Simulation method of dopant evaporation, crystal bar, battery piece and computer program product

Abstract

The invention relates to a dopant evaporation simulation method, a crystal bar, a battery piece and a computer program product, and the simulation method comprises the steps: obtaining at least two head resistivity, and the at least two head resistivity comprise the head resistivity at a shouldering stage and the head resistivity at an equal-diameter initial stage under the condition of consistent doping conditions. The difference value between the head resistivity and the expected head resistivity is obtained, the dopant evaporation capacity is calculated according to the difference value, and the dopant evaporation capacity is obtained. And obtaining an evaporation constant according to the evaporation capacity of the dopant. Parameters of the crystal bars in the initial stages of shouldering and equal diameter in the manufacturing process are obtained; and related parameters related to the evaporation constants of the corresponding stages in the parameters of the crystal bar in the manufacturing process are screened. And obtaining a relational expression of the relevant parameters and the evaporation constants. By adopting the scheme provided by the invention, the evaporation constant of the crystal bar in the leading and releasing stage can be obtained, the evaporation capacity of the crystal bar in the leading and releasing stage can be calculated, the electrical characteristics of the crystal bar can be adjusted, and the quality of the crystal bar can be improved.

Description

Technical Field

[0001] The present application relates to the field of semiconductor manufacturing technology, and in particular to a simulation method for dopant evaporation, a crystal rod, a battery cell and a computer program product. Background Art

[0002] With the development of technology, photovoltaic modules have become an important energy device in people's daily life. Manufacturing silicon rods is an important step in the production of photovoltaic modules. Usually, when manufacturing silicon rods, dopants need to be added to the silicon material to adjust the electrical properties of the silicon rods. However, during the lead-in stage of the crystal rod, the dopant will evaporate, causing the ratio of the dopant to the silicon material in the crystal rod to change, affecting the electrical properties of the crystal rod. Summary of the invention

[0003] In view of this, the present application provides a simulation method for dopant evaporation, a crystal rod, a battery cell and a computer program product to facilitate the calculation of the evaporation amount of the dopant in the lead-in stage.

[0004] In a first aspect, an embodiment of the present application provides a simulation method for dopant evaporation, the simulation method for dopant evaporation comprising:

[0005] Obtain at least two head resistivities, wherein the at least two head resistivities include the head resistivities of the crystal rods at the initial stage of shoulder release and equal diameter respectively under the same doping conditions;

[0006] Obtaining a difference between each of the head resistivities and an expected head resistivity, and calculating a dopant evaporation amount according to the difference to obtain at least two dopant evaporation amounts;

[0007] Obtaining at least two evaporation constants according to at least two evaporation amounts of the dopant;

[0008] Obtaining parameters of the crystal ingot in the manufacturing process at the initial stage of shoulder release and equal diameter;

[0009] Screening parameters related to the evaporation constant at the corresponding stage in the manufacturing process of the crystal rods at the initial stage of shoulder release and equal diameter;

[0010] The relationship between the relevant parameters and the evaporation constant at each stage is obtained.

[0011] In a possible implementation manner, the mass of the dopant is m, the mass of the silicon material of the crystal rod is n, and 0.000015≤m / n≤0.000025.

[0012] In a possible implementation, the step of obtaining at least two head resistivities includes:

[0013] The resistivity of the crystal rod at the head position with a length of 0.5 mm to 3 mm at the initial stage of shoulder release and equal diameter is obtained respectively.

[0014] In a possible implementation, the step of obtaining parameters of a crystal rod in the early stages of shoulder release and equal diameter during the manufacturing process includes:

[0015] Obtain parameter information of at least one of crystal length, residual material weight, growth rate setting, crystal growth rate, main heater power, diameter value, actual argon flow rate, main chamber pressure value, actual crystal pulling speed, crystal weight, sub-chamber pressure value, crucible speed output, crystal speed output, average furnace pressure, average liquid surface temperature, actual crucible speed, actual crystal speed, water flow rate of water cooling jacket, liquid surface temperature measurement, and lead-in time.

[0016] In a possible implementation, the step of screening parameters related to the evaporation constant at the corresponding stage in the manufacturing process of the crystal rods in the early stages of shoulder release and equal diameter includes:

[0017] Calculate the correlation coefficient p between the parameters of the crystal rod in the early stage of shoulder release and equal diameter in the manufacturing process and the evaporation constant in the corresponding stage respectively;

[0018] When the correlation coefficient of the parameter satisfies p≤0.05, the corresponding parameter is the correlation parameter;

[0019] When the correlation coefficient of the parameter satisfies p>0.05, the corresponding parameter is not the correlation parameter.

[0020] In a possible implementation, the step of screening parameters related to the evaporation constant at the corresponding stage in the manufacturing process of the crystal rods in the early stages of shoulder release and equal diameter includes:

[0021] At least two related parameters related to the evaporation constant are screened and obtained.

[0022] In a possible implementation manner, the relevant parameters include crystal length, residual material weight, actual argon flow rate, main chamber pressure value, average liquid surface temperature, and lead-in time, and the step of obtaining the relationship between the relevant parameters and the evaporation constant at each stage includes:

[0023] Obtaining a relationship between the crystal length, the weight of the remaining material, the actual argon flow rate, the main chamber pressure value, the average liquid surface temperature, the lead-in time and the evaporation constant;

[0024] The relationship between the crystal length, the weight of the remaining material, the actual argon flow rate, the main chamber pressure value, the average liquid surface temperature, the lead-in time and the evaporation constant is processed by regression analysis to obtain the relationship between the final variable and the evaporation constant;

[0025] The final variable is the release time, and the relationship between the release time and the evaporation constant is: E v =aQ b , where E -5 ≤a≤E -3 , 0.01≤b≤1, E v is the evaporation constant, and Q is the release time.

[0026] A second aspect of the present application provides a crystal rod, wherein the manufacturing parameters of the crystal rod are adjusted according to the evaporation constant of the dopant during the processing of the crystal rod, and the evaporation constant of the dopant when the crystal rod is in the shoulder release stage and the initial equal diameter stage is calculated by the simulation method of dopant evaporation according to any one of claims 1 to 7.

[0027] A third aspect of the present application provides a battery cell, the battery cell comprising a silicon wafer, and the silicon wafer is processed from the crystal rod according to claim 8.

[0028] A fourth aspect of the present application provides a computer program product, which includes executable instructions. When the executable instructions are executed on a computer, the computer executes any one of the above-mentioned methods for simulating dopant evaporation.

[0029] The present application provides a simulation method for dopant evaporation, a crystal rod, a battery cell and a computer program product. The simulation method for dopant evaporation includes obtaining at least two head resistivities, and the at least two head resistivities include the head resistivities in the shoulder release stage and the initial stage of equal diameter under the same doping conditions. Obtain the difference between the head resistivity and the expected head resistivity, calculate the dopant evaporation amount based on the difference, and obtain the dopant evaporation amount. Obtain an evaporation constant based on the dopant evaporation amount. Obtain the parameters of the crystal rods in the shoulder release and the initial stage of equal diameter during the manufacturing process. Filter the relevant parameters related to the evaporation constant of the corresponding stage in the parameters of the crystal rod in the manufacturing process. Obtain the relationship between the relevant parameters and the evaporation constant. By adopting the scheme provided by the present application, the evaporation constant of the crystal rod in the lead-in stage can be obtained, and the evaporation amount of the crystal rod in the lead-in stage can be calculated, which is conducive to adjusting the electrical characteristics of the crystal rod, reducing the waste of dopants, and improving the quality of the crystal rod.

[0030] It should be understood that the foregoing general description and the following detailed description are exemplary only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0032] Figure 1 A flow chart of a simulation method for dopant evaporation provided in an embodiment of the present application;

[0033] Figure 2 A flowchart of screening related variables provided in an embodiment of the present application;

[0034] Figure 3 A schematic diagram of the relationship between the relevant parameters and the evaporation constant provided in the embodiment of the present application;

[0035] Figure 4 The evaporation constant model obtained by different algorithms provided in the embodiments of the present application;

[0036] Figure 5 A model of the release time and evaporation constant provided in the embodiments of the present application;

[0037] Figure 6 A schematic diagram of the relationship between the length of the crystal rod and the expected resistivity provided in an embodiment of the present application. DETAILED DESCRIPTION

[0038] In order to better understand the technical solution of the present application, the embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0039] It should be clear that the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0040] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms "a", "said" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

[0041] It should be understood that the term "and / or" used in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0042] In the process of photovoltaic module processing, it is usually necessary to manufacture crystal rods, and then process the crystal rods to obtain solar cells. In the process of processing the crystal rods, it is necessary to add specific impurity atoms to change the electrical properties of the material, thereby improving the photoelectric conversion efficiency of the solar cell. Usually, the commonly used dopants in photovoltaic cells mainly include n-type dopants and p-type dopants. N-type dopants usually include phosphorus (P) and antimony (Sb). By adding n-type dopants, additional free electrons can be introduced into the silicon lattice, thereby increasing the electron concentration of the material. P-type dopants usually include boron (B) and gallium (Ga). By adding p-type dopants, holes, that is, positions where electrons are missing, can be introduced into the silicon lattice, thereby increasing the hole concentration of the material.

[0043] Take antimony doping as an example. Antimony is a pentavalent element. During the doping process, it replaces atoms in the crystal lattice of semiconductor materials (such as silicon Si or germanium Ge), thereby introducing additional free electrons. In semiconductor materials such as silicon or germanium, each atom usually has four valence electrons, and they share electrons with adjacent atoms to form covalent bonds. When pentavalent antimony atoms are doped, since the silicon or germanium atom has one more valence electron, this extra electron will not participate in the formation of covalent bonds, so it can move freely in the lattice. These free electrons form conductive carriers in the doped semiconductor, which increases the conductivity of the material. Since these free electrons carry negative charges, the doped semiconductor is also called an N-type semiconductor (N stands for negative charge carriers, i.e., electrons). The conductivity of antimony-doped N-type semiconductors is enhanced. Compared with pure semiconductor materials, the conductivity of N-type semiconductors is better due to the increased concentration of self-retained electrons. The doping concentration will affect the guiding properties of N-type semiconductors. Generally, the higher the doping concentration, the higher the concentration of free electrons, and the better the conductivity of N-type semiconductors.

[0044] Taking antimony as an example, when calculating the evaporation amount of the dopant in the lead-in stage, multiple factors need to be involved. It is usually necessary to consider the evaporation characteristics of antimony, such as saturated vapor pressure, evaporation rate, etc., which need to be determined through time data or theoretical calculations, and the process is relatively complicated. At the same time, the conditions of the doping process need to be considered. The temperature, pressure, doping time and other conditions in the doping process will affect the evaporation amount of antimony. These conditions need to be set according to the specific doping process, and the optimization of process conditions often needs to be determined through experiments. In the actual production process, these factors are all changing, so it is difficult to determine. At the same time, the uniformity of doping is also an important indicator in the doping process. The uniformity of doping depends not only on the control of the evaporation amount, but also on the temperature distribution and airflow distribution in the doping process. Due to the complexity of the doping process, theoretical calculations often need to be verified by experiments. Experimental verification not only takes time, but also requires corresponding experimental equipment and materials. In order to calculate the evaporation amount, it may be necessary to establish a complex physical model, including thermodynamic models, kinetic models, etc. The establishment and solution of these models require professional knowledge and skills, and it is difficult to establish models. Therefore, it is difficult to calculate the evaporation amount. When calculating the expected resistivity of the crystal rod, the evaporation amount in the lead-in stage is usually not calculated. However, in the lead-in stage of the crystal rod, the dopant will evaporate, causing the ratio of the dopant to the silicon material to change, which in turn causes a difference between the resistivity of the crystal rod and the expected resistivity, affecting the performance of the photovoltaic cell.

[0045] like Figure 1 As shown, the embodiment of the present application provides a simulation method for dopant evaporation, which can be used to obtain the evaporation constant of the dopant in the crystal rod drawing stage, and then the corresponding dopant evaporation amount can be obtained according to the evaporation constant. The simulation method for dopant evaporation includes:

[0046] At least two head resistivities are obtained, wherein the at least two head resistivities include the head resistivities in the shoulder release stage and the initial equal diameter process respectively under the same doping conditions.

[0047] The difference between each head resistivity and the expected head resistivity is obtained, and the dopant evaporation amount is calculated according to the difference to obtain at least two dopant evaporation amounts.

[0048] At least two evaporation constants are obtained according to the at least two dopant evaporation amounts.

[0049] The parameters of the crystal rod in the manufacturing process are obtained when it is in the shoulder release process and the initial process of equal diameter.

[0050] The parameters related to the evaporation constant in the corresponding stage among the parameters of the crystal rod in the manufacturing process which are in the initial process of shoulder release and equal diameter are screened.

[0051] Obtain the relationship between the relevant parameters of each stage and the evaporation constant.

[0052] During the manufacturing process of the crystal rod, the introduction and release stage usually includes temperature adjustment, seeding, shoulder release, and initial equal diameter. The temperature adjustment stage refers to the process of adjusting the temperature to the temperature required for seeding after the melt. The seeding step refers to the process of using a seed crystal (seed crystal) to lead out a thin neck after the temperature of the silicon material is fully melted and stabilized, so that the seed crystal gradually grows into a larger silicon single crystal. The shoulder release step can also be called shoulder rotation, which refers to the process of enlarging the crystal to the target diameter size by controlling the shoulder release quality, speed, and shape after the seeding process is completed. The equal diameter step refers to the process of pulling the crystal rod within the target diameter range after the shoulder release adjusts the crystal size to the target diameter size. Since there is no crystal rod output in the temperature adjustment stage, only a thin neck is generated in the seeding stage. Although crystals are generated, the accuracy of the measurement results is poor, that is, the temperature adjustment and seeding stages can be considered to have no formed crystal rod output. Therefore, when collecting the crystal rods in the introduction and release stage, it is sufficient to collect the crystal rods in the shoulder release stage and the initial equal diameter process respectively, and the output of the seeding stage can be omitted. At the same time, the equal diameter included in the lead-in stage usually refers to the initial stage of equal diameter, that is, the equal diameter mentioned in the embodiments provided in this application refers to the crystal rod in the initial stage of equal diameter. Usually, when the growth length of the crystal rod in the equal diameter stage does not exceed 500 mm, the crystal rod can be considered to be in the initial stage of equal diameter. When collecting crystal rods, according to the preset time, the crystal rods that have passed the preset time after the equal diameter step starts can be collected. In a possible implementation, the crystal rods with a processing time of half a minute to two minutes after the equal diameter stage starts can be collected. According to the test requirements, the crystal rods with equal diameter time of 30 seconds, 60 seconds, 90 seconds, 120 seconds, etc. can be selected. In order to save the test cost, when collecting crystal rods, the crystal rods that failed to pull crystals due to fracture in the shoulder release stage and the equal diameter stage can be collected for testing.

[0053] The crystal rod includes a head and a tail. Usually, the head refers to the end of the crystal rod that is formed first, and the tail refers to the end of the crystal rod that is formed last. Since the crystal rod in the lead-in stage is an unfinished crystal rod, that is, the tail of the crystal rod is not formed, the head resistivity is usually detected when detecting the resistivity. By obtaining a crystal rod with consistent doping conditions, the head resistivity of the crystal rod at different stages can be obtained. According to the doping amount of the dopant, the expected head resistivity of the crystal rod can be obtained. The expected head resistivity can be calculated based on the quality of polysilicon and the quality of the dopant. Since the evaporation amount of the dopant is not calculated in the process of calculating the expected resistivity, the evaporation amount of the dopant can be calculated by the difference between the expected head resistivity and the actual head resistivity measured. The evaporation amount is calculated as follows: N = (C0-C)·V, where N is the evaporation amount, C0 is the initial concentration of the dopant, C is the concentration of the dopant after time t, and V is the volume of the remaining material, in cubic centimeters. The concentration C of the dopant after time t is calculated as follows: Where A is the melt evaporation surface area, E v is the dopant evaporation constant, W is the mass of molten silicon, and C0 is the initial concentration of the dopant. The above formula can be used to obtain the relationship between the evaporation constant and the evaporation amount of the dopant in the lead-in stage, so the corresponding evaporation constant can be calculated by the evaporation amount of the dopant. At the same time, the process parameters in the initial process of shoulder release and equal diameter can also be collected to obtain the processing information of the crystal rod in the lead-in stage. After obtaining the parameters, the parameters are screened to obtain the relevant parameters of the evaporation constant, and the relationship between the relevant parameters and the evaporation constant is obtained. Screening the parameters can reduce the variables in the relationship and reduce the difficulty of obtaining the relationship between the relevant parameters and the evaporation constant. In the subsequent manufacturing process of the crystal rod, the relationship can be used to obtain the corresponding evaporation constant through the process parameters in the crystal rod manufacturing process, and then the corresponding dopant evaporation amount can be calculated through the evaporation constant, so that when calculating the resistivity of the crystal rod, the relevant information of the dopant evaporation amount is added to improve the accuracy of the expected resistivity, so that the expected resistivity of the crystal rod can be better obtained.

[0054] After obtaining the relationship between the relevant parameters and the evaporation constant, the concentration of the dopant in the semiconductor material can be better controlled by calculating the evaporation amount of the dopant, which is beneficial to controlling the electrical properties of the solar silicon single crystal. By accurately controlling the evaporation amount of the dopant, it is possible to ensure that the doping concentration between different crystal rods remains consistent during mass production, improve the consistency and reliability of the doping concentration between different crystal rods, and thus help improve the quality of photovoltaic cells. Evaporation calculation can help optimize the doping process, and the doping effect can be adjusted by adjusting the evaporation temperature, time, amount of dopant and other parameters according to the evaporation amount, so that the resistivity of the crystal rod can reach the expected resistivity. By calculating the evaporation amount of the dopant, the ratio of the dopant to the silicon material can be calculated more accurately, which is beneficial to avoid excessive use of dopants, reduce waste of dopants, and reduce costs. Through the relationship between the relevant parameters and the evaporation constant, the evaporation behavior under different conditions can be simulated and predicted to obtain the expected doping effect, which is beneficial to reduce the number of experiments and costs.

[0055] By obtaining the relationship between the relevant parameters and the evaporation constant, the evaporation amount of the dopant in the lead-in stage can be better calculated, so that the electrical properties of the crystal rod can be better obtained, which is beneficial to improving the production quality of the crystal rod, reducing the waste of dopants and silicon materials, reducing production costs, and better meeting actual production and use needs.

[0056] In a possible implementation manner, the mass of the dopant is m, the mass of the silicon material is n, and 0.000015≤m / n≤0.000025.

[0057] The mass of the dopant can be the mass of antimony element, and the mass of the silicon material can be the mass of the polysilicon that can be put in. By limiting the ratio of the dopant to the silicon material, the expected head resistivity of the crystal rod can be obtained, so as to compare it with the head resistivity obtained by actual processing, and then the evaporation amount of the dopant can be obtained through corresponding calculation according to the difference between the actual head resistivity and the expected head resistivity.

[0058] The feeding amount of polysilicon can range from 800kg to 1000kg, and the feeding amount of polysilicon is 800kg, 820kg, 840kg, 860kg, 880kg, 900kg, 920kg, 940kg, 960kg, 980kg, 1000kg, etc. The mass of antimony can range from 15g to 20g, and the mass of antimony can be 15g, 16g, 17g, 18g, 19g, 20g, etc. In a possible implementation, in the process of obtaining the relationship between the relevant parameters and the evaporation constant, the feeding amount of polysilicon of the manufactured crystal rod can be 920kg, and the mass of antimony can be 17g. The specific ratio of polysilicon and antimony can be adjusted according to the electrical characteristics of the crystal rod actually produced.

[0059] In a possible implementation, the step of obtaining at least two head resistivities includes:

[0060] The resistivity of the crystal rod at the head position with a length of 0.05 mm to 3 mm in the initial process of shoulder release and equal diameter is obtained respectively.

[0061] Since the collected crystal rods are crystal rods in the shoulder release process and crystal rods in the early stage of equal diameter, that is, unfinished crystal rods, the resistivity at the head position can be obtained to obtain the difference between the actual head resistivity and the expected head resistivity of the crystal rod in the lead-in stage, thereby obtaining the dopant evaporation amount.

[0062] When measuring the head resistivity, the resistivity at positions such as 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1.0 mm, 1.2 mm, 1.4 mm, 1.6 mm, 1.8 mm, 2.0 mm, 2.2 mm, 2.4 mm, 2.6 mm, 2.8 mm, and 3.0 mm can be selected as the head resistivity according to demand. In actual measurement, one or more positions within the range of 0.5 mm to 3 mm in length of the crystal rod head can be selected for measurement.

[0063] In a possible implementation, the step of obtaining parameters of a crystal rod in the initial process of shoulder release and equal diameter during the manufacturing process may include:

[0064] Obtain parameter information of at least one of crystal length, residual material weight, growth rate setting, crystal growth rate, main heater power, diameter value, actual argon flow rate, main chamber pressure value, actual crystal pulling speed, crystal weight, sub-chamber pressure value, crucible speed output, crystal speed output, average furnace pressure, average liquid surface temperature, actual crucible speed, actual crystal speed, water flow rate of water cooling jacket, liquid surface temperature measurement, and lead-in time.

[0065] By obtaining the parameters of the crystal rod during the manufacturing process, it is easy to obtain the independent variables related to the evaporation amount, and then the independent variables related to the evaporation constant can be obtained, which is conducive to obtaining the evaporation constant of the crystal rod during the lead-in stage. The more parameters of the crystal rod obtained during the manufacturing process, the easier it is to find the independent variables related to the evaporation constant, so that in the subsequent processing process, the evaporation amount of the dopant during the manufacturing process of the crystal rod can be calculated according to the corresponding parameters.

[0066] like Figure 2 As shown, in a possible implementation manner, the step of screening parameters related to the evaporation constant of the corresponding stage in the parameters of the crystal rods in the early stage of shoulder release and equal diameter in the manufacturing process includes:

[0067] The correlation coefficient p between the parameters of the crystal rod in the process of shoulder release and initial equal diameter and the evaporation constant in the corresponding stage is calculated respectively.

[0068] When the correlation coefficient p of a parameter satisfies p≤0.05, the corresponding parameter is the correlation parameter.

[0069] When the correlation coefficient p of a parameter satisfies p>0.05, the corresponding parameter is not the correlation parameter.

[0070] It is possible to obtain whether there is a certain statistical correlation between the parameter and the evaporation constant through correlation analysis, and obtain the correlation coefficient p. According to the correlation coefficient p, the correlation between the parameter and the evaporation constant can be obtained. The corresponding threshold value can be set for the correlation coefficient. When the correlation coefficient meets the threshold condition, the corresponding parameter can be considered to be related to the evaporation constant. When the correlation coefficient does not meet the threshold condition, the corresponding parameter can be considered to be unrelated to the evaporation constant. In a possible implementation, the critical point of the threshold value can be set to 0.05. When the correlation coefficient p of the parameter satisfies p≤0.05, the corresponding parameter is a related parameter. When the correlation coefficient p of the parameter satisfies p>0.05, the corresponding parameter is not the related parameter. The parameters of the crystal rod lead-out stage can be screened by the correlation coefficient, so as to obtain parameters with a greater correlation with the evaporation constant. The parameters with a smaller correlation with the evaporation constant can be considered to have a smaller impact on the evaporation amount in the crystal rod lead-out stage. When calculating the evaporation amount in the lead-out stage, the impact of the parameter on the evaporation amount can be ignored.

[0071] When calculating the relevant parameters, relevant analysis software, including but not limited to SPSS, Minitab, SPSSAU and other software, can be used to place the evaporation amount in the priming stage in the dependent variable Y of the analysis item, and the remaining items in the analysis item X. In a possible implementation, after actual sampling and calculation, the following Table 1 is obtained. When the correlation between the parameter and the evaporation amount is high, the correlation between the parameter and the evaporation constant is also relatively high; when the correlation between the parameter and the evaporation amount is low, the correlation between the parameter and the evaporation constant is also relatively low, so the correlation between the parameter and the evaporation constant can be obtained through the correlation between the parameter and the evaporation amount.

[0072] Table 1

[0073]

[0074]

[0075] The above table can be used to obtain the correlation parameter p of each parameter and the evaporation amount in the lead-in stage during the crystal rod manufacturing process, thereby obtaining the correlation between each parameter and the evaporation constant. Among them, the parameters marked with "*" are parameters with correlation parameter p less than 0.05, and the parameters marked with "**" are parameters with correlation parameter p less than 0.01. It should be noted here that the data in the table are not the numerical values ​​of the relevant parameters p, but another form of expression of the relevant parameters. Positive data indicates that the corresponding parameter is positively correlated with the evaporation amount, and negative data indicates that the corresponding parameter is negatively correlated with the evaporation amount. Parameters related to the evaporation amount can be considered to be related to the evaporation constant.

[0076] In a possible implementation, the step of screening parameters related to the evaporation constant of the corresponding stage in the manufacturing process of the crystal rods in the initial process of shoulder release and equal diameter includes:

[0077] At least two relevant parameters related to the evaporation constant were screened.

[0078] When only one correlation coefficient is screened out, the relationship between the correlation coefficient and the evaporation constant is directly obtained.

[0079] When there are at least two related parameters related to the evaporation constant obtained by screening, the related parameters are factors affecting the evaporation constant. The more related parameters obtained by screening, the more accurate the evaporation constant obtained by the related parameters. When screening, the accuracy of the relationship between the obtained related parameters and the evaporation constant can be improved by obtaining more related parameters.

[0080] In a possible implementation, the relevant parameters screened may include crystal length, residual material weight, actual argon flow rate, main chamber pressure, average liquid surface temperature and lead-in time.

[0081] Through screening, it can be found that the parameters in the above processing process have a high correlation with the evaporation constant. Therefore, by obtaining the relationship between the above parameters and the evaporation constant, the evaporation amount can be calculated according to the relationship between the relevant parameters and the evaporation constant, which is beneficial to adjust the electrical properties of the crystal rod.

[0082] like Figure 3 As shown, in a possible implementation manner, the step of obtaining the relationship between the relevant parameters of each stage and the evaporation constant includes:

[0083] Obtain the relationship between crystal length, residual weight, actual weight, actual argon flow rate, main chamber pressure value, average liquid surface temperature, lead-in time and evaporation constant.

[0084] The relationship between crystal length, residual weight, actual weight, actual argon flow rate, main chamber pressure value, average liquid surface temperature, lead-in time and evaporation constant is obtained through mathematical methods. When manufacturing crystal rods, the evaporation amount of dopants can be calculated according to the crystal rod parameter information, which is beneficial to improve the quality of the crystal rod, improve the electrical properties of the crystal rod, and better meet actual needs.

[0085] Through mathematical methods, the relationship between various related parameters and the evaporation constant can be integrated into a relational expression. During manufacturing, the evaporation constant can be obtained through the corresponding parameters, and then the evaporation amount can be obtained. When obtaining the relational expression, different algorithms can be used to establish multiple models and then select the best one. Figure 4 As shown, the relationship model between the relevant parameters and the evaporation constant obtained according to different algorithms provided in the embodiment of the present application is selected after obtaining multiple algorithm models. The actual evaporation constant of the collected crystal rod can be obtained and compared with each model to select the model that best matches the actual evaporation constant. Figure 4 The ordinate represents the evaporation constant in centimeters per second, and the abscissa represents the weight of the remaining melt in the furnace in kilograms.

[0086] In one possible implementation, after obtaining the relationship between the relevant variables and the evaporation constant, the obtained relationship is optimized through regression analysis, and the relationship is processed through steps such as model setting, data collection, data preprocessing parameter estimation, model diagnosis, and model verification to further optimize the relationship between the relevant parameters and the evaporation constant, thereby reducing the difficulty of calculating the evaporation constant.

[0087] After the relationship is optimized through regression analysis, some related parameters in the relationship may become constant terms, and the influence of the related parameters that become constant terms on the evaporation constant can be ignored. In a possible implementation, the related parameters that become constant terms in the relationship can be deleted after processing. The deleted related parameters include residual weight, actual argon gas flow rate, main chamber pressure, and average liquid surface temperature. Then, the crystal length in the related variables can be deleted through the variance expansion factor (variance expansion factor, VIF). The remaining related parameters obtained after regression analysis are the final variables. The relationship after regression analysis is the relationship between the final variable and the related parameters, so as to reduce the difficulty of calculating the evaporation constant and facilitate the acquisition of the evaporation amount of the dopant in the induced release stage.

[0088] After processing the relationship between the relevant variables and the evaporation constant through regression analysis, the remaining relevant variable is the release time, that is, the release time is the final variable. The relationship between the release time and the final variable is: E v =aQ b , where E -5 ≤a≤E -3 , 0.01≤b≤1, E v is the evaporation constant, Q is the release time. Figure 5 As shown, after screening, we get Figure 5 The model shown, Figure 5 The horizontal axis represents the release time in minutes, and the vertical axis represents the evaporation constant in centimeters per second.

[0089] In a possible implementation, the relationship between the release time and the final variable may be: v =0.000104194Q 0.463774 .

[0090] In the subsequent crystal rod manufacturing process, the corresponding evaporation constant can be obtained according to the release time of the crystal rod in the release stage, and the evaporation amount of the crystal rod in the release stage during the manufacturing process can be obtained according to the evaporation constant, which can better adjust the ratio of dopant and silicon material, thereby helping to improve the electrical properties of the crystal rod and the manufacturing quality of the crystal rod.

[0091] By adopting the method provided in the embodiment of the present application, the evaporation amount of the dopant during the crystal rod lead-out process can be calculated, so that the electrical characteristics of the crystal rod can be better obtained. Moreover, after sorting and optimizing the parameter information during the crystal rod processing process and the relationship between the relevant parameters and the evaporation constant by means of correlation analysis, regression analysis, etc., the obtained relationship only includes one variable, the lead-out time. Since there are fewer variables included, when modeling the relationship between the relevant variables and the evaporation constant, the difficulty of modeling can be reduced, thereby improving the calculation efficiency. In actual production and processing, the parameters of the crystal rod in the manufacturing process can be adjusted by the evaporation amount of the dopant.

[0092] When manufacturing a crystal rod, the expected resistivity of the crystal rod can be obtained by calculation, and the electrical characteristics of the manufactured crystal rod can be known according to the expected resistivity of the crystal rod, which is helpful to judge whether the crystal rod meets the use requirements. The scheme provided in the embodiment of the present application can obtain the relationship between the parameters of the crystal rod in the lead-in stage and the evaporation constant of the dopant, and then the dopant evaporation amount of the crystal rod in the lead-in stage can be calculated by the evaporation constant, so that the dopant evaporation amount can be introduced when calculating the expected resistivity of the crystal rod. By introducing the calculation of the dopant evaporation amount of the crystal rod in the lead-in stage when calculating the resistivity of the crystal rod, the expected resistivity of the crystal rod can be obtained more accurately, so as to adjust the process parameters during the manufacture of the crystal rod and reduce the difference between the actual resistivity of the manufactured crystal rod and the expected resistivity.

[0093] In a possible implementation, the size of the hot field is 36 inches, the polysilicon feed amount is 920 kg, the diameter of the pulled crystal rod is 263 mm, and 15.32 g of antimony is added to the silicon material. Under this doping condition, the relationship between the length of the crystal rod and the expected resistivity is as follows: Figure 6 As shown in the figure, the expected resistivity here is the expected resistivity without introducing the evaporation amount. From the figure, we can get the expected resistivity of the crystal rod at different length positions. When obtaining the expected head resistivity of the crystal rod, we can get the expected head resistivity according to the set length of the head position. Figure 6 In the solution provided in the embodiment of the present application, the expected head resistivity of the crystal rod can be 1Ω·cm, and the actual head-bottom unit cell resistivity of the crystal rod can be obtained through actual measurement.

[0094] The method of calculating the evaporation amount of the dopant is to use the expected impurity number n1 obtained by simulation and the actual impurity number n2 to calculate, and n1-n2 can get the evaporation amount of the dopant. The impurity number can be calculated by impurity concentration * residual material volume, and the impurity concentration can be calculated by the formula Calculate, where N D is the dopant concentration in cubic centimeters (cm -3 ), ρ is the resistivity, the unit is ohm-centimeter (Ω·cm), A0 = -3.1083, A1 = -3.2626, A2 = -1.2196, A3 = -0.13923, B1 = 1.0265, B2 = 0.38755, B3 = 0.041833. When calculating the evaporation amount, the dopant concentration can be calculated based on the resistivity, and the number of impurities can be calculated based on the dopant concentration. The expected number of impurities and the actual number of impurities can be obtained by respectively substituting the expected resistivity and the actual resistivity, and the evaporation amount of the dopant can be obtained by the difference between the two.

[0095] In a possible implementation manner, before adjusting the parameters of the crystal rod during the manufacturing process, the parameters are as shown in Table 2 below:

[0096] Table 2

[0097]

[0098]

[0099] The length in Table 2 is the length of the crystal rod in the lead-in stage, in mm, and the length of the crystal rod changes with time. The power change is that in the process of crystal rod manufacturing, different powers need to be used in the shoulder release stage according to the different target shoulder shapes, so that the crystal rod forms the target shoulder shape during the shoulder release process. The scheme provided in the embodiment of the present application involves three shoulder shapes, and the corresponding powers in the manufacturing process are power change 1, power change 2 and power change 3, respectively, and the unit of power change is kilowatt. In the scheme provided in the embodiment of the present application, the power corresponding to the three shoulder shapes can be the same. Crystal rise is the pulling rate of the crystal, in millimeters per hour. Crucible rise is the rate of rise of the crucible, in millimeters per hour. Crucible rotation is the rotation rate of the crucible during the crystal rod manufacturing process. Crystal rotation is the rotation rate of the crystal during the crystal rod manufacturing process, and the argon flow rate is the flow rate of argon introduced during the crystal rod manufacturing process, in lmp. The pressure setting is the pressure in the furnace during the crystal rod manufacturing process, in Torr. The diameter is the diameter size of the crystal growing during the crystal rod manufacturing process, which usually changes with time. Diameter change refers to the growth rate of the crystal diameter during the crystal rod manufacturing process, and the unit is millimeter per ten seconds. Liquid mouth distance refers to the distance from the lower edge of the guide tube to the liquid surface in the crucible, and the unit is millimeter.

[0100] The data in Table 2 are the manufacturing parameters involved in the crystal rod drawing stage. During the crystal rod drawing process, the parameters of power, crystal lift and crucible lift change with the growth of the crystal rod. As the crystal rod grows, the diameter of the crystal rod gradually increases, so that the crystal rod is gradually drawn into shape.

[0101] Table 3 below shows the adjusted processing parameters:

[0102] Table 3

[0103]

[0104] It can be seen from the data in Table 2 above that in the solution provided in the embodiment of the present application, the crucible rotation, pressure flow rate and pressure setting of the crystal rod in the manufacturing process are adjusted. By increasing the crucible rotation, the pressure flow rate is increased and the furnace pressure is reduced. By increasing the crucible rotation, the crystal pulling process can be made smoother, which is beneficial to reduce the oxygen content of the crystal rod and improve the electrical properties of the crystal rod. By adjusting the argon flow rate and furnace pressure, it is beneficial to improve the forward gain for oxygen. The evaporated oxygen in the crystal rod manufacturing process can be taken away by the flow of argon, thereby reducing the oxygen content of the crystal rod, which is more in line with actual use requirements. By increasing the argon flow rate and pressure setting of the crystal rod in the lead-in stage, the evaporation amount in the crystal rod manufacturing process can be reduced, which is beneficial to improve the electrical properties of the crystal rod and reduce the difference between the actual resistivity and the expected resistivity of the crystal rod.

[0105] Based on the simulation method of dopant evaporation involved in the above embodiments, the embodiment of the present application also provides a crystal rod. During the processing of the crystal rod, the manufacturing parameters of the crystal rod can be adjusted according to the evaporation constant of the dopant, so that the electrical characteristics of the crystal rod can be adjusted. When calculating the evaporation constant of the dopant, the above simulation method of dopant evaporation can be used for calculation. The embodiment of the present application also provides a battery cell, which includes a silicon wafer, and the silicon wafer can be processed by the above silicon rod.

[0106] Based on the simulation method of dopant evaporation involved in the above embodiments, the embodiments of the present application also provide a computer program product, which includes executable instructions. When the executable instructions are executed on a computer, the computer executes the simulation method of dopant evaporation involved in any of the above embodiments.

[0107] The embodiments of the present application relate to a simulation method for dopant evaporation, a crystal rod, a battery cell and a computer program product. The simulation method for dopant evaporation includes obtaining at least two head resistivities, and the at least two head resistivities include the head resistivities in the shoulder release stage and the equal diameter initial process respectively under the same doping conditions. The difference between the head resistivity and the expected head resistivity is obtained, and the dopant evaporation amount is calculated according to the difference to obtain the dopant evaporation amount. The evaporation constant is obtained according to the dopant evaporation amount. The parameters of the crystal rod in the manufacturing process are obtained. The relevant parameters related to the evaporation constant of the corresponding stage in the parameters of the crystal rod in the manufacturing process are screened. The relationship between the relevant parameters and the evaporation constant is obtained. By adopting the scheme provided in the present application, the evaporation constant of the crystal rod in the lead-in stage can be obtained, and the evaporation amount of the crystal rod in the lead-in stage can be calculated, which is conducive to adjusting the electrical characteristics of the crystal rod, reducing the waste of dopants, and improving the quality of the crystal rod.

[0108] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for simulating dopant evaporation, characterized in that: The simulation method of dopant evaporation comprises: Obtain at least two head resistivities, wherein the at least two head resistivities include the head resistivities of the crystal rods at the initial stage of shoulder release and equal diameter respectively under the same doping conditions; Obtaining a difference between each of the head resistivities and an expected head resistivity, and calculating a dopant evaporation amount according to the difference to obtain at least two dopant evaporation amounts; Obtaining at least two evaporation constants according to at least two evaporation amounts of the dopant; Obtaining parameters of the crystal ingot in the manufacturing process at the initial stage of shoulder release and equal diameter; Screening parameters related to the evaporation constant at the corresponding stage in the manufacturing process of the crystal rods at the initial stage of shoulder release and equal diameter; The relationship between the relevant parameters and the evaporation constant at each stage is obtained.

2. The method for simulating dopant evaporation according to claim 1, characterized in that: The mass of the dopant is m, the mass of the silicon material of the crystal rod is n, and 0.000015≤m / n≤0.000025.

3. The method for simulating dopant evaporation according to claim 1, characterized in that: The steps of obtaining at least two head resistivities include: The resistivity of the crystal rod at the head position with a length of 0.5 mm to 3 mm at the initial stage of shoulder release and equal diameter is obtained respectively.

4. The method for simulating dopant evaporation according to claim 1, characterized in that: The steps of obtaining parameters of the crystal ingot in the early stages of shoulder release and equal diameter during the manufacturing process include: Obtain parameter information of at least one of crystal length, residual material weight, growth rate setting, crystal growth rate, main heater power, diameter value, actual argon flow rate, main chamber pressure value, actual crystal pulling speed, crystal weight, sub-chamber pressure value, crucible speed output, crystal speed output, average furnace pressure, average liquid surface temperature, actual crucible speed, actual crystal speed, water flow rate of water cooling jacket, liquid surface temperature measurement, and lead-in time.

5. The method for simulating dopant evaporation according to claim 1, characterized in that: The step of screening the parameters of the crystal rods in the early stage of shoulder release and equal diameter in the manufacturing process that are related to the evaporation constant in the corresponding stage includes: Calculate the correlation coefficient p between the parameters of the crystal rod in the early stage of shoulder release and equal diameter in the manufacturing process and the evaporation constant in the corresponding stage respectively; When the correlation coefficient of the parameter satisfies p≤0.05, the corresponding parameter is the correlation parameter; When the correlation coefficient of the parameter satisfies p>0.05, the corresponding parameter is not the correlation parameter.

6. The method for simulating dopant evaporation according to any one of claims 1 to 5, characterized in that: The step of screening the parameters of the crystal rods in the early stage of shoulder release and equal diameter in the manufacturing process that are related to the evaporation constant in the corresponding stage includes: At least two related parameters related to the evaporation constant are screened and obtained.

7. The method for simulating dopant evaporation according to claim 6, characterized in that: The relevant parameters include crystal length, residual material weight, actual argon flow rate, main chamber pressure value, average liquid surface temperature, and lead-out time. The steps of obtaining the relationship between the relevant parameters and the evaporation constant at each stage include: Obtaining a relationship between the crystal length, the weight of the remaining material, the actual argon flow rate, the main chamber pressure value, the average liquid surface temperature, the lead-in time and the evaporation constant; The relationship between the crystal length, the weight of the remaining material, the actual argon flow rate, the main chamber pressure value, the average liquid surface temperature, the lead-in time and the evaporation constant is processed by regression analysis to obtain the relationship between the final variable and the evaporation constant; The final variable is the release time, and the relationship between the release time and the evaporation constant is: E v =aQ b , where E -5 ≤a≤E -3 , 0.01≤b≤1, E v is the evaporation constant, and Q is the release time.

8. A crystal rod, characterized in that: During the processing of the crystal rod, the manufacturing parameters of the crystal rod are adjusted according to the evaporation constant of the dopant, and the evaporation constant of the dopant when the crystal rod is in the shoulder release stage and the initial equal diameter stage is calculated by the simulation method of dopant evaporation according to any one of claims 1 to 7.

9. A battery cell, characterized in that: The battery cell comprises a silicon wafer, and the silicon wafer is processed from the crystal rod according to claim 8.

10. A computer program product, characterized in that The computer program product comprises executable instructions, and when the executable instructions are executed on a computer, the computer is caused to execute the simulation method of dopant evaporation according to any one of claims 1 to 7.

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