A method for controlling the resistivity of a Group V element-doped crystal rod

Abstract

The present invention relates to the technical field of semiconductor material preparation, and provides a method for controlling the resistivity of a crystal rod doped with group V elements. By differentiating the crystal pulling time in different crystal pulling stages and adjusting the volatilization coefficient of the doped element at different times, the volatilization amount of the doped element in each time interval can be calculated more accurately, so as to calculate more accurately the amount of the doped element required to control the resistance. It can adjust the resistance of the crystal rod more effectively and accurately, which is beneficial to better reducing the resistance difference between the head and tail of the single crystal rod. At the same time, by timely adjusting the control process of the grade and the volatilization amount at the end, the conditions for supplementary doping during the crystal pulling process are clarified, the resistance hit rate of the crystal rod is improved, and the resistance difference between the head and tail is reduced, so as to accurately control the resistivity of each part of the crystal rod to ensure the consistency of the quality of the subsequent silicon wafer products.

Description

Technical Field

[0001] The present 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 group V elements. Background Art

[0002] In the existing preparation methods of single crystal silicon rods, metal antimony, phosphorus, arsenic, bismuth and other dopants are used to adjust the resistance of the single crystal rod. By controlling the concentration of the dopant element in the single crystal silicon rod, a single crystal silicon rod with excellent resistivity range and resistivity concentration is obtained, thereby improving the overall finished product quality of the single crystal silicon rod product.

[0003] However, the above-mentioned preparation method of the single crystal silicon rod has the following problems: that is, the addition method of the doping master alloy is the same as the conventional N-type single crystal pulling doping addition method, and the process stages (including: high temperature stage, shoulder releasing stage, shoulder turning stage and finishing stage) are dynamically adjusted according to the crystal pulling process. The process time of each stage is different, and the theoretical calculation of the dopant volatilization coefficient does not match the actual volatilization of the dopant within the process time of each stage. The volatilization amount of the dopant cannot be accurately predicted and is uncontrollable; the actual volatilization of the dopant added with the silicon material fluctuates greatly, and the loss of the added dopant is large, which seriously affects the accurate control of the addition of the dopant and leads to inaccurate control of the resistivity. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for controlling the resistivity of a crystal rod doped with group V elements to solve the problem that the resistivity cannot be accurately controlled during the preparation of the existing single crystal silicon rod.

[0005] The embodiment of the present invention provides a method for controlling the resistivity of a crystal rod doped with group V elements, including:

[0006] S100, controlling the time interval ratio of each process stage during the crystal pulling process of the furnace platform; the process stages sequentially include: high temperature stage, shoulder releasing stage, shoulder turning stage and finishing stage;

[0007] S200, determining the volatilization coefficient corresponding to different process stages according to the experimental verification of each process stage;

[0008] S300, determining the doping volatilization amount corresponding to each process stage when each process stage runs in a single process stage according to the volatilization coefficient corresponding to each different process stage;

[0009] 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 of the corresponding process stage; the supplementary dopant is a group V element dopant;

[0010] In S500, additional dopant and new silicon material are added into the crucible containing molten silicon through a charging bucket. After the added materials are melted, crystal pulling is restarted.

[0011] Optionally, in S100, the time interval ratios of the respective process stages are specifically as follows:

[0012] The time interval of the high-temperature stage is: 300 min - 800 min;

[0013] The time interval of the shoulder broadening stage is: 200 min - 350 min;

[0014] The time interval of the shoulder transition stage is: 5 min - 10 min;

[0015] The time interval of the tailing stage is: 100 min - 180 min.

[0016] Optionally, in S300, determining the doping volatilization amount corresponding to single-process-stage operation of each process stage according to the volatilization coefficients corresponding to the respective different process stages includes:

[0017] Obtaining the doping element volatilization amount of the group V elements corresponding thereto according to the experimentally verified volatilization coefficient table that changes with time for each process stage.

[0018] Optionally, in S400, determining the doping amount of the added dopant according to the actual process stage where doping is required and the doping volatilization amount of the corresponding process stage includes:

[0019] Selecting a doping replenishment method according to the broken wire length of the crystal bar on the crystal pulling furnace platform and the head resistance condition of the actually produced crystal bar;

[0020] If the broken wire length of the crystal bar on the crystal pulling furnace platform is less than or equal to 200 mm, no doping replenishment is required;

[0021] If the broken wire length of the crystal bar on the crystal pulling furnace platform is greater than 200 mm, new silicon material needs to be re-added and dopant needs to be added.

[0022] Optionally, if the broken wire length of the crystal bar on the crystal pulling furnace platform is greater than 200 mm, re-adding new silicon material and adding dopant includes:

[0023] When new material needs to be re-added and dopant needs to be added, the doping amount of the added dopant is determined according to the target resistance required doping amount, the remaining silicon material content in the crucible, and the first-process doping volatilization amount;

[0024] The remaining silicon material content in the crucible is equal to the difference between the total initial doping amount, the doping amount extracted during the solidification of the silicon liquid, and the doping volatilization amount in the second process; where 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.

[0025] Optionally, the remaining doping concentration in the crucible = NA × Z 1 / (resistivity corresponding to the length of the pulled crystal bar / segregation coefficient);

[0026] 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) ,

[0027] The doping concentration of the pulled crystal bar = NA × initial doping concentration × (1 - solidification ratio) （0.35-1） / (1 - initial solidification ratio) （0.35-1） ;

[0028] The doping amount extracted during the solidification of the silicon liquid = doping concentration of the pulled crystal bar / segregation coefficient; segregation coefficient = 0.023;

[0029] The doping concentration required for the target resistance = NA × Z 2 / target resistance;

[0030] 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) ;

[0031] Initial doping amount = Initial doping concentration / segregation coefficient;

[0032] Doping volatilization amount in the first process = Time of each process stage of the target × Volatilization coefficient;

[0033] Doping volatilization amount in the second process = Time of each actual process stage × Volatilization coefficient.

[0034] Optionally, in S200, according to the experimental verification of each process stage, determine the volatilization coefficient corresponding to different process stages, including:

[0035] The volatilization coefficient of the high-temperature stage is 0.05 - 2.2;

[0036] The volatilization coefficient of the shoulder release stage is 0.05 - 0.35;

[0037] The volatilization coefficient of the shoulder transition stage is 0.05 - 0.1;

[0038] The volatilization coefficient of the finishing stage is 0.1 - 0.25.

[0039] Optionally, in S400, when determining the doping amount of the supplementary doping agent according to the actual process stage where the supplementary doping is required and the doping volatilization amount of the corresponding process stage, it further includes:

[0040] Select the supplementary doping method according to the number of single-segment drawing and releasing times and the head resistance situation of the actual ingot output;

[0041] If the number of single-segment drawing and releasing times is less than or equal to 2 times, no supplementary doping is required;

[0042] If the number of single-segment drawing and releasing times is greater than 2 times, add new silicon material and supplementary doping agent again.

[0043] Optionally, in S500, when adding the supplementary doping agent and new silicon material into the crucible containing molten silicon through the feed barrel and restarting crystal pulling after the supplementary materials are melted, it includes:

[0044] Adjust the adding position of the supplementary doping agent according to the dosage of the supplementary doping agent and new silicon material; among them, the adding position of the supplementary doping agent is quantitatively controlled by the proportion of the total feeding amount of a single barrel, and the supplementary doping agent 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 supplementary doping agent and the amount of added new silicon material; when the total feeding amount is less than or equal to the single-barrel feeding amount, the total feeding amount is equal to the single-barrel total feeding amount; when the total feeding amount is greater than the single-barrel feeding amount, the single-barrel total feeding amount is the maximum amount that can be added to the feed barrel at one time; the position of the supplementary doping agent is the surface position of the silicon material in the feed barrel after adding 10 - 50% of the single-barrel total feeding amount of silicon material, and the remaining silicon material is added after adding the supplementary doping agent.

[0045] Optionally, the silicon material below the supplementary dopant is lower silicon particles, and the new silicon material above the supplementary dopant is upper silicon particles; 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.

[0046] The embodiments of the present invention have at least the following technical effects:

[0047] The method for controlling the resistivity of a Group V element-doped crystal rod provided by the embodiments of the present invention clearly divides the crystal pulling time for different crystal pulling stages, obtains the actual volatilization coefficient within the fixed interval of the clearly divided crystal pulling time for different crystal pulling stages through experiments, determines the doping volatilization amount corresponding to each process stage when operating in a single process stage, thereby more accurately calculating the volatilization amount of the doping element within each time interval, and thus more accurately calculating the amount of doping element required to control the resistance. It can more effectively and accurately adjust the resistance of the crystal rod, avoiding the problems in the process stage (including: high-temperature stage, shoulder release stage, shoulder turning stage, and ending stage) such as dynamic adjustment according to the crystal pulling process, different lengths of process time in each stage, inconsistent with the actual volatilization situation of the dopant in the process time of each stage through theoretical calculation of the dopant volatilization coefficient, uncontrollable volatilization amount of the dopant, etc. It is beneficial to better narrow the resistance difference between the head and tail of the single crystal rod. At the same time, by timely adjusting the control process of the equal-diameter and ending volatilization amounts, clarifying the supplementary doping conditions during the crystal pulling process, improving the hit rate of the crystal rod resistance and reducing the head-tail resistance difference, thereby precisely controlling the resistivity of each part of the crystal rod and ensuring the parameter consistency of the subsequent silicon wafer products as much as possible.

[0048] Furthermore, the position of the supplementary dopant is quantitatively controlled by the proportion of the total feeding amount of a single barrel, that is, the position of the supplementary dopant is above the material surface after adding silicon material accounting for 10 - 50% of the total feeding amount of a single barrel into the barrel. After adding the supplementary dopant, the remaining silicon material is added on top of the dopant. In this way, the volatilization amount of the dopant is conducive to being determined through experiments, that is, by adopting the feeding method with a fixed dopant position, the reduced volatilization amount and controllability of the supplementary dopant are achieved, avoiding the large fluctuations in the actual volatilization situation of the dopant added with the silicon material and the large loss of the added dopant, which seriously affect the accurate control of the addition of the dopant. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0050] Figure 1 Flow chart of a method for doping a crystal bar with a Group V element to control the resistivity according to an embodiment of the present invention. Detailed implementation manners

[0051] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0052] Those skilled in the art of the present technology can understand that, unless otherwise defined, all terms (including technical terms and scientific terms) used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention belongs. It should also be understood that terms such as those defined in a general dictionary should be understood to have a meaning consistent with the meaning in the context of the prior art, and will not be interpreted in an idealized or overly formal sense unless specifically defined as herein.

[0053] Those skilled in the art of the present technology can understand that, unless specifically stated, the singular forms "a", "an", "the" and "said" used herein may also include the plural forms. It should be further understood that the term "comprising" used in the specification of the present invention means the presence of the described 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 their groups. The phrase "and / or" used herein includes all or any unit and all combinations of one or more of the associated listed items.

[0054] As Figure 1 shown, an embodiment of the present invention provides a method for controlling the resistivity of a doped crystal bar, including:

[0055] S100, controlling the time interval ratio of each process stage during the crystal pulling process of the furnace platform; the process stages sequentially include: a high-temperature stage, a shoulder releasing stage, a shoulder turning stage, and a finishing stage.

[0056] Optionally, in S100, the time interval ratio of each process stage is specifically:

[0057] The time interval of the high-temperature stage is: 300 min - 800 min. Among them, the time interval of the high-temperature stage refers to the time between the end of adding the last bucket of material in a single addition and the start of seeding.

[0058] The time interval of the shoulder releasing stage is: 200 min - 350 min. Among them, the shoulder releasing time is the time between the start of seeding and the start of shoulder turning.

[0059] The time interval of the shoulder-rotating stage is: 5 min - 10 min.

[0060] The time interval of the finishing stage is: 100 min - 180 min.

[0061] S200. Determine the volatilization coefficients corresponding to different process stages according to the experimental verification of each process stage.

[0062] Optionally, when the dopant is antimony, in S200, determine the volatilization coefficients corresponding to different process stages according to the experimental verification of each process stage, including:

[0063] The volatilization coefficient of the high-temperature stage is 0.05 - 2.2;

[0064] The volatilization coefficient of the shoulder-releasing stage is 0.05 - 0.35;

[0065] The volatilization coefficient of the shoulder-rotating stage is 0.05 - 0.1;

[0066] The volatilization coefficient of the finishing stage is 0.1 - 0.25.

[0067] In this step, by stabilizing the operation time of each process stage, the volatilization amount of the dopant corresponding to each process stage is stabilized, which is beneficial to reducing resistance and controlling abnormalities, improving the resistance hit rate. Calculate the volatilization amount of doping for the high-temperature stage time, shoulder-releasing stage time, shoulder-rotating stage time, and finishing stage time of the furnace platform separately for different process stages, so as to monitor the volatilization amount of antimony in different process stages separately.

[0068] S300. Determine the volatilization amount of doping corresponding to each process stage when each process stage operates in a single process stage according to the volatilization coefficients corresponding to different process stages.

[0069] Optionally, in S300, the determination of the volatilization amount of doping corresponding to each process stage when each process stage operates in a single process stage according to the volatilization coefficients corresponding to different process stages includes:

[0070] According to the experimental verification volatilization coefficient table of each process stage changing with time, query to obtain the volatilization coefficients corresponding to each process stage, and obtain the volatilization amount of the doping element of the fifth main group element corresponding thereto. Volatilization amount of doping element = time of each process stage × volatilization coefficient, that is, first query the volatilization coefficients corresponding to the time of each process stage from the time of each process stage, so as to obtain the volatilization amount of the doping element of each process stage, and finally add up the volatilization amounts of the doping elements of each process stage to obtain the total volatilization amount of the doping element. The corresponding relationship between the volatilization coefficients and volatilization amounts of each process stage is shown in Tables 1 to 4 below:

[0071] Table 1 Corresponding Relationship of Volatilization Coefficient in High Temperature Stage

[0072]

[0073] Table 2 Corresponding Relationship of Volatilization Coefficient in Shoulder Expansion Stage

[0074]

[0075] Table 3 Corresponding Relationship of Volatilization Coefficient in Shoulder Turning Stage

[0076]

[0077] Table 4 Corresponding Relationship of Volatilization Coefficient in Ending Stage

[0078]

[0079] S400. Determine the doping amount of the added dopant according to the actual process stage where doping needs to be supplemented and the doping volatilization amount in the corresponding process stage; the added dopant is a Group V main element dopant.

[0080] In the embodiments of the present invention, the dopant is illustrated by taking metallic antimony as an example. Substitution with elements in the same main group (Group V main group) can be adopted. The corresponding volatilization coefficient will change accordingly with different element substitutions. According to the selection of different elements in the same main group, the corresponding volatilization coefficient is adjusted according to different stages and different time nodes, so as to control and adjust the head and tail resistances and their distributions of the single crystal silicon rod, and control the head and tail uniformity of the resistance of the crystal rod. The calculation method of the corresponding doping amount for other elements is not specifically described here.

[0081] In some embodiments, in S400, the determining the doping amount of the added dopant according to the actual process stage where doping needs to be supplemented and the doping volatilization amount in the corresponding process stage includes:

[0082] Select the doping supplement method according to the broken wire length of the crystal rod on the pulling furnace platform and the head resistance of the actually produced crystal rod;

[0083] If the broken wire length of the crystal rod on the pulling furnace platform is less than or equal to 200 mm, no doping supplement is required;

[0084] If the broken wire length of the crystal rod on the pulling furnace platform is greater than 200 mm, new silicon material needs to be added again and the dopant needs to be supplemented.

[0085] Optionally, the if the broken wire length of the crystal rod on the pulling furnace platform is greater than 200 mm, new silicon material needs to be added again and the dopant needs to be supplemented includes:

[0086] When new materials need to be re-added and dopants need to be supplemented, the doping amount of the supplemented dopants is determined according to the doping amount required for the target resistance, the content of the remaining silicon materials in the crucible, and the doping volatilization amount in the first process, that is, the required doping amount to be supplemented = the doping amount required for the target resistance - the content of the remaining silicon materials in the crucible - the volatilization amount in the first process.

[0087] The content of the remaining silicon materials in the crucible = the difference between the total initial doping amount - the doping amount extracted during the solidification of the silicon liquid - the doping volatilization amount in the second process; among them, the doping volatilization amount in the first process is the doping volatilization amount in the theoretical process, and the doping volatilization amount in the second process is the doping volatilization amount in the actual process.

[0088] The specific calculation of the required doping amount to be supplemented is as follows:

[0089] The concentration of the remaining doping amount in the crucible = NA×Z 1 / (the resistivity corresponding to the length of the drawn crystal bar / segregation coefficient);

[0090] 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) ,

[0091] The doping concentration of the drawn crystal bar = NA×initial doping concentration×(1 - solidification ratio) （0.35-1） / (1 - initial solidification ratio) （0.35-1） ;

[0092] The doping amount extracted during the solidification of the silicon liquid = the doping concentration of the drawn crystal bar / segregation coefficient; segregation coefficient = 0.023;

[0093] The doping concentration required for the target resistance = NA×Z 2 / target resistance;

[0094] NA = 6.02×10 23 ,Z 2 = (-3.1083 - 3.2626×X 2 - 1.2196×X 2 ² - 0.13923×X2 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) ;

[0095] Initial doping amount = Initial doping concentration / segregation coefficient;

[0096] Doping volatilization amount in the first process = Time of each process stage of the target × Volatilization coefficient;

[0097] Doping volatilization amount in the second process = Time of each process stage × Volatilization coefficient;

[0098] From this, the subsequent supplementary doping dose can be calculated; it should be noted that the doping volatilization amount in the first process is the theoretical doping volatilization amount in the process, the doping volatilization amount in the second process is the actual doping volatilization amount in the process, and the time of each process stage of the target is the theoretical process time (for example: the theoretical process time of the high - temperature stage is that the time interval of the high - temperature stage refers to the time between the end of feeding the last barrel of material in a single addition and the start of crystal seeding. Theoretically (for example, it can be the theoretically ideal process time stored in the control system between the end of feeding the last barrel of material in a single addition and the start of crystal seeding without considering situations such as crystal seeding failure), the theoretical process time required for successful crystal seeding in one go), and the actual time of each process stage is the actual process time (for example: in the high - temperature stage process, the actual process time between the end of feeding the last barrel of material in a single addition and the start of crystal seeding, which includes the time lost in process operations such as re - crystal seeding after crystal seeding failure, and is greater than or equal to the theoretical process time). There is a certain difference between the two.

[0099] In some other embodiments, in S400, when determining the doping amount of the supplementary dopant according to the actual process stage where the doping needs to be supplemented and the doping volatilization amount in the corresponding process stage, it further includes:

[0100] Select the supplementary doping method according to the number of single - segment drawing and placing times and the head resistance situation of the actual crystal bar output;

[0101] If the number of single - segment drawing and placing times is less than or equal to 2 times, no supplementary doping is required;

[0102] If the number of single - segment drawing and placing times is greater than 2 times, new silicon material is re - added and the dopant is supplemented.

[0103] In the embodiments of the present invention, by controlling the proportion of time intervals in each process stage during the crystal pulling process on the furnace platform, the volatilization amount of doping elements in each process stage is controlled. According to experimental verification, the experimental verification volatilization coefficients under different operation times in different process stages are obtained. Further, for different process stages, the high-temperature time, shoulder releasing time, shoulder turning time, and ending time of the furnace platform are distinguished to calculate the doping volatilization amount during the single-process stage operation, and then the accurately predicted doping amount in each process stage is obtained, realizing the separate monitoring and supplementary doping of the volatilization amount of doping elements in different process stages, and realizing the reasonable control of the antimony doping amount in the crystal bar under the condition of high volatility of doping agents such as antimony; by obtaining the experimental verification volatilization coefficients under different operation times in different process stages and establishing an experimental verification volatilization coefficient table that changes with time for the process stage, a more accurate antimony volatilization amount is obtained, and then the calculation accuracy of the antimony doping amount is improved, avoiding the large deviation between the selected volatilization coefficient and the actual antimony volatilization situation due to the different volatilization conditions of antimony in each process stage under the condition of high antimony volatility, resulting in inaccurate calculation of the antimony doping amount and thus unable to achieve effective control of antimony doping, and at the same time avoiding the problem of large error in the theoretically calculated volatilization coefficient and serious deviation from the actual situation.

[0104] S500. Add the supplementary doping agent and new silicon material into the crucible containing molten silicon through the material bucket, and restart crystal pulling after the supplementary materials are melted; wherein, the addition amount of the new silicon material is determined according to the actual process stage where supplementary doping is required.

[0105] Optionally, in S500, the step of adding the supplementary doping agent and new silicon material into the crucible containing molten silicon through the material bucket and restarting crystal pulling after the supplementary materials are melted includes:

[0106] Adjust the addition position of the supplementary doping agent according to the dosages of the supplementary doping agent and the new silicon material.

[0107] Further, the step of adjusting the addition position of the supplementary doping agent according to the dosages of the supplementary doping agent and the new silicon material includes:

[0108] Quantitatively control the addition position of the supplementary doping agent according to the proportion of the total feeding amount of a single bucket, and isolate the supplementary doping agent from the molten silicon through part of the new silicon material. The total feeding amount is the sum of the doping amount of the supplementary doping agent and the amount of the added new silicon material; when the total feeding amount is less than or equal to the single-bucket feeding amount, the total feeding amount is equal to the total feeding amount of a single bucket; when the total feeding amount is greater than the single-bucket feeding amount, the total feeding amount of a single bucket is the maximum amount that can be added to the material bucket at one time; the addition position of the supplementary doping agent is the material surface position after adding silicon material accounting for 10 - 50% of the total feeding amount of a single bucket into the material bucket, and then add the remaining silicon material after adding the supplementary doping agent.

[0109] Table 5 Doping Agent Addition Rules

[0110]

[0111] 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. After covering part of the molten silicon liquid surface with part of the bottom silicon material, the dopant is placed on the bottom silicon material. During the melting process of the bottom silicon material, the dopant is preheated, so that the dopant does not directly melt, thus 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. During the feeding process, the upper silicon material covers the upper part and the periphery of the dopant and covers up to the molten silicon liquid surface, thus forming a comprehensive coverage of the part other than the bottom, such as the upper part and the side part of the dopant, further reducing the possibility of the direct contact between the dopant and the molten silicon liquid surface, thereby reducing the excessive volatilization of the dopant and improving the utilization rate. And through the coverage of the appropriate upper silicon material, when antimony volatilizes and permeates upward through the silicon material, it condenses. As the subsequent upper silicon material melts, it remains in the silicon melt, which can further improve the utilization rate of antimony. Through the above quantitative control of the dopant position by the proportion of the total feeding amount of a single barrel, a sandwich feeding structure in which the dopant is comprehensively protected by silicon material all around is formed when the dopant is added and fed into the molten silicon liquid surface, thus effectively solving the problems of high volatility and low utilization rate of antimony, making the dopant not directly melt, thus 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 materials in the addition barrel (both the upper layer and the lower layer of the dopant are silicon materials), which can reduce the phenomenon of silicon jumping during the falling process of the upper silicon particles, that is, the small-sized silicon particles are impacted and rebound (adhering to the crucible wall feeding device, affecting the precise control of the feeding amount and polluting the equipment), improving the utilization rate of raw materials and avoiding the pollution of the material barrel, etc.

[0112] Optionally, the silicon material below the co-dopant is the lower silicon particles, and the new silicon material above the co-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 - 30 mm. This can avoid the impact of large silicon particles on the quartz crucible at high temperature during the falling process, which is beneficial to protecting the high-temperature quartz crucible. The lower silicon particles have a small particle size and a small weight, which is beneficial for the silicon particle material to float on the surface of the silicon liquid for covering, avoiding sinking into the silicon melt too quickly, achieving a better effect of isolating the dopant from the silicon melt, delaying the direct contact between the dopant and the silicon melt, reducing the rapid volatilization of the dopant, and improving the utilization rate. The upper silicon particles have a larger particle size, and the particle size of the upper silicon particles is 9 - 50 mm. The larger the silicon particle size, the greater the gravity, which can avoid the silicon jumping of small particle size silicon particles, that is, the small particle size silicon particles rebound under impact (adhere to the feeding device on the crucible wall, affecting the accurate control of the feeding amount and polluting the equipment), which is beneficial to improving the utilization rate of raw materials and avoiding the problem of barrel pollution. At the same time, the greater gravity is beneficial for silicon to melt into the silicon melt downward; at the same time, due to the large particle size, the gap between particles is large, which can accommodate more dopants such as antimony condensed when volatilizing upward through the silicon material, avoiding the inability of dopants such as antimony to volatilize due to small gaps, improving the dispersion and retention of dopants such as antimony in the upper silicon particles, and being more conducive to the subsequent melting of the upper silicon material by the dopant and remaining in the silicon melt.

[0113] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions 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 antimony; S500, adding additional dopant and new silicon material into the crucible containing molten silicon through a material barrel, and re-pulling the crystal after the additional material is melted; wherein the amount of the new silicon material added is determined according to the actual process stage where the additional doping is required; 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 wire of the crystal rod on the crystal pulling furnace is greater than 200mm, it is necessary to add new silicon material and dopant again; when it is necessary to add new material and dopant again, the doping amount of the added 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 and the doping amount proposed by the solidification of the silicon liquid and the doping volatilization amount of the second process; wherein the doping volatilization amount of the first process is the theoretical process doping volatilization amount, and the doping volatilization amount of the second process is the actual process doping volatilization amount; The position for adding additional dopants is the position of 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 after the additional dopants are added; the silicon material below the additional dopants is the lower silicon particles, and the new silicon material above the additional dopants is the upper silicon particles; 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 8-30mm, and the particle size of the upper silicon particles is 9-50mm.

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: 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 amount of doping volatilization in the first process = 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 × the volatility coefficient.

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: 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.

6. 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.

7. 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 6, 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 based on 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.

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