Preparation method for single-crystal silicon ingot and single-crystal silicon ingot

Abstract

Disclosed are a preparation method for a single-crystal silicon ingot and a single-crystal silicon ingot. The preparation method comprises: calculating a doping ratio between a volatile dopant and a non-volatile dopant corresponding to a head portion of a single-crystal silicon ingot to be drawn; using the resistivity of the head portion of the single-crystal silicon ingot to be drawn and the doping ratio to calculate a first theoretical doping concentration of the volatile dopant and a second theoretical doping concentration of the non-volatile dopant; using the first theoretical doping concentration and a volatilization proportion of the head portion to calculate a supplemental doping concentration of the volatile dopant; determining a condition of a remaining silicon melt in a single-crystal furnace, and, according to the supplemental doping concentration, the first theoretical doping concentration, the second theoretical doping concentration, the condition of the remaining silicon melt in the single-crystal furnace, and an addition amount of the silicon melt, calculating a first actual addition amount of the volatile dopant and a second actual addition amount of the non-volatile dopant; and, according to the first actual addition amount and the second actual addition amount, adding to the silicon melt the non-volatile dopant and the volatile dopant, and using the silicon melt containing the non-volatile dopant and the volatile dopant to draw the single-crystal silicon ingot to be drawn. The resistivity of the single-crystal silicon ingot is precisely regulated and the consistency of resistivity in the axial direction of the single-crystal silicon ingot is ensured.

Description

Method for preparing single crystal silicon rod and single crystal silicon rod

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Chinese Patent Application No. 202411345906.7, filed September 25, 2024, the entire contents of which are incorporated herein by reference. TECHNICAL FIELD

[0003] The present disclosure relates to a method for preparing a single crystal silicon rod and a single crystal silicon rod. BACKGROUND

[0004] For the process of drawing a single crystal silicon rod using a silicon solution with volatile dopants such as antimony, arsenic, etc., during the drawing process of the single crystal silicon rod, the volatile dopants will volatilize, and part of the volatilization will not enter the single crystal silicon rod. If the theoretical doping amount calculated based on the required resistivity of the single crystal silicon rod is still used to add the theoretical doping amount of dopants to the silicon solution, the actual doping amount of dopants in the single crystal silicon rod will be low, not only causing the resistivity of the drawn single crystal silicon rod to deviate, but also causing the head resistivity and tail resistivity of the single crystal silicon rod to change greatly. If the dopants are added in excess in the silicon solution, it brings uncertainty to the resistivity of the drawn single crystal silicon rod, and it is difficult to ensure the consistency of the resistivity of the single crystal silicon rod in the axial direction, especially, the head and tail of the single crystal silicon rod have a relatively large resistivity difference. Therefore, the addition of volatile dopants brings great challenges to the precise control of the resistivity of the single crystal silicon rod and the consistency of the resistivity of the single crystal silicon rod in the axial direction, and the single crystal silicon rod has a low yield.

[0005] SUMMARY

[0006] Therefore, the present disclosure provides a method for preparing a single crystal silicon rod and a single crystal silicon rod, which can precisely control the resistivity of a single crystal silicon rod with volatile doping elements, ensure the consistency of the resistivity of the single crystal silicon rod in the axial direction, and improve the yield of the single crystal silicon rod.

[0007] To solve the above technical problems, the present disclosure provides the following technical solutions:

[0008] In a first aspect, the present disclosure provides a method for preparing a single crystal silicon rod, comprising:

[0009] Step 1, based on the preset solidification rate of the tail of the single crystal silicon rod to be drawn, calculating the doping ratio between the volatile dopant and the non-volatile dopant corresponding to the head of the single crystal silicon rod to be drawn;

[0010] Step 2, calculating a first theoretical doping concentration of the volatile dopant and a second theoretical doping concentration of the non-volatile dopant to be added into the silicon solution respectively according to the head resistivity of the single crystal silicon rod to be drawn and the doping ratio between the volatile dopant and the non-volatile dopant corresponding to the head of the single crystal silicon rod to be drawn;

[0011] Step 3, calculating a head preset volatile proportion of the volatile dopant corresponding to the head of the single crystal silicon rod to be drawn, and calculating a supplementary doping concentration of the volatile dopant according to the first theoretical doping concentration and the preset head volatile proportion of the volatile dopant corresponding to the head of the single crystal silicon rod to be drawn;

[0012] Step 4, determining the remaining silicon solution in the single crystal furnace, and calculating the remaining total amount of the remaining silicon solution and the first remaining doping concentration of the volatile dopant and the second remaining doping concentration of the non-volatile dopant in the remaining silicon solution;

[0013] Step 5, calculating a first actual adding amount of the volatile dopant according to the supplementary doping concentration, the first theoretical doping concentration, the first remaining doping concentration, the remaining total amount of the remaining silicon solution and the preset adding amount of the silicon solution, and calculating a second actual adding amount of the non-volatile dopant according to the second theoretical doping concentration, the second remaining doping concentration, the remaining total amount of the remaining silicon solution and the adding amount of the silicon solution;

[0014] Step 6, adding the non-volatile dopant and the volatile dopant into the silicon solution according to the first actual adding amount and the second actual adding amount, and drawing the single crystal silicon rod to be drawn by using the silicon solution containing the non-volatile dopant and the volatile dopant.

[0015] In a second aspect, the embodiments of the present disclosure provide a single crystal silicon rod, which is obtained based on the preparation method of the single crystal silicon rod provided in the first aspect.

[0016] In a third aspect, the embodiments of the present disclosure provide a silicon wafer, which is prepared from the single crystal silicon rod provided in the second aspect.

[0017] In a fourth aspect, the embodiments of the present disclosure provide a solar cell, which is prepared from the silicon wafer provided in the third aspect.

[0018] In a fifth aspect, the embodiments of the present disclosure provide a photovoltaic module, which comprises a plurality of solar cells provided in the third aspect connected in series and / or in parallel.

[0019] In a sixth aspect, the embodiments of the present disclosure provide an electronic device, which comprises:

[0020] one or more processors;

[0021] a storage device storing one or more programs,

[0022] When the one or more programs are executed by the one or more processors, the one or more processors implement the method provided by the above-mentioned first aspect embodiment.

[0023] In a seventh aspect, the embodiments of the present disclosure provide a computer readable medium having stored thereon a computer program, which, when executed by a processor, implements the method provided by the above-mentioned first aspect embodiment.

[0024] The technical solution of the first aspect of the above-mentioned disclosure has the following advantages or beneficial effects:

[0025] The method for preparing a single crystal silicon rod provided by the embodiments of the present disclosure is directed to co-doping a single crystal silicon rod with volatile dopants (such as arsenic, antimony, etc.) and non-volatile dopants (phosphorus, boron, etc.). The tail preset solidification rate of the single crystal silicon rod to be drawn is preset, and the doping ratio between the volatile dopant and the non-volatile dopant corresponding to the head of the single crystal silicon rod to be drawn is calculated. The control of the doping ratio in combination with subsequent steps can make the resistivity of the single crystal silicon rod consistent in the axial direction. Subsequently, the head resistivity of the single crystal silicon rod to be drawn and the doping ratio between the volatile dopant and the non-volatile dopant corresponding to the head of the single crystal silicon rod to be drawn are used to calculate the first theoretical doping concentration of the volatile dopant and the second theoretical doping concentration of the non-volatile dopant, so that the first theoretical doping concentration of the volatile dopant and the second theoretical doping concentration of the non-volatile dopant meet the doping requirements of the single crystal silicon rod. Then, the head preset volatile proportion of the volatile dopant corresponding to the head of the single crystal silicon rod to be drawn is calculated, and the first theoretical doping concentration and the head preset volatile proportion of the volatile dopant corresponding to the head of the single crystal silicon rod to be drawn are used to calculate the supplementary doping concentration of the volatile dopant. By determining the condition of the remaining silicon solution in the single crystal furnace, the total amount of the remaining silicon solution and the first remaining doping concentration corresponding to the volatile dopant and the second remaining doping concentration corresponding to the non-volatile dopant in the remaining silicon solution are calculated. The first actual addition amount of the volatile dopant is calculated by using the supplementary doping concentration, the first theoretical doping concentration, the first remaining doping concentration, the total amount of the remaining silicon solution, and the preset addition amount of the silicon solution. The calculation of the first actual addition amount of the volatile dopant takes into account the volatilization of the volatile dopant and the influence of the remaining amount in the remaining silicon solution on the volatile dopant, so as to correct the first theoretical doping concentration of the volatile dopant. In the process of calculating the first actual addition amount of the volatile dopant and the second actual addition amount of the non-volatile dopant, the condition of the remaining silicon solution in the single crystal furnace is further considered, so as to ensure that the volatile dopant and the non-volatile dopant added to the silicon solution can meet the head resistivity requirements of the single crystal silicon rod to be drawn, accurately control the resistivity of the single crystal silicon rod, ensure that the resistivity of the single crystal silicon rod is consistent in the axial direction, and effectively improve the yield of the drawn single crystal silicon rod. BRIEF DESCRIPTION OF DRAWINGS

[0026] FIG. 1 is a main flow diagram of a method for preparing a single crystal silicon rod according to an embodiment of the present disclosure;

[0027] FIG. 2 is a main flow diagram of calculating the first theoretical doping concentration of the volatile dopant and the second theoretical doping concentration of the non-volatile dopant according to an embodiment of the present disclosure;

[0028] FIG. 3 is a main flow diagram of calculating the first actual addition amount of the volatile dopant and the second actual addition amount of the non-volatile dopant for a first single crystal silicon rod according to an embodiment of the present disclosure;

[0029] FIG. 4 is a main flowchart of an embodiment of calculating a first actual addition amount of a volatile dopant and a second actual addition amount of a non-volatile dopant for a second or more single crystal silicon rod according to an embodiment of the present disclosure;

[0030] FIG. 5 is a main flowchart of an embodiment of calculating a first tail doping concentration corresponding to a volatile dopant and a second tail doping concentration corresponding to a non-volatile dopant in a tail portion of a last single crystal silicon rod according to an embodiment of the present disclosure;

[0031] FIG. 6 is a main flowchart of constructing a preset function relationship of a volatile proportion of a volatile dopant and a solidification rate according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0032] The resistivity is one of important electrical performance characterization parameters of a Czochralski single crystal silicon rod. Currently, the Czochralski single crystal silicon rod can be divided into P-type and N-type. In the production process of the Czochralski single crystal silicon, the PN type and the resistivity can be controlled by adding a dopant or a master alloy. The P-type master alloy can contain one or more of trivalent elements such as boron (B), aluminum (Al), gallium (Ga), and indium (In). The N-type dopant or master alloy can contain one or more of pentavalent elements such as phosphorus (P), nitrogen (N), arsenic (As), and antimony (Sb).

[0033] Currently, the dopant or the master alloy is placed in the silicon material. In particular, for co-doping in the silicon material using a volatile dopant (such as arsenic, antimony, etc.) and a non-volatile dopant (such as phosphorus, boron, etc.), after heating and melting in a single crystal furnace, the silicon material is mixed with the master alloy or the co-doped dopant, and then the crystal is drawn by the Czochralski method. In the drawing process, the various doping elements of the co-doped dopant in the silicon solution will undergo segregation phenomenon. The segregation coefficients of different doping elements are different, and the volatile dopant will also be volatilized with the airflow, resulting in a large variation in the resistivity of the finally prepared single crystal silicon rod along the length direction. The present technical solution fully considers the volatility of the volatile dopant and the segregation of the non-volatile dopant, calculates the proportion of the volatile dopant and the non-volatile dopant in the head portion of the silicon rod, and then adjusts or corrects the doping amount of the co-doped volatile dopant and non-volatile dopant added into the silicon solution based on the proportion of the volatile dopant and the non-volatile dopant in the head portion of the silicon rod, thereby improving the resistivity consistency of the single crystal silicon rod along the length direction.

[0034] The present disclosure provides a single crystal silicon rod preparation method, which is used for drawing a single crystal silicon rod from a silicon solution containing co-doped volatile dopant and non-volatile dopant. Understandably, the co-doped volatile dopant and non-volatile dopant in the silicon solution belong to the same conduction type, such as P-type or N-type.

[0035] Embodiments of the present disclosure are described in detail below with reference to the attached drawing figures, wherein the same or like component have the same or similar designations. The embodiments described below are presented by way of example only and are not intended to limit the present disclosure as there are a number of variations which will be readily apparent to one of ordinary skill in the art.

[0036] It should be noted that the terms "first", "second" are used only for descriptive purposes and should not be construed as indicating or implying relative importance or an indicated number of technical features. Thus, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present disclosure, the meaning of "a plurality of" is two or more, unless otherwise explicitly and specifically limited.

[0037] Wherein, Fig. 1 shows a main flowchart of a method for preparing a single crystal silicon rod according to an embodiment of the present disclosure; Fig. 2 shows a main flowchart of an embodiment of calculating a first theoretical doping concentration of a volatile dopant and a second theoretical doping concentration of a non-volatile dopant; Fig. 3 shows a main flowchart of an embodiment of calculating a first actual addition amount of a volatile dopant and a second actual addition amount of a non-volatile dopant for a first rod single crystal silicon rod; Fig. 4 shows a main flowchart of an embodiment of calculating a first actual addition amount of a volatile dopant and a second actual addition amount of a non-volatile dopant for a second rod or more single crystal silicon rod; Fig. 5 shows a main flowchart of an embodiment of calculating a first tail doping concentration corresponding to a volatile dopant and a second tail doping concentration corresponding to a non-volatile dopant in a tail of a last rod single crystal silicon rod; and Fig. 6 shows a main flowchart of an embodiment of constructing a preset functional relationship between a volatile ratio of a volatile dopant and a solidification rate. It should be noted that the method for preparing a single crystal silicon rod, the main flowchart of calculating a first theoretical doping concentration of a volatile dopant and a second theoretical doping concentration of a non-volatile dopant, etc. according to an embodiment of the present disclosure can be implemented by an execution program in the form of software or plug-in loaded on a controller or processor or server for controlling a single crystal furnace. In addition, the main flowchart of the first embodiment of calculating a first tail doping concentration corresponding to a volatile dopant and a second tail doping concentration corresponding to a non-volatile dopant in a tail of a last rod single crystal silicon rod, the main flowchart of constructing a preset functional relationship between a volatile ratio of a volatile dopant and a solidification rate, etc. according to an embodiment of the present disclosure can also be implemented by a terminal device such as a laptop, a desktop computer, a mobile phone, a tablet, etc. in the form of software or plug-in.

[0038] As shown in Fig. 1, the method for preparing a single crystal silicon rod can include the following steps:

[0039] Step S101: based on the preset solidification rate of the tail of the single crystal silicon rod to be drawn, the doping ratio between the volatile dopant and the non-volatile dopant corresponding to the head of the single crystal silicon rod to be drawn is calculated;

[0040] Specifically, this step uses the following calculation formula (1) to calculate the doping ratio between the volatile dopant and the non-volatile dopant of the head of the single crystal silicon rod to be drawn;

[0041] Wherein, X represents the first doping proportion of the volatile dopant in the head of the single crystal silicon rod to be drawn; Y represents the second doping proportion of the non-volatile dopant in the head of the single crystal silicon rod to be drawn; The doping ratio between the volatile dopant and the non-volatile dopant of the head of the single crystal silicon rod to be drawn; a represents the first segregation coefficient of the volatile dopant; b represents the second segregation coefficient of the non-volatile dopant; ω represents the preset solidification rate of the tail of the single crystal silicon rod to be drawn; F represents the tail volatile proportion of the volatile dopant corresponding to the tail of the single crystal silicon rod to be drawn.

[0042] As described above, the tail volatile proportion represented by F can be a fixed value determined by the user according to experience, or the volatile proportion of the volatile dopant in the silicon solution corresponding to the solidification rate of the tail of the single crystal silicon rod to be drawn (i.e. the solidification rate of the silicon solution after the single crystal silicon rod to be drawn is drawn), which is the volatile proportion of the volatile dopant in the silicon solution corresponding to the solidification rate of the tail of the single crystal silicon rod to be drawn, which is calculated according to the preset function relationship between the volatile proportion of the volatile dopant and the solidification rate given in the following embodiments, and the specific calculation process will be described in detail in the process of introducing the preset function relationship between the volatile proportion of the volatile dopant and the solidification rate in the following embodiments. It is not repeated here. It is worth noting that the value of F is generally related to the doping concentration of the volatile dopant in the silicon solution, the pressure of the single crystal furnace and other single crystal rod drawing parameters. Therefore, even if the same volatile dopant, the value of F will be different under the condition that the doping concentration of the volatile dopant in the silicon solution, the pressure of the single crystal furnace and other single crystal rod drawing parameters are different.

[0043] The above calculation formula (1) is derived based on the fact that the total amount of volatile and non-volatile doping elements in the head of the single crystal silicon rod is equal to the total amount of volatile and non-volatile doping elements in the tail of the single crystal silicon rod.

[0044] Specifically, assuming that the amount of volatile doping elements in the head of the single crystal silicon rod is M, and the doping amount of non-volatile doping elements in the head of the single crystal silicon rod is N, then the total amount of doping in the head of the single crystal silicon rod is M+N;

[0045] The amount of volatile dopant element in the head of the single crystal silicon rod is M, the doping amount of non-volatile dopant element in the head of the single crystal silicon rod is N, and the total doping amount of the tail of the single crystal silicon rod is calculated as follows:

[0046] Wherein, a represents the segregation coefficient of the volatile dopant; ω represents the solidification rate of the tail of the single crystal silicon rod; F represents the tail volatile proportion of the volatile dopant corresponding to the tail of the single crystal silicon rod to be drawn; b represents the segregation coefficient of the non-volatile dopant;

[0047] Let:

[0048] Through the above derivation And The above calculation formula (1) is obtained.

[0049] From the derivation process of the above calculation formula (1), it can be seen that the above calculation formula (1) is based on the equal total amount of doping in the head and tail of the single crystal silicon rod, and the doping ratio between the volatile dopant and the non-volatile dopant in the head of the single crystal silicon rod to be drawn is calculated. The difference between the resistivity of the head of the single crystal silicon rod and the resistivity of the tail of the single crystal silicon rod can be effectively controlled, so that the difference between the resistivity of the head of the single crystal silicon rod and the resistivity of the tail of the single crystal silicon rod is less than the required silicon wafer resistivity fluctuation range of the battery product, and the resistivity of the single crystal silicon rod in the axial direction is consistent. Therefore, the whole single crystal silicon rod can meet the demand of the battery product, and the utilization rate and the yield of the drawn single crystal silicon rod are improved.

[0050] Step S102: using the head resistivity of the single crystal silicon rod to be drawn and the doping ratio between the volatile dopant and the non-volatile dopant corresponding to the head of the single crystal silicon rod to be drawn, the first theoretical doping concentration of the volatile dopant and the second theoretical doping concentration of the non-volatile dopant added into the silicon solution are calculated respectively;

[0051] Wherein, the head resistivity of the single crystal silicon rod to be drawn is generally determined by the demand of the required solar cell type such as TopCon cell, BC cell, etc.

[0052] Wherein, the volatile dopant and the non-volatile dopant in the silicon solution belong to the same conductive type P type or N type. For example, the volatile dopant and the non-volatile dopant co-doped in the silicon solution belong to N type, the non-volatile dopant element can select phosphorus element, the volatile dopant can select arsenic element, etc. The co-doping of the phosphorus element and the arsenic element is only an example, and those skilled in the art can select the required co-doped dopant element according to the demand.

[0053] The co-doping involved in the embodiments of the present disclosure is generally co-doping of one volatile dopant and one non-volatile dopant or co-doping of one or more volatile dopants and one or more non-volatile dopants.

[0054] Step S103: calculating a head preset volatile proportion of the volatile dopant corresponding to the head of the single crystal silicon rod to be drawn, calculating a supplementary doping concentration of the volatile dopant by using the first theoretical doping concentration and the head preset volatile proportion of the volatile dopant corresponding to the head of the single crystal silicon rod to be drawn.

[0055] This step calculates the supplementary doping concentration of the volatile dopant by using the following calculation formula (2).

[0056] wherein N D-CH represents the supplementary doping concentration of the volatile dopant; N D-LH represents the first theoretical doping concentration of the volatile dopant to be added into the silicon solution calculated in step S102; F t represents the head preset volatile proportion of the volatile dopant corresponding to the head of the single crystal silicon rod to be drawn.

[0057] wherein the volatile proportion of the volatile dopant generally refers to the proportion of the volatile amount of the volatile dopant to the total amount of the volatile dopant. The head preset volatile proportion of the volatile dopant corresponding to the head of the single crystal silicon rod to be drawn refers to the proportion of the volatile amount of the volatile dopant in the silicon solution to the total amount of the volatile dopant added into the silicon solution after the head of the single crystal silicon is drawn.

[0058] The head preset volatile proportion can be a fixed value determined by the user according to experience, can be the volatile proportion of the volatile dopant corresponding to the solidification rate of 0 (i.e. the volatile proportion of the volatile dopant in the material melting stage after the doping agent is added before the drawing), or can be calculated according to the preset function relationship between the volatile proportion of the volatile dopant and the solidification rate and the solidification rate corresponding to the head of the single crystal silicon rod. The specific calculation process will be described in detail in the process of introducing the preset function relationship between the volatile proportion of the volatile dopant and the solidification rate in the following embodiments, and will not be described here.

[0059] Step S104: determining the condition of the remaining silicon solution in the single crystal furnace, calculating the total amount of the remaining silicon solution and the first remaining doping concentration of the volatile dopant and the second remaining doping concentration of the non-volatile dopant in the remaining silicon solution.

[0060] Step S105: using the supplementary doping concentration, the first theoretical doping concentration, the first residual doping concentration, the residual total amount of the residual silicon solution and the preset adding amount of the silicon solution, to calculate the first actual adding amount of the volatile dopant; using the second theoretical doping concentration, the second residual doping concentration, the residual total amount of the residual silicon solution and the adding amount of the silicon solution, to calculate the second actual adding amount of the non-volatile dopant;

[0061] Step S106: adding the non-volatile dopant and the volatile dopant into the silicon solution according to the first actual adding amount and the second actual adding amount, and using the silicon solution containing the non-volatile dopant and the volatile dopant to draw the single crystal silicon rod to be drawn.

[0062] The preparation method of the single crystal silicon rod is directed to co-doping of a single crystal silicon rod with volatile dopants (such as arsenic, antimony, etc.) and non-volatile dopants (phosphorus, boron, etc.). By using the solidification rate of the tail of the single crystal silicon rod to be drawn and formula (1), the doping ratio between the volatile dopant and the non-volatile dopant corresponding to the head of the single crystal silicon rod to be drawn is calculated. As described above, formula (1) is derived on the premise that the total amount of doping at the head and tail of the single crystal silicon rod is equal. Therefore, the doping ratio between the volatile dopant and the non-volatile dopant at the head of the single crystal silicon rod to be drawn calculated in this way can regulate the consistency of the doping amount in the length direction of the single crystal silicon rod during drawing, thereby regulating the consistency of the resistivity in the length direction of the single crystal silicon rod. Subsequently, by using the resistivity of the head of the single crystal silicon rod to be drawn and the doping ratio between the volatile dopant and the non-volatile dopant corresponding to the head of the single crystal silicon rod to be drawn, the first theoretical doping concentration of the volatile dopant and the second theoretical doping concentration of the non-volatile dopant are calculated again, so that the first theoretical doping concentration of the volatile dopant and the second theoretical doping concentration of the non-volatile dopant meet the doping requirements of the single crystal silicon rod. Then, the head preset volatile proportion of the volatile dopant corresponding to the head of the single crystal silicon rod to be drawn is calculated, and the first theoretical doping concentration and the head preset volatile proportion of the volatile dopant corresponding to the head of the single crystal silicon rod to be drawn are used to calculate the supplementary doping concentration of the volatile dopant. By determining the condition of the remaining silicon solution in the single crystal furnace, the total amount of the remaining silicon solution and the first remaining doping concentration corresponding to the volatile dopant and the second remaining doping concentration corresponding to the non-volatile dopant in the remaining silicon solution are calculated. The first actual addition amount of the volatile dopant is calculated by using the supplementary doping concentration, the first theoretical doping concentration, the first remaining doping concentration, the total amount of the remaining silicon solution and the preset addition amount of the silicon solution. This calculation of the first actual addition amount of the volatile dopant takes into account the volatilization of the volatile dopant and the influence of the remaining amount in the remaining silicon solution on the volatile dopant, so as to correct the first theoretical doping concentration of the volatile dopant. In the process of calculating the first actual addition amount of the volatile dopant and the second actual addition amount of the non-volatile dopant, the condition of the remaining silicon solution in the single crystal furnace is further considered, so as to ensure that the volatile dopant and the non-volatile dopant added to the silicon solution can meet the resistivity requirements of the head of the single crystal silicon rod to be drawn, accurately regulate the resistivity of the single crystal silicon rod, ensure that the resistivity of the single crystal silicon rod remains consistent in the axial direction, and effectively improve the yield of the drawn single crystal silicon rod.

[0063] In the specific embodiment of step S102, as shown in FIG. 2, the step S102 can include the following steps:

[0064] Step S1021: calculating the total doping concentration of the head of the single crystal silicon rod to be drawn by using the resistivity of the head of the single crystal silicon rod to be drawn.

[0065] For this step, mainly using the general conversion relationship between resistivity and doping concentration and the resistivity of the head of the single crystal silicon rod to be pulled, the total doping concentration of the head of the single crystal silicon rod to be pulled is calculated; wherein, for different conductive types of co-doped elements, different conversion relationships are selected. Next, taking N-type co-doped doping elements or P-type co-doped doping elements as examples, the general conversion relationship of N-type doping elements and the general conversion relationship of P-type doping elements are described in detail.

[0066] For example, for N-type co-doped elements, this step uses the following general calculation formula group (A) to calculate the total doping concentration of the head of the single crystal silicon rod to be pulled;

[0067] Wherein, N D1 represents the total doping concentration of the head of the single crystal silicon rod to be pulled; ρ1 represents the resistivity of the head of the single crystal silicon rod to be pulled; A0=-3.1083; A1=-3.2626; A2=-1.2196; A3=-0.13923; B1=1.0265; B2=0.38755; B3=0.041833.

[0068] For example, for P-type co-doped elements, this step uses the following general calculation formula (3) to calculate the total doping concentration of the head of the single crystal silicon rod to be pulled;

[0069] The corresponding conversion relationship is shown in the following calculation formula (3).

[0070] Wherein, N D1 represents the total doping concentration of the head of the single crystal silicon rod to be pulled; ρ1 represents the resistivity of the head of the single crystal silicon rod to be pulled.

[0071] Through research, it is found that for this step, the general conversion relationship between resistivity and doping concentration of N-type doping elements co-doped (i.e. the above calculation formula group A) and the general conversion relationship between resistivity and doping concentration of P-type doping elements co-doped (i.e. the above calculation formula 3) are selected, which can more accurately calculate the first theoretical doping concentration of the volatile dopant to be added to the silicon solution and the second theoretical doping concentration of the non-volatile dopant to be added to the silicon solution in cooperation with the following steps S1022 and S1023.

[0072] Step S1022: using the doping ratio between the volatile dopant and the non-volatile dopant corresponding to the head of the single crystal silicon rod to be pulled and the total doping concentration of the head, respectively calculating the first head doping concentration corresponding to the volatile dopant and the second head doping concentration corresponding to the non-volatile dopant of the head;

[0073] Specifically, the first head doping concentration corresponding to the volatile dopant of the head of the single crystal silicon rod to be drawn is calculated by using the following calculation formula (4). N D1-H = N D1 X (4)

[0074] N D1-H represents the first head doping concentration corresponding to the volatile dopant of the head of the single crystal silicon rod to be drawn; X represents the first doping proportion of the volatile dopant in the head of the single crystal silicon rod to be drawn; N D1 represents the total doping concentration of the head of the single crystal silicon rod to be drawn.

[0075] The second head doping concentration corresponding to the non-volatile dopant of the head of the single crystal silicon rod to be drawn is calculated by using the following calculation formula (5). N D1-F = N D1 Y (5)

[0076] N D1-F represents the second head doping concentration corresponding to the non-volatile dopant of the head of the single crystal silicon rod to be drawn; Y represents the second doping proportion of the non-volatile dopant in the head of the single crystal silicon rod to be drawn; N D1 represents the total doping concentration of the head of the single crystal silicon rod to be drawn.

[0077] Step S1023: calculating the first theoretical doping concentration of the volatile dopant to be added into the silicon solution by using the first head doping concentration and the segregation coefficient of the volatile dopant, and calculating the second theoretical doping concentration of the non-volatile dopant to be added into the silicon solution by using the second head doping concentration and the segregation coefficient of the non-volatile dopant.

[0078] Specifically, the first theoretical doping concentration of the volatile dopant to be added into the silicon solution is calculated by using the following calculation formula (6).

[0079] wherein, N D-LH represents the first theoretical doping concentration of the volatile dopant to be added into the silicon solution; N D1-H represents the first head doping concentration corresponding to the volatile dopant of the head of the single crystal silicon rod to be drawn; a represents the first segregation coefficient of the volatile dopant.

[0080] The second theoretical doping concentration of the non-volatile dopant to be added into the silicon solution is calculated by using the following calculation formula (7).

[0081] wherein, N D-LF represents the second theoretical doping concentration of the non-volatile dopant to be added into the silicon solution; N D1-Fa represents a second head doping concentration of the non-volatile dopant corresponding to the head of the single crystal silicon rod to be drawn; b represents a second segregation coefficient of the non-volatile dopant.

[0082] The first theoretical doping concentration of the volatile dopant is determined based on the resistivity corresponding to the head of the single crystal silicon rod to be drawn and the doping ratio between the volatile dopant and the non-volatile dopant in the head of the single crystal silicon rod to be drawn without considering the volatility of the volatile dopant.

[0083] The remaining silicon solution in the single crystal furnace has a relatively large difference for the single crystal silicon rod to be drawn being the first rod single crystal silicon rod and the second rod or more single crystal silicon rod. Based on this, the step S104 can have different implementation manners.

[0084] Specifically, for the case that the single crystal silicon rod to be drawn is the first rod single crystal silicon rod, the remaining silicon solution in the single crystal furnace is that the amount of the remaining silicon solution is 0, and the specific implementation manner of the step S104 can include: determining that the total amount of the remaining silicon solution in the single crystal furnace and the remaining concentrations of the volatile dopant and the non-volatile dopant in the remaining silicon solution are all 0.

[0085] Correspondingly, as shown in FIG. 3, the step S105 includes:

[0086] Step S1051: calculating the first actual addition amount of the volatile dopant by using the replenishment doping concentration, the first theoretical doping concentration and the addition amount of the silicon solution;

[0087] This step calculates the first actual addition amount of the volatile dopant by using the following calculation formula (8).

[0088] Wherein, m a represents the first actual addition amount of the volatile dopant calculated for the single crystal silicon rod to be drawn being the first rod single crystal silicon rod; N D-LH represents the first theoretical doping concentration of the volatile dopant; N D-BH represents the replenishment doping concentration of the volatile dopant; m t-Si represents the addition amount of the silicon solution; M t-Si represents the density of the silicon solution.

[0089] Step S1052: calculating the second actual addition amount of the non-volatile dopant by using the second theoretical doping concentration and the addition amount of the silicon solution.

[0090] This step calculates the second actual addition amount of the non-volatile dopant by using the following calculation formula (9).

[0091] Wherein, m brepresents the second actual addition amount of the non-volatile dopant calculated; m D-LF represents the second theoretical doping concentration of the non-volatile dopant; m t-Si represents the addition amount of the silicon solution; M t-Si represents the density of the silicon solution.

[0092] It is worth noting that there is no strict execution order between the above-mentioned step S1051 and step S1052. Step S1051 can be executed first, and step S1052 can be executed later. Step S1052 can be executed first, and step S1051 can be executed later. Step S1051 and step S1052 can be executed synchronously.

[0093] For the case of drawing a single crystal silicon rod using a silicon solution co-doped with a volatile dopant and a non-volatile dopant, the second actual addition amount of the non-volatile dopant required to be added to the silicon solution at the start of the drawing process is determined by the above-mentioned step S1051 and step S1052, which ensures that the resistivity of the drawn first rod single crystal silicon rod meets the requirements, and improves the yield of the single crystal silicon rod.

[0094] Specifically, for the case of the single crystal silicon rod to be drawn being a second rod or a single crystal silicon rod of two or more rods, there will be residual silicon solution in the single crystal furnace after the last rod is drawn. Based on this, as shown in FIG. 4, the specific implementation mode of step S104 can include:

[0095] Step S1041': using the total amount of silicon solution in the single crystal furnace corresponding to the last rod single crystal silicon rod and the tail solidification rate of the last rod single crystal silicon rod, calculating the residual total amount of residual silicon solution in the single crystal furnace;

[0096] The amount of residual silicon solution in the single crystal furnace is calculated using the following calculation formula (10). m s-Si = m z-Si × (1 - ω s ) (10)

[0097] Wherein, m s-Si represents the calculated amount of residual silicon solution in the single crystal furnace; m z-Si represents the total amount of silicon solution in the single crystal furnace corresponding to the last rod single crystal silicon rod; ω s represents the solidification rate corresponding to the last rod single crystal silicon rod. The solidification rate corresponding to the last rod single crystal silicon rod refers to the solidification rate of the silicon solution after the last rod single crystal silicon rod is drawn.

[0098] Step S1042' : calculating a first tail doping concentration corresponding to the volatile dopant and a second tail doping concentration corresponding to the non-volatile dopant in the tail of the last single crystal silicon rod respectively by using the tail resistivity of the last single crystal silicon rod, the segregation coefficient of the non-volatile dopant, the solidification rate corresponding to the last single crystal silicon rod and the first initial doping concentration of the non-volatile dopant in the total amount of the silicon solution in the single crystal furnace corresponding to the last single crystal silicon rod;

[0099] There are two specific implementations for this step, which will be described in detail below, and will not be repeated here.

[0100] Step S1043' : calculating a first residual doping concentration corresponding to the volatile dopant in the remaining silicon solution in the single crystal furnace by using the first tail doping concentration and the segregation coefficient corresponding to the volatile dopant;

[0101] The first residual doping concentration corresponding to the volatile dopant in the remaining silicon solution in the single crystal furnace is calculated by using the following calculation formula (11).

[0102] Wherein, N D-sH represents the calculated first residual doping concentration corresponding to the volatile dopant in the remaining silicon solution in the single crystal furnace; N D-swH represents the first tail doping concentration corresponding to the volatile dopant in the tail of the last single crystal silicon rod; a represents the first segregation coefficient of the volatile dopant.

[0103] Step S1044' : calculating a second residual doping concentration corresponding to the non-volatile dopant in the remaining silicon solution in the single crystal furnace by using the second tail doping concentration and the segregation coefficient corresponding to the non-volatile dopant;

[0104] The second residual doping concentration corresponding to the non-volatile dopant in the remaining silicon solution in the single crystal furnace is calculated by using the following calculation formula (12).

[0105] Wherein, N D-sF represents the calculated second residual doping concentration corresponding to the non-volatile dopant in the remaining silicon solution in the single crystal furnace; N D-swF represents the second tail doping concentration corresponding to the non-volatile dopant in the tail of the last single crystal silicon rod; b represents the second segregation coefficient of the volatile dopant.

[0106] Correspondingly, as shown in FIG. 4, step S105 includes:

[0107] Step S1051' : calculating a first actual addition amount of the volatile dopant by using the supplementary doping concentration, the first theoretical doping concentration, the first residual doping concentration, the amount of the remaining silicon solution and the addition amount of the silicon solution;

[0108] This step calculates the first actual addition amount of the volatile dopant by using the following calculation formula (13).

[0109] wherein, m a indicates the first actual addition amount of the volatile dopant calculated for the single crystal silicon rod to be drawn as the second rod or the single crystal silicon rod of the second rod or above; N D-LH indicates the first theoretical doping concentration of the volatile dopant; N D-BH indicates the complementary doping concentration of the volatile dopant; N D-sH indicates the first remaining doping concentration corresponding to the volatile dopant; m t-Si indicates the addition amount of the silicon solution; M t-Si indicates the density of the silicon solution.

[0110] Step S1052': calculating the second actual addition amount of the non-volatile dopant by using the second theoretical doping concentration, the second remaining doping concentration, the amount of the remaining silicon solution and the addition amount of the silicon solution.

[0111] This step calculates the first actual addition amount of the volatile dopant by using the following calculation formula (13).

[0112] wherein, m b indicates the second actual addition amount of the non-volatile dopant calculated for the single crystal silicon rod to be drawn as the second rod or the single crystal silicon rod of the second rod or above; N D-LF indicates the second theoretical doping concentration of the non-volatile dopant; N D-sF indicates the second remaining doping concentration corresponding to the non-volatile dopant; m t-Si indicates the addition amount of the silicon solution; M t-Si indicates the density of the silicon solution.

[0113] It is worth mentioning that there is no strict execution sequence between the above-mentioned step S1051' and step S1052', which can be that the step S1051' is executed before the step S1052', or the step S1051' is executed after the step S1052', or the step S1051' and the step S1052' are executed synchronously.

[0114] Through the above-mentioned steps S1041' to step S1052', the doping amount of the volatile dopant and the non-volatile dopant in the silicon solution can be controlled for each single crystal silicon rod according to the actual process requirement, so that the doping of the volatile dopant and the non-volatile dopant in the silicon solution is targeted, the yield of the drawn single crystal silicon rod is improved, and the stability of the drawing process can be ensured.

[0115] Specifically, as shown in FIG. 5, the specific implementation of step S1042' can include the following steps:

[0116] Step S1042'-1, calculating the total tail dopant concentration of the previous single crystal silicon rod by using the tail resistivity of the previous single crystal silicon rod.

[0117] For this step, the total tail dopant concentration of the previous single crystal silicon rod is calculated by using the general conversion relationship between resistivity and dopant concentration and the tail resistivity of the previous single crystal silicon rod; for different co-doped elements of different conductivity types, different conversion relationships are selected. Next, taking N-type co-doped dopant elements or P-type co-doped dopant elements as examples, the general conversion relationship for N-type dopant elements and the general conversion relationship for P-type dopant elements are described in detail.

[0118] For example, for N-type co-doped elements, this step uses the following general calculation formula group (B) to calculate the total tail dopant concentration of the previous single crystal silicon rod:

[0119] wherein, N D2 represents the total tail dopant concentration of the previous single crystal silicon rod; ρ2 represents the tail resistivity of the previous single crystal silicon rod; A0 = -3.1083; A1 = -3.2626; A2 = -1.2196; A3 = -0.13923; B1 = 1.0265; B2 = 0.38755; B3 = 0.041833.

[0120] For example, for P-type co-doped elements, this step uses the following general calculation formula (15) to calculate the total tail dopant concentration of the previous single crystal silicon rod:

[0121] The corresponding conversion relationship is shown in the following calculation formula (15).

[0122] wherein, N D2 represents the total tail dopant concentration of the previous single crystal silicon rod; ρ2 represents the tail resistivity of the previous single crystal silicon rod.

[0123] Step S1042'-2, calculating the second tail dopant concentration of the non-volatile dopant in the tail of the previous single crystal silicon rod by using the segregation coefficient of the non-volatile dopant, the solidification rate corresponding to the previous single crystal silicon rod, and the first initial dopant concentration of the non-volatile dopant in the total amount of silicon solution in the single crystal furnace corresponding to the previous single crystal silicon rod.

[0124] This step calculates the second tail dopant concentration of the non-volatile dopant in the tail of the previous single crystal silicon rod by using the following calculation formula (16): D2-F = b × N s-F × (1-g)b-1 (16)

[0125] wherein, N D2-F represents the second tail doping concentration of the non-volatile dopant in the tail of the last single crystal silicon rod; b represents the segregation coefficient of the non-volatile dopant; N s-F represents the first actual doping concentration of the non-volatile dopant in the total amount of the silicon solution in the single crystal furnace corresponding to the last single crystal silicon rod; g represents the solidification rate corresponding to the last single crystal silicon rod, which refers to the solidification rate of the silicon solution after the last single crystal silicon rod is drawn.

[0126] Step S1042'-3, subtracting the second tail doping concentration of the non-volatile dopant from the total doping concentration, to calculate the first tail doping concentration of the volatile dopant in the tail of the last single crystal silicon rod.

[0127] Further, the embodiment of the present disclosure can further comprise, before the above step S101, calculating the tail volatile proportion of the volatile dopant corresponding to the tail of the to-be-drawn single crystal silicon rod, by using a preset function relationship between the volatile proportion and the solidification rate of the volatile dopant and the preset solidification rate of the tail of the to-be-drawn single crystal silicon rod.

[0128] It is found through research that the preset function relationship can be obtained by data statistics or model training on the solidification rate of the drawn multiple single crystal silicon rods and the volatile proportion of the volatile dopant. The specific function relationship can be a linear function, a quadratic function, etc.

[0129] For example, the preset function relationship between the volatile proportion and the solidification rate of the volatile dopant constructed by the embodiment of the present disclosure is the following relationship (17): γ = ω + N (17)

[0130] wherein, γ represents the volatile proportion of the volatile dopant; ω represents the solidification rate of the silicon solution; N represents the fitting difference value between the volatile proportion and the solidification rate based on sample data statistics. The fitting difference value between the volatile proportion and the solidification rate is obtained by data statistics, which is related to the drawing parameters such as the volatile dopant and the pressure of the single crystal furnace, that is, the N value is different for different volatile dopants.

[0131] Further, in order to obtain the preset function relationship between the volatile proportion and the solidification rate of the volatile dopant, as shown in FIG. 6, the above preparation method can further comprise the following steps:

[0132] For the same process conditions, using a silicon solution containing volatile dopants and non-volatile dopants to draw multiple single crystal silicon rod samples, for each single crystal silicon rod in the sample, the following steps S601-S603 are performed:

[0133] Step S601: Detect the resistivity of a plurality of predetermined positions of the single crystal silicon rod, and determine the solidification rate corresponding to the predetermined position;

[0134] Wherein, the predetermined position can be selected according to the needs, such as, every 10%, 20% of the total length from the constant diameter as the preset position. The solidification rate corresponding to the predetermined position generally refers to the ratio of the amount of crystalline silicon used by the single crystal silicon rod from the start of drawing the single crystal silicon rod or the constant diameter to the total amount of silicon solution in the single crystal furnace before drawing.

[0135] The solidification rate corresponding to the predetermined position can be calculated according to the solidification rate after the single crystal silicon rod is drawn and the proportion of the length of the single crystal rod from the start of drawing the single crystal silicon rod to the predetermined position to the total length of the single crystal silicon rod.

[0136] Step S602: For each predetermined position, the following steps S7021-S7023 are performed:

[0137] Step S6021: Calculate the second total actual doping concentration of the predetermined position using the resistivity of the predetermined position;

[0138] This step calculates the second total actual doping concentration of the predetermined position, which can be calculated using the general conversion relationship between resistivity and doping concentration and the resistivity of the predetermined position. Among them, the general conversion relationship between resistivity and doping concentration is selected for different conductive types of co-doped elements. The above calculation formula group (A) shows the general conversion relationship for N-type co-doped elements. Only need to replace the resistivity in the calculation formula group (A) with the resistivity of the predetermined position, the second actual doping concentration of the predetermined position for N-type co-doped elements can be calculated; The calculation formula (3) shows the general conversion relationship for P-type co-doped elements. Only need to replace the resistivity in the calculation formula (3) with the resistivity of the predetermined position, the second actual doping concentration of the predetermined position for P-type co-doped elements can be calculated.

[0139] Step S6022: Calculate the third actual doping concentration of the non-volatile dopant at the predetermined position using the segregation coefficient of the non-volatile dopant, the first initial doping concentration of the non-volatile dopant in the silicon solution, and the solidification rate corresponding to the predetermined position;

[0140] This step calculates the third actual doping concentration of the non-volatile dopant at the predetermined position using the following calculation formula (18).

[0141] b-1 N DP-F = b x N D-F1 x (1 - g) (18)

[0142] wherein N DP-F represents the third actual doping concentration of the non-volatile dopant at the predetermined position of the single crystal silicon ingot; b represents the segregation coefficient of the non-volatile dopant; N D-F1 represents the first initial doping concentration of the non-volatile dopant in the silicon solution; g represents the solidification rate corresponding to the predetermined position; wherein the solidification rate corresponding to the predetermined position means the solidification rate of the silicon solution after the single crystal silicon ingot is drawn to the predetermined position.

[0143] Step S6023: subtracting the third actual doping concentration from the second actual doping concentration to obtain the fourth actual doping concentration of the volatile dopant;

[0144] Step S6024: calculating the third theoretical doping concentration of the volatile dopant at the predetermined position by using the segregation coefficient of the volatile dopant, the second initial doping concentration of the volatile dopant in the silicon solution, and the solidification rate corresponding to the predetermined position;

[0145] This step calculates the third theoretical doping concentration of the volatile dopant at the predetermined position by using the following calculation formula (19). DP-HL = a x N D-H1 x (1 - g) a-1 (19)

[0146] wherein N DP-HL represents the third theoretical doping concentration of the volatile dopant at the predetermined position of the single crystal silicon ingot; a represents the segregation coefficient of the volatile dopant; N D-H1 represents the first initial doping concentration of the volatile dopant in the silicon solution; g represents the solidification rate corresponding to the predetermined position; wherein the solidification rate corresponding to the predetermined position means the solidification rate of the silicon solution after the single crystal silicon ingot is drawn to the predetermined position.

[0147] Step S6025: obtaining the volatile proportion of the volatile dopant corresponding to the predetermined position by using the third theoretical doping concentration and the fourth actual doping concentration;

[0148] This step calculates the volatile proportion of the volatile dopant corresponding to the predetermined position at the predetermined position by using the following calculation formula (20).

[0149] wherein γ i represents the volatile proportion of the volatile dopant corresponding to the predetermined position i of the single crystal silicon ingot; N DP-HLa third theoretical doping concentration corresponding to the volatile dopant representing the predetermined position of the single crystal silicon rod; N DP-HS a fourth actual doping concentration corresponding to the volatile dopant representing the predetermined position; g represents the solidification rate corresponding to the predetermined position; wherein the solidification rate corresponding to the predetermined position refers to the solidification rate of the silicon solution after the single crystal silicon rod is drawn to the predetermined position.

[0150] Step S603: determining the correspondence between the solidification rate of the plurality of preset positions and the volatile proportion of the volatile dopant;

[0151] Exemplarily, the correspondence between the solidification rate of the plurality of preset positions and the volatile proportion of the volatile dopant determined through the step is shown in Table 1.

[0152] Table 1

[0153] It is worth noting that the correspondence between the solidification rate of the plurality of preset positions and the volatile proportion of the volatile dopant shown in Table 1 is only an example, and the correspondence between the solidification rate of the plurality of preset positions and the volatile proportion of the volatile dopant may be different according to the differences in the process parameters of the single crystal silicon drawing, the single crystal furnace, etc.

[0154] Step S604: using the correspondence between the solidification rate of the plurality of preset positions and the volatile proportion of the volatile dopant of each single crystal silicon rod to construct a preset function relationship between the volatile proportion of the volatile dopant and the solidification rate.

[0155] The constructed function relationship can be obtained through data statistics, model training, machine learning, etc.

[0156] Further, the embodiment of the present disclosure also provides a single crystal silicon rod, which is obtained based on the preparation method of the single crystal silicon rod provided in any of the above embodiments.

[0157] The single crystal silicon rod provided by the embodiment of the present disclosure satisfies the following conditions:

[0158] 15% < (the concentration of the volatile dopant at the head of the single crystal silicon rod - the concentration of the volatile dopant at the tail of the single crystal silicon rod) / the concentration of the volatile dopant at the head of the single crystal silicon rod ≤ 40%.

[0159] Further, the embodiment of the present disclosure also provides a silicon wafer prepared according to the single crystal silicon rod provided in the above embodiments.

[0160] Further, the embodiment of the present disclosure also provides a solar cell prepared according to the silicon wafer provided in the above embodiments.

[0161] Further, the present disclosure provides a photovoltaic module, comprising a plurality of the above-mentioned solar cells connected in series and / or in parallel.

[0162] The preparation method of the single crystal silicon rod according to the present disclosure is described below with a specific example. The resistivity and oxygen content of the single crystal silicon rod drawn by the example and the comparative example corresponding to different solidification rates are compared.

[0163] Further, the present disclosure provides an electronic device, which can include:

[0164] one or more processors;

[0165] a storage device for storing one or more programs,

[0166] when the one or more programs are executed by the one or more processors, the one or more processors implement the preparation method of the single crystal silicon rod according to any of the above-mentioned embodiments.

[0167] Further, the present disclosure provides a computer readable medium having a computer program stored thereon, the program being executed by a processor to implement the preparation method of the single crystal silicon rod according to any of the above-mentioned embodiments.

[0168] In particular, according to the embodiments of the present disclosure, the processes described above with reference to the flowcharts can be implemented as a computer software program. For example, the embodiments of the present disclosure include a computer program product comprising a computer program carried on a computer readable medium, the computer program comprising program code for executing the method shown in the flowchart. In such embodiments, the computer program can be downloaded and installed from a network by a communication part, and / or installed from a detachable medium. When the computer program is executed by a central processing unit (CPU), the above-mentioned functions defined in the system of the present disclosure are executed.

[0169] It should be noted that the computer-readable medium shown in the present disclosure can be a computer-readable signal medium or a computer-readable storage medium or any combination of the two. The computer-readable storage medium may, for example, but is not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device or apparatus, or any combination of the above. More specific examples of computer-readable storage media can include, but are not limited to, an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In the present disclosure, the computer-readable storage medium can be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, device or apparatus. In the present disclosure, the computer-readable signal medium can include a data signal carried in a baseband or as a part of a carrier wave, which carries computer-readable program code. Such a propagated data signal can take many forms, including but not limited to an electromagnetic signal, an optical signal, or any suitable combination of the above. The computer-readable signal medium can also be any computer-readable medium other than the computer-readable storage medium, which can send, propagate or transmit a program for use by or in conjunction with an instruction execution system, device or apparatus. The program code contained on the computer-readable medium can be transmitted by any suitable medium, including but not limited to wireless, wire, optical cable, RF, etc., or any suitable combination of the above.

[0170] The above steps provide an introduction to help understand the structure, method and core idea of the present disclosure. For those skilled in the art, without departing from the principles of the present disclosure, the present disclosure can be improved and modified in several ways, and these improvements and modifications also belong to the scope of protection of the present disclosure.

Claims

1. A method for preparing a single crystal silicon rod, comprising: Step 1, calculating a doping ratio between a volatile dopant and a non-volatile dopant corresponding to a head of a single crystal silicon rod to be drawn based on a preset solidification rate of a tail of the single crystal silicon rod to be drawn; Step 2, calculating a first theoretical doping concentration of the volatile dopant and a second theoretical doping concentration of the non-volatile dopant to be added into a silicon solution respectively by using a resistivity of the head of the single crystal silicon rod to be drawn and the doping ratio between the volatile dopant and the non-volatile dopant corresponding to the head of the single crystal silicon rod to be drawn; Step 3, calculating a preset head volatile proportion of the volatile dopant corresponding to the head of the single crystal silicon rod to be drawn, and calculating a supplementary doping concentration of the volatile dopant by using the first theoretical doping concentration and the preset head volatile proportion of the volatile dopant corresponding to the head of the single crystal silicon rod to be drawn; Step 4, determining a condition of a remaining silicon solution in a single crystal furnace, calculating a remaining total amount of the remaining silicon solution and a first remaining doping concentration of the volatile dopant and a second remaining doping concentration of the non-volatile dopant corresponding to the remaining silicon solution; Step 5, calculating a first actual adding amount of the volatile dopant by using the supplementary doping concentration, the first theoretical doping concentration, the first remaining doping concentration, the remaining total amount of the remaining silicon solution and a preset adding amount of the silicon solution, and calculating a second actual adding amount of the non-volatile dopant by using the second theoretical doping concentration, the second remaining doping concentration, the remaining total amount of the remaining silicon solution and the adding amount of the silicon solution; Step 6, adding the non-volatile dopant and the volatile dopant into the silicon solution according to the first actual adding amount and the second actual adding amount, and drawing the single crystal silicon rod to be drawn by using the silicon solution containing the non-volatile dopant and the volatile dopant.

2. The method of producing a single crystal silicon ingot according to claim 1, wherein Step 1 comprises: calculating the doping ratio between the volatile dopant and the non-volatile dopant corresponding to the head of the single crystal silicon rod to be drawn based on the preset solidification rate of the tail of the single crystal silicon rod to be drawn by using the following calculation formula: doping ratio of the first and second dopants; wherein X represents a first doping proportion of the volatile dopant at the head of the single crystal silicon rod to be drawn; Y represents a second doping proportion of the non-volatile dopant at the head of the single crystal silicon rod to be drawn; F = a * (1 - ω) / (b * ω) represents the doping ratio between the volatile dopant and the non-volatile dopant corresponding to the head of the single crystal silicon rod to be drawn; a represents a first segregation coefficient of the volatile dopant; b represents a second segregation coefficient of the non-volatile dopant; ω represents the preset solidification rate of the tail of the single crystal silicon rod to be drawn; F represents a tail volatile proportion of the volatile dopant corresponding to the tail of the single crystal silicon rod to be drawn.

3. The method of producing a single crystal silicon ingot according to claim 1 or 2, wherein Step 2 comprises: Step 21, calculating a head total doping concentration of the head of the single crystal silicon rod to be drawn by using the resistivity of the head of the single crystal silicon rod to be drawn; Step 22, calculating a first head doping concentration corresponding to the volatile dopant and a second head doping concentration corresponding to the non-volatile dopant of the head respectively by using the doping ratio between the volatile dopant and the non-volatile dopant corresponding to the head of the single crystal silicon rod to be drawn and the head total doping concentration. Step 23, calculating a first theoretical doping concentration of the volatile dopant to be added into the silicon solution by using the first head doping concentration and the segregation coefficient of the volatile dopant, and calculating a second theoretical doping concentration of the non-volatile dopant to be added into the silicon solution by using the second head doping concentration and the segregation coefficient of the non-volatile dopant.

4. The method of claim 1, wherein, for the case that the single crystal silicon rod to be pulled is a first single crystal silicon rod, and the remaining silicon solution in the single crystal furnace is the case that the amount of the remaining silicon solution is 0, Step 4 comprises: determining that the total amount of the remaining silicon solution in the single crystal furnace and the remaining concentrations of the volatile dopant and the non-volatile dopant in the remaining silicon solution are all 0; or, for the case that the single crystal silicon rod to be pulled is a second single crystal silicon rod or more, Step 4 comprises: Step 41', calculating the total amount of the remaining silicon solution in the single crystal furnace by using the total amount of the silicon solution in the single crystal furnace corresponding to the previous single crystal silicon rod and the tail solidification rate of the previous single crystal silicon rod; Step 42', calculating the first tail doping concentration corresponding to the volatile dopant and the second tail doping concentration corresponding to the non-volatile dopant in the tail of the previous single crystal silicon rod by using the tail resistivity of the previous single crystal silicon rod, the segregation coefficient of the non-volatile dopant, the solidification rate corresponding to the previous single crystal silicon rod, and the first initial doping concentration of the non-volatile dopant in the total amount of the silicon solution in the single crystal furnace corresponding to the previous single crystal silicon rod, respectively; Step 43', calculating the first remaining doping concentration corresponding to the volatile dopant in the remaining silicon solution in the single crystal furnace by using the first tail doping concentration and the segregation coefficient corresponding to the volatile dopant; Step 44', calculating the second remaining doping concentration corresponding to the non-volatile dopant in the remaining silicon solution in the single crystal furnace by using the second tail doping concentration and the segregation coefficient corresponding to the non-volatile dopant.

5. The method of producing a single crystal silicon ingot according to claim 4, wherein Step 42' comprises: Step 42'-1, calculating the total doping concentration of the tail of the previous single crystal silicon rod by using the tail resistivity of the previous single crystal silicon rod; Step 42'-2, calculating the second tail doping concentration corresponding to the non-volatile dopant in the tail of the previous single crystal silicon rod by using the segregation coefficient of the non-volatile dopant, the solidification rate corresponding to the previous single crystal silicon rod, and the first initial doping concentration of the non-volatile dopant in the total amount of the silicon solution in the single crystal furnace corresponding to the previous single crystal silicon rod; Step 42'-3, calculating the first tail doping concentration corresponding to the volatile dopant in the tail of the previous single crystal silicon rod by subtracting the second tail doping concentration of the non-volatile dopant from the total doping concentration. Step 1 further comprises:

6. The method of producing a single crystal silicon ingot according to claim 2, wherein calculating the tail volatile proportion of the volatile dopant corresponding to the tail of the single crystal silicon rod to be pulled by using a preset functional relationship between the volatile proportion and the solidification rate of the volatile dopant and the preset tail solidification rate of the single crystal silicon rod to be pulled; ​ The preset functional relationship between the volatile proportion of the volatile dopant and the solidification rate is as follows: γ = ω + N Wherein, γ represents the volatile proportion of the volatile dopant; ω represents the solidification rate of the silicon solution; N represents the fitting difference value between the volatile proportion and the solidification rate based on sample data statistics.

7. The method of producing a single crystal silicon ingot according to claim 6, wherein Further comprising: For the same process conditions, using the silicon solution containing the volatile dopant and the non-volatile dopant to draw out multiple single crystal silicon rod samples, for each single crystal silicon rod in the sample, the following steps M1 to M3 are performed: M1: detecting the resistivity of multiple predetermined positions of the single crystal silicon rod, and determining the solidification rate corresponding to the predetermined positions; M2: for each of the predetermined positions, the following steps M21 to M25 are performed: M21: using the resistivity of the predetermined position, calculating the second actual total doping concentration of the predetermined position; M22: using the segregation coefficient of the non-volatile dopant, the first initial doping concentration of the non-volatile dopant in the silicon solution, and the solidification rate corresponding to the predetermined position, calculating the third actual doping concentration of the predetermined position corresponding to the non-volatile dopant; M23: subtracting the third actual doping concentration from the second actual total doping concentration to obtain the fourth actual doping concentration of the volatile dopant; M24: using the segregation coefficient of the volatile dopant, the second initial doping concentration of the volatile dopant in the silicon solution, and the solidification rate corresponding to the predetermined position, calculating the third theoretical doping concentration of the predetermined position corresponding to the volatile dopant; M25: using the third theoretical doping concentration and the fourth actual doping concentration to obtain the volatile proportion of the volatile dopant; M3: determining the corresponding relationship between the solidification rate of multiple predetermined positions and the volatile proportion of the volatile dopant; Using the determined corresponding relationship between the solidification rate of multiple predetermined positions and the volatile proportion of the volatile dopant of each rod in the sample, the preset functional relationship between the volatile proportion of the volatile dopant and the solidification rate under the same process conditions is constructed.

8. A single crystal silicon rod obtained by the preparation method of the single crystal silicon rod according to any one of claims 1 to 7.

9. The single crystal silicon ingot of claim 8 wherein, The single crystal silicon rod satisfies the following conditions: 15% < (the concentration of the volatile dopant at the head of the single crystal silicon rod - the concentration of the volatile dopant at the tail of the single crystal silicon rod) / the concentration of the volatile dopant at the head of the single crystal silicon rod ≤ 40%.

10. A silicon wafer prepared from the single crystal silicon rod according to claim 8 or 9.

11. A solar cell prepared from the silicon wafer according to claim 10.

12. A photovoltaic module comprising: Multiple solar cells according to claim 11 connected in series and / or in parallel.

13. An electronic device, comprising: one or more processors; a storage device for storing one or more programs, when the one or more programs are executed by the one or more processors, the one or more processors implement the preparation method of the single crystal silicon rod according to any one of claims 1 to 7.

14. A computer readable medium having stored thereon a computer program which, when executed by a processor, implements the method of producing a single crystal silicon ingot according to any one of claims 1 to 7.

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