Method for producing nitrogen-doped single crystal silicon rod and nitrogen-doped single crystal silicon rod

Abstract

The embodiments of the present application disclose a method for producing a nitrogen-doped single crystal silicon rod and a nitrogen-doped single crystal silicon rod, the method including: cutting a reference nitrogen-doped single crystal silicon rod into sample silicon wafers, selecting a plurality of silicon wafers to be detected, and evaluating the distribution of defect areas of the plurality of silicon wafers to be detected; determining the distribution positions of each defect area in the reference nitrogen-doped single crystal silicon rod based on the distribution positions of each defect area in the plurality of silicon wafers to be detected; and during the production process of the current nitrogen-doped single crystal silicon rod, pulling up the reference nitrogen-doped single crystal silicon rod at the distribution positions of each defect area in the reference nitrogen-doped single crystal silicon rod at a target pulling speed corresponding to each set defect area to produce the current nitrogen-doped single crystal silicon rod.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority from China Patent Application No. 202111165312.4, filed in China on September 30, 2021, the entire contents of which are incorporated herein by reference. The embodiments of the present application relate to the technical field of semiconductors, in particular to a method for preparing a nitrogen-doped single crystal silicon rod and a nitrogen-doped single crystal silicon rod. [Background technology]

[0002] Silicon wafers used as substrates for semiconductor integrated circuits are mainly manufactured by slicing single crystal silicon rods extracted by the Czochralski method. The Czochralski method involves melting polysilicon raw material in a quartz crucible to obtain a silicon melt, immersing a seed crystal into the silicon melt, and continuously lifting the seed crystal and moving it away from the surface of the silicon melt so that a single crystal silicon rod grows at the phase interface during the moving process.

[0003] In the above production process, it is very advantageous to provide a silicon wafer having a denuded zone (DZ) extending from the front side into the bulk and a region adjacent to the DZ and containing bulk micro defects (BMD) extending further into the bulk, where the front side refers to the surface of the silicon wafer on which electronic components need to be formed. The DZ is important because, in order to form electronic components on the silicon wafer, it is required that there be no crystal defects in the electronic component formation region, otherwise defects such as circuit breaks will occur. However, by forming the electronic components in the DZ, the influence of crystal defects can be avoided. The role of the BMD is to have an intrinsic getter (IG) effect on metal impurities, and to keep metal impurities in the silicon wafer away from the DZ, thereby avoiding adverse effects such as an increase in leakage current due to metal impurities and deterioration of the quality of the gate oxide film.

[0004] However, during the production process of the silicon wafer having the above-mentioned BMD region, it is very advantageous to dope the silicon wafer with nitrogen. For example, when the silicon wafer is doped with nitrogen, it can promote the formation of BMDs with nitrogen as nuclei, so that the BMDs reach a certain density, and the BMDs can not only effectively function as metal gettering sources, but also have a beneficial effect on the density distribution of the BMDs, such as making the density distribution of the BMDs in the radial direction of the silicon wafer more uniform, making the density of the BMDs higher in the region near the DZ and gradually decreasing toward the bulk of the silicon wafer, etc.

[0005] However, in the conventional growth process of nitrogen-doped single crystal silicon rods, in addition to doping the silicon melt with nitrogen, the silicon wafers made from the nitrogen-doped single crystal silicon rods also need to undergo a heat treatment process to generate BMDs inside the silicon wafers, promote the adsorption of impurities on the surface of the silicon wafer near the BMDs, and further improve the surface cleanliness of the silicon wafers. Meanwhile, currently, when producing a whole doped single crystal silicon rod, the ratio of the pulling speed / intra-crystal temperature in the pulling axis direction (V / G) remains unchanged, so that the whole doped single crystal silicon rod produced contains various grown-in defects, resulting in non-uniform content and density of BMDs in the whole doped single crystal silicon rod, and the proportion of silicon wafers with high surface cleanliness in the whole doped single crystal silicon rod is low, leading to waste of doped single crystal silicon rods. Summary of the Invention [Problem to be solved by the invention]

[0006] In view of this, the embodiment of the present application is as follows: Vacancy The present invention provides a method for producing nitrogen-doped single crystal silicon rods that can produce nitrogen-doped single crystal silicon rods having only rich regions and that can produce a greater proportion of silicon wafers with high surface cleanliness, and provides such nitrogen-doped single crystal silicon rods. [Means for solving the problem]

[0007] The technical solution of the embodiments of the present application is realized as follows.

[0008] In a first aspect, the present application provides a method for producing a nitrogen-doped single crystal silicon rod, comprising: After cutting into sample silicon wafers based on the reference nitrogen-doped single crystal silicon rod, selecting a plurality of silicon wafers to be detected, and evaluating the distribution of defect areas of the plurality of silicon wafers to be detected; Determining the distribution position of each defect area in the reference nitrogen-doped single crystal silicon rod based on the distribution of defect areas of the plurality of silicon wafers to be detected; During the process of producing the current nitrogen-doped single crystal silicon rod, the reference nitrogen-doped single crystal silicon rod is pulled at a target pulling speed corresponding to each of the set defect regions at the distribution position of each defect region in the reference nitrogen-doped single crystal silicon rod to produce the current nitrogen-doped single crystal silicon rod; Among them, the defect area includes: Vacancy A rich region and an interstitial rich region, Vacancy A method for making nitrogen-doped single crystal silicon rods is provided, the rods including alternating nitrogen-rich and interstitial-rich regions.

[0009] In a second aspect, an embodiment of the present application provides a nitrogen-doped single crystal silicon rod produced by the production method described in the first aspect. Effect of the Invention

[0010] The embodiments of the present application provide a method for producing a nitrogen-doped single crystal silicon rod and a nitrogen-doped single crystal silicon rod. The production method can determine the distribution position of each defect area in a reference nitrogen-doped single crystal silicon rod based on the distribution status of multiple silicon wafer defect areas to be detected. During the production process of the current nitrogen-doped single crystal silicon rod, when it is pulled up to the distribution position of each defect area in the reference nitrogen-doped single crystal silicon rod, it is pulled up at a target pulling speed corresponding to each set defect area, thereby producing the current nitrogen-doped single crystal silicon rod. According to the production method, the target pulling speed of the current single crystal silicon rod can be adjusted step by step, Vacancy It is possible to obtain nitrogen-doped single crystal silicon rods having only rich regions, and furthermore, it is possible to obtain a larger number of silicon wafers having high surface cleanliness. [Brief description of the drawings]

[0011] [Figure 1]FIG. 2 is a schematic diagram showing the distribution of various defect regions present in a conventional nitrogen-undoped single crystal silicon rod according to an embodiment of the present application. [Diagram 2] 1 shows one form of alternating distribution of vacancy-rich regions and interstitial-rich regions according to an embodiment of the present application. [Diagram 3] 13 is another form of alternating distribution of vacancy-rich regions and interstitial-rich regions according to an embodiment of the present application. [Figure 4] 1 is a schematic flow diagram of a method for producing a nitrogen-doped single crystal silicon rod according to an embodiment of the present application. [Diagram 5] FIG. 1 is a schematic flow diagram of a process for preparing a silicon wafer to be detected using a reference nitrogen-doped single crystal silicon rod according to an embodiment of the present application. [Figure 6] 1 is a schematic diagram of positions corresponding to different defect regions in a reference nitrogen-doped single crystal silicon rod according to an embodiment of the present application. [Figure 7] FIG. 2 is a schematic diagram of the use of different target pulling rates at different positions in a current single crystal silicon rod according to an embodiment of the present application. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the technical solutions in the embodiments of the present application will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present application.

[0013] Referring to FIG. 1, a conventional nitrogen-doped single crystal silicon rod S 0 In the present embodiment, a radial cross section is specifically used to show the distribution of the various defect areas. As shown in FIG. 1, mainly Vacancy Defective area (shown as the area shaded on the left in the figure), Vacancy The figure includes a rich region (shown as a filled diamond region in the figure), an interstitial rich region (shown as a filled right diagonal region in the figure), and an interstitial defect region (shown as a filled blank region in the figure). VacancyThe defect area includes large-sized defects such as lattice grown-in point defects (Crystal Originated Particles, COPs) in nitrogen-doped single crystal silicon rods and flow pattern defects (FPDs). Vacancy The interstitial defect region includes large interstitial defects such as dislocations and slip lines, which are defects formed by the diffusion and aggregation of vacancy point defects during the cooling process. The interstitial defect region includes large interstitial defects such as dislocations and slip lines, which are defects formed by the diffusion and aggregation of interstitial point defects during the cooling process. Vacancy The rich region is an oxygen precipitation promotion region where oxygen precipitation occurs, and the interstitial rich region is Vacancy an oxygen precipitation suppression region located between the rich region and the interstitial defect region, in which oxygen precipitation does not occur; Vacancy Both the rich and interstitial rich regions contain defects of very small dimensions, on the order of nanometer-scale defects, and therefore both of these regions are considered defect-free regions with very few grown-in defects.

[0014] Most of the defect-free nitrogen-doped single crystal silicon rods currently on the market are mainly Vacancy It is an alternating distribution of rich and interstitial rich regions. Vacancy The alternating distribution of the rich regions and the interstitial rich regions can be mainly divided into two forms, as specifically shown in FIG. 2 and FIG.

[0015] On the other hand, BMD is a type of Vacancy In actual production, BMDs are formed by depositing on defects. Vacancy Defective area and Vacancy If the single crystal silicon rod is deposited in the rich region, Vacancy If a defect region is included, it will affect the integrity of the gate oxide film of the silicon wafer produced from the single crystal silicon rod. In the interstitial rich region, impurity oxygen cannot accumulate, so BMD cannot be formed. Vacancy Only in the nitrogen-rich region of the single crystal silicon rod, a high density of BMD can be produced, and furthermore, silicon wafers with high surface cleanliness can be obtained. However, there are many defects in the nitrogen-doped single crystal silicon rods currently on the market. Vacancy A rich region and an interstitial rich region, Vacancy Rich regions and interstitial rich regions are alternately distributed in defect regions, and this situation reduces the percentage of silicon wafers with high surface cleanliness that can be provided from a single nitrogen-doped single crystal silicon rod.

[0016] Based on the above description, in order to achieve a uniform BMD content throughout a single nitrogen-doped single crystal silicon rod and increase the proportion of silicon wafers with high surface cleanliness, the embodiment of the present application controls and adjusts the parameter V / G to: Vacancy The aim is to produce nitrogen-doped single crystal silicon rods having only rich regions, and to obtain a greater proportion of silicon wafers with high surface cleanliness. However, in the case of a fixed hot zone structure, the G value is constant, so in the embodiment of this application, the growth rate is obtained by adjusting only the pulling speed V. Vacancy The aim is to obtain a nitrogen-doped single crystal silicon rod having only a rich region. Therefore, referring to FIG. 4, an embodiment of the present application provides a method for producing a nitrogen-doped single crystal silicon rod, the method comprising: After cutting into sample silicon wafers based on the reference nitrogen-doped single crystal silicon rod, a plurality of silicon wafers to be detected are selected, and the distribution of defect areas of the plurality of silicon wafers to be detected is evaluated, among which, the defect areas include: Vacancy A rich region and an interstitial rich region, Vacancy Step S401 includes alternating rich and interstitial rich distribution regions; The method includes step S402 of determining a position of distribution of each defect area in the reference nitrogen-doped single crystal silicon rod based on the distribution of defect areas of the plurality of silicon wafers to be detected; and step S403 of, during the production process of the current nitrogen-doped single crystal silicon rod, pulling up the reference nitrogen-doped single crystal silicon rod at the position of distribution of each defect area at a target pulling speed corresponding to each set defect area, to produce the current nitrogen-doped single crystal silicon rod.

[0017] The technical solution shown in Figure 4 can determine the distribution position of each defect area in the reference nitrogen-doped single crystal silicon rod based on the distribution status of multiple silicon wafer defect areas to be detected, so that during the production process of the current nitrogen-doped single crystal silicon rod, when it is pulled up to the distribution position of each defect area in the reference nitrogen-doped single crystal silicon rod, it is pulled up at the target pulling speed corresponding to each set defect area, thereby producing the current nitrogen-doped single crystal silicon rod. According to this production method, the target pulling speed of the current single crystal silicon rod is adjusted in stages, Vacancy It is possible to obtain nitrogen-doped single crystal silicon rods having only rich regions, and furthermore, it is possible to obtain a larger number of silicon wafers having high surface cleanliness.

[0018] For the technical solution shown in FIG. 4, in some examples, the following steps are performed: after cutting into sample silicon wafers based on the above-mentioned reference nitrogen-doped single crystal silicon rod, a plurality of silicon wafers to be detected are selected, and the distribution of defect areas of the plurality of silicon wafers to be detected are evaluated; Pulling the reference nitrogen-doped single crystal silicon rod at a reference pulling speed to prepare the reference nitrogen-doped single crystal silicon rod, and cutting the reference nitrogen-doped single crystal silicon rod to obtain the sample silicon wafer; selecting a plurality of the sample silicon wafers located at different positions of the reference nitrogen-doped single crystal silicon rod as the silicon wafers to be detected, and evaluating a distribution of defect areas of the plurality of the silicon wafers to be detected.

[0019] As can be seen, the reference lifting speed V 0 The reference nitrogen-doped single crystal silicon rod S was pulled using 1 After preparing the reference nitrogen-doped single crystal silicon rod S 1 In order to determine the distribution of the defect regions in the reference nitrogen-doped single crystal silicon rod S in the embodiment of the present application, 1 is sliced ​​to obtain a plurality of sample silicon wafers W, and some of the sample silicon wafers W are selected as silicon wafers W to be detected for evaluating the distribution of defective areas.

[0020] It should be noted that the number of silicon wafers W to be detected is selected according to the specific actual situation.

[0021] On the other hand, in order to fully obtain the distribution of defect regions at each position in the reference nitrogen-doped single crystal silicon rod, in the embodiment of the present application, the silicon wafer W to be detected is, as shown in FIG. 1 The sample silicon wafers W are selected from the sample silicon wafers W at the head, middle and tail positions of the sample silicon wafers W. However, it should be noted that the method of selecting the silicon wafers W to be detected in the embodiment of the present application is not limited to the above and the selection method shown in FIG. 5, and can be specifically adjusted according to the actual situation.

[0022] Regarding the above example, in some specific implementations, evaluating the distribution of defect areas of the plurality of silicon wafers to be detected as described above includes: Obtaining minority carrier lifetime data on the surfaces of the plurality of silicon wafers to be detected, and plotting a minority carrier lifetime map according to the minority carrier lifetime data on the surfaces of the plurality of silicon wafers to be detected; and evaluating a distribution of defect areas of the plurality of silicon wafers to be detected based on the minority carrier lifetime map.

[0023] Regarding the above example, in some specific embodiments, evaluating the distribution of defect regions of the plurality of silicon wafers to be detected based on the above-mentioned minority carrier lifetime map includes: In the case where the minority carrier lifetime map is a map having a circular shape and a long lifetime, a silicon wafer to be detected corresponding to the map having a circular shape and a long lifetime is Vacancy determining that the first silicon wafer to be detected contains only rich regions; In the case where the minority carrier lifetime map is a map with a circular and low lifetime, a silicon wafer to be detected corresponding to the map with a circular and low lifetime is Vacancy determining that the second silicon wafer to be detected includes an interstitial rich region surrounding the rich region; When the minority carrier lifetime map is a circular high lifetime map, the silicon wafer to be detected corresponding to the circular high lifetime map surrounds the interstitial rich region. Vacancy determining that the third silicon wafer to be detected includes a rich region; and when the minority carrier lifetime map is a circular, low lifetime map, determining that the silicon wafer to be detected corresponding to the circular, low lifetime map is a fourth silicon wafer to be detected that includes only interstitial rich regions.

[0024] It should be noted that the minority carrier lifetime data on the surface of the silicon wafer W to be detected can be obtained by a microwave photoconductive decay method, but the specific method is not described in detail in this application.

[0025] As can be understood, in the embodiment of the present application, the minority carrier lifetime of the silicon wafer to be detected is the lifetime of the excited carriers when excited with energy (1.12 eV) greater than the forbidden band width of the semiconductor. Vacancy -refers to the average time it takes for minority carriers in an electron pair to recombine. Vacancybecome majority carriers and electrons become minority carriers. Vacancy The cause of the formation of the rich defects is the promotion of oxygen precipitation during the crystal pulling process, which results in circular defects. Vacancy Due to the occurrence of a rich region, the average time for minority carriers to recombine is long in this region. Vacancy A minority carrier lifetime map including only rich regions is a map with a circular shape and a high lifetime. As a result, by scanning the minority carrier lifetime map of the entire surface of the silicon wafer to be detected, the silicon wafer to be detected corresponding to the circular map with a high lifetime is Vacancy It can be determined that the first silicon wafer to be detected contains only rich regions.

[0026] Similarly, the formation of interstitial rich defects is caused by the suppression of oxygen precipitation during the crystal pulling process, resulting in the formation of circular interstitial rich regions, in which the average time for minority carriers to recombine is short. Therefore, the minority carrier lifetime map that includes only interstitial rich regions will be circular and have a low lifetime. As a result, by scanning the minority carrier lifetime map over the entire surface of the silicon wafer to be detected, it can be determined that the silicon wafer to be detected that corresponds to the circular and low lifetime map is the fourth silicon wafer to be detected that includes only interstitial rich regions. Therefore, by analyzing the minority carrier lifetime map, Vacancy A distinction can be made between rich regions and interstitially rich regions.

[0027] at the same time, Vacancy For a second silicon wafer to be detected including an interstitial rich region surrounding the rich region, Vacancy Since the lifetime of minority carriers in the rich region is longer than that of minority carriers in the interstitial rich region, as shown in Figure 2 VacancyIn the case of a pattern including an interstitial rich region that is distributed to surround a rich region, a circular minority carrier lifetime map is obtained, whereas a map with a short lifetime is obtained for the minority carrier lifetime map surrounding the interstitial rich region. Vacancy For the third silicon wafer to be detected including the rich region, Vacancy Since the lifetime of minority carriers in the rich region is longer than that of the interstitial rich region, the minority carriers are distributed around the interstitial rich region as shown in Figure 3. Vacancy In the case of a shape including a rich region, a circular map with a long lifetime is obtained as the minority carrier lifetime map.

[0028] For the technical solution shown in FIG. 4, in some examples, determining the location of the distribution of each defect area in the reference nitrogen-doped single crystal silicon rod based on the distribution of the defect areas of the plurality of silicon wafers to be detected as described above; The above Vacancy Based on the first silicon wafer to be detected that contains only the rich region, Vacancy Determining the location I of the distribution of rich regions; The above Vacancy Based on a second silicon wafer to be detected that includes an interstitial rich region surrounding the rich region, Vacancy determining a distribution position II of interstitial rich regions surrounding the interstitial rich regions; Vacancy Based on a third silicon wafer to be detected that includes a rich region, the reference nitrogen-doped single crystal silicon rod is surrounded by an interstitial rich region. Vacancy determining a position III of the distribution of interstitial rich regions; and determining a position IV of the distribution of interstitial rich regions in the reference nitrogen-doped single crystal silicon rod based on a fourth silicon wafer to be detected that includes only the interstitial rich regions.

[0029] It can be understood that, as shown in FIG. 6, by performing defect evaluation on multiple silicon wafers W to be detected and determining the defect distribution conditions in each silicon wafer W to be detected, it is possible to determine the types of defects contained in different positions in the reference nitrogen-doped single crystal silicon rod corresponding to each silicon wafer W to be detected and the positions of the defect areas.

[0030] Regarding the technical solution shown in FIG. 4, in some examples, during the preparation process of the above-mentioned current nitrogen-doped single crystal silicon rod, the reference nitrogen-doped single crystal silicon rod is pulled at the distribution position of each defect region in the reference nitrogen-doped single crystal silicon rod at a target pulling speed corresponding to each set defect region to prepare the current nitrogen-doped single crystal silicon rod; When the hot zone structure of the current nitrogen-doped single crystal silicon rod is consistent with the hot zone structure of the reference nitrogen-doped single crystal silicon rod, during the preparation process of the current nitrogen-doped single crystal silicon rod, In the reference nitrogen-doped single crystal silicon rod Vacancy Pulling using a reference crystal pull rate based on the location I of the distribution of rich regions; In the reference nitrogen-doped single crystal silicon rod Vacancy Based on the location II of the distribution of interstitial rich regions surrounding the rich region, a first target crystal pulling speed V 1 and extracting the same using Surrounding the interstitial rich region in the reference nitrogen-doped single crystal silicon rod Vacancy Based on the location of the rich region distribution III, the second target crystal pulling speed V 2 and extracting the same using Based on the position IV of the distribution of the interstitial rich region in the reference nitrogen-doped single crystal silicon rod, a third target crystal pulling speed V 3 and extracting the same using a

[0031] For the above example, in some specific embodiments, the first target crystal pull rate V 1 is the reference crystal pulling speed V 0±0.001mm / min~0.002mm / min, The second target crystal pulling speed V 2 is the reference crystal pulling speed V 0 ±0.002mm / min~0.003mm / min, The third target crystal pulling speed V 3 is the reference crystal pulling speed V 0 ±0.003mm / min~0.006mm / min.

[0032] As can be seen, as shown in Figure 7, Vacancy Current nitrogen-doped single crystal silicon rod S with only rich region 2 In order to obtain the above, different target lifting speeds are used for different defect areas. By using such a method of setting the target lifting speed in stages, Vacancy Current nitrogen-doped single crystal silicon rod S with only rich region 2 This makes it possible to produce silicon wafers with high surface cleanliness at a higher rate.

[0033] It can be understood that, comparing the current nitrogen-doped single crystal silicon rod with the reference nitrogen-doped single crystal, the two manufacturing processes have the same manufacturing process parameters except for the corresponding crystal pulling speed, specifically, the rotation speed of the crucible, the doping method of the nitrogen dopant, the hot zone structure and the protective atmosphere are all the same. Therefore, by studying the defect area of ​​the reference nitrogen-doped single crystal silicon rod, a method for improving the distribution of the defect area of ​​the current nitrogen-doped single crystal silicon rod can be obtained.

[0034] It should be noted that in the embodiment of the present application, the current nitrogen-doped single crystal silicon rod S is adjusted by adjusting the pulling speed in the conventional technical solution. 2 The target lifting speed can be controlled within the above range.

[0035] Referring to FIG. 7, an embodiment of the present application further provides a nitrogen-doped single crystal silicon rod prepared by the preparation method described in the above technical solution.

[0036] It should be noted that the technical solutions described in the embodiments of this application can be arbitrarily combined unless there is a contradiction.

[0037] The above is merely a specific embodiment of the present application, and the scope of protection of the present application is not limited thereto, and those skilled in the art can easily think of modifications and alternatives within the technical scope disclosed in the present application, and all such modifications and alternatives should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be in accordance with the scope of protection of the attached claims.

Claims

1. A method for producing a nitrogen-doped single crystal silicon rod, comprising: After cutting into sample silicon wafers based on the reference nitrogen-doped single crystal silicon rod, selecting a plurality of silicon wafers to be detected, and evaluating the distribution of defect areas of the plurality of silicon wafers to be detected; Determining the distribution position of each defect area in the reference nitrogen-doped single crystal silicon rod based on the distribution of defect areas of the plurality of silicon wafers to be detected; During the process of producing the current nitrogen-doped single crystal silicon rod, the reference nitrogen-doped single crystal silicon rod is pulled at a target pulling speed corresponding to each of the set defect regions at the distribution position of each defect region in the reference nitrogen-doped single crystal silicon rod to produce the current nitrogen-doped single crystal silicon rod; The defect region includes a vacancy rich region, an interstitial rich region, and an alternating distribution region of vacancy rich and interstitial rich, According to the above-mentioned reference nitrogen-doped single crystal silicon rod, after cutting into sample silicon wafers, selecting a plurality of silicon wafers to be detected, and evaluating the distribution of defect areas of the plurality of silicon wafers to be detected, Pulling the reference nitrogen-doped single crystal silicon rod at a reference pulling speed to prepare the reference nitrogen-doped single crystal silicon rod, and cutting the reference nitrogen-doped single crystal silicon rod to obtain the sample silicon wafer; Selecting a plurality of the sample silicon wafers at different positions of the reference nitrogen-doped single crystal silicon rod as the silicon wafers to be detected, and evaluating the distribution of defect areas of the plurality of the silicon wafers to be detected; The above-mentioned evaluating the distribution of defect regions of the plurality of silicon wafers to be detected includes: acquiring minority carrier lifetime data of the surfaces of the plurality of silicon wafers to be detected, and plotting a minority carrier lifetime map according to the minority carrier lifetime data of the surfaces of the plurality of silicon wafers to be detected; Evaluating a distribution of defect regions of the plurality of silicon wafers to be detected based on the minority carrier lifetime map; Evaluating the distribution of defect regions of the plurality of silicon wafers to be detected based on the above-mentioned minority carrier lifetime map includes: When the minority carrier lifetime map is a map with a circular shape and a long lifetime, determining that the silicon wafer to be detected corresponding to the map with the circular shape and the long lifetime is a first silicon wafer to be detected that includes only a vacancy-rich region; When the minority carrier lifetime map is an annular, low lifetime map, determining that the silicon wafer to be detected corresponding to the annular, low lifetime map is a second silicon wafer to be detected that includes an interstitial rich region surrounding a vacancy rich region; When the minority carrier lifetime map is an annular high lifetime map, determining that the silicon wafer to be detected corresponding to the annular high lifetime map is a third silicon wafer to be detected that includes a vacancy rich region surrounding an interstitial rich region; and when the minority carrier lifetime map is a circular map with a low lifetime, determining that the silicon wafer to be detected corresponding to the circular map with a low lifetime is a fourth silicon wafer to be detected that includes only an interstitial rich region.

2. Determining the location of the distribution of each defect area in the reference nitrogen-doped single crystal silicon rod based on the distribution of defect areas of the plurality of silicon wafers to be detected, Determining the distribution position I of the vacancy-rich region in the reference nitrogen-doped single crystal silicon rod based on the first silicon wafer to be detected that contains only the vacancy-rich region; Based on a second silicon wafer to be detected, which includes an interstitial rich region surrounding the vacancy rich region, determining a distribution position II of the interstitial rich region surrounding the vacancy rich region in the reference nitrogen-doped single crystal silicon rod; Based on a third silicon wafer to be detected, which includes a vacancy rich region surrounding the interstitial rich region, determining a distribution position III of the vacancy rich region surrounding the interstitial rich region in the reference nitrogen-doped single crystal silicon rod; and determining a position IV of the distribution of the interstitial rich region in the reference nitrogen-doped single crystal silicon rod based on a fourth silicon wafer to be detected that includes only the interstitial rich region.

3. During the above-mentioned process of producing the current nitrogen-doped single crystal silicon rod, the reference nitrogen-doped single crystal silicon rod is pulled at a target pulling speed corresponding to each set defect region at the distribution position of each defect region in the reference nitrogen-doped single crystal silicon rod to produce the current nitrogen-doped single crystal silicon rod; When the hot zone structure of the current nitrogen-doped single crystal silicon rod is consistent with the hot zone structure of the reference nitrogen-doped single crystal silicon rod, during the preparation process of the current nitrogen-doped single crystal silicon rod, Pulling out the reference nitrogen-doped single crystal silicon rod using a reference crystal pull rate based on the position I of the distribution of vacancy-rich regions in the reference nitrogen-doped single crystal silicon rod; Based on the distribution position II of the interstitial rich region surrounding the vacancy rich region in the reference nitrogen-doped single crystal silicon rod, a first target crystal pulling speed V １ and extracting the same using Based on the distribution position III of the vacancy rich region surrounding the interstitial rich region in the reference nitrogen-doped single crystal silicon rod, a second target crystal pulling speed V ２ and extracting the same using Based on the position IV of the distribution of the interstitial rich region in the reference nitrogen-doped single crystal silicon rod, a third target crystal pulling speed V ３ and drawing the film using a drawing mechanism.

4. The first target crystal pulling speed V １ is the reference crystal pulling speed V ０ ±0.001 to 0.002 mm / min, The second target crystal pulling speed V ２ is the reference crystal pulling speed V ０ ±0.002 mm / min to 0.003 mm / min, The third target crystal pulling speed V ３ is the reference crystal pulling speed V ０ The method according to claim 3, wherein the rate is from ±0.003 mm / min to ±0.006 mm / min.

5. A nitrogen-doped single crystal silicon rod produced by the method according to any one of claims 1 to 4.

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