Crystal bar axial resistivity control method, device, equipment and product

Abstract

The invention relates to a crystal bar axial resistivity control method and device, and the method comprises the steps: predicting the first antimony evaporation capacity of a crystal pulling equal-diameter process in an antimony-phosphorus co-doped single crystal furnace according to the incidence relation between the evaporation constant in the antimony-phosphorus co-doped single crystal furnace and the excess material weight, and controlling the antimony-phosphorus doping ratio of the equal-diameter process according to the first antimony evaporation capacity; according to the incidence relation between the evaporation constant and the lead-discharge duration, the second antimony evaporation capacity in the crystal pulling lead-discharge process in the antimony-phosphorus co-doped single crystal furnace is predicted, and the antimony-phosphorus doping proportion in the lead-discharge process is controlled according to the second antimony evaporation capacity; and according to the target re-feeding evaporation calculation model, predicting a third antimony evaporation capacity in a re-feeding stage in the antimony-phosphorus co-doped single crystal furnace, and controlling an antimony-phosphorus doping ratio in the re-feeding stage according to the third antimony evaporation capacity, so that the axial resistivity uniformity of the crystal bar obtained by straight pulling is within a target range. At least the uniformity of axially doped elements in monocrystalline silicon can be improved in the crystal pulling process, and the uniformity of the axial resistivity of a crystal bar is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of Czochralski silicon single crystals, and specifically relates to a method, device, equipment and product for controlling the axial resistivity of a crystal rod. Background Art

[0002] The Czochralski method is a relatively simple method for preparing single crystal silicon, which uses a rotating seed crystal to gradually pull the single crystal silicon. This method has a relatively low production cost and can be mass-produced to produce high-quality, large-sized semiconductor-grade or solar-grade single crystal silicon wafers, so it is widely used in the preparation of single crystal silicon.

[0003] ‌However, the axial resistivity of CZ-Si is difficult to control and there are many crystal defects, which reduce the minority carrier lifetime. The oxygen donors formed by its high oxygen content will cause the conversion efficiency of the cell to decay, limiting the improvement of the conversion efficiency of the cell. ‌

[0004] Therefore, in order to ensure the quality and performance of single crystal silicon produced by the Czochralski method, it is necessary to provide effective control and optimization means for the axial resistivity uniformity of the Czochralski single crystal silicon. Summary of the invention

[0005] Based on this, it is necessary to provide a method, device, equipment and product for controlling the axial resistivity of a crystal rod in response to the problems in the above-mentioned background technology, which can at least ensure that the uniformity of axial doping elements in single crystal silicon is improved during the crystal pulling process, achieve precise control of the resistivity, and improve the uniformity of the axial resistivity of the crystal rod.

[0006] According to various embodiments of the present disclosure, in a first aspect, the present disclosure provides a method for controlling axial resistivity of a crystal rod, comprising:

[0007] According to the correlation between the evaporation constant and the weight of the residual material in the antimony-phosphorus co-doped single crystal furnace, the first antimony evaporation amount in the crystal pulling equal diameter process in the antimony-phosphorus co-doped single crystal furnace is predicted, and the antimony-phosphorus doping ratio in the equal diameter process is controlled according to the first antimony evaporation amount;

[0008] According to the correlation between the evaporation constant and the drawing time, the second antimony evaporation amount during the crystal pulling and drawing process in the antimony-phosphorus co-doped single crystal furnace is predicted, and the antimony-phosphorus doping ratio during the drawing and drawing process is controlled according to the second antimony evaporation amount;

[0009] According to the target re-feeding evaporation calculation model, the third antimony evaporation amount in the re-feeding stage in the antimony-phosphorus co-doped single crystal furnace is predicted, and the antimony-phosphorus doping ratio in the re-feeding stage is controlled according to the third antimony evaporation amount, so that the axial resistivity uniformity of the crystal rod obtained by direct pulling is within the target range.

[0010] In the above-mentioned embodiment, the method for controlling the axial resistivity of the crystal rod is adopted. Since the manufacturing process of the CZ silicon single crystal includes feeding, melting, necking, shouldering, equal diameter and other stages, the antimony-phosphorus co-doped CZ silicon single crystal manufacturing process is adopted. The antimony evaporation amount in the equal diameter process, the drawing and releasing process and the re-throwing stage has a great influence on the uniformity of the axial resistivity of the crystal rod. Firstly, according to the correlation between the evaporation constant and the weight of the residual material in the antimony-phosphorus co-doped single crystal furnace, the first antimony evaporation amount in the equal diameter process of the crystal pulling in the antimony-phosphorus co-doped single crystal furnace is predicted. According to the first antimony evaporation amount, the antimony-phosphorus doping ratio in the equal diameter process is controlled to ensure the accurate doping of the antimony element in the equal diameter process. According to the correlation between the evaporation constant and the drawing and releasing time, the antimony evaporation amount in the equal diameter process of the crystal pulling in the antimony-phosphorus co-doped single crystal furnace is predicted. Measure the second antimony evaporation amount during the crystal pulling and releasing process in the antimony-phosphorus co-doped single crystal furnace, and control the antimony-phosphorus doping ratio in the releasing process according to the second antimony evaporation amount; ensure the precise doping of antimony elements in the releasing process; further predict the third antimony evaporation amount in the re-investment stage in the antimony-phosphorus co-doped single crystal furnace according to the target re-investment evaporation calculation model, and control the antimony-phosphorus doping ratio in the re-investment stage according to the third antimony evaporation amount, ensure the precise doping of antimony elements in the re-investment stage, ensure that the uniformity of axial doping elements in single crystal silicon is improved during the crystal pulling process, achieve precise control of resistivity, and make the axial resistivity uniformity of the crystal rod obtained by direct pulling within the target range, thereby improving the uniformity of the axial resistivity of the crystal rod.

[0011] In some embodiments, the method for controlling the axial resistivity of the crystal rod further includes the following step of obtaining a target re-investment evaporation calculation model:

[0012] The correlation analysis algorithm is used to determine the irrelevant variables whose correlation with antimony evaporation is less than the threshold value during the reinvestment stage;

[0013] Determine the target variables associated with the antimony evaporation amount in the re-investment stage according to the irrelevant variables, and the target variables include the antimony concentration of the disconnected wire, the weight of the residual material and the time for re-investment;

[0014] A linear fitting algorithm was used to determine the functional relationship between antimony evaporation and the target variable.

[0015] The crystal rod axial resistivity control method in the above embodiment uses a correlation analysis algorithm to determine the irrelevant variables whose correlation with the antimony evaporation amount is less than a threshold value in the reinvestment stage, thereby determining the target variables associated with the antimony evaporation amount in the reinvestment stage based on the irrelevant variables, and the target variables include the antimony concentration of broken wire, the weight of residual material and the time for reinvestment, and then a linear fitting algorithm can be used to determine the functional relationship between the antimony evaporation amount and the target variable, so that the third antimony evaporation amount in the reinvestment stage in the antimony-phosphorus co-doped single crystal furnace can be predicted based on the functional relationship, and the antimony-phosphorus doping ratio in the reinvestment stage can be controlled based on the third antimony evaporation amount, so as to ensure the accurate doping of antimony elements in the reinvestment stage.

[0016] In some embodiments, the method for controlling the axial resistivity of the crystal rod further includes using a correlation analysis method to determine the constant values ​​in the following target re-investment evaporation calculation model:

[0017] P = i + kQ;

[0018] In the above formula, P is the third antimony evaporation amount, Q is the weight of the remaining material in the re-investment stage, and i and k are both constants.

[0019] The crystal rod axial resistivity control method in the above embodiment establishes a specific functional relationship expression between the antimony evaporation amount and the target variable, so that the third antimony evaporation amount in the re-investment stage in the antimony-phosphorus co-doped single crystal furnace can be predicted according to the specific functional relationship expression, thereby reducing the calculation complexity of the prediction algorithm and reducing the calculation time. The antimony-phosphorus doping ratio in the re-investment stage can be controlled according to the third antimony evaporation amount, thereby ensuring the accurate doping of the antimony element in the re-investment stage.

[0020] In some embodiments, the furnace pressure in the antimony-phosphorus co-doped single crystal furnace is a preset pressure value and the argon gas flow rate is a preset flow rate value; the method for controlling the axial resistivity of the crystal rod further includes:

[0021] Obtaining the antimony diffusion constant after a preset amount of antimony is doped into the silicon melt in the single crystal furnace;

[0022] According to the antimony diffusion constant, the simulated distribution curve of the axial resistance of the crystal rod caused by antimony segregation is simulated and calculated when the resistivity at the beginning of crystal pulling is the target value;

[0023] Determine the measured resistivity distribution curve according to the simulated distribution curve;

[0024] According to the measured resistivity distribution curve, the correlation analysis method was used to determine the correlation between the evaporation constant and the weight of the residual material in the equal diameter process.

[0025] In the above-mentioned embodiment of the method for controlling the axial resistivity of the crystal rod, the diffusion constant of antimony in the molten silicon affects its distribution and concentration in the molten silicon, thereby affecting the growth rate and quality of the single crystal. Experiments have shown that this diffusion constant is related to factors such as the kinematic viscosity coefficient and relative rotation speed of the molten silicon, and under specific growth conditions, this value can be determined. Therefore, by setting the furnace pressure to a preset pressure value and the argon flow rate to a preset flow rate value, multiple experiments are conducted to obtain the antimony diffusion constant after a preset amount of antimony is doped into the silicon melt in the single crystal furnace, and to determine whether the antimony diffusion constant and the corresponding growth parameters can meet the current mass production needs. Then, based on the aforementioned antimony diffusion constant, the simulated distribution curve of the axial resistivity of the crystal rod caused by antimony segregation is simulated and calculated when the resistivity at the starting point of crystal pulling is the target value, and the measured resistivity distribution curve is determined based on the simulated distribution curve, so that the fit between the measured resistivity distribution curve and the simulated distribution curve is greater than or equal to a preset threshold value; then, based on the measured resistivity distribution curve, the correlation analysis method is used to determine the correlation between the evaporation constant and the residual material weight in the equal-diameter process, so that the corresponding antimony evaporation constant can be accurately calculated based on the real-time residual material weight in the single crystal furnace and the correlation, thereby accurately calculating the predicted antimony evaporation amount of the direct pulling equal-diameter process.

[0026] In some embodiments, a correlation analysis method is used to determine the constant value in the correlation relationship between the evaporation constant and the weight of the residual material in the following equal diameter process:

[0027] Ev=a+bW+cW 2 +dW 3 ;

[0028] In the above formula, Ev is the antimony evaporation constant of the equal diameter process, W is the weight of the residual material of the equal diameter process, and a, b, c and d are all constants.

[0029] The crystal rod axial resistivity control method in the above-mentioned embodiment uses the correlation analysis method to determine that the antimony evaporation constant is mainly related to the residual material weight. Therefore, after obtaining a large amount of actual data, the constant value in the correlation relationship between the evaporation constant and the residual material weight in the above-mentioned equal-diameter process is determined, and the function expression of the evaporation constant and the residual material weight in the equal-diameter process is determined, so as to accurately calculate the corresponding antimony evaporation constant according to the real-time residual material weight in the single crystal furnace and the function expression, and accurately calculate the predicted antimony evaporation amount of the CZE equal-diameter process according to the antimony evaporation constant and the correlation relationship between the antimony evaporation amount in the CZE equal-diameter process and the antimony evaporation constant, thereby realizing accurate dynamic prediction of the predicted antimony evaporation amount of the CZE equal-diameter process.

[0030] In some embodiments, the temperature of the crystal pulling process is a preset temperature value; and the method for controlling the axial resistivity of the crystal rod further includes:

[0031] Obtain the variation curve of the antimony evaporation constant during the discharge process as a function of the discharge time in the single crystal furnace;

[0032] The functional expression between the antimony evaporation constant and the discharge time is determined according to the change curve.

[0033] In the above-mentioned embodiment, the method for controlling the axial resistivity of the crystal rod is basically constant in the temperature of other crystal pulling states except the CZE process. Therefore, after obtaining the variation curve of the antimony evaporation constant with the drawing and releasing time in the single crystal furnace, the function expression between the antimony evaporation constant and the drawing and releasing time can be determined according to the variation curve. Therefore, the current antimony evaporation constant of the CZE process can be accurately calculated according to the function expression and the real-time drawing and releasing time. The predicted antimony evaporation amount of the CZE process can be accurately calculated or predicted according to the current antimony evaporation constant and the correlation between the antimony evaporation amount of the CZE process and the antimony concentration after antimony evaporation.

[0034] In some embodiments, determining a functional expression between the antimony evaporation constant and the discharge time includes:

[0035] Determine the values ​​of the constants in the following formulas:

[0036] Ev=m*t n ;

[0037] In the above formula, Ev is the antimony evaporation constant of the discharge process, t is the discharge time, and m and n are both constants.

[0038] The crystal rod axial resistivity control method in the above embodiment can determine the constant value in the function expression between the antimony evaporation constant and the release time according to a large amount of real data after determining that the antimony evaporation constant in the direct pulling and releasing process is mainly related to the release time, thereby determining the specific function expression between the antimony evaporation constant and the release time in the direct pulling and releasing process.

[0039] In a second aspect, the present disclosure provides a crystal rod axial resistivity control device, including an equal-diameter process control module, a lead-out process control module and a re-investment stage control module, wherein the equal-diameter process control module is used to predict a first antimony evaporation amount in a crystal pulling equal-diameter process in an antimony-phosphorus co-doped single crystal furnace according to a correlation between an evaporation constant and a residual weight in the antimony-phosphorus co-doped single crystal furnace, and control an antimony-phosphorus doping ratio in the equal-diameter process according to the first antimony evaporation amount; the lead-out process control module is used to predict a second antimony evaporation amount in a crystal pulling lead-out process in the antimony-phosphorus co-doped single crystal furnace according to a correlation between the evaporation constant and the lead-out time, and control an antimony-phosphorus doping ratio in the lead-out process according to the second antimony evaporation amount; the re-investment stage control module is used to predict a third antimony evaporation amount in a re-investment stage in the antimony-phosphorus co-doped single crystal furnace according to a target re-investment evaporation calculation model, and control an antimony-phosphorus doping ratio in the re-investment stage according to the third antimony evaporation amount, so that the axial resistivity uniformity of the crystal rod obtained by direct pulling is within a target range.

[0040] In the above-mentioned embodiment, the crystal rod axial resistivity control device, since the CZ silicon single crystal manufacturing process includes feeding, melting, necking, shouldering, equal diameter and other stages, adopts the antimony-phosphorus co-doped CZ silicon single crystal manufacturing process, and utilizes the antimony evaporation amount in the equal diameter process, the drawing and releasing process and the re-throwing stage, which has a great influence on the uniformity of the axial resistivity of the crystal rod. Firstly, based on the equal diameter process control module, according to the correlation between the evaporation constant and the residual weight in the antimony-phosphorus co-doped single crystal furnace, the first antimony evaporation amount of the crystal pulling equal diameter process in the antimony-phosphorus co-doped single crystal furnace is predicted, and the antimony-phosphorus doping ratio of the equal diameter process is controlled according to the first antimony evaporation amount, so as to ensure the accurate doping of the antimony element in the equal diameter process; then, based on the drawing and releasing process control module, according to the correlation between the evaporation constant and the drawing and releasing time, the antimony evaporation amount of the crystal pulling equal diameter process in the antimony-phosphorus co-doped single crystal furnace is predicted, and the antimony-phosphorus doping ratio of the equal diameter process is controlled according to the first antimony evaporation amount, so as to ensure the accurate doping of the antimony element in the equal diameter process. The correlation relationship is established, and the second antimony evaporation amount in the crystal pulling and releasing process in the antimony-phosphorus co-doped single crystal furnace is predicted, and the antimony-phosphorus doping ratio in the pulling and releasing process is controlled according to the second antimony evaporation amount; the accurate doping of antimony element in the pulling and releasing process is ensured; further based on the re-investment stage control module and the target re-investment evaporation calculation model, the third antimony evaporation amount in the re-investment stage in the antimony-phosphorus co-doped single crystal furnace is predicted, and the antimony-phosphorus doping ratio in the re-investment stage is controlled according to the third antimony evaporation amount, to ensure the accurate doping of antimony element in the re-investment stage, to ensure that the uniformity of axial doping elements in single crystal silicon is improved during the crystal pulling process, to achieve precise control of resistivity, so that the axial resistivity uniformity of the crystal rod obtained by direct pulling is within the target range, thereby improving the uniformity of the axial resistivity of the crystal rod.

[0041] In a third aspect, the present disclosure provides a crystal rod axial resistivity control device, including a memory and a processor, the memory stores a computer program, and the processor implements the steps of the method described in any embodiment of the present disclosure when executing the computer program.

[0042] In a fourth aspect, the present disclosure provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the method described in any one of the embodiments of the present disclosure.

[0043] In a fifth aspect, the present disclosure provides a computer program product, including a computer program, which, when executed by a processor, implements the steps of the method described in any embodiment of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, drawings of other embodiments can be obtained based on these drawings without creative work.

[0045] FIG1 is a schematic flow chart of a method for controlling axial resistivity of a crystal rod provided in an embodiment of the present disclosure;

[0046] FIG2 is a schematic diagram showing a comparison of curves of axial resistivity of a single crystal obtained by co-doping with antimony and phosphorus under three furnace pressure conditions in one embodiment of the present disclosure;

[0047] FIG3a is a simulated distribution curve of the axial resistivity of a crystal rod and a measured distribution curve of the axial resistivity of a crystal rod obtained without adjusting the growth parameters in an embodiment of the present disclosure;

[0048] FIG3 b is a simulated distribution curve of the axial resistivity of a crystal rod and a measured distribution curve of the axial resistivity of a crystal rod obtained by adjusting growth parameters in an embodiment of the present disclosure;

[0049] FIG4 is a curve showing a change in the evaporation constant with the crystal length obtained when the curve shown in FIG3b is obtained in one embodiment of the present disclosure;

[0050] FIG5 is a correlation curve between the residual material weight and the evaporation constant in one embodiment of the present disclosure;

[0051] FIG6 is a graph showing two antimony evaporation constant change curves obtained based on the first calculation method and the second calculation method under the experimental conditions corresponding to the change curve in FIG5 ;

[0052] FIG7 is a curve showing the variation of the antimony evaporation constant with the drawing time during the direct drawing process obtained in one embodiment of the present disclosure;

[0053] FIG8 is a schematic structural diagram of a crystal rod axial resistivity control device provided in an embodiment of the present disclosure.

[0054] Reference numerals and descriptions:

[0055] 10. Equal diameter process control module; 20. Introducing and releasing process control module; 30. Reinvestment stage control module. DETAILED DESCRIPTION

[0056] In order to facilitate the understanding of the present disclosure, the present disclosure will be described more fully below with reference to the relevant drawings. The preferred embodiments of the present disclosure are given in the drawings. However, the present disclosure can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present disclosure more thorough and comprehensive.

[0057] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the present disclosure belongs. The terms used herein in the specification of the present disclosure are only for the purpose of describing specific embodiments and are not intended to limit the present disclosure. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0058] In the case of using “including”, “having”, and “comprising” described herein, another component may be added unless a clear limiting term such as “only”, “consisting of”, etc. is used. Unless mentioned otherwise, a term in the singular form may include a plural form and should not be understood as being one in number.

[0059] The segregation principle of antimony-phosphorus co-doped single crystals mainly involves the change in the concentration distribution of doping elements during the crystal growth process. During the growth of single crystal silicon, the introduction of doping elements (such as antimony and phosphorus) will significantly affect the physical and chemical properties of the crystal. There is a difference in the solubility of these doping elements in the melt and the solid. Usually, the solubility in the liquid is greater than the solubility in the solid, which is defined as the segregation coefficient ‌1. The equilibrium segregation coefficient of antimony in silicon is also very small (about 0.023), resulting in poor axial resistivity uniformity of antimony-doped CZ single crystal silicon.

[0060] Segregation refers to the phenomenon that when a crystalline material containing impurities is melted and then recrystallized, the concentration of impurities in the solid crystal and the uncrystallized liquid are different. During the growth of antimony-phosphorus co-doped single crystals, due to the different segregation coefficients of antimony and phosphorus, their distribution in the crystal will also be different.

[0061] Specifically, the incorporation of antimony and phosphorus into the silicon lattice can cause lattice distortion, thereby affecting the dynamics of dislocations. At high temperatures, these doping atoms can interact with dislocation cores to form complexes, which act as pinning centers and can inhibit the slip of dislocations. However, due to the different segregation coefficients of antimony and phosphorus, their distribution in the crystal will show a certain gradient. For example, the segregation coefficient of phosphorus is small, which means that during crystal growth, phosphorus atoms are more likely to be enriched in the tail of the crystal, while the segregation coefficient of antimony may be relatively large, and its distribution may be more uniform or have different characteristics.

[0062] In antimony-phosphorus co-doped single crystals, due to the co-existence of the two doping elements, their interaction will further affect the properties of the crystal. For example, antimony and phosphorus may jointly affect the conductivity, mechanical strength and other properties of the crystal by forming a complex or changing the dislocation behavior.

[0063] Antimony co-doped semiconductors have excellent photoelectric properties and have broad application prospects in the fields of solar cells, light-emitting diodes and lasers. Especially in the field of solar cells, phosphorus antimony co-doped semiconductors can enhance the photoelectric conversion efficiency and improve the performance of solar cells.

[0064] Existing control methods often rely on preset fixed growth parameters, which are difficult to adapt to slight changes in the actual growth process. They lack real-time monitoring and dynamic adjustment of growth parameters during the growth process, lack precision and controllability, and are difficult to achieve optimal resistivity distribution, resulting in uneven resistivity distribution and affecting device performance.

[0065] The embodiments of the present disclosure aim to provide a method, device, equipment and product for controlling the axial resistivity of a crystal rod, which can at least ensure that the uniformity of axial doping elements in single crystal silicon is improved during the crystal pulling process, achieve precise control of the resistivity, and improve the uniformity of the axial resistivity of the crystal rod.

[0066] Referring to FIG. 1 , in some embodiments, a method for controlling axial resistivity of a crystal rod is provided, comprising:

[0067] Step S20: predicting the first antimony evaporation amount of the crystal pulling equal diameter process in the antimony-phosphorus co-doped single crystal furnace according to the correlation between the evaporation constant and the residual material weight in the antimony-phosphorus co-doped single crystal furnace, and controlling the antimony-phosphorus doping ratio in the equal diameter process according to the first antimony evaporation amount;

[0068] Step S40: predicting the second antimony evaporation amount during the crystal pulling and releasing process in the antimony-phosphorus co-doped single crystal furnace according to the correlation between the evaporation constant and the pulling and releasing time, and controlling the antimony-phosphorus doping ratio during the pulling and releasing process according to the second antimony evaporation amount;

[0069] Step S60: predict the third antimony evaporation amount in the re-doping stage in the antimony-phosphorus co-doped single crystal furnace according to the target re-doping evaporation calculation model, and control the antimony-phosphorus doping ratio in the re-doping stage according to the third antimony evaporation amount, so that the axial resistivity uniformity of the crystal rod obtained by direct pulling is within the target range.

[0070] For example, since the manufacturing process of a Czochralski silicon single crystal includes feeding, melting, necking, shouldering, equalizing diameter and other stages, an antimony-phosphorus co-doped Czochralski silicon single crystal manufacturing process is adopted, and the antimony evaporation amount in the equalizing diameter process, the drawing and releasing process and the re-throwing stage has a greater influence on the uniformity of the axial resistivity of the crystal rod. Firstly, according to the correlation between the evaporation constant and the weight of the residual material in the antimony-phosphorus co-doped single crystal furnace, the first antimony evaporation amount in the equalizing diameter process of the crystal pulling in the antimony-phosphorus co-doped single crystal furnace is predicted, and the antimony-phosphorus doping ratio in the equalizing diameter process is controlled according to the first antimony evaporation amount, so as to ensure the accurate doping of the antimony element in the equalizing diameter process; according to the correlation between the evaporation constant and the drawing and releasing time, the antimony evaporation amount in the equalizing diameter process of the antimony-phosphorus co-doped single crystal furnace is predicted. The second antimony evaporation amount during the crystal pulling and releasing process in the crystal furnace is used to control the antimony-phosphorus doping ratio in the releasing process according to the second antimony evaporation amount, so as to ensure the precise doping of antimony elements in the releasing process; further, according to the target re-investment evaporation calculation model, the third antimony evaporation amount in the re-investment stage of the antimony-phosphorus co-doped single crystal furnace is predicted, and the antimony-phosphorus doping ratio in the re-investment stage is controlled according to the third antimony evaporation amount, so as to ensure the precise doping of antimony elements in the re-investment stage, and to ensure that the uniformity of axial doping elements in single crystal silicon is improved during the crystal pulling process, so as to achieve precise control of resistivity, so that the axial resistivity uniformity of the crystal rod obtained by direct pulling is within the target range, thereby improving the uniformity of the axial resistivity of the crystal rod.

[0071] The diffusion behavior and diffusion constant of antimony in silicon single crystals are affected by many factors, including temperature, doping concentration, and other doping elements. The incorporation of antimony affects the performance of silicon single crystals through its interaction with dislocations. This effect is of great significance for the application and processing of silicon single crystals, especially in the process of integrated circuit manufacturing, and plays a key role in improving the mechanical strength of silicon wafers and device performance.

[0072] However, in the related art, in the antimony-phosphorus co-doped crystal pulling process, the diffusion constants and evaporation constants of P and Sb are fixed values ​​as shown in Table 1 below.

[0073] Table 1

[0074]

[0075] As shown in Table 1, the diffusion constants and evaporation constants of P and Sb in the table are all values ​​obtained by testing in solid silicon at 1200°C. In the actual CZ process, P and Sb are doped into molten silicon at a temperature of more than 1400°C, and the applicability of the diffusion constants in Table 1 will deteriorate. Among them, the diffusion constant of phosphorus has been verified by a large number of experiments to be about 2.80E-5, which is 7 orders of magnitude different from the value in the table.

[0076] In some embodiments of the present disclosure, the process of multiple experiments to determine the diffusion constant of antimony in molten silicon mainly includes:

[0077] Sample preparation: Silicon single crystals containing antimony were prepared by the Czochralski method. During the process, a preset amount of antimony was added to the silicon melt as a dopant and was incorporated into the silicon lattice during the crystal growth process.

[0078] Cooling and slicing: After diffusion treatment, the silicon single crystal is slowly cooled to fix the distribution of antimony atoms in the crystal lattice. Subsequently, the silicon single crystal is sliced ​​into a series of thin slices for subsequent resistivity measurements.

[0079] Data processing and analysis: A four-probe resistivity / square resistance detector is used to collect the resistivity data of the profile. The diffusion constant of antimony is calculated based on the measured resistivity data. The process usually involves calculation processes such as effective segregation. The diffusion constant is determined by fitting the test data with the theoretical numerical value. The diffusion constant of antimony in molten silicon is found to be 2.914E-6.

[0080] Result verification: In order to ensure the accuracy of the experimental results, multiple experiments were conducted to verify the repeatability of the data. The influence of experimental conditions (such as temperature, pressure, purity of silicon and antimony, etc.) on the diffusion constant was taken into account. It was found that the diffusion constant of antimony in molten silicon is 2.914E-6, which can meet the current mass production needs.

[0081] Please refer to FIG. 2 . In some embodiments, the preset state includes the furnace pressure being a preset pressure value and the argon gas flow being a preset flow value. The method for controlling the axial resistivity of the crystal rod further includes the following step of obtaining the first correlation relationship:

[0082] Step S12: obtaining the antimony diffusion constant after a preset amount of antimony is doped into the silicon melt in the single crystal furnace;

[0083] Step S14: simulating and calculating the distribution curve of the axial resistivity of the crystal rod caused by antimony segregation when the resistivity at the start of crystal pulling is the target value according to the antimony diffusion constant;

[0084] Step S16: determining the measured resistivity distribution curve according to the simulated distribution curve;

[0085] Step S18: According to the measured resistivity distribution curve, a first correlation relationship between the antimony evaporation constant and the weight of the residual material in the single crystal furnace is determined by using a correlation analysis method.

[0086] For example, step S12 can refer to the aforementioned test steps to determine that the antimony diffusion constant is 2.914E-6.

[0087] For example, in the preset state: the preset pressure value of the furnace pressure is 3torr-15torr, for example, the preset pressure value can be 3torr, 7torr, 12torr or 15torr, etc.; the preset flow value of the argon flow rate can be 30slpm-170slpm, for example, the preset flow value can be 30slpm, 60slp, 90slp, 110slp, 140slp, 160slp or 170slpm, etc.; the thermal field size in the single crystal furnace is 28 inches-42 inches, for example, the thermal field size can be 28 inches, 32 inches, 36 inches, 40 inches or 42 inches, etc.

[0088] In step S14, a silicon single crystal containing antimony can be prepared by the Czochralski method. During the process, a certain amount of antimony is added to the silicon melt as a dopant and is incorporated into the silicon lattice during the crystal growth process. Three furnace pressing processes can be used for pulling verification. Then, a portable four-probe detector is used to collect the axial resistivity data of the crystal rod, for example, at three points with an interval of 50 mm in the axial direction and equidistantly distributed in the circumferential direction of the concentric circles of the cross section, and the resistivity curve with the crystal length shown in FIG2 is measured. In FIG2, the unit of the resistivity of the vertical axis is ohm·meter (Ω·m), and the unit of the crystal length of the horizontal axis is mm.

[0089] As shown in Figure 2, BSL is the axial resistivity distribution of phosphorus-doped single crystals. The yellow BSL straight line indicates that the axial resistivity of phosphorus-doped single crystals is little affected by changes in furnace pressure. Since the evaporation effect of antimony is greater than the segregation effect of antimony, the green curve in Figure 2 is obtained by reducing the furnace pressure from 9.4 Torr to 2 Torr; the orange curve in Figure 2 is obtained by maintaining the furnace pressure at 6 Torr to 7 Torr; the gray curve in Figure 2 is obtained by increasing the furnace pressure from 7 Torr to 10 Torr. Therefore, the control of antimony evaporation can be achieved by presetting the furnace pressure and argon parameters, indicating that the evaporation effect of antimony can be enhanced or suppressed by changing the furnace pressure.

[0090] For example, in step S14, based on the antimony diffusion constant, the resistivity at the beginning of crystal pulling (head-controlled resistivity) is simulated and calculated to be consistent with the target value. Then, the simulated distribution curve of the axial resistivity of the crystal rod caused by antimony segregation is shown in FIG3a, wherein the horizontal axis represents the crystal length in mm, and the vertical axis represents the axial resistivity in Ω·cm; the green curve in FIG3a represents the simulated distribution curve of the axial resistivity of the crystal rod caused by antimony segregation; the red curve in FIG3a represents the simulated distribution curve of the axial resistivity of the crystal rod actually measured. In the actual process, the segregation effect of antimony is smaller than the evaporation effect of antimony, and the segregation effect of antimony and the evaporation effect of antimony jointly affect the axial resistivity distribution of the crystal rod.

[0091] For example, in step S16, the measured resistivity distribution curve is determined according to the simulated distribution curve, for example, by simulating and calculating the antimony evaporation constant (Ev) and the evaporation amount (N) at different lengths (along the axial direction), to obtain the simulated resistivity curve and the measured resistivity curve shown in FIG3b, so that the fitting degree between the simulated resistivity curve shown in FIG3b and the measured resistivity curve is ≥99.8%.

[0092] In the process of obtaining the simulated resistivity curve and the measured resistivity curve shown in FIG. 3 b , the evaporation constants at different crystal lengths are obtained as shown in FIG. 4 .

[0093] Furthermore, in step S18, the first correlation between the antimony evaporation constant (Ev) and the residual weight in the single crystal furnace can be determined by using a correlation analysis method based on the measured resistivity distribution curve shown in FIG3b and the evaporation constant versus crystal length variation curve shown in FIG4.

[0094] In the correlation analysis method, the relevant independent variables include the background monitoring data of the furnace, such as 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, auxiliary 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 the water cooling jacket, liquid surface temperature measurement, and equal diameter time, etc.

[0095] Statistical methods are used to determine the correlation between the antimony evaporation constant (Ev) and at least one of the aforementioned furnace background monitoring data. After the correlation analysis, the size, direction and significance of the correlation coefficient need to be explained. A positive correlation coefficient indicates that an increase in one variable is accompanied by an increase in another variable, while a negative correlation coefficient indicates that an increase in one variable is accompanied by a decrease in another variable. The closer the absolute value of the correlation coefficient is to 1 or -1, the stronger the correlation. The significance level is usually set to 0.05 or 0.01, and if the p-value is less than these thresholds, the correlation is considered to be statistically significant. Through the stratification of the thresholds of the above significance levels, the independent variables with a significance level of P≤0.05 are identified, including: crystal length, residual weight, actual argon flow rate, main chamber pressure value, average liquid surface temperature, and equal diameter time.

[0096] Through regression analysis, the constant term was deleted, and the independent variables included: actual argon flow rate, main chamber pressure value, and average liquid surface temperature; the crystal length and equal diameter time were further deleted through the variance inflation factor (VIF) method, and finally the relationship between the residual weight and the evaporation constant was established as follows:

[0097] Ev=a+bW+cW 2 +dW 3 ;

[0098] In the above formula, Ev is the antimony evaporation constant, W is the weight of the residual material, and a, b, c and d are all constants.

[0099] Based on the test data in the same experiment in Figures 3b and 4, the correlation curve between the residual material weight and the evaporation constant is shown in Figure 5, where the horizontal axis represents the residual material weight in g, and the vertical axis represents the evaporation constant in cm / s.

[0100] The correlation analysis method is used to determine the constant value in the first correlation relationship, and the specific function expression between the residual weight and the evaporation constant is obtained as follows:

[0101] Ev=0.000301638354296996-2.847079761568·10 -11 W+2.374013120331233•10 - 15 W 2 -2.82524056437763•10 -21 W 3 .

[0102] In some embodiments, obtaining a first predicted antimony evaporation amount in a CZE process includes:

[0103] The first predicted antimony evaporation amount N1 is calculated according to the following formula:

[0104] N1=Ev•A•C1First calculation method;

[0105] In the above formula, Ev is the antimony evaporation constant, A is the antimony evaporation surface area, and C1 is the antimony concentration in the single crystal furnace.

[0106] In the above-mentioned embodiment, the antimony evaporation constant determined by the correlation analysis method is mainly related to the residual material weight. Therefore, after obtaining a large amount of actual data, the constant value in the above-mentioned first correlation relationship is determined, and the function expression of the first correlation relationship is determined, so as to achieve accurate calculation of the corresponding antimony evaporation constant according to the real-time residual material weight in the single crystal furnace and the first correlation relationship, and accurately calculate the first predicted antimony evaporation amount of the CZE process according to the antimony evaporation constant and the correlation relationship between the antimony evaporation amount of the CZE process and the antimony evaporation constant, thereby achieving accurate dynamic prediction of the first predicted antimony evaporation amount of the CZE process.

[0107] The diffusion constant of antimony in molten silicon affects its distribution and concentration in the molten silicon, and thus affects the growth rate and quality of the single crystal. Experiments have shown that this diffusion constant is related to factors such as the kinematic viscosity coefficient and relative rotation speed of molten silicon, and under specific growth conditions, this value can be determined. Therefore, by setting the furnace pressure to a preset pressure value and the argon gas flow rate to a preset flow rate value, multiple experiments are conducted to obtain the antimony diffusion constant after a preset amount of antimony is doped into the silicon melt in the single crystal furnace, and to determine whether the antimony diffusion constant and the corresponding growth parameters can meet the current mass production needs. Then, based on the aforementioned antimony diffusion constant, a simulated distribution curve of the axial resistivity of the crystal rod caused by antimony segregation is simulated and calculated when the resistivity at the starting point of crystal pulling is the target value, and the measured resistivity distribution curve is determined based on the simulated distribution curve, so that the fit degree between the measured resistivity distribution curve and the simulated distribution curve is greater than or equal to a preset threshold value; then, based on the measured resistivity distribution curve, a correlation analysis method is used to determine a first correlation relationship between the antimony evaporation constant and the weight of the residual material in the single crystal furnace, so that the corresponding antimony evaporation constant can be accurately calculated based on the real-time residual material weight in the single crystal furnace and the first correlation relationship, thereby accurately calculating the first predicted antimony evaporation amount of the CZE process.

[0108] Compared with the calculation of the first predicted antimony evaporation amount N1 in the CZE state, the changes in the weight of the remaining material (remaining raw material weight), power, furnace pressure, and argon flow rate in the single crystal furnace are relatively small in other crystal pulling states and stages; therefore, a different calculation method (second calculation method) from the above-mentioned antimony evaporation amount in the equal diameter process is used to calculate the second predicted antimony evaporation amount N2 while considering the latent heat of evaporation:

[0109] C = C0e^-(Ev•A / U);

[0110] N2=(C0-C)•V;

[0111] In the above formula, C is the antimony concentration after antimony evaporation, C0 is the antimony concentration after time t, Ev is the antimony evaporation constant, A is the antimony evaporation surface area, U is the silicon mass in the single crystal furnace, and V is the residual material volume in the single crystal furnace.

[0112] As the temperature of water rises, the latent heat of evaporation gradually decreases, and the difficulty of evaporation of water increases; the evaporation phenomenon of antimony is similar to that of water. Using the data under the aforementioned experimental conditions, the change of the antimony evaporation constant during the straight pulling equal diameter process was simulated and calculated, and the results are shown in Figure 6. In Figure 6, the horizontal axis represents the weight of the residual material in g, and the vertical axis represents the evaporation constant in cm / s. The antimony evaporation constants obtained by the two calculation methods are significantly different in the first section, and the latter section basically overlaps. It is judged that the difference is caused by the latent heat of evaporation of antimony in silicon, and the latent heat of evaporation of antimony in silicon satisfies a similar change relationship to the latent heat of evaporation of water.

[0113] Since the temperature in other crystal pulling states except the CZ pulling equal diameter process is basically constant, for example, the temperature in the CZ pulling and releasing process is a preset temperature value; the crystal rod axial resistivity control method also includes the following step of obtaining the second correlation relationship:

[0114] Step S52: obtaining a curve of the variation of the antimony evaporation constant with the time of being placed in the single crystal furnace;

[0115] Step S54: determining a functional expression between the antimony evaporation constant and the discharge time according to the variation curve.

[0116] For example, after obtaining the variation curve of the antimony evaporation constant with the release time in the single crystal furnace, the function expression between the antimony evaporation constant and the release time can be determined according to the variation curve, so that the current antimony evaporation constant of the direct pulling release process can be accurately calculated according to the function expression and the real-time release time, so as to accurately calculate or predict the second predicted antimony evaporation amount of the direct pulling release process according to the current antimony evaporation constant and the correlation between the antimony evaporation amount of the direct pulling release process and the antimony concentration after antimony evaporation.

[0117] The data under the above test conditions can be used to simulate the change curve of the antimony evaporation constant during the direct pulling process with the drawing time, as shown in Figure 7. In Figure 7, the horizontal axis represents the drawing time, in min, and the vertical axis represents the evaporation constant, in cm / s.

[0118] In some embodiments, determining a functional expression between the antimony evaporation constant and the discharge time includes:

[0119] Determine the values ​​of the constants in the following formulas:

[0120] Ev=m •t n ;

[0121] In the above formula, Ev is the antimony evaporation constant, t is the release time, and m and n are both constants.

[0122] For example, after determining that the antimony evaporation constant of the direct-pull release process is mainly related to the release time, the constant value in the function expression between the antimony evaporation constant and the release time can be determined by fitting according to the curve in FIG. 7, so as to determine the specific function expression between the antimony evaporation constant Ev and the release time t in the direct-pull release process as follows:

[0123] Ev=0.000104194 •t 0.463774 .

[0124] In some embodiments, the first correlation between the antimony evaporation constant and the weight of the residual material in the single crystal furnace and the first calculation method are combined, and the least squares method is used to calculate the optimal antimony-phosphorus doping ratio. Combined with the correlation between the antimony evaporation amount in the direct pulling process and the antimony concentration after antimony evaporation, the second predicted antimony evaporation amount in the direct pulling process is accurately calculated or predicted, thereby achieving optimized control of the axial resistivity of the direct pulling equal-diameter process and the direct pulling process in the antimony-phosphorus co-doping process.

[0125] The CZE process and the CZE release process are relatively fixed and repetitive. Compared with the calculation of antimony evaporation in the CZE process and the calculation of antimony evaporation in the CZE release process, the re-feeding stage is diverse and is affected by many factors such as the weight of the remaining material in the single crystal furnace (residual material amount), the residual concentration of antimony, the re-feeding amount, the furnace pressure, and the temperature.

[0126] In some embodiments, the method for controlling the axial resistivity of the crystal rod further includes the following step of obtaining a target re-investment evaporation calculation model:

[0127] Step S52: using a correlation analysis algorithm to determine irrelevant variables in the reinvestment phase whose correlation with the antimony evaporation amount is less than a threshold value;

[0128] Step S54: determining the target variable associated with the antimony evaporation amount in the re-investment stage according to the irrelevant variables, the target variable including the antimony concentration of the disconnected wire, the weight of the remaining material and the time required for re-investment;

[0129] Step S56: using a linear fitting algorithm to determine the functional relationship between the antimony evaporation amount and the target variable.

[0130] For example, a correlation analysis algorithm is used to determine irrelevant variables whose correlation with the antimony evaporation amount in the reinvestment stage is less than a threshold value, and then a target variable associated with the antimony evaporation amount in the reinvestment stage is determined based on the irrelevant variables. The target variables include the antimony concentration of broken wire, the weight of residual material and the time for reinvestment. Then, a linear fitting algorithm can be used to determine the functional relationship between the antimony evaporation amount and the target variable, so that the third antimony evaporation amount in the reinvestment stage of the antimony-phosphorus co-doped single crystal furnace can be predicted based on the functional relationship, and the antimony-phosphorus doping ratio in the reinvestment stage can be controlled based on the third antimony evaporation amount, thereby ensuring the accurate doping of the antimony element in the reinvestment stage.

[0131] Through the collection of a large amount of relevant data, correlation analysis and elimination of irrelevant variables, the relationship between the three variables of antimony concentration at line break (unit: atoms / cm³), residual material amount (unit: kg), re-investment time (unit: min) and evaporation amount Y (unit: atoms) is confirmed as shown in Table 2.

[0132] The average deviation of the established antimony concentration of disconnection, residual material, re-investment time and evaporation volume Y is ≤1%, which meets the use requirements. However, the correlation model of antimony concentration of disconnection, residual material, re-investment time and evaporation volume contains the relationship between three independent variables (antimony concentration of disconnection, residual material, re-investment time) and one dependent variable Y (evaporation volume). When the amount of original training data is small, the deviation calculated without training will reach 50% or more, which is not convenient for actual production use.

[0133] Table 2

[0134]

[0135] It is preferred to establish the relationship between the amount of residual material and the amount of re-investment evaporation. The correlation analysis method can be used to determine the constant values ​​in the target re-investment evaporation calculation model as follows:

[0136] P = i + kQ;

[0137] In the above formula, P is the evaporation capacity of re-investment, Q is the weight of the remaining material (residual material amount) in the re-investment stage, and i and k are both constants.

[0138] The specific functional expressions of the residual material amount and the re-investment evaporation amount can be determined by the relevant fitting algorithm as follows:

[0139] P=1.1891-0.001Q.

[0140] Please refer to Table 3. Combined with the first correlation between the antimony evaporation constant and the weight of the residual material in the single crystal furnace and the first calculation method, the least squares method is used to calculate the optimal antimony-phosphorus doping ratio for preparing N-type single crystal silicon by the direct pulling method. Combined with the correlation between the antimony evaporation amount in the direct pulling process and the antimony concentration after antimony evaporation, the second predicted antimony evaporation amount in the direct pulling process is accurately calculated or predicted to ensure the precise doping of antimony elements in the release process. Further, according to the target re-investment evaporation calculation model, the third antimony evaporation amount in the re-investment stage in the antimony-phosphorus co-doped single crystal furnace is predicted, and the antimony-phosphorus doping ratio in the re-investment stage is controlled according to the third antimony evaporation amount to ensure the precise doping of antimony elements in the re-investment stage. Finally, the axial resistivity of the crystal rod is obtained to be 0.952Ω·m-0.964Ω·m, which effectively realizes the optimization control of the axial resistivity of the antimony-phosphorus co-doped whole furnace crystal pulling.

[0141] Table 3

[0142]

[0143] It should be understood that, although the various steps in the flowchart of FIG. 1 are shown in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence according to the order indicated by the arrows. Unless there is a clear explanation in this article, the execution of these steps is not strictly limited in order, and these steps can be executed in other orders. Moreover, at least a part of the steps in FIG. 1 may include a plurality of sub-steps or a plurality of stages, and these sub-steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these sub-steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a part of the sub-steps or stages of other steps.

[0144] Please refer to FIG8. In some embodiments, a device for controlling the axial resistivity of a crystal rod is provided, including an equal-diameter process control module 10, a lead-out process control module 20, and a reinvestment stage control module 30. The equal-diameter process control module 10 is used to predict the first antimony evaporation amount of the crystal pulling equal-diameter process in the antimony-phosphorus co-doped single crystal furnace according to the correlation between the evaporation constant and the weight of the residual material in the antimony-phosphorus co-doped single crystal furnace, and control the antimony-phosphorus doping ratio of the equal-diameter process according to the first antimony evaporation amount; the lead-out process control module 20 is used to predict the second antimony evaporation amount of the crystal pulling lead-out process in the antimony-phosphorus co-doped single crystal furnace according to the correlation between the evaporation constant and the lead-out time, and control the antimony-phosphorus doping ratio of the lead-out process according to the second antimony evaporation amount; the reinvestment stage control module 30 is used to predict the third antimony evaporation amount of the reinvestment stage in the antimony-phosphorus co-doped single crystal furnace according to the target reinvestment evaporation calculation model, and control the antimony-phosphorus doping ratio of the reinvestment stage according to the third antimony evaporation amount, so that the axial resistivity uniformity of the crystal rod obtained by direct pulling is within the target range.

[0145] Please continue to refer to FIG8 . Since the manufacturing process of the CZ silicon single crystal includes feeding, melting, necking, shouldering, equal diameter and other stages, the antimony-phosphorus co-doped CZ silicon single crystal manufacturing process is adopted, and the antimony evaporation amount in the equal diameter process, the drawing and releasing process and the re-investment stage has a greater influence on the uniformity of the axial resistivity of the crystal rod. Firstly, based on the equal diameter process control module 10, according to the correlation between the evaporation constant and the residual weight in the antimony-phosphorus co-doped single crystal furnace, the first antimony evaporation amount in the equal diameter process of the crystal pulling in the antimony-phosphorus co-doped single crystal furnace is predicted, and the antimony-phosphorus doping ratio in the equal diameter process is controlled according to the first antimony evaporation amount, so as to ensure the accurate doping of the antimony element in the equal diameter process; then, based on the drawing and releasing process control module 20, according to the correlation between the evaporation constant and the drawing and releasing time, the antimony-phosphorus co-doped single crystal furnace is controlled according to the correlation between the evaporation constant and the drawing and releasing time. , predict the second antimony evaporation amount during the crystal pulling and releasing process in the antimony-phosphorus co-doped single crystal furnace, and control the antimony-phosphorus doping ratio in the pulling and releasing process according to the second antimony evaporation amount; ensure the precise doping of antimony elements in the pulling and releasing process; further based on the re-investment stage control module 30, according to the target re-investment evaporation calculation model, predict the third antimony evaporation amount during the re-investment stage in the antimony-phosphorus co-doped single crystal furnace, and control the antimony-phosphorus doping ratio in the re-investment stage according to the third antimony evaporation amount, ensure the precise doping of antimony elements in the re-investment stage, ensure that the uniformity of axial doping elements in single crystal silicon is improved during the crystal pulling process, and realize precise control of resistivity, so that the axial resistivity uniformity of the crystal rod obtained by direct pulling is within the target range, thereby improving the uniformity of the axial resistivity of the crystal rod.

[0146] In some embodiments, the crystal rod axial resistivity control device also includes a reinvestment evaporation calculation model acquisition module, which is used to use a correlation analysis algorithm to determine irrelevant variables whose correlation with the antimony evaporation amount is less than a threshold value in the reinvestment stage; determine the target variables associated with the antimony evaporation amount in the reinvestment stage based on the irrelevant variables, and the target variables include the antimony concentration of broken wire, the weight of residual material and the time for reinvestment; and use a linear fitting algorithm to determine the functional relationship between the antimony evaporation amount and the target variable.

[0147] The crystal rod axial resistivity control device in the above embodiment adopts a correlation analysis algorithm to determine the irrelevant variables whose correlation with the antimony evaporation amount is less than a threshold value in the reinvestment stage, thereby determining the target variables associated with the antimony evaporation amount in the reinvestment stage based on the irrelevant variables, and the target variables include the antimony concentration of broken wire, the weight of residual material and the time for reinvestment, and then a linear fitting algorithm can be used to determine the functional relationship between the antimony evaporation amount and the target variable, so that the third antimony evaporation amount in the reinvestment stage in the antimony-phosphorus co-doped single crystal furnace can be predicted based on the functional relationship, and the antimony-phosphorus doping ratio in the reinvestment stage can be controlled based on the third antimony evaporation amount, so as to ensure the accurate doping of antimony element in the reinvestment stage.

[0148] In some embodiments, the preset state includes the furnace pressure being a preset pressure value and the argon gas flow being a preset flow value; a crystal rod axial resistivity control device also includes a first correlation relationship acquisition module, which is used to obtain the antimony diffusion constant after a preset amount of antimony is doped into the silicon melt in the single crystal furnace, and based on the antimony diffusion constant, simulate and calculate the simulated distribution curve of the axial resistivity of the crystal rod caused by antimony segregation when the resistivity at the starting point of crystal pulling is the target value, determine the measured resistivity distribution curve based on the simulated distribution curve, and use the correlation analysis method to determine the first correlation relationship between the antimony evaporation constant and the weight of the residual material in the single crystal furnace based on the measured resistivity distribution curve.

[0149] By setting the furnace pressure to a preset pressure value and the argon gas flow rate to a preset flow rate value, multiple experiments are conducted to obtain the antimony diffusion constant after a preset amount of antimony is doped into the silicon melt in the single crystal furnace, and to determine whether the antimony diffusion constant and the corresponding growth parameters can meet the current mass production needs. Then, based on the aforementioned antimony diffusion constant, the simulated distribution curve of the axial resistivity of the crystal rod caused by antimony segregation is simulated and calculated when the resistivity at the start of the crystal pulling is the target value, and the measured resistivity distribution curve is determined based on the simulated distribution curve, so that the fit between the measured resistivity distribution curve and the simulated distribution curve is greater than or equal to the preset threshold value; then, based on the measured resistivity distribution curve, the correlation analysis method is used to determine the first correlation between the antimony evaporation constant and the weight of the residual material in the single crystal furnace, so that the corresponding antimony evaporation constant can be accurately calculated based on the real-time residual material weight in the single crystal furnace and the first correlation, thereby accurately calculating the predicted antimony evaporation amount of the straight pulling equal diameter process.

[0150] In some embodiments, the temperature of the CZ pulling process is a preset temperature value; a crystal rod axial resistivity control device further includes a second correlation relationship acquisition module, which is used to obtain the variation curve of the antimony evaporation constant with the duration of the single crystal furnace; and determine the function expression between the antimony evaporation constant and the duration of the single crystal furnace according to the variation curve. Since the temperature of other crystal pulling states except the CZ equal diameter process is basically constant, after obtaining the variation curve of the antimony evaporation constant with the duration of the single crystal furnace, the function expression between the antimony evaporation constant and the duration of the single crystal furnace can be determined according to the variation curve, so that the current antimony evaporation constant of the CZ pulling process can be accurately calculated according to the function expression and the real-time duration of the direct release, so as to accurately calculate or predict the predicted antimony evaporation amount of the CZ pulling process according to the current antimony evaporation constant and the correlation between the antimony evaporation amount of the CZ pulling process and the antimony concentration after antimony evaporation.

[0151] For example, a device for controlling the axial resistivity of a crystal rod can be applied to fields such as solar cells, light-emitting diodes, and lasers.

[0152] In some embodiments of the present disclosure, an energy storage device is provided, including a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, the steps of the crystal rod axial resistivity control method in any embodiment of the present disclosure are implemented.

[0153] In some embodiments of the present disclosure, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps of the method for controlling the axial resistivity of a crystal rod in any embodiment of the present disclosure are implemented.

[0154] In some embodiments of the present disclosure, a computer program product is provided, including a computer program, which, when executed by a processor, implements the steps of the method for controlling the axial resistivity of a crystal rod in any embodiment of the present disclosure.

[0155] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0156] The above-described embodiments only express several implementation methods of the present disclosure, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present disclosure, and these all belong to the protection scope of the present disclosure. Therefore, the protection scope of the patent of the present disclosure shall be subject to the attached claims.

Claims

1. A method for controlling the axial resistivity of a crystal rod, characterized in that: include: According to the correlation between the evaporation constant and the weight of the residual material in the antimony-phosphorus co-doped single crystal furnace, the first antimony evaporation amount of the crystal pulling equal diameter process in the antimony-phosphorus co-doped single crystal furnace is predicted, and the antimony-phosphorus doping ratio of the equal diameter process is controlled according to the first antimony evaporation amount; According to the correlation between the evaporation constant and the drawing time, predict the second antimony evaporation amount during the crystal pulling and drawing process in the antimony-phosphorus co-doped single crystal furnace, and control the antimony-phosphorus doping ratio during the drawing and drawing process according to the second antimony evaporation amount; According to the target re-investment evaporation calculation model, the third antimony evaporation amount in the re-investment stage in the antimony-phosphorus co-doped single crystal furnace is predicted, and the antimony-phosphorus doping ratio in the re-investment stage is controlled according to the third antimony evaporation amount, so that the axial resistivity uniformity of the crystal rod obtained by direct pulling is within the target range.

2. The method for controlling the axial resistivity of a crystal rod according to claim 1, characterized in that: The step of obtaining the target reinvestment evaporation calculation model is also included: Using a correlation analysis algorithm to determine irrelevant variables in the reinvestment stage whose correlation with the antimony evaporation amount is less than a threshold value; Determine the target variable associated with the antimony evaporation amount in the reinvestment stage according to the irrelevant variable, the target variable including the antimony concentration of the disconnected wire, the weight of the residual material and the time for reinvestment; A linear fitting algorithm is used to determine the functional relationship between the antimony evaporation amount and the target variable.

3. The method for controlling the axial resistivity of a crystal rod according to claim 1, characterized in that: It also includes using correlation analysis to determine the constant values ​​in the target reinvestment evaporation calculation model as follows: P = i + kQ; In the above formula, P is the third antimony evaporation amount, Q is the weight of the remaining material in the re-investment stage, and i and k are both constants.

4. The method for controlling the axial resistivity of a crystal rod according to any one of claims 1 to 3, characterized in that: The furnace pressure in the antimony-phosphorus co-doped single crystal furnace is a preset pressure value and the argon gas flow rate is a preset flow rate value; the method further includes: Obtaining an antimony diffusion constant after a preset amount of antimony is doped into the silicon melt in the single crystal furnace; According to the antimony diffusion constant, a simulated distribution curve of the axial resistance of the crystal rod caused by antimony segregation is simulated and calculated when the resistivity at the start of crystal pulling is a target value; Determining a measured resistivity distribution curve according to the simulated distribution curve; According to the measured resistivity distribution curve, the correlation analysis method is used to determine the correlation between the evaporation constant and the weight of the residual material in the equal diameter process.

5. The method for controlling the axial resistivity of a crystal rod according to claim 4, characterized in that: The correlation analysis method is used to determine the constant value in the correlation between the evaporation constant and the residual weight in the equal diameter process as described below: Home=a+bW+cW 2 +dW 3 ; In the above formula, Ev is the antimony evaporation constant of the equal diameter process, W is the weight of the residual material of the equal diameter process, and a, b, c and d are all constants.

6. The method for controlling the axial resistivity of a crystal rod according to any one of claims 1 to 3, characterized in that: The temperature of the crystal pulling and drawing process is a preset temperature value; the crystal rod axial resistivity control method also includes: Obtaining a curve of the antimony evaporation constant of the discharge process versus the discharge time in the single crystal furnace; A functional expression between the antimony evaporation constant and the discharge time is determined according to the change curve.

7. The method for controlling the axial resistivity of a crystal rod according to claim 6, characterized in that: Determining the functional expression between the antimony evaporation constant and the discharge time comprises: Determine the values ​​of the constants in the following formulas: Ev=m *t n ; In the above formula, Ev is the antimony evaporation constant of the discharge process, t is the discharge time, and m and n are both constants.

8. A device for controlling the axial resistivity of a crystal rod, characterized in that: include: The equal diameter process control module is used to predict the first antimony evaporation amount of the crystal pulling equal diameter process in the antimony-phosphorus co-doped single crystal furnace according to the correlation between the evaporation constant and the residual weight in the antimony-phosphorus co-doped single crystal furnace, and control the antimony-phosphorus doping ratio of the equal diameter process according to the first antimony evaporation amount; A drawing and releasing process control module, used to predict the second antimony evaporation amount of the crystal pulling and releasing process in the antimony-phosphorus co-doped single crystal furnace according to the correlation between the evaporation constant and the drawing and releasing time, and control the antimony-phosphorus doping ratio of the drawing and releasing process according to the second antimony evaporation amount; The re-investment stage control module is used to predict the third antimony evaporation amount in the re-investment stage in the antimony-phosphorus co-doped single crystal furnace according to the target re-investment evaporation calculation model, and control the antimony-phosphorus doping ratio in the re-investment stage according to the third antimony evaporation amount, so that the axial resistivity uniformity of the crystal rod obtained by direct pulling is within the target range.

9. A crystal rod axial resistivity control device, comprising a memory and a processor, wherein the memory stores a computer program, characterized in that: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 7 are implemented.

10. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 7 are implemented.

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