 Pa. [9]: A method for manufacturing an epitaxial wafer according to [1], [2], [3], [4], [5], [6], [7] or [8], comprising setting the thickness of the epitaxial film to 0.005 μm to 3.0 μm.

[10] : A method for manufacturing an epitaxial wafer according to [1], [2], [3], [4], [5], [6], [7], [8] or [9], comprising setting the thickness of the epitaxial film to 0.025 μm to 1.0 μm.

[11] : A method for manufacturing an epitaxial wafer according to [1], [2], [3], [4], [5], [6], [7], [8], [9] or

[10] , comprising forming the epitaxial film at a temperature of 600°C to 800°C.

[12] : A method for manufacturing an epitaxial wafer according to [1], [2], [3], [4], [5], [6], [7], [8], [9],

[10] , or

[11] , comprising using a silicon substrate as the substrate and forming the epitaxial film made of carbon or germanium gas-doped silicon in a mixed gas atmosphere containing silicon and carbon or germanium.

[13] : A method for manufacturing an epitaxial wafer according to [1], [2], [3], [4], [5], [6], [7], [8], [9],

[10] ,

[11] , or

[12] , comprising using a silicon substrate as the substrate and forming the epitaxial film made of carbon-doped silicon in a mixed gas atmosphere containing silicon and carbon.

[14] : The method for manufacturing an epitaxial wafer according to

[12] , comprising controlling the lattice constant of the epitaxial film by changing the carbon concentration or germanium concentration of the epitaxial film.

[15] : A method for manufacturing an epitaxial wafer according to

[12] ,

[13] , or

[14] , comprising controlling the lattice constant of the epitaxial film by changing the carbon concentration of the epitaxial film.

[16] : A method for manufacturing an epitaxial wafer according to

[14] or

[15] , comprising setting the carbon concentration in the range of 0.0004 to 0.02 mol%.

[17] : A method for manufacturing an epitaxial wafer according to

[14] ,

[15] , or

[16] , comprising setting the carbon concentration in the range of 0.006 to 0.02 mol%.

[18] : The method for manufacturing an epitaxial wafer according to

[14] , comprising setting the germanium concentration to a range of 0.15 to 100 mol%.

[19] : A method for manufacturing an epitaxial wafer according to

[14] or

[18] , comprising setting the germanium concentration to a range of 1 to 35 mol%.

[20] : A method for manufacturing an epitaxial wafer according to

[12] ,

[13] ,

[14] ,

[15] ,

[16] ,

[17] ,

[18] or

[19] , comprising using SiH4, SiH2Cl2, SiHCl3, Si2H6 or SiCl4 as the silicon source of the mixed gas containing silicon and carbon or germanium.

[21] : A method for manufacturing an epitaxial wafer according to

[12] ,

[13] ,

[14] ,

[15] ,

[16] ,

[17] ,

[18] ,

[19] or

[20] , comprising using SiH(CH3)3, CH3SiH3, and C3H8 as the carbon source of the mixed gas containing silicon and carbon or germanium.

[22] : A method for manufacturing an epitaxial wafer according to

[12] ,

[13] ,

[14] ,

[15] ,

[16] ,

[17] ,

[18] ,

[19] ,

[20] or

[21] , comprising using GeH4 as the germanium source of the mixed gas containing silicon and carbon or germanium.

[23] : An epitaxial wafer having a substrate and an epitaxial film on the substrate having a different lattice constant from the substrate, wherein the degree of lattice mismatch between the substrate and the epitaxial film is in the range of 0.00005 to 0.13.

[24] : The epitaxial wafer of the above

[23] , wherein the lattice mismatch is in the range of 0.0023 to 0.13.

[25] : The epitaxial wafer according to

[23] or

[24] , wherein the substrate is a silicon substrate and the epitaxial film is a silicon epitaxial film gas-doped with carbon or germanium.

[0103] It should be noted that the present invention is not limited to the embodiments described above. The embodiments described above are illustrative, and any configuration that is substantially identical to the technical idea described in the claims of the present invention and achieves similar effects is included within the technical scope of the present invention. [Explanation of Symbols]

[0104] 1…Epitaxial wafer, 2…Substrate 3... Epitaxial film (gettering epitaxial film), 4... Interface.

Claims

1. A method for manufacturing an epitaxial wafer, comprising forming an epitaxial film on a substrate with a different lattice constant from the substrate, A method for manufacturing an epitaxial wafer, characterized by selecting a degree of lattice mismatch between the substrate and the epitaxial film, and forming an epitaxial film on the substrate with a lattice constant that satisfies the selected degree of lattice mismatch, thereby producing an epitaxial wafer in which the oxygen or nitrogen gettering ability of the epitaxial film is controlled.

2. The method for manufacturing an epitaxial wafer according to claim 1, characterized in that an epitaxial wafer is produced in which the oxygen gettering ability of the epitaxial film is controlled.

3. Determine the relationship between the degree of lattice mismatch between the substrate and the epitaxial film and the concentration of oxygen or nitrogen accumulated at the interface between the substrate and the epitaxial film. The method for manufacturing an epitaxial wafer according to claim 1, characterized in that an epitaxial wafer is produced in which the concentration of oxygen or nitrogen accumulated at the interface between the substrate and the epitaxial film is controlled by selecting the degree of lattice mismatch between the substrate and the epitaxial film based on the relational expression.

4. Determine the relationship between the degree of lattice mismatch between the substrate and the epitaxial film and the concentration of oxygen accumulated at the interface between the substrate and the epitaxial film. The method for manufacturing an epitaxial wafer according to claim 1, characterized in that an epitaxial wafer is produced in which the concentration of oxygen accumulated at the interface between the substrate and the epitaxial film is controlled by selecting the degree of lattice mismatch between the substrate and the epitaxial film based on the relational expression.

5. The method for manufacturing an epitaxial wafer according to claim 1, characterized in that the lattice mismatch is selected from the range of 0.00005 to 0.

13.

6. The method for manufacturing an epitaxial wafer according to claim 1, characterized in that the lattice mismatch is selected from the range of 0.0023 to 0.

13.

7. The method for manufacturing an epitaxial wafer according to claim 1, characterized in that the epitaxial film is formed under a pressure of 133 Pa to 10666 Pa.

8. The method for manufacturing an epitaxial wafer according to claim 1, characterized in that the epitaxial film is formed under a pressure of 667 Pa to 2666 Pa.

9. The method for manufacturing an epitaxial wafer according to claim 1, characterized in that the thickness of the epitaxial film is 0.005 μm to 3.0 μm.

10. The method for manufacturing an epitaxial wafer according to claim 1, characterized in that the thickness of the epitaxial film is 0.025 μm to 1.0 μm.

11. The method for manufacturing an epitaxial wafer according to claim 1, characterized in that the epitaxial film is formed at a temperature of 600°C to 800°C.

12. A method for manufacturing an epitaxial wafer according to any one of claims 1 to 11, characterized in that a silicon substrate is used as the substrate, and the epitaxial film made of carbon or germanium-doped silicon is formed in a mixed gas atmosphere containing silicon and carbon or germanium.

13. The method for manufacturing an epitaxial wafer according to claim 1, characterized in that a silicon substrate is used as the substrate, and the epitaxial film made of carbon-doped silicon is formed in a mixed gas atmosphere containing silicon and carbon.

14. The method for manufacturing an epitaxial wafer according to claim 12, characterized in that the lattice constant of the epitaxial film is controlled by changing the carbon concentration or germanium concentration of the epitaxial film.

15. The method for manufacturing an epitaxial wafer according to claim 12, characterized in that the lattice constant of the epitaxial film is controlled by changing the carbon concentration of the epitaxial film.

16. The method for manufacturing an epitaxial wafer according to claim 14, characterized in that the carbon concentration is in the range of 0.0004 to 0.02 mol%.

17. The method for manufacturing an epitaxial wafer according to claim 14, characterized in that the carbon concentration is in the range of 0.006 to 0.02 mol%.

18. The method for manufacturing an epitaxial wafer according to claim 14, characterized in that the germanium concentration is in the range of 0.15 to 100 mol%.

19. The method for manufacturing an epitaxial wafer according to claim 14, characterized in that the germanium concentration is in the range of 1 to 35 mol%.

20. As the silicon source for the mixed gas containing silicon and carbon or germanium, SiH ４ SiH ２ Cl ２ , SiHCl ３ Si ２ H ６ or SiCl ４ A method for manufacturing an epitaxial wafer according to claim 12, characterized by using [the specified method].

21. As the carbon source of the mixed gas containing silicon and carbon or germanium, SiH(CH ３ ), ３ CH ３ SiH ３ , C ３ H ８ is used. The method for manufacturing an epitaxial wafer according to claim 12, characterized by this.

22. As the germanium source for the mixed gas containing silicon and carbon or germanium, GeH ４ A method for manufacturing an epitaxial wafer according to claim 12, characterized by using [the specified method].

23. An epitaxial wafer comprising a substrate and an epitaxial film on the substrate having a different lattice constant from the substrate, An epitaxial wafer characterized in that the lattice mismatch between the substrate and the epitaxial film is in the range of 0.00005 to 0.

13.

24. The epitaxial wafer according to claim 23, characterized in that the lattice mismatch is in the range of 0.0023 to 0.

13.

25. The epitaxial wafer according to claim 23 or 24, characterized in that the substrate is a silicon substrate and the epitaxial film is a silicon epitaxial film gas-doped with carbon or germanium.

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