Method for improving concentration ratio of resistivity

Abstract

The invention relates to the technical field of photovoltaic crystal pulling manufacturing, in particular to a method for improving resistivity concentration ratio, which comprises the following steps: preparation before monocrystalline silicon pulling is started; melting the polycrystalline silicon raw material; a doping agent is added into the single crystal furnace through a doping agent feeding device while the seeding and shouldering steps are carried out; the steps of shoulder rotation, diameter equalization and ending are carried out, online resistivity monitoring is carried out, the introduced temperature, the furnace pressure, the pulling speed, the rotating speed and the airflow are calculated in total, meanwhile, a doping agent during calculation is determined, and the relation between parameters of the crystal pulling process during volatilization is calculated. And the pulling speed and the dopant feeding speed are fed back and adjusted in real time, so that the silicon single crystal rod with high resistivity concentration ratio is obtained. According to the technical scheme, a new doping agent is introduced as solid alloy granular antimony, precise control over the feeding speed of the antimony is achieved through the granular solid alloy body, and the head and tail resistance difference is reduced by means of the high-temperature and volatile physical and chemical characteristics of the antimony element, so that the resistivity concentration ratio is increased.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic crystal pulling manufacturing technology, and specifically to a method for improving resistivity concentration. Background Technology

[0002] The Czochralski method (CZ method) is one of the most mainstream technologies for producing single-crystal silicon in industry. It is named after Jan Czochralski, a Polish scientist who invented it in 1918. Its core principle is to grow single-crystal silicon directionally from molten silicon through a "melt-crystallization" process, ultimately forming a silicon rod with a complete single-crystal structure. In the CZ method, reducing the axial and radial resistivity fluctuations of the silicon ingot is a key objective in producing high-quality semiconductor-grade silicon rods. Phosphorus has a segregation coefficient of 0.35 (solid concentration / liquid concentration), much less than 1. During crystal growth, in the Czochralski method for producing single-crystal silicon, phosphorus continuously accumulates in the melt, resulting in a significantly higher phosphorus concentration at the tail of the silicon rod than at the head, with a resistivity difference of 3-7 times. This segregation effect is the main reason for the uneven resistivity of traditional phosphorus-doped silicon rods. Chinese patent CN118621425A discloses a method for controlling the resistivity of antimony-doped single crystals. This method involves doping antimony into a master alloy rod with a known antimony content before single crystal pulling. During single crystal growth, the master alloy rod is raised and lowered rhythmically into the molten silicon and melted. The high-temperature volatility of antimony is utilized to improve resistivity concentration. However, the antimony master alloy rod needs to melt gradually in the crucible. Since the end of each master alloy rod falls directly into the crucible when it detaches from the clamping and conveying device, the melting and feeding rates of the master alloy rod cannot be precisely controlled. To ensure control over the rate at which the master alloy rod enters the crucible, the clamping and conveying device needs to be as close as possible to the crucible, even close to the surface of the molten silicon. Otherwise, significant vibrations will occur when the master alloy rod enters the molten silicon, which will have a significant impact on the equipment and the synthesis of single crystal silicon. Summary of the Invention

[0003] To address the aforementioned technical shortcomings, the present invention aims to provide a method for improving resistivity concentration, comprising the following steps: S1. Preparations before starting the single-crystal silicon pulling process; S2, melting polycrystalline silicon raw materials; S3. While performing the crystal pulling and shoulder forming steps, dopant is added to the single crystal furnace through the dopant feeding device. The dopant is evenly distributed in the crucible and melts with the silicon liquid as the crucible rotates. S4. Perform shoulder turning, equal diameter, and finishing steps, and monitor resistivity online. Calculate the introduction temperature, furnace pressure, pulling speed, rotation speed, and airflow. Simultaneously, determine the relationship between dopant, volatilization time, and various parameters of the crystal pulling process. Adjust the pulling speed and dopant feeding rate through real-time feedback to obtain a single-crystal silicon rod with high resistivity concentration.

[0004] Preferably, the dopant comprises antimony in the form of solid alloy particles with a particle size of 2-8 mm.

[0005] To control the feeding speed of solid alloy antimony particles and ensure smooth feeding, the following features are specifically designed: The dopant feeding device includes a dopant hopper installed inside the single crystal furnace and a hopper located outside the dopant hopper. The hopper is connected to the dopant hopper via a feed pipe. A discharge pipe extending vertically to the low-temperature zone at the center of the melt inside the crucible is provided at the bottom of the dopant hopper. An extension pipe extending horizontally to the outside of the single crystal furnace is provided on the discharge pipe. A sealing valve core is slidably installed inside the extension pipe. The end of the sealing valve core located inside the discharge pipe has a shape that matches the internal cross-sectional shape of the discharge pipe. A connecting seat is provided at the end of the sealing valve core located outside the single crystal furnace. An adjustment unit and a vibration unit are provided at the end of the extension pipe located outside the single crystal furnace. The adjustment unit adjusts the position of the sealing valve core to change the passage area inside the discharge pipe, and the vibration unit causes the sealing valve core to vibrate along its length.

[0006] In order to adjust the material passage area in the discharge pipe, the following features are specifically provided: the adjustment unit includes an adjustment seat sleeved on one end of the extension tube located outside the single crystal furnace. The adjustment seat and the connecting seat are connected by a connecting block. A protruding connecting arm is provided on one side of the adjustment seat. The connecting arm is fixedly connected to the working end of a linear driver fixedly installed outside the single crystal furnace. The linear driver drives the adjustment seat to move the extension tube along the length of the extension tube.

[0007] In order to achieve precise control over the material passage area in the discharge pipe, the following features are specifically designed: the adjustment unit also includes a distance sensor, which is installed in the mounting cavity inside the sealing valve core. The mounting cavity has a detection hole that runs through the sealing valve core along the length of the extension pipe on the side near the discharge pipe.

[0008] Preferably, the mounting cavity is sealed by a sealing and limiting block, which restricts the detection end of the ranging sensor from being in the same straight line as the detection hole.

[0009] To achieve the vibration of the sealing valve core, the following features are specifically designed: a vertical shaft is provided at the top of the connecting seat; the vibration unit includes a driven gear rotatably mounted on the top of the adjusting seat; a vertical eccentric rod is provided on the driven gear; the two ends of the connecting arm rotate the shaft and the driven gear respectively; the vibration unit also includes a drive gear fixedly mounted on the adjusting seat; the working end of the drive gear is connected to a rotary driver; and the rotary driver is meshed with the driven gear.

[0010] Preferably, the distance between the axis of the driven gear and the axis of the eccentric rod is less than the minimum radius of the fixed alloy granular antimony.

[0011] To prevent the dopant from clogging at the connection between the discharge pipe and the dopant hopper, the following feature is specifically provided: the sealing valve core is provided with an inclined guide surface on the upper side of one end inside the discharge pipe.

[0012] Preferably, the inner wall of the discharge pipe is provided with a sleeve, the axis of the sleeve is parallel to the discharge pipe and located on the upper side of the connection between the discharge pipe and the extension pipe, a sliding push rod is coaxially installed inside the sleeve, the round head at the bottom of the sliding push rod fits against the inclined guide surface of the sealing valve core, and the top of the sliding push rod extends into the dopant hopper.

[0013] The advantages of this invention compared to the prior art are: Firstly, this invention introduces a new dopant: solid alloy granular antimony. The granular solid alloy body enables precise control of the antimony feeding speed. The granular antimony falling into the crucible has a smaller impact on the silicon melt. Antimony is introduced at the same time as phosphorus doping. By utilizing the physicochemical properties of antimony, which is easily volatilized at high temperatures, the resistance difference between the beginning and end is reduced, thereby improving the resistance concentration.

[0014] Secondly, in the non-working state, the discharge pipe of this invention is blocked by the sealing valve core inside the extension pipe. During feeding, the adjustment unit adjusts the position of the sealing valve core inside the extension pipe, thereby adjusting the flow area inside the discharge pipe to achieve precise control of the feeding speed of solid alloy particles antimony. This meets the dynamic requirements of doping amount at different growth stages. Finally, the material is transported through the discharge pipe to the low-temperature zone at the center of the melt in the crucible. With the rotation of the crucible, the dopant is fed uniformly. Combined with a stable feeding speed, the volatilization loss of antimony in the high-temperature zone can be reduced, the doping uniformity can be improved, and thus the resistivity concentration of single crystal silicon can be improved.

[0015] Thirdly, in this invention, the vibration unit drives the sealing valve core to vibrate along the length direction. The vibration is transmitted to the material in the discharge pipe through the valve core, causing the solid alloy particles of antimony to fall smoothly. The sealing valve core pushes the bottom round head of the sliding push rod that is in contact with it through the inclined guide surface, so that the sliding push rod slides up and down along the axis in the sleeve, mechanically disturbing the dopant at the connection between the dopant hopper and the discharge pipe, preventing the solid alloy particles of antimony from sticking and blocking in the discharge pipe, and ensuring that the dopant feeding process is continuous and smooth. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a perspective view of a dopant feeding device installed on a single crystal furnace in a method for improving resistivity concentration.

[0018] Figure 2 A front view of a dopant feeding device installed on a single crystal furnace in a method for improving resistivity concentration.

[0019] Figure 3 for Figure 2 Sectional view at point AA.

[0020] Figure 4 for Figure 3 A three-dimensional sectional view.

[0021] Figure 5 for Figure 4 A magnified view of section B.

[0022] Figure 6 This is a perspective view of a dopant feeding device in a method for improving resistivity concentration.

[0023] Figure 7 for Figure 6 A magnified view of a portion of point C.

[0024] Figure 8 3D structural breakdown of a dopant feeding device in a method for improving resistivity concentration Figure 1 .

[0025] Figure 9 3D structural breakdown of a dopant feeding device in a method for improving resistivity concentration Figure 2 .

[0026] Explanation of reference numerals in the attached drawings: 1. Dopant hopper; 1a. Hopper; 1a1. Feed pipe; 1b. Discharge pipe; 1b1. Sleeve; 1b2. Sliding push rod; 1c. Extension pipe; 1c1. Sealing valve core; 1c2. Connecting seat; 1c3. Mounting cavity; 1c4. Detection hole; 1c5. Sealing limit block; 1c6. Shaft; 1d. Adjustment unit; 1d1. Adjustment seat; 1d2. Connecting block; 1d3. Connecting arm; 1d4. Linear actuator; 1d5. Distance sensor; 1e. Vibration unit; 1e1. Driven gear; 1e2. Eccentric rod; 1e3. Drive gear; 1e4. Rotary actuator. Detailed Implementation

[0027] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] Reference Figures 1 to 9 : A method for increasing resistivity concentration includes the following steps: S1. Preparations before starting the single-crystal silicon pulling process; S2, melting polycrystalline silicon raw materials; S3. While performing the crystal pulling and shoulder forming steps, dopant is added to the single crystal furnace through the dopant feeding device. The dopant is evenly distributed in the crucible and melts with the silicon liquid as the crucible rotates. S4. Perform shoulder turning, equal diameter, and finishing steps, and monitor resistivity online. Calculate the introduction temperature, furnace pressure, pulling speed, rotation speed, and airflow. Simultaneously, determine the relationship between dopant, volatilization time, and various parameters of the crystal pulling process. Adjust the pulling speed and dopant feeding rate through real-time feedback to obtain a single-crystal silicon rod with high resistivity concentration.

[0029] The dopant includes solid alloy particles of antimony with a particle size of 2-8 mm.

[0030] This application introduces a new dopant: solid alloy granular antimony. Compared to antimony-containing master alloy rods, the granular solid alloy body allows for more precise control of the antimony feeding rate. The granular antimony falling into the crucible has less impact on the molten silicon. Introducing antimony simultaneously with phosphorus doping utilizes its high-temperature volatility to reduce the head-to-tail resistance difference, thereby improving resistance concentration. For phosphorus-doped N-type silicon, this is the ultimate method to achieve extremely high radial resistivity uniformity. It uses neutron irradiation to transpose uniformly distributed Si-30 into P-31 (phosphorus), thus achieving near-perfect radial uniformity. However, this method is costly, time-consuming, and requires radioactive treatment. Optimizing the thermal field ensures high axisymmetry and stability. Any asymmetry or fluctuation will lead to uneven temperature gradients within the melt, causing changes in the melt convection pattern and affecting dopant transport and distribution. Optimizing the crystal and crucible rotation rates helps improve radial symmetry; reverse crucible rotation can shear the melt flow, weaken natural convection intensity, and promote stirring. The rotation speed combination of both needs to be precisely optimized to achieve the best mixing effect and stability, avoiding the introduction of unwanted oscillations or fluctuations. Strict control of growth parameters is crucial in S4, with the pulling speed directly affecting the crystal growth rate and solid-liquid interface shape. Maintaining a highly stable pulling speed is key to achieving axial uniformity. Fluctuations can lead to changes in impurity segregation behavior, causing resistivity streaks. A precise weighing or level detection system, combined with crucible acceleration control, is used to maintain a constant position of the melt free surface relative to the thermal field. Changes in liquid level height alter the thermal field distribution and melt convection patterns. Through thermal field design and control of growth parameters (pulling speed, rotation speed, argon flow), the solid-liquid interface should be made as flat or slightly convex as possible towards the melt. A flat or slightly convex interface contributes to better radial uniformity. A deeply concave interface exacerbates radial inhomogeneity. Smooth crystal pulling and a controllable shoulder formation process are essential for the uniformity of the crystal head. Rapid shoulder formation or parameter abrupt changes must be avoided, and furnace pressure and pulling speed must be precisely controlled. The process monitoring and feedback control in S4 includes online resistivity monitoring, which involves using a non-contact resistivity probe (eddy current method) to monitor the crystal resistivity in real time during crystal growth. This data can be used to: provide real-time feedback for adjusting growth parameters (such as pulling speed and dopant replenishment); identify and mark areas of abnormal resistivity, providing a basis for subsequent processes (slicing, grading); and input sensor data (temperature, weight, resistivity, location, etc.) into the APC system, using model predictive control or artificial intelligence algorithms to optimize parameter setpoints in real time to maintain resistivity within the target range.

[0031] To control the feeding speed of solid alloy antimony particles and ensure smooth feeding, the following features were specifically designed: The dopant feeding device includes a dopant hopper 1 installed inside a single crystal furnace and a hopper 1a located outside the dopant hopper 1. The hopper 1a is connected to the dopant hopper 1 through a feed pipe 1a1. A discharge pipe 1b is provided at the bottom of the dopant hopper 1, extending vertically to the low-temperature zone of the center of the melt inside the crucible. An extension pipe 1c is provided on the discharge pipe 1b, extending horizontally to the outside of the single crystal furnace. A sealing valve core 1c1 is slidably installed inside the extension pipe 1c. The end of the sealing valve core 1c1 located inside the discharge pipe 1b has a shape that matches the internal cross-sectional shape of the discharge pipe 1b. A connecting seat 1c2 is provided at the end of the sealing valve core 1c1 located outside the single crystal furnace. An adjustment unit 1d and a vibration unit 1e are provided at the end of the extension pipe 1c located outside the single crystal furnace. The adjustment unit 1d adjusts the position of the sealing valve core 1c1 to change the passage area inside the discharge pipe 1b, and the vibration unit 1e causes the sealing valve core 1c1 to vibrate along its length.

[0032] refer to Figures 3 to 5 In this application, the dopant is temporarily stored in the dopant silo 1 by workers through the feed pipe 1a1 via the hopper 1aa. The bottom of the dopant silo 1 is tapered to guide the solid alloy antimony particles to the discharge pipe 1b. When not in operation, the discharge pipe 1b is blocked by the sealing valve core 1c1 inside the extension pipe 1c. During feeding, the regulating unit 1d adjusts the position of the sealing valve core 1c1 inside the extension pipe 1c, thereby adjusting the flow area inside the discharge pipe 1b to achieve precise control of the feeding speed of the solid alloy antimony particles, meeting the dynamic requirements of dopant content at different growth stages. Simultaneously, the vibration unit 1e drives the sealing valve core 1c1 to vibrate along its length. The vibration is transmitted to the material in the discharge pipe 1b through the valve core, causing the solid alloy particles of antimony to fall smoothly and preventing them from sticking or clogging in the discharge pipe 1b. This ensures that the dopant feeding process is continuous and smooth, and finally, the material is transported through the discharge pipe 1b to the low-temperature zone at the center of the melt in the crucible. The rotation of the crucible helps to achieve uniform dopant feeding. Combined with a stable feeding speed, this reduces the volatilization loss of antimony in the high-temperature zone, improves doping uniformity, and thus helps to improve the resistivity concentration of single crystal silicon.

[0033] To adjust the material flow area within the discharge pipe 1b, the following features are specifically configured: The adjustment unit 1d includes an adjustment seat 1d1 sleeved on one end of the extension tube 1c located outside the single crystal furnace. The adjustment seat 1d1 is connected to the connecting seat 1c2 through the connecting block 1d2. A protruding connecting arm 1d3 is provided on one side of the adjustment seat 1d1. The connecting arm 1d3 is fixedly connected to the working end of the linear actuator 1d4 fixedly installed outside the single crystal furnace. The linear actuator 1d4 drives the adjustment seat 1d1 to move the extension tube 1c along the length direction of the extension tube 1c.

[0034] refer to Figures 3 to 6In this embodiment, when it is necessary to adjust the material passage area in the discharge pipe 1b, the linear actuator 1d4 is activated. Its working end drives the connecting arm 1d3 and the connected adjusting seat 1d1 to move along the length of the extension pipe 1c. The adjusting seat 1d1 drives the connecting seat 1c2 and the sealing valve core 1c1 to move synchronously through the connecting block 1d2, thereby changing the insertion depth of the sealing valve core 1c1 in the discharge pipe 1b, thus adjusting the gap between the sealing valve core 1c1 and the inner wall of the discharge pipe 1b, and achieving precise adjustment of the material passage area. In this embodiment, the linear actuator 1d4 can be a cylinder, hydraulic cylinder, or electric push rod installed outside the single crystal furnace.

[0035] To achieve precise control over the material flow area within the discharge pipe 1b, the following features are specifically designed: The adjustment unit 1d also includes a ranging sensor 1d5, which is installed in the mounting cavity 1c3 inside the sealing valve core 1c1. The mounting cavity 1c3 is provided with a detection hole 1c4 that runs through the sealing valve core 1c1 along the length of the extension pipe 1c on the side near the discharge pipe 1b.

[0036] The mounting cavity 1c3 is sealed by the sealing and limiting block 1c5, which restricts the detection end of the ranging sensor 1d5 from being in the same straight line as the detection hole 1c4.

[0037] refer to Figure 4 and Figure 5 In this embodiment, the ranging sensor 1d5 is installed in the mounting cavity 1c3 of the sealing valve core 1c1. Under the limiting action of the sealing limit block 1c5, the detection end of the ranging sensor 1d5 and the detection hole 1c4 remain in the same straight line. When the linear actuator 1d4 drives the sealing valve core 1c1 to move, the ranging sensor 1d5 detects the change in distance from the inner wall of the discharge pipe 1b in real time through the detection hole 1c4. The distance is then calculated to obtain the material passage area in the discharge pipe 1b, and the position signal is fed back to the control system to form a closed-loop control to accurately determine the insertion depth of the sealing valve core 1c1, thereby realizing closed-loop control of the material passage area and improving the accuracy of dopant feeding. The sealing limit block 1c5 ensures that the position of the detection end of the ranging sensor 1d5 is stable.

[0038] To achieve the vibration of the sealing valve core 1c1, the following features are specifically designed: The top of the connecting seat 1c2 is provided with a vertical shaft 1c6. The vibration unit 1e includes a driven gear 1e1 rotatably mounted on the top of the adjusting seat 1d1. A vertical eccentric rod 1e2 is provided on the driven gear 1e1. The two ends of the connecting arm 1d3 rotate the shaft 1c6 and the driven gear 1e1 respectively. The vibration unit 1e also includes a drive gear 1e3 fixedly mounted on the adjusting seat 1d1. The working end of the drive gear 1e3 is connected to the rotary driver 1e4. The rotary driver 1e4 is meshed with the driven gear 1e1.

[0039] The distance between the axes of the driven gear 1e1 and the eccentric rod 1e2 is less than the minimum radius of the fixed alloy granular antimony.

[0040] refer to Figures 6 to 9 In this embodiment, the rotary driver 1e4 can be a servo motor. The rotary driver 1e4 starts, causing the drive gear 1e3 to rotate. The drive gear 1e3 drives the meshing driven gear 1e1 to rotate on top of the adjusting seat 1d1, causing the eccentric rod 1e2 on the driven gear 1e1 to perform circular motion. Since the two ends of the connecting arm 1d3 are rotatably connected to the shaft 1c6 and the driven gear 1e1 respectively, the circular motion of the eccentric rod 1e2 is converted into the reciprocating motion of the shaft 1c6 through the connecting arm 1d3. This, in turn, causes the connecting seat 1c2 and the sealing valve core 1c1 to vibrate along the length of the extension pipe 1c, achieving vibration loosening of the material in the discharge pipe 1b. The axial distance between the driven gear 1e1 and the eccentric rod 1e2 is less than the minimum radius of the antimony particles, which can avoid material splashing or abnormal fluctuations in the flow area within the discharge pipe 1b caused by excessive vibration amplitude. While ensuring the anti-clogging effect, it maintains the stability of doping control, which is beneficial for improving the resistivity concentration of single-crystal silicon.

[0041] To prevent the dopant from clogging at the connection between the discharge pipe 1b and the dopant hopper 1, the following features are specifically designed: The sealing valve core 1c1 is located inside the discharge pipe 1b and has an inclined guide surface on its upper side.

[0042] A sleeve 1b1 is provided on the inner wall of the discharge pipe 1b. The axis of the sleeve 1b1 is parallel to the discharge pipe 1b and is located on the upper side of the connection between the discharge pipe 1b and the extension pipe 1c. A sliding push rod 1b2 is coaxially installed inside the sleeve 1b1. The round head at the bottom of the sliding push rod 1b2 fits against the inclined guide surface of the sealing valve core 1c1. The top of the sliding push rod 1b2 extends into the dopant hopper 1.

[0043] refer to Figure 5 In this embodiment, when the sealing valve core 1c1 vibrates along the length of the extension tube 1c, its inclined guide surface will simultaneously push the bottom round head of the sliding top rod 1b2 that is in contact with it, so that the sliding top rod 1b2 slides up and down axially inside the sleeve 1b1; the top of the sliding top rod 1b2 then reciprocates at the connection between the dopant hopper 1 and the discharge pipe 1b, mechanically disturbing the dopant in this area, and together with the vibration of the sealing valve core 1c1, jointly preventing the material from accumulating and blocking at the connection.

[0044] Working principle: Before the start of monocrystalline silicon pulling, during the preparation, melting of polycrystalline silicon raw materials, and crystal pulling and shoulder formation steps, dopant is added to the monocrystalline furnace through a dopant feeding device. The dopant is evenly distributed within the crucible as it rotates, fusing with the molten silicon. Shoulder formation, equal diameter formation, and finishing steps are then performed, while online resistivity monitoring is conducted. The system calculates and combines the introduction temperature, furnace pressure, pulling speed, rotation speed, and airflow, while simultaneously determining the relationship between the dopant, volatilization time, and other parameters of the crystal pulling process. By adjusting the pulling speed and dopant feeding rate through real-time feedback, monocrystalline silicon rods with high resistivity concentration are obtained. During dopant feeding, the dopant is transported by workers through hopper 1a and feed pipe 1a1 to dopant silo 1 for temporary storage. During discharge, the regulating unit 1d adjusts the position of the sealing valve core 1c1 in the extension pipe 1c, thereby adjusting the flow area inside the discharge pipe 1b to achieve precise control of the discharge speed of solid alloy antimony particles, meeting the dynamic requirements of dopant amount at different growth stages. At the same time, the vibration unit 1e drives the sealing valve core 1c1 to vibrate along the length direction to prevent solid alloy antimony particles from sticking and clogging in the discharge pipe 1b.

[0045] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A method for increasing resistivity concentration, characterized in that, Includes the following steps: S1. Preparations before starting the single-crystal silicon pulling process; S2, melting polycrystalline silicon raw materials; S3. While performing the crystal pulling and shoulder forming steps, dopant is added to the single crystal furnace through the dopant feeding device. The dopant is evenly distributed in the crucible and melts with the silicon liquid as the crucible rotates. S4. Perform shoulder turning, equal diameter, and finishing steps, and monitor resistivity online. Calculate the introduction temperature, furnace pressure, pulling speed, rotation speed, and airflow. Simultaneously, determine the relationship between dopant, volatilization time, and various parameters of the crystal pulling process. Adjust the pulling speed and dopant feeding rate through real-time feedback to obtain a single-crystal silicon rod with high resistivity concentration.

2. The method for improving resistivity concentration according to claim 1, characterized in that, The dopant includes solid alloy particles of antimony with a particle size of 2-8 mm.

3. The method for improving resistivity concentration according to claim 1, characterized in that, The dopant feeding device includes a dopant hopper (1) installed inside the single crystal furnace and a hopper (1a) located outside the dopant hopper (1). The hopper (1a) is connected to the dopant hopper (1) through a feed pipe (1a1). The bottom of the dopant hopper (1) is provided with a discharge pipe (1b) that extends vertically to the low-temperature zone of the center of the melt in the crucible. An extension pipe (1c) that extends horizontally to the outside of the single crystal furnace is provided on the discharge pipe (1b). A sealing valve core (1c1) is slidably installed inside the extension pipe (1c). One end of the sealing valve core (1c1) located inside the discharge pipe (1b) has a shape that matches the internal cross-sectional shape of the discharge pipe (1b). A connecting seat (1c2) is provided at the other end of the sealing valve core (1c1) located outside the single crystal furnace. The extension tube (1c) is equipped with an adjustment unit (1d) and a vibration unit (1e) at one end outside the single crystal furnace. The adjustment unit (1d) adjusts the position of the sealing valve core (1c1) to change the passing area in the discharge pipe (1b), and the vibration unit (1e) makes the sealing valve core (1c1) vibrate along the length direction.

4. The method for improving resistivity concentration according to claim 3, characterized in that, The adjustment unit (1d) includes an adjustment seat (1d1) sleeved on one end of the extension tube (1c) located outside the single crystal furnace. The adjustment seat (1d1) and the connecting seat (1c2) are connected by a connecting block (1d2). A protruding connecting arm (1d3) is provided on one side of the adjustment seat (1d1). The connecting arm (1d3) is fixedly connected to the working end of a linear actuator (1d4) fixedly installed outside the single crystal furnace. The linear actuator (1d4) drives the adjustment seat (1d1) to move the extension tube (1c) along the length direction of the extension tube (1c).

5. The method for improving resistivity concentration according to claim 4, characterized in that, The adjustment unit (1d) also includes a distance sensor (1d5), which is installed in the mounting cavity (1c3) inside the sealing valve core (1c1). The mounting cavity (1c3) near the discharge pipe (1b) has a detection hole (1c4) that runs through the sealing valve core (1c1) along the length of the extension pipe (1c).

6. The method for improving resistivity concentration according to claim 5, characterized in that, The mounting cavity (1c3) is sealed by a blocking limit block (1c5), which restricts the detection end of the ranging sensor (1d5) from being in the same straight line as the detection hole (1c4).

7. The method for improving resistivity concentration according to claim 4, characterized in that, The connecting seat (1c2) is provided with a vertical shaft (1c6) at the top. The vibration unit (1e) includes a driven gear (1e1) rotatably mounted on the top of the adjusting seat (1d1). A vertical eccentric rod (1e2) is provided on the driven gear (1e1). The two ends of the connecting arm (1d3) rotate the shaft (1c6) and the driven gear (1e1) respectively. The vibration unit (1e) also includes a drive gear (1e3) fixedly mounted on the adjusting seat (1d1). The working end of the drive gear (1e3) is connected to a rotary driver (1e4). The rotary driver (1e4) is meshed with the driven gear (1e1).

8. The method for improving resistivity concentration according to claim 7, characterized in that, The distance between the axes of the driven gear (1e1) and the eccentric rod (1e2) is less than the minimum radius of the fixed alloy granular antimony.

9. A method for improving resistivity concentration according to claim 7, characterized in that, The sealing valve core (1c1) has an inclined guide surface on the upper side of one end inside the discharge pipe (1b).

10. A method for improving resistivity concentration according to claim 9, characterized in that, The inner wall of the discharge pipe (1b) is provided with a sleeve (1b1). The axis of the sleeve (1b1) is parallel to the discharge pipe (1b) and located on the upper side of the connection between the discharge pipe (1b) and the extension pipe (1c). A sliding push rod (1b2) is coaxially installed inside the sleeve (1b1). The round head at the bottom of the sliding push rod (1b2) fits against the inclined guide surface of the sealing valve core (1c1). The top of the sliding push rod (1b2) extends into the dopant hopper (1).

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