Single crystal furnace and dopant supplementing device thereof

Abstract

The utility model discloses a dopant supplementing device which comprises a containing cavity used for containing a spherical dopant, the containing cavity is provided with a cavity outlet and a furnace cover connecting part, the cavity outlet is provided with a switch piece and connected with a telescopic pipe body, and a dopant counting component is arranged on the outer side of the switch piece and connected with the furnace cover connecting part. The control assembly is in communication connection with the dopant counting part and the switch part, is also in communication connection with a furnace body control system, and is used for starting the switch part and the dopant counting part according to the number of dopants needing to be doped; and when the counting quantity reaches the quantity of the dopants required to be doped, the switch piece and the dopant counting component are closed. According to the dopant supplementing device, the required number of dopants can be supplemented in real time according to the edge breaking condition, the doping effect can be achieved immediately after supplementing doping, volatilization of the dopants in multiple processes can be avoided, and the resistivity of the crystal bar can be controlled more accurately. The utility model further discloses a single crystal furnace which has the same advantages.

Description

TECHNICAL FIELD

[0001] The utility model relates to single crystal drawing equipment technical field more specifically, relate to a single crystal furnace and its adulterant supplement device. BACKGROUND

[0002] In the process of preparing single crystal silicon through the Czochralski method, the third and fifth main group elements (such as phosphorus, gallium, boron, antimony, etc. dopant) are generally needed to be doped to control the resistivity of photovoltaic single crystal silicon rod. At present, the silicon dopant for preparing N-type photovoltaic single crystal is mainly phosphorus and antimony. Among them, phosphorus as a conventional dopant has a larger diffusion coefficient, which is not conducive to the subsequent cell process after doping. Although antimony as a dopant has a very low segregation coefficient, which causes a greater difference in resistivity between the head and tail of the crystal rod, antimony has strong volatility and single volatility characteristics, which can cause the head of the crystal rod to be low and the tail to be high. Under the theory of segregation, antimony can also cause the head of the crystal rod to be high and the tail to be low. Under the combined action of these two factors, the resistivity of the crystal rod can be balanced, and the effect of the head and tail resistivity being basically consistent can be achieved.

[0003] The existing process of preparing single crystal silicon through the Czochralski method is to first place the polycrystalline silicon material into a quartz crucible, vacuumize the quartz crucible and maintain the pressure for a period of time, then place it into the single crystal furnace heat field to melt the material. After almost all the silicon material is melted, the doping agent is mixed into the silicon material in the last cylinder through the quartz feeding cylinder from the auxiliary chamber, thereby achieving the purpose of adding the doping agent into the silicon melt. Then the last cylinder of silicon material is melted, and finally the crystal pulling process (including temperature adjustment, crystal pulling, shoulder setting, etc.) is carried out. In this crystal pulling process, due to the influence of various factors, dislocations or other lattice defects are easily produced in the crystal rod during the crystal pulling, shoulder setting and equal diameter stages, which leads to single crystal breakage. This includes crystal pulling breakage, shoulder setting breakage and equal diameter breakage. After breakage, the temperature adjustment, crystal pulling and shoulder setting processes need to be performed again.

[0004] Based on the above situation, antimony doping or phosphorus, antimony and other binary or even multi-element antimony doping will face a common problem: invalid working hours caused by broken edge will make the antimony element continue to evaporate, and then cause the head resistance of the next crystal bar to be too high, so it is necessary to supplement after each broken edge phenomenon, but the conventional supplement method can only be in the stage of re-feeding silicon material, and the dopant and the last cylinder of silicon material are mixed in the quartz feeder through the sub-chamber operation, the main chamber and the sub-chamber are isolated under the condition that the single crystal furnace is appropriately cooled, the sub-chamber is rotated, then the quartz feeder is lifted into the sub-chamber, the sub-chamber is pressurized to a low pressure environment, then the main chamber and the sub-chamber are connected, the feeder is slowly moved down until the feeding is completed, and the subsequent process is similar, the main chamber and the sub-chamber are isolated, the feeder is lifted out, and the sub-chamber is pressurized, and the process from the beginning of feeding to the completion of feeding and the final complete melting takes 7-12 hours. It can be seen that this way of adding dopant and silicon material through the sub-chamber at the same time when re-feeding silicon material is very complicated, the doping effect is also relatively lagging, and the doping agent mixed with the silicon material during re-feeding will evaporate part of it during the subsequent material melting stage, resulting in a low utilization rate of the doping agent, the amount of doping agent put in cannot achieve the desired doping effect, and after the feeding is completed, the second drawing cannot be determined by other factors. The number of broken edges in the future will evaporate part of the antimony, and multiple broken edges will cause the resistance of the next crystal bar to be too high. It can be seen that the existing way of supplementing the doping agent by putting it into the silicon material through the sub-chamber when re-feeding the silicon material is greatly affected by the number of broken edges on site, the doping effect is lagging, and the resistance of the next crystal bar cannot be accurately controlled. Practical new type content

[0005] To solve the above technical problems, the utility model provides a single crystal furnace and its doping material supplementing device, which can supplement the required amount of doping material in real time according to the broken edge condition, without wasting too much time, and can immediately achieve the doping effect after supplementing, and can also avoid the evaporation of the doping material in multiple processes, thereby more accurately controlling the resistance of the crystal bar.

[0006] The utility model provides a kind of doping material supplementing device, including the cavity for containing spherical doping material, the cavity has cavity outlet and furnace cover connecting portion, the cavity outlet is provided with switch piece, the cavity outlet is also connected with telescopic pipe body, the outside of the switch piece is also provided with doping material counting component, also include with the communication connection of doping material counting component and the switch piece control assembly, the control assembly is also with the communication connection of furnace body control system to obtain the required doping amount, the control assembly is used to open the switch piece and the doping material counting component according to the required doping amount, when the number of counting reaches the required doping amount, the switch piece and the doping material counting component are closed.

[0007] Preferably, in the above-mentioned dopant supplementing device, the accommodating cavity further has a cavity inlet, and the cavity inlet is further connected with an outwardly extending dopant inlet pipe body.

[0008] Preferably, in the above-mentioned dopant supplementing device, the telescopic pipe body comprises a preset number of high-temperature-resistant pipe bodies which are threadedly connected and sleeved layer by layer, and the control assembly comprises a first type of driving motor which is connected with the high-temperature-resistant pipe body located at the inside and used for driving the high-temperature-resistant pipe body to rotate so as to realize extension or retraction.

[0009] Preferably, in the above-mentioned dopant supplementing device, the switch part comprises an upper circular cover and a lower circular cover which are both provided with a circular through hole and are rotationally connected at the center through a bearing, the diameter of the through hole is greater than the diameter of the dopant and less than twice the diameter of the dopant, and the centers of the two through holes are located at the same radial position of the upper circular cover and the lower circular cover, and the control assembly comprises a second type of driving motor which is connected with the upper circular cover and used for driving the upper circular cover to rotate relative to the lower circular cover around the bearing so as to align the two through holes to form a channel for the dopant to pass through or block the two through holes to close the channel.

[0010] Preferably, in the above-mentioned dopant supplementing device, a threaded hole is formed in the side surface of the dopant inlet pipe body, and the threaded hole is further connected with a pressure gauge.

[0011] Preferably, in the above-mentioned dopant supplementing device, the diameter of the spherical dopant ranges from 0.442 mm to 0.660 mm.

[0012] Preferably, in the above-mentioned dopant supplementing device, the high-temperature-resistant pipe body is a quartz pipe.

[0013] Preferably, in the above-mentioned dopant supplementing device, the dopant counting component is an infrared counter.

[0014] Preferably, in the above-mentioned dopant supplementing device, the furnace cover connecting part is a thread.

[0015] The single crystal furnace provided by the utility model discloses a single crystal furnace, a furnace cover of the single crystal furnace body is provided with a threaded hole, and a dopant supplementing device as claimed in any one of the above is fixed in the threaded hole.

[0016] From the above technical scheme can be seen, the utility model provides above -mentioned adulterant supplementary device, because including for containing cavity of ball -shaped adulterant, the containing cavity has cavity export and furnace cover connecting portion, the cavity export is provided with switch spare, the cavity export still is connected with telescopic pipe body, like this can carry out adulteration in the vicinity of liquid level to avoid liquid splashing, and the outside of switch spare still is provided with adulterant counting component, still including with control assembly of adulterant counting component and switch spare communication connection, control assembly still with furnace body control system communication connection to obtain the adulterant quantity of required adulteration, control assembly is used for according to the adulterant quantity of required adulteration opens switch spare and adulterant counting component, when counting quantity reaches the adulterant quantity of required adulteration, closes switch spare and adulterant counting component, thus can see that the device can separate feeding and supplementary adulterant, can according to real -time demand, in the temperature -adjusting stage separately supplement corresponding quantity's adulterant, will not again because of supplementary adulterant and carry out complicated operation, can see that the device can according to the situation of broken edge real -time supplement the adulterant quantity required, need not waste too much time, can play adulteration effect immediately after supplementing adulterant, also can avoid adulterant volatilization in multiple processes, thereby more accurately control the resistivity of crystal bar, the utility model provides above -mentioned single crystal furnace has same advantages. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the technical scheme in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description only constitute the embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of the provided drawings.

[0018] Figure 1 It is an overall schematic view of an embodiment of the adulterant supplementing device provided by the present application.

[0019] Figure 2 It is an enlarged schematic view of the upper part of an embodiment of the adulterant supplementing device provided by the present application.

[0020] Figure 3 It is a control connection schematic view of an embodiment of the adulterant supplementing device provided by the present application.

[0021] Figure 4 It is a local enlarged schematic view of the switch.

[0022] Figure 5 It is a schematic view of the adulterant supplementing device installed on the single crystal furnace. DETAILED DESCRIPTION

[0023] The utility model discloses a single crystal furnace and its doping material supplement device, can supplement the required quantity of doping material according to the broken edge condition in real time, need not spend too much time, can play doping effect immediately after supplementing, also can avoid the volatilization of doping material in multiple processes, thereby more accurately control the resistivity of crystal bar.

[0024] The technical solutions in the embodiments of the utility model will be clearly and completely described below with reference to the drawings in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, rather than all the embodiments. Based on the embodiments in the utility model, all the other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the utility model.

[0025] The utility model provides a kind of doping material supplement device's embodiment as shown in Figure 1 、 Figure 2 And Figure 3 The utility model provides a kind of doping material supplement device's embodiment of the whole schematic diagram, Figure 1 As the upper enlarged schematic diagram of a kind of doping material supplement device's embodiment provided by the utility model, Figure 2 As the control connection schematic diagram of a kind of doping material supplement device's embodiment provided by the utility model, the doping material supplement device can include the containing cavity 2 for containing spherical doping material 1, Figure 3 Figure 2 ​Only a dopant 1 is shown, in fact, a large number of dopants 1 are placed in the accommodating cavity 2, even can be filled, the required dopant is spherical, is convenient for rolling down under the action of gravity and easy to pass through the corresponding channel, the accommodating cavity 2 has a cavity outlet 21 and a furnace cover connecting portion 22, so that the dopant 1 can fall down from the cavity outlet 21 under the action of gravity, the furnace cover connecting portion 22 is used to firmly and sealingly install the entire dopant supplementing device on the furnace cover of the single crystal furnace, the connection mode is not limited, the cavity outlet 21 is provided with a switch piece 3 for controlling the rolling out of the dopant 1 or remaining in the accommodating cavity 2, when the switch piece 3 is in the open state, the dopant 1 can roll out from the cavity outlet 21 to supplement the doping operation of the silicon liquid in the single crystal furnace, and when the switch piece 3 is closed, the dopant 1 cannot roll out from the cavity outlet 21, and the supplementing operation is ended, the cavity outlet 21 is also connected with a telescopic pipe body 4, the dopant 1 rolled out from the cavity outlet 21 can reach the position near the surface of the silicon liquid through the telescopic pipe body 4 and fall into the silicon liquid to realize doping, the outside of the switch piece 3 is also provided with a dopant counting component 5, which can be arranged close to the lower part of the switch piece 3 to count the number of falling dopants, so that the number of dopants reaches the required number, and when the required number is reached, the switch piece 3 can be quickly closed, so that the supplementing number of dopants is controlled more accurately, and the control assembly 6 in communication connection with the dopant counting component 5 and the switch piece 3 is also in communication connection with the furnace body control system 9 to obtain the required doping amount of dopants, the user can input the required doping amount of dopants into the furnace body control system 9 through the touch screen, and the doping amount of dopants can be obtained according to the weight of the required doping amount of dopants divided by the weight of each dopant, the control assembly 6 is used to open the switch piece 3 and the dopant counting component 5 according to the required doping amount of dopants, and close the switch piece 3 and the dopant counting component 5 when the counted number reaches the required doping amount of dopants, it can be seen that the number of dopants can be accurately controlled by using the control assembly 6, and the operation can be performed in the temperature adjusting stage, without going through multiple stages and complicated operation as in the prior art.

[0026] It should be noted that the diameter of the spherical dopant can be but is not limited to 0.442mm to 0.660mm, taking the common antimony doping as an example, the single supplementing weight is generally 5g to 20g, the density of antimony is 6.684g / cm 3 , the volume of antimony ball is calculated according to the standard sphere: 4 / 3*Π*r 3, the weight of the single dopant is controlled to be greater than 0.3 g, so that the diameter of the antimony ball is calculated to be greater than 0.442 mm, the weight of the single antimony ball mainly affects the doping accuracy, in order to ensure that the doping accuracy is high enough, the weight of the single antimony ball is required to be between 0.3 g and 1 g, which calculates that the diameter of the dopant is preferably between 0.442 mm and 0.660 mm, in order to accurately count the counter, the diameter of the cavity outlet at this time needs to be controlled to be less than 2 times the diameter of the dopant, that is, 0.884 mm < the diameter of the cavity outlet < 1.320 mm, so as to ensure that there is only one dopant at the same height of the cavity outlet at each moment, and avoid interference with the counting process to cause counting error. Of course, the diameter of the cavity outlet needs to be matched with the diameter of the dopant, when the diameter of the dopant changes, the diameter of the cavity outlet must also be adapted to it, and when other elements are doped, the corresponding diameter range can be obtained according to the density and other parameters of the elements, and the diameter of the cavity outlet can be selected accordingly.

[0027] From the above technical solution, it can be seen that in the embodiment of the above dopant supplementing device provided by the utility model, the containing cavity for containing spherical dopants is included, the containing cavity has a cavity outlet and a furnace cover connecting portion, the cavity outlet is provided with a switching piece, and the cavity outlet is further connected with a telescopic pipe body. In this way, doping can be carried out near the liquid surface to avoid splashing of the liquid. In addition, the outer side of the switching piece is further provided with a dopant counting component. The control assembly is in communication connection with the dopant counting component and the switching piece, and the control assembly is further in communication connection with the furnace body control system to obtain the required amount of dopants to be added. The control assembly is used for opening the switching piece and the dopant counting component according to the required amount of dopants to be added, and closing the switching piece and the dopant counting component when the counting amount reaches the required amount of dopants to be added. It can be seen that the device can separate the feeding and the supplementing of the dopant. The corresponding amount of dopant can be supplemented separately in the temperature adjusting stage according to the real-time demand. The device can supplement the required amount of dopant according to the breaking situation in real time, without consuming too much time. The doping effect can be achieved immediately after the supplementing. The volatilization of the dopant in multiple processes can be avoided, so that the resistivity of the crystal bar can be controlled more accurately.

[0028] In one specific embodiment of the above dopant supplementing device, with reference to Figure 1 and Figure 2The accommodating cavity 2 can also have a cavity inlet 23, and the cavity inlet 23 is also connected with an outwardly extending dopant inlet pipe body 7. It should be noted that when the amount of dopant in the accommodating cavity 2 is not much, the dopant needs to be supplemented, and the cavity inlet 23 can conveniently supplement the dopant. In operation, the entire device needs to be removed from the furnace cover of the single crystal furnace first, and then the dopant is supplemented. The dopant inlet pipe body 7 has two advantages, one is convenient for supplementing the dopant, and the other is convenient for vacuumizing. The vacuumizing equipment is connected to the dopant inlet pipe body 7 to vacuumize. It can be seen that the dopant inlet pipe body can play different roles at different stages. On this basis, the side of the dopant inlet pipe body 7 can be provided with a threaded hole 71, and the threaded hole 71 can be connected with a pressure gauge 8. The pressure gauge 8 can make relevant personnel more conveniently see the current pressure in the cavity to identify the vacuum degree. When the required vacuum degree is reached, the vacuumizing is stopped. The threaded hole 71 can realize higher firmness of the connection of the pressure gauge. Of course, other types of connection modes can also be selected according to actual needs, which are not limited here.

[0029] In another specific embodiment of the above-mentioned dopant supplementing device, the telescopic pipe body 4 can include a plurality of high-temperature-resistant pipe bodies 41 which are connected by threads and are sleeved layer by layer, and the control assembly 6 can include a first type of driving motor (not shown) which is connected with the high-temperature-resistant pipe bodies 41 in the interior and is used to drive the high-temperature-resistant pipe bodies 41 to rotate to realize extension or retraction. In this case, the adjacent high-temperature-resistant pipe bodies 41 can be connected by threads. When the dopant needs to be supplemented, the first type of driving motor is used to drive the high-temperature-resistant pipe bodies 41 to rotate to extend, and finally the high-temperature-resistant pipe body 41 located at the lowermost position reaches a position close to the surface of the molten silicon above the surface of the molten silicon. In this way, the dopant can fall into the molten silicon. The small falling height difference can reduce the splashing and loss of the dopant when falling into the molten silicon. After the supplementing is completed, the first type of driving motor is controlled to rotate reversely to retract the high-temperature-resistant pipe bodies 41 to the original high position, so as not to affect the normal crystal growth process. It can be seen that the supplementing convenience is greatly improved.

[0030] In another specific embodiment of the above-mentioned dopant supplementing device, reference is made to Figure 4 , Figure 4As shown in the enlarged view of the switch part, the switch part 3 can include an upper circular cover 32 and a lower circular cover 33, both of which are provided with circular through holes 30 and are rotationally connected by bearings 31. The diameter of the through holes 30 is greater than the diameter of the dopant 1 and less than twice the diameter of the dopant 1, and the centers of the two through holes 30 are at the same radial position of the upper circular cover 32 and the lower circular cover 33. The control assembly 6 includes a second type of driving motor 61 connected to the upper circular cover 32, which is used to drive the upper circular cover 32 to rotate around the bearing 31 relative to the lower circular cover 33 to align the two through holes 30 to form a passage for the dopant 1 to pass through or to block the two through holes 30 to close the passage. It should be noted that the size limitation of the through holes 30 is to ensure that only one dopant 1 can exist at the same height during the falling process, and there is no case that two dopants 1 are at the same height at the same time, so as to ensure the accuracy of the dopant counting, and finally ensure the accuracy of the doping and the resistivity of the single crystal product. Figure 4 In the state shown, the two through holes 30 are aligned, at which time the dopant 1 can fall down one by one, and the dopant counting component 5 can start counting the number of dopants 1. When the required number is reached, the upper circular cover 32 can be rotated to let the through hole on the upper circular cover 32 be offset from the through hole on the lower circular cover 33 by a distance or be completely offset to close the switch part 3, so that the dopant 1 will not fall down. After the doping is completed, the dopant counting component also stops counting. It can be seen that this provides a way to quickly control the switch part, which is simple in structure and easy to quickly control. Of course, other ways can also be selected according to actual needs, which are not limited here.

[0031] In another preferred embodiment of the above-mentioned dopant supplementing device, the above-mentioned high-temperature-resistant tube body 4 can be preferably a quartz tube, which not only has sufficient strength and hardness, but also can avoid introducing other impurities. Of course, other materials that can meet such requirements can also be selected according to actual needs, which are not limited here. Moreover, the above-mentioned dopant counting component 5 can be preferably an infrared counter, which can detect spherical dopants by infrared method and will not be affected by light, and the counting is more accurate. When a spherical dopant passes through the infrared counter, it can be sensed by the infrared counter. After the desired number of dopants is reached, the corresponding information can be transmitted to the control assembly, and the control assembly can close the switch part to complete the doping operation. In addition, the above-mentioned furnace cover connecting part 22 can be preferably a screw thread. In this case, when the dopant supplementing device needs to be installed on the single crystal furnace, the furnace cover connecting part 22 can be rotated into the screw hole provided in the single crystal furnace cover to realize stable connection of the two. At this time, as shown in the figure, Figure 5 Figure 5 ​The schematic diagram of the dopant supplement device installed on the single crystal furnace shows that the single crystal furnace comprises a furnace cover 501, a sub-chamber 502, an internal water-cooled screen 503 and a crucible 504, and the dopant supplement device 505 is fixed to the furnace cover 501, so that the high-temperature-resistant pipe body 4 can pass through the water-cooled screen 503 to approach the upper part of the liquid surface in the crucible 504, so that the dopant can be dropped into the liquid to realize supplementing, and loss of the dopant due to splashing of the liquid can be avoided, and of course, other connection modes can be selected according to actual needs, which is not limited herein.

[0032] In the embodiment of the single crystal furnace, a screw hole is formed in the furnace cover of the single crystal furnace body, and the dopant supplement device according to any one of the above is fixed in the screw hole, so that the single crystal furnace can supplement the required amount of dopant in real time according to the broken edge condition, without consuming too much time, and the doping effect can be achieved immediately after supplementing, and the volatilization of the dopant in multiple processes can be avoided, so that the resistivity of the crystal bar can be more accurately controlled.

[0033] It should be further noted that when it is necessary to supplement the dopant into the accommodating cavity 2 of the above-mentioned dopant supplement device, the dopant supplement device needs to be separated from the single crystal furnace first, and after being fully supplemented with the dopant, the dopant supplement device needs to be kept at a pressure of 1 torr to 10 torr for 3 hours to 6 hours, and the pressure change is not more than 0.1% to 1%, and then the dopant supplement device can be connected to the single crystal furnace after pressure keeping. The above-mentioned dopant supplement device can maintain a vacuum environment inside in advance, and the related operation can be performed at the adjusted specific process stage to complete the supplementing, without waiting for the doping to be performed following the feeding process, and the supplementing operation can be performed at any time according to the needs, so that the resistivity of the single crystal can be more accurately adjusted.

[0034] The use mode of the above-mentioned dopant supplement device can be as follows:

[0035] (1) When the single crystal furnace process enters the temperature adjustment stage, the signal receiver connected to the control assembly captures the time from the last end / broken edge to this time according to the digital signal given by the single crystal furnace, calculates the volatilization amount of antimony in this time period according to the volatilization rate, and manually inputs the weight of the dopant that needs to be normally supplemented;

[0036] (2) After the calculation is completed, the signal receiver issues an alarm to remind that the supplementing needs to be performed, the high-temperature-resistant pipe body is stretched into the water-cooled screen by controlling the first type of driving motor, and is stopped above the silicon liquid, the second type of driving motor is controlled to rotate the upper circular cover to align the through holes on the two circular covers, so as to open the channel for the dopant to fall, and the dopant counting component is opened to start counting, the antimony beads as the dopant roll down along the channel, pass through the dopant counting component, and finally enter the silicon liquid through the high-temperature-resistant pipe body, to realize the supplementing operation of the antimony element;

[0037] (3) When the number of the supplementing reaches the preset requirement, that is, the number of the dopant calculated by the dopant counting component reaches the required number, the second type of driving motor is controlled to rotate the upper circular cover back to stagger the through holes on the two circular covers by a certain distance, thereby rotating to close, close the channel of the dopant falling, and rotate the high-temperature-resistant pipe body to shrink back, so the whole supplementing process is completed.

[0038] The above description of disclosed embodiments enables those skilled in the art to carry out or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown herein, but will accord with the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A dopant replenishment apparatus, characterized by, The device comprises a cavity for containing spherical dopants, the cavity has a cavity outlet and a furnace cover connecting part, the cavity outlet is provided with a switch part, the cavity outlet is also connected with a telescopic tube, the outer side of the switch part is also provided with a dopant counting part, the device further comprises a control assembly in communication with the dopant counting part and the switch part, the control assembly is also in communication with a furnace body control system to obtain the required number of dopants to be doped, the control assembly is used to open the switch part and the dopant counting part according to the required number of dopants to be doped, and the switch part and the dopant counting part are closed when the counted number reaches the required number of dopants to be doped.

2. The dopant replenishment device of claim 1, wherein The cavity also has a cavity inlet, and the cavity inlet is also connected with a outwardly extending dopant inlet tube.

3. The dopant replenishment device of claim 2, wherein, The telescopic tube comprises a preset number of high-temperature-resistant tubes which are connected by threads and are sleeved layer by layer, and the control assembly comprises a first type of driving motor which is connected with the high-temperature-resistant tube located inside, and the first type of driving motor is used to drive the high-temperature-resistant tube to rotate to realize extension or retraction.

4. The dopant replenishment device of claim 3, wherein, The switch part comprises an upper circular cover and a lower circular cover which are both provided with a circular through hole and are rotationally connected by a bearing, the diameter of the through hole is greater than the diameter of the dopant and less than twice the diameter of the dopant, and the centers of the two through holes are located at the same radial position of the upper circular cover and the lower circular cover, the control assembly comprises a second type of driving motor which is connected with the upper circular cover, and the second type of driving motor is used to drive the upper circular cover to rotate around the bearing relative to the lower circular cover to align the two through holes to form a channel for the dopant to pass through or to block the two through holes to close the channel.

5. The dopant replenishment device of claim 2, wherein, The side of the dopant inlet tube is provided with a threaded hole, and the threaded hole is also connected with a pressure gauge.

6. The dopant replenishment device of claim 1, wherein, The diameter of the spherical dopant ranges from 0.442 mm to 0.660 mm.

7. The dopant replenishment device of claim 4, wherein, The high-temperature-resistant tube is a quartz tube.

8. The dopant replenishment device of claim 1, wherein, The dopant counting part is an infrared counter.

9. The dopant replenishment device of claim 1, wherein, The furnace cover connecting part is a thread.

10. A single crystal furnace characterized by comprising: The device comprises a single crystal furnace body, a screw hole is formed on the furnace cover of the single crystal furnace body, and a dopant supplementing device as claimed in any one of claims 1-9 is fixed in the screw hole.

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