Method for controlling resistivity of fifth main group element doped crystal bar

Abstract

The invention relates to the technical field of semiconductor material preparation, and provides a method for controlling the resistivity of a fifth main group element doped crystal bar, crystal pulling time is distinguished in different crystal pulling stages, the volatilization coefficient of doped elements in different time periods is adjusted, the volatilization amount of the doped elements in each time interval is calculated more accurately, and the resistivity of the doped crystal bar is controlled. Therefore, the amount of doping elements required for controlling the resistance can be calculated more accurately, the resistance of the crystal bar can be adjusted more effectively and more accurately, the resistance difference between the head and the tail of the single-crystal crystal bar can be better reduced, meanwhile, through timely adjustment of the control process of the grade and the ending volatilization amount, the supplementary doping condition in the crystal pulling process is defined, and the crystal pulling efficiency is improved. And the resistance hit rate of the crystal bar is improved, and the head and tail resistance difference is reduced, so that the resistivity of each part of the crystal bar is accurately controlled, and the consistency of subsequent silicon wafer product quality is ensured.

Description

Technical Field

[0001] The invention relates to the technical field of semiconductor material preparation, and in particular to a method for controlling the resistivity of a crystal rod doped with a fifth main group element. Background Art

[0002] In the existing method for preparing single crystal silicon rods, the single crystal rods use dopants such as metal antimony, phosphorus, arsenic, and bismuth to adjust the resistance. By controlling the concentration of the doping elements in the single crystal silicon rods, single crystal silicon rods with excellent resistivity range and resistivity concentration are obtained, thereby improving the overall finished product quality of the single crystal silicon rod products.

[0003] However, the above-mentioned method for preparing single crystal silicon rods has the following problems: the method of adding the doping master alloy is the same as the conventional N-type single crystal pulling doping addition method, the process stages (including: high temperature stage, shoulder release stage, shoulder rotation stage and finishing stage) are dynamically adjusted according to the crystal pulling process, the process time of each stage is different, the theoretical calculation of the dopant volatilization coefficient, etc. is inconsistent with the actual volatilization of the dopant during the process time of each stage, the volatilization amount of the dopant cannot be accurately predicted, and the volatilization amount is uncontrollable; the actual volatilization of the dopant added with the silicon material fluctuates greatly, and the loss of the dopant addition is relatively large, which seriously affects the accurate control of the addition of the dopant, resulting in inaccurate control of the resistivity. Summary of the invention

[0004] The object of the present invention is to provide a method for controlling the resistivity of a crystal rod doped with a fifth main group element, so as to solve the problem that the resistivity cannot be accurately controlled during the preparation of the existing single crystal silicon rod.

[0005] An embodiment of the present invention provides a method for controlling the resistivity of a crystal rod doped with a fifth main group element, comprising: S100, controlling the time interval ratio of each process stage in the crystal pulling process of the furnace; the process stages include: high temperature stage, shoulder release stage, shoulder rotation stage and finishing stage; S200, determining volatility coefficients corresponding to different process stages based on experimental verification of each process stage; S300, determining the corresponding doping volatilization amount when each process stage is operated in a single process stage according to the volatilization coefficient corresponding to each different process stage; S400, determining the doping amount of the supplementary dopant according to the actual process stage where the supplementary doping is required and the doping volatilization amount in the corresponding process stage; the supplementary dopant is a dopant of the fifth main group element; S500, adding additional dopants and new silicon materials into the crucible containing molten silicon through a material barrel, and re-pulling the crystal after the additional materials are melted.

[0006] Optionally, in S100, the time interval ratio of each process stage is specifically: The time interval of the high temperature stage is: 300min-800min; The time interval of the shoulder release phase is: 200min-350min; The time interval of the shoulder rotation stage is: 5min-10min; The time interval of the closing stage is: 100min-180min.

[0007] Optionally, in S300, determining the corresponding doping volatilization amount when each process stage is operated in a single process stage according to the volatility coefficient corresponding to each different process stage includes: According to the experimental verification volatility coefficient table of each process stage changing with time, the corresponding volatilization amount of the fifth main group element doping element is obtained.

[0008] Optionally, in S400, determining the doping amount of the additional dopant according to the actual process stage where the additional doping is required and the doping volatilization amount in the corresponding process stage includes: The doping method is selected according to the length of the broken wire of the crystal ingot on the crystal pulling furnace and the actual head resistance of the crystal ingot output; If the length of the broken wire of the crystal ingot on the crystal pulling furnace is less than or equal to 200mm, no additional doping is required; If the length of the broken crystal rod in the crystal pulling furnace is greater than 200mm, new silicon material and dopant must be added.

[0009] Optionally, if the length of the broken wire of the crystal ingot on the crystal pulling furnace is greater than 200 mm, new silicon material and dopant must be added again, including: When it is necessary to add new material and dopant, the doping amount of the dopant is determined according to the doping amount required for the target resistance, the remaining silicon material content in the crucible, and the doping volatilization amount of the first process; The remaining silicon material content in the crucible is equal to the difference between the total doping amount initially added, the doping amount extracted by solidification of the silicon liquid, and the doping volatilization amount in the second process; wherein the doping volatilization amount in the first process is the theoretical process doping volatilization amount, and the doping volatilization amount in the second process is the actual process doping volatilization amount.

[0010] Optionally, the remaining doping concentration in the crucible = NA*Z 1 / (resistivity corresponding to the length of the pulled crystal rod / segregation coefficient); NA=6.02*10 23 ,Z 1 =(-3.1083-3.2626*X 1 -1.2196*X 1 ² -0.13923*X 13 ) / (1+1.0265*X 1 +0.38755*X 1 ² +0.041833*X 1 3 ), X 1 =log 10 (拉出晶棒长度对应电阻率 / 分凝系数) , Pulled crystal rod doping concentration = NA * initial doping concentration * (1-solidification ratio) （0.35-1） / (1-initial solidification ratio) （0.35-1） ; The doping amount of silicon liquid solidification = doping concentration of the pulled crystal rod / segregation coefficient; segregation coefficient = 0.023; Target resistor doping concentration = NA*Z 2 / target resistance; NA=6.02*10 23 ,Z 2 =(-3.1083-3.2626*X 2 -1.2196*X 2 ² -0.13923*X 2 3 ) / (1+1.0265*X 2 +0.38755*X 2 ² +0.041833*X 2 3 ), X 2 =log 10 (目标电阻率 / 分凝系数) ; Initial doping amount = initial doping concentration / segregation coefficient; The first process doping volatilization amount = the time of each process stage of the target * volatility coefficient; The amount of doping volatilization in the second process = the actual time of each process stage * volatility coefficient.

[0011] Optionally, in S200, the volatility coefficients corresponding to different process stages are determined based on experimental verification of each process stage, including: The volatility coefficient in the high temperature stage is 0.05-2.2; The volatility coefficient of the shoulder release stage is 0.05-0.35; The volatility coefficient of the shoulder transition stage is 0.05-0.1; The volatility coefficient in the final stage is 0.1-0.25.

[0012] Optionally, in S400, the step of determining the doping amount of the additional dopant according to the actual process stage where the additional doping is required and the doping volatilization amount in the corresponding process stage further includes: The doping method is selected according to the number of single-stage lead-in times and the actual head resistance of the crystal ingot output; If the number of single-stage discharges is less than or equal to 2 times, no additional doping is required; If the number of single-stage discharges is greater than 2 times, new silicon material and additional dopants are added.

[0013] Optionally, in S500, the step of adding additional dopants and new silicon materials into a crucible containing molten silicon through a material barrel, and re-pulling the crystal after the additional materials are melted, comprises: According to the dosage of the additional dopant and the new silicon material, the adding position of the additional dopant is adjusted; wherein, the additional dopant position is quantitatively controlled by the proportion of the total addition amount of a single barrel, and the additional dopant is isolated from the molten silicon by part of the new silicon material, and the total addition amount is the sum of the doping amount of the additional dopant and the amount of the added new silicon material; when the total addition amount is less than or equal to the addition amount of a single barrel, the total addition amount is equal to the total addition amount of a single barrel; when the total addition amount is greater than the addition amount of a single barrel, the total addition amount of a single barrel is the maximum addition amount of a single barrel; the position of the additional dopant is the material surface position after 10-50% of the silicon material of the total addition amount of a single barrel is added to the barrel, and the remaining silicon material is added after the additional dopant is added.

[0014] Optionally, the silicon material below the complementary dopant is a lower silicon particle, and the new silicon material above the complementary dopant is an upper silicon particle; wherein the particle size of the lower silicon particles is smaller than that of the upper silicon particles, the particle size of the lower silicon particles is 8-30 mm, and the particle size of the upper silicon particles is 9-50 mm.

[0015] The embodiments of the present invention have at least the following technical effects: The method for controlling the resistivity of a crystal rod doped with a fifth main group element provided in an embodiment of the present invention clearly divides the crystal pulling time according to different crystal pulling stages, obtains the actual volatilization coefficient within the crystal pulling time within the fixed intervals clearly divided in different crystal pulling stages through experiments, determines the corresponding doping volatilization amount during the operation of each process stage in a single process stage, thereby more accurately calculating the volatilization amount of the doping element within each time interval, thereby more accurately calculating the amount of doping element required for controlling the resistance, and can more effectively and accurately adjust the resistance of the crystal rod, avoiding the process stages (including: high temperature stage, shoulder release stage, shoulder transfer stage and The process of the finishing stage is dynamically adjusted according to the crystal pulling process. The process time of each stage is different. The theoretical calculation of the dopant volatilization coefficient is inconsistent with the actual volatilization of the dopant during the process time of each stage. The volatilization amount of the dopant cannot be accurately predicted and the volatilization amount is uncontrollable. This is conducive to better narrowing the resistance difference between the head and tail of the single crystal ingot. At the same time, by timely adjusting the control process of the equal diameter and the finishing volatilization amount, the conditions for supplementary doping during the crystal pulling process are clarified, the resistance hit rate of the crystal ingot is improved, and the resistance difference between the head and the tail is reduced, thereby accurately controlling the resistivity of each part of the crystal ingot and trying to ensure the parameter consistency of subsequent silicon wafer products.

[0016] Furthermore, the position of additional dopant is quantitatively controlled based on the proportion of the total amount of material added in a single barrel, that is, the position of additional dopant is the position above the material surface after silicon material accounting for 10-50% of the total amount of material added in a single barrel is added to the material barrel, and the remaining silicon material is added on the dopant after the additional dopant is added. This method is conducive to determining the volatilization amount of the dopant by experimental means, that is, the addition method of fixing the dopant position is adopted, which realizes the reduction of the volatilization amount of the additional dopant and the controllability, avoids large fluctuations in the actual volatilization of the dopant added with the silicon material, and large losses of the dopant added, which seriously affect the accurate control of the addition of the dopant. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 A flow chart of a method for calculating the resistivity of a crystal rod doped with a fifth main group element provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0019] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] Those skilled in the art will understand that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as those generally understood by those skilled in the art in the field to which the present invention belongs. It should also be understood that terms such as those defined in common dictionaries should be understood to have meanings consistent with the meanings in the context of the prior art, and will not be interpreted with idealized or overly formal meanings unless specifically defined as here.

[0021] Those skilled in the art will appreciate that, unless otherwise stated, the singular forms "a", "an", "said" and "the" used herein may also include plural forms. It should be further understood that the term "comprising" used in the specification of the present invention refers to the presence of the features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof. The term "and / or" used herein includes all or any unit and all combinations of one or more associated listed items.

[0022] like Figure 1 As shown, an embodiment of the present invention provides a method for controlling the resistivity of a doped crystal rod, comprising: S100, controlling the time interval ratio of each process stage in the crystal pulling process of the furnace; the process stages include: high temperature stage, shoulder release stage, shoulder rotation stage and finishing stage.

[0023] Optionally, in S100, the time interval ratio of each process stage is specifically: The time interval of the high temperature stage is 300 min-800 min, wherein the time interval of the high temperature stage refers to the time between the end of the last barrel of material addition and the start of seeding.

[0024] The time interval of the shoulder release stage is: 200min-350min. The shoulder release time is the time between the start of seeding and the start of shoulder rotation.

[0025] The time interval of the shoulder rotation stage is: 5min-10min.

[0026] The time interval of the closing stage is: 100min-180min.

[0027] S200, determining volatility coefficients corresponding to different process stages based on experimental verification of each process stage.

[0028] Optionally, when the dopant is antimony, in S200, the volatility coefficients corresponding to different process stages are determined based on experimental verification of each process stage, including: The volatility coefficient in the high temperature stage is 0.05-2.2; The volatility coefficient of the shoulder release stage is 0.05-0.35; The volatility coefficient of the shoulder transition stage is 0.05-0.1; The volatility coefficient in the final stage is 0.1-0.25.

[0029] This step stabilizes the operation time of each process stage, thereby stabilizing the corresponding dopant volatilization amount of each process stage, which is beneficial to reducing resistance and controlling abnormalities and improving resistance hit rate. According to different process stages, the high-temperature stage time of the furnace, the shoulder release stage time, the shoulder transfer stage time, and the finishing stage time of the furnace are distinguished and the calculation of the dopant volatilization amount is performed separately, so that the volatilization amount of antimony in different process stages can be monitored separately.

[0030] S300, determining the doping volatilization amount corresponding to each process stage when each process stage is operated in a single process stage according to the volatility coefficient corresponding to each process stage.

[0031] Optionally, in S300, determining the corresponding doping volatilization amount when each process stage is operated in a single process stage according to the volatility coefficient corresponding to each different process stage includes: According to the experimental verification volatility coefficient table of each process stage changing with time, the volatility coefficient corresponding to each process stage is queried, and the corresponding volatilization amount of the fifth main group element doping element is obtained from the volatility coefficient. The volatilization amount of doping element = the time of each process stage * volatility coefficient, that is, the volatility coefficient corresponding to the time of each process stage is first queried from the time of each process stage, so as to obtain the volatilization amount of doping element in each process stage, and finally the volatilization amount of doping element in each process stage is accumulated to obtain the total volatilization amount of doping element. The corresponding relationship between the volatility coefficient and the volatilization amount of each process stage is shown in Tables 1 to 4 below: Table 1 Corresponding relationship of volatility coefficient in high temperature stage

[0032] Table 2 Corresponding relationship of volatility coefficient in the shoulder release stage

[0033] Table 3 Corresponding relationship of volatility coefficient in the shoulder transition stage

[0034] Table 4 Corresponding relationship of volatility coefficient in the final stage

[0035] S400, determining the doping amount of the supplementary dopant according to the actual process stage where the supplementary doping is required and the doping volatilization amount in the corresponding process stage; the supplementary dopant is a dopant of the fifth main group element. The dopant in the embodiment of the present invention is explained by taking metal antimony as an example, and can be replaced by elements of the same main group (fifth main group). The volatility coefficient corresponding to different element replacements will change accordingly. According to the selection of different elements of the same main group, the corresponding volatility coefficient is adjusted according to different stages and different time nodes, so as to control and adjust the head and tail resistance and distribution of the single crystal silicon rod, and control the head and tail uniformity of the crystal rod resistance. The calculation method of the doping amount corresponding to other elements is not specifically described here.

[0036] In some embodiments, in S400, determining the doping amount of the additional dopant according to the actual process stage where the additional doping is required and the doping volatilization amount in the corresponding process stage includes: The doping method is selected according to the length of the broken wire of the crystal ingot on the crystal pulling furnace and the actual head resistance of the crystal ingot output; If the length of the broken wire of the crystal ingot on the crystal pulling furnace is less than or equal to 200mm, no additional doping is required; If the length of the broken crystal rod in the crystal pulling furnace is greater than 200mm, new silicon material and dopant must be added.

[0037] Optionally, if the length of the broken wire of the crystal ingot on the crystal pulling furnace is greater than 200 mm, new silicon material needs to be added and dopant needs to be added, including: When it is necessary to add new material and additional dopant, the doping amount of the additional dopant is determined according to the required doping amount of the target resistor, the remaining silicon material content in the crucible and the volatilization amount of the doping in the first process, that is, the required additional doping amount = the required doping amount of the target resistor - the remaining silicon material content in the crucible - the volatilization amount in the first process.

[0038] The remaining silicon material content in the crucible = the difference between the total doping amount initially added - the doping amount removed during solidification of the silicon liquid - the doping volatilization amount in the second process; wherein the doping volatilization amount in the first process is the theoretical doping volatilization amount in the process, and the doping volatilization amount in the second process is the actual doping volatilization amount in the process.

[0039] The specific calculation of the additional doping dosage is as follows: Remaining doping concentration in crucible = NA*Z 1 / (resistivity corresponding to the length of the pulled crystal rod / segregation coefficient); NA=6.02*10 23 ,Z 1=(-3.1083-3.2626*X 1 -1.2196*X 1 ² -0.13923*X 1 3 ) / (1+1.0265*X 1 +0.38755*X 1 ² +0.041833*X 1 3 ), X 1 =log 10 (拉出晶棒长度对应电阻率 / 分凝系数) , Pulled crystal rod doping concentration = NA * initial doping concentration * (1-solidification ratio) （0.35-1） / (1-initial solidification ratio) （0.35-1） ; The doping amount of silicon liquid solidification = doping concentration of the pulled crystal rod / segregation coefficient; segregation coefficient = 0.023; Target resistor doping concentration = NA*Z 2 / target resistance; NA=6.02*10 23 ,Z 2 =(-3.1083-3.2626*X 2 -1.2196*X 2 ² -0.13923*X 2 3 ) / (1+1.0265*X 2 +0.38755*X 2 ² +0.041833*X 2 3 ), X 2 =log 10 (目标电阻率 / 分凝系数) ; Initial doping amount = initial doping concentration / segregation coefficient; The first process doping volatilization amount = the time of each process stage of the target * volatility coefficient; The amount of doping volatilization in the second process = the time of each process stage * volatility coefficient; The subsequent additional doping dosage can be calculated from this; it should be noted that the doping volatilization amount in the first process is the theoretical doping volatilization amount in the process, and the doping volatilization amount in the second process is the actual doping volatilization amount in the process, and the time of each target process stage is the theoretical process time (for example, the theoretical process time of the high-temperature stage is: the time interval of the high-temperature stage refers to the time between the end of the addition of the last bucket of material in a single addition and the start of crystal seeding, which is theoretically (for example, it can be the theoretical ideal process time between the end of the addition of the last bucket of material in a single addition and the start of crystal seeding stored in the control system without considering the situation of crystal seeding failure) the theoretical process time required for a one-time successful crystal seeding), the time of each actual process stage is the actual process time (for example, the high-temperature stage process stage, the actual process time between the end of the addition of the last bucket of material in a single addition and the start of crystal seeding, which includes the time lost for process operations such as re-seeding after crystal seeding failure, which is greater than or equal to the theoretical process time), and there is a certain difference between the two.

[0040] In some other embodiments, in S400, determining the doping amount of the additional dopant according to the actual process stage where the additional doping is required and the doping volatilization amount in the corresponding process stage further includes: The doping method is selected according to the number of single-stage lead-in times and the actual head resistance of the crystal ingot output; If the number of single-stage discharges is less than or equal to 2 times, no additional doping is required; If the number of single-stage discharges is greater than 2 times, new silicon material and additional dopants are added.

[0041] The embodiment of the present invention controls the time interval ratio of each process stage in the process of crystal pulling on the furnace to control the volatilization amount of the doping elements in each process stage, obtains the experimentally verified volatilization coefficients at different operation times in different process stages according to experimental verification, further distinguishes the furnace high temperature time, shoulder release time, shoulder transfer time, and tail time in different process stages to calculate the volatilization amount of doping in a single process stage, thereby obtaining the accurately predicted doping amount in each process stage, and realizing the separate monitoring and supplementary doping of the volatilization amount of the doping elements in different process stages, so as to realize the reasonable control of the antimony doping amount in the crystal rod under the condition of high volatility of dopants such as antimony; by obtaining the experimentally verified volatilization coefficients at different operation times in different process stages, an experimentally verified volatilization coefficient table of the process stage changing with time is established, thereby obtaining a more accurate antimony volatilization amount, thereby realizing the improvement of the calculation accuracy of the antimony doping amount, avoiding the problem that under the condition of high volatility of antimony, the volatilization conditions of antimony in each process stage are different, resulting in a large deviation between the volatilization coefficient selection and the actual antimony volatilization conditions, thereby causing inaccurate calculation of the antimony doping amount, thereby failing to realize the effective control of antimony doping, and also avoiding the problem that the error of the theoretically calculated volatilization coefficient is large and seriously deviates from the actual.

[0042] S500, adding additional dopants and new silicon materials into the crucible containing molten silicon through a material barrel, and re-pulling the crystal after the additional materials are melted; wherein, the amount of new silicon material added is determined according to the actual process stage where the additional doping is required.

[0043] Optionally, in S500, the step of adding additional dopants and new silicon materials into a crucible containing molten silicon through a material barrel, and re-pulling the crystal after the additional materials are melted, comprises: The adding position of the supplementary dopant is adjusted according to the dosage of the supplementary dopant and the new silicon material.

[0044] Further, adjusting the adding position of the supplementary dopant according to the dosage of the supplementary dopant and the new silicon material includes: The position of additional dopant is quantitatively controlled based on the proportion of the total feeding amount of a single barrel, and the additional dopant is isolated from the molten silicon by part of the new silicon material. The total feeding amount is the sum of the doping amount of the additional dopant and the amount of new silicon material added; when the total feeding amount is less than or equal to the feeding amount of a single barrel, the total feeding amount is equal to the total feeding amount of a single barrel; when the total feeding amount is greater than the feeding amount of a single barrel, the total feeding amount of a single barrel is the maximum feeding amount of a single barrel; the position of additional dopant is the material surface position after silicon material accounting for 10-50% of the total feeding amount of a single barrel is added to the barrel, and the remaining silicon material is added after the additional dopant.

[0045] Table 5 Dopant addition rules

[0046] In this embodiment, the position of the dopant is quantitatively controlled by the proportion of the total feeding amount of a single barrel, so that the dopant does not directly contact the molten silicon material after being added from the feeding barrel. The dopant is placed on the bottom silicon material after covering part of the molten silicon liquid surface with part of the bottom silicon material. The dopant is preheated during the melting process of the bottom silicon material so that the dopant does not melt directly, thereby forming a delayed melting of the dopant, which can reduce the excessive volatilization of the dopant and improve the utilization rate of the dopant; more silicon material is covered on the upper part of the dopant, and the upper silicon material covers the upper part and the surrounding part of the dopant during the discharge process, and covers the molten silicon liquid surface, thereby forming a comprehensive coverage of the upper part and the side part of the dopant other than the bottom, further reducing the dopant The possibility of direct contact with the molten silicon liquid surface can reduce the excessive volatilization of the dopant and improve the utilization rate. Moreover, through the covering of the appropriate silicon material on the top, the antimony condenses when it passes through the silicon material upward after volatilization. As the upper silicon material melts subsequently, it remains in the silicon melt, which can further improve the utilization rate of antimony. The above-mentioned dopant position is quantitatively controlled by the proportion of the total feeding amount of a single barrel. When the dopant is added and the material is discharged into the molten silicon liquid surface, a sandwich feeding structure is formed in which the dopant is fully protected by the silicon material on all sides, thereby effectively solving the problems of high volatility and low utilization rate of antimony, preventing the dopant from melting directly, thereby forming a delayed melting of the dopant, which can reduce the excessive volatilization of the dopant and improve the utilization rate of the dopant. In addition, the dopant is a metal and is in the middle layer of the material in the addition barrel (the upper and lower layers of the dopant are both silicon materials). This can reduce the silicon jumping phenomenon during the falling process of the upper silicon particles, that is, the small-size silicon particles rebound by impact (sticking to the crucible wall feeding device, affecting the precise control of the feeding amount and causing the equipment to be contaminated), improve the utilization rate of raw materials and avoid pollution from the material barrel.

[0047] Optionally, the silicon material below the supplementary dopant is the lower silicon particles, and the new silicon material above the supplementary dopant is the upper silicon particles. The particle size of the lower silicon particles is smaller than that of the upper silicon particles, and the particle size of the lower silicon particles is 8-30mm. This can avoid the impact of large silicon particles on the high-temperature quartz crucible during the falling process, so as to protect the high-temperature quartz crucible. The particle size of the lower silicon particles is small and the weight is light, which is conducive to the silicon particles floating on the surface of the silicon liquid to cover it and avoid sinking into the silicon melt too quickly, thereby better isolating the dopant from the silicon melt, delaying the direct contact between the dopant and the silicon melt, reducing the excessive volatilization of the dopant, and improving the utilization rate. The upper silicon particles are larger in size, with a particle size of 9-50mm. The larger the particle size, the greater the gravity, which can prevent small-sized silicon particles from jumping, that is, small-sized silicon particles from rebounding under impact (sticking to the crucible wall feeding device, affecting the precise control of the feeding amount, and causing equipment contamination), which is beneficial to improving the utilization rate of raw materials and avoiding the problem of barrel contamination. At the same time, the large gravity is conducive to the silicon melting downward into the silicon melt; at the same time, due to the large particles and the large gaps between the particles, more dopants such as antimony can be accommodated, which condense when they volatilize and pass through the silicon material upward, avoiding the small gap that prevents dopants such as antimony from volatilizing, thereby improving the dispersion and retention of dopants such as antimony in the upper silicon particles, and is more conducive to improving the subsequent melting of the upper silicon material and retaining it in the silicon melt.

[0048] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for controlling the resistivity of a crystal rod doped with a fifth main group element, characterized in that: include: S100, controlling the time interval ratio of each process stage during the crystal pulling process of the furnace; The process stages include: high temperature stage, shoulder release stage, shoulder transfer stage and finishing stage; S200, determining volatility coefficients corresponding to different process stages based on experimental verification of each process stage; S300, determining the corresponding doping volatilization amount when each process stage is operated in a single process stage according to the volatilization coefficient corresponding to each different process stage; S400, determining the doping amount of the additional dopant according to the actual process stage where the additional doping is required and the doping volatilization amount in the corresponding process stage; wherein the additional dopant is a dopant of a Group V element; S500, adding additional dopants and new silicon materials into the crucible containing molten silicon through a material barrel, and re-pulling the crystal after the additional materials are melted; wherein, the amount of new silicon material added is determined according to the actual process stage where the additional doping is required.

2. The method for controlling the resistivity of a crystal rod doped with a fifth main group element according to claim 1, characterized in that: In S100, the time interval ratio of each process stage is specifically as follows: The time interval of the high temperature stage is: 300min-800min; The time interval of the shoulder release phase is: 200min-350min; The time interval of the shoulder rotation stage is: 5min-10min; The time interval of the closing stage is: 100min-180min.

3. The method for controlling the resistivity of a crystal rod doped with a fifth main group element according to claim 1, characterized in that: In S300, the step of determining the corresponding doping volatilization amount when each process stage is operated in a single process stage according to the volatilization coefficient corresponding to each different process stage includes: According to the experimentally verified volatility coefficient table of each process stage changing with time, the volatility coefficient corresponding to each process stage is queried and obtained, and the corresponding volatility amount of the fifth main group element doping element is obtained from the volatility coefficient.

4. The method for controlling the resistivity of a crystal rod doped with a fifth main group element according to claim 1, characterized in that: In S400, the doping amount of the additional dopant is determined according to the actual process stage where the additional doping is required and the doping volatilization amount in the corresponding process stage, including: The doping method is selected according to the length of the broken wire of the crystal ingot on the crystal pulling furnace and the actual head resistance of the crystal ingot output; If the length of the broken wire of the crystal ingot on the crystal pulling furnace is less than or equal to 200mm, no additional doping is required; If the length of the broken crystal rod in the crystal pulling furnace is greater than 200mm, new silicon material and dopant must be added.

5. The method for controlling the resistivity of a crystal rod doped with a fifth main group element according to claim 4, characterized in that: If the length of the broken wire of the crystal ingot on the crystal pulling furnace is greater than 200 mm, new silicon material and dopant must be added again, including: When it is necessary to add new material and dopant, the doping amount of the dopant is determined according to the doping amount required for the target resistance, the remaining silicon material content in the crucible, and the doping volatilization amount of the first process; The remaining silicon material content in the crucible is equal to the difference between the total doping amount initially added, the doping amount extracted by solidification of the silicon liquid, and the doping volatilization amount in the second process; wherein the doping volatilization amount in the first process is the theoretical process doping volatilization amount, and the doping volatilization amount in the second process is the actual process doping volatilization amount.

6. The method for controlling the resistivity of a crystal rod doped with a fifth main group element according to claim 5, characterized in that: The remaining doping concentration in the crucible = NA*Z1 / (resistivity corresponding to the length of the pulled crystal rod / segregation coefficient); NA=6.02*10 23 ,Z1=(-3.1083-3.2626*X1-1.2196*X1 ² -0.13923*X1 3 ) / (1+1.0265*X1+0.38755*X1 ² +0.041833*X1 3 ),X1=log 10 (拉出晶棒长度对应电阻率 / 分凝系数) , Pulled crystal rod doping concentration = NA * initial doping concentration * (1-solidification ratio) （0.35-1） / (1-initial solidification ratio) （0.35-1） ; The doping amount of silicon liquid solidification = doping concentration of the pulled crystal rod / segregation coefficient; segregation coefficient = 0.023; Target resistance required doping concentration = NA*Z2 / target resistance; NA=6.02*10 23 ,Z2=(-3.1083-3.2626*X2-1.2196*X2 ² -0.13923*X2 3 ) / (1+1.0265*X2+0.38755*X2 ² +0.041833*X2 3 ),X2=log 10 (目标电阻率 / 分凝系数) ; Initial doping amount = initial doping concentration / segregation coefficient; The first process doping volatilization amount = the time of each process stage of the target * volatility coefficient; The amount of doping volatilization in the second process = the actual time of each process stage * volatility coefficient.

7. The method for controlling the resistivity of a crystal rod doped with a fifth main group element according to claim 6, characterized in that: In S200, based on the experimental verification of each process stage, the volatility coefficient corresponding to the different process stages is determined, including: The volatility coefficient in the high temperature stage is 0.05-2.2; The volatility coefficient of the shoulder release stage is 0.05-0.35; The volatility coefficient of the shoulder transition stage is 0.05-0.1; The volatility coefficient in the final stage is 0.1-0.

25.

8. The method for controlling the resistivity of a crystal rod doped with a fifth main group element according to claim 1, characterized in that: In S400, the step of determining the doping amount of the additional dopant according to the actual process stage where the additional doping is required and the doping volatilization amount in the corresponding process stage further includes: The doping method is selected according to the number of single-stage lead-in times and the actual head resistance of the crystal ingot output; If the number of single-stage discharges is less than or equal to 2 times, no additional doping is required; If the number of single-stage discharges is greater than 2 times, new silicon material and additional dopants are added.

9. The method for controlling the resistivity of a crystal rod doped with a fifth main group element according to any one of claims 1 to 8, characterized in that: In S500, the process of adding additional dopants and new silicon materials into a crucible containing molten silicon through a material barrel, and re-pulling the crystal after the additional materials are melted, includes: According to the dosage of the additional dopant and the new silicon material, the adding position of the additional dopant is adjusted; wherein, the additional dopant position is quantitatively controlled by the proportion of the total addition amount of a single barrel, and the additional dopant is isolated from the molten silicon by part of the new silicon material, and the total addition amount is the sum of the doping amount of the additional dopant and the amount of the added new silicon material; when the total addition amount is less than or equal to the addition amount of a single barrel, the total addition amount is equal to the total addition amount of a single barrel; when the total addition amount is greater than the addition amount of a single barrel, the total addition amount of a single barrel is the maximum addition amount of a single barrel; the position of the additional dopant is the material surface position after 10-50% of the silicon material of the total addition amount of a single barrel is added to the barrel, and the remaining silicon material is added after the additional dopant is added.

10. The method for controlling the resistivity of a crystal rod doped with a fifth main group element according to claim 9, characterized in that: The silicon material below the complementary dopant is the lower silicon particle, and the new silicon material above the complementary dopant is the upper silicon particle; wherein the particle size of the lower silicon particle is smaller than that of the upper silicon particle, the particle size of the lower silicon particle is 8-30 mm, and the particle size of the upper silicon particle is 9-50 mm.

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