CN113122919A

CN113122919A - Secondary feeding method and device, and monocrystalline silicon growth method and device

Info

Publication number: CN113122919A
Application number: CN202110413783.6A
Authority: CN
Inventors: 沈伟民; 李寅锋; 黄瀚艺
Original assignee: Zing Semiconductor Corp
Current assignee: Zing Semiconductor Corp
Priority date: 2021-04-16
Filing date: 2021-04-16
Publication date: 2021-07-16

Abstract

The embodiment of the specification provides a secondary feeding method and device and a monocrystalline silicon growth method and device, and is applied to the technical field of semiconductors. Wherein the secondary feeding scheme comprises: monitoring the melting state of the silicon raw material in the crucible; when the melting state is monitored to enter a preset state, applying a magnetic field with target intensity to the silicon liquid in the crucible according to a preset magnetic field applying strategy; after the magnetic field is applied, the silicon raw material in the feeding tube is dropped into the crucible for a preset time. Through the processing scheme, the splashing of the silicon liquid in secondary feeding can be avoided, the service life of the monocrystalline silicon growth equipment part is prolonged, and the crystal pulling success rate is improved.

Description

Secondary feeding method and device, and monocrystalline silicon growth method and device

Technical Field

The specification relates to the technical field of semiconductors, in particular to a secondary feeding method and device and a monocrystalline silicon growth method and device.

Background

In a process for growing a semiconductor silicon single crystal, a polycrystalline silicon raw material having a purity of 9 to 11N (i.e., 9 to 11 purities of 9) is charged into a crucible (e.g., a quartz crucible), and then the polycrystalline silicon raw material is melted by heating with electricity by a heater in a thermal field under the protection of an inert gas in a Czochralski (Czochralski) crystal growth furnace, and as a result, a semiconductor single crystal is pulled out.

After the lump polycrystalline silicon raw material is loaded into the quartz crucible, a large amount of gap space is usually reserved between the raw materials, and the polycrystalline silicon raw material can be loaded into only half of the volume of the crucible. However, in order to draw a larger volume or a longer length of crystal, it is necessary to charge as much raw material as possible into the quartz crucible, and therefore, in the single crystal silicon growth process, after the raw material initially charged is melted, a polycrystalline silicon material having a small volume is charged into the quartz tube apparatus and suspended into the furnace body, so that the lower port of the quartz tube is opened above the crucible to drop the raw material into the silicon liquid to continue melting, and this process is generally called a secondary charging process (collectively referred to as secondary charging). In practice, in order to charge the quartz crucible with sufficient polycrystalline silicon raw material, one or even several times of secondary charging operations are generally performed.

In the secondary feeding of the prior art, as shown in fig. 1, when the polysilicon raw material falls into the silicon liquid from the feeding tube (e.g. a quartz tube), the silicon liquid is often splashed, and the splashed silicon liquid is often splashed on the thermal field components such as a quartz crucible, a graphite crucible, a heater, a draft tube, etc., and the thermal expansion coefficients of the silicon raw material and the surface materials of these components are different, for example, the thermal expansion coefficients of silicon and graphite are different, so that when the silicon liquid is attached to the surface of graphite, graphite surface exfoliation easily occurs, which not only reduces the service life of the thermal field components, but also leads to the problems of impurity increase in the silicon liquid, dislocation generation in the growth of single crystal, etc., because exfoliated particles fall into the silicon liquid.

In the existing corresponding method, polycrystalline silicon in the crucible can only be melted incompletely, for example, a secondary feeding process is carried out when a small part of solid silicon exists in the center of the crucible, so that most of silicon raw materials in the feeding pipe can fall on the solid silicon to partially relieve splashing of silicon liquid, but part of the silicon raw materials still fall into the silicon liquid in actual operation to generate splashing of the silicon liquid.

Therefore, a new secondary feeding scheme is needed.

Disclosure of Invention

In view of the above, embodiments of the present disclosure provide a secondary feeding method and apparatus, and a single crystal silicon growth method and apparatus, which can prevent splashing of silicon liquid during secondary feeding in a single crystal silicon growth process, thereby prolonging a component life and increasing a crystal pulling success rate (i.e., a crystal yield).

The embodiment of the specification provides the following technical scheme:

the embodiment of the specification provides a secondary feeding method, which comprises the following steps: monitoring the melting state of the silicon raw material in the crucible; when the melting state is monitored to enter a preset state, applying a magnetic field with target intensity to the silicon liquid in the crucible according to a preset magnetic field applying strategy; after the magnetic field is applied, the silicon raw material in the feeding tube is dropped into the crucible for a preset time.

Preferably, the magnetic field comprises a superconducting magnetic field or an electrically conductive magnetic field;

and/or the direction of the magnetic field comprises one of the following magnetic field directions: horizontal direction, vertical direction, and the direction of a cusp magnetic field formed by using upper and lower coils.

Preferably, the target intensity ranges from 500 gauss to 4000 gauss, or the target intensity ranges from 2000 gauss to 3000 gauss.

Preferably, the preset time comprises 30 minutes or 15 minutes.

Preferably, the secondary feeding method further comprises: after the preset time has elapsed, the magnetic field is turned off.

Preferably, the secondary feeding method further comprises: and when the melting state is monitored to enter a preset state, adjusting the output power of the heater to a first power value according to a preset power change strategy.

Preferably, the secondary feeding method further comprises: and after the preset time, adjusting the output power of the heater to a second power value.

This specification embodiment still provides a secondary feeding device, includes: a control unit configured to perform the secondary charging method as in any one of the preceding embodiments.

Embodiments of the present disclosure also provide a method for growing single crystal silicon, which includes the secondary feeding method according to any one of the preceding embodiments, so as to perform a secondary feeding operation in a single crystal silicon growing procedure.

The embodiment of the specification also provides a monocrystalline silicon growing device which comprises the secondary feeding device in any one of the preceding embodiments.

Compared with the prior art, the beneficial effects that can be achieved by the at least one technical scheme adopted by the embodiment of the specification at least comprise:

by turning on and increasing the magnetic field strength, for example, to 500G to 4000G (G is a unit of magnetic field strength, gauss) in a short time in a process requiring secondary charging, for example, before the silicon raw material in the crucible is almost melted, thereby the magnetic field acts on the silicon liquid in the crucible, the silicon liquid is enabled to rapidly reduce the surface temperature of the silicon liquid at the center of the crucible, for example, the surface of the silicon liquid at the center of the crucible is rapidly reduced under the action of the magnetic field, the crystallization solidification phenomenon appears on the surface to form a crystallization layer with a certain thickness and a larger radius, and the silicon liquid at the surface flows under the magnetic field to generate Lorentz force to block the flow, the viscosity of the silicon material is obviously increased, then the silicon material in the feeding pipe falls into the crucible, and the silicon material falls on the crystallization layer, and as the weight of the blanking is increased, the crystallization layer slowly sinks, and the silicon liquid has larger viscosity, so that the silicon liquid can not splash in the blanking. After the secondary feeding scheme provided by the embodiment of the specification is adopted, the splashing of silicon liquid in secondary feeding is effectively avoided, the service life of a thermal field component in monocrystalline silicon generation can be prolonged, for example, the number of times of using the guide cylinder is increased by 30%, impurities enter the silicon liquid and the problems of dislocation and the like caused by monocrystalline growth are avoided, the monocrystalline growth success rate is improved, and for example, the success rate of crystal pulling is relatively improved by 20%.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

FIG. 1 is a schematic diagram of splashing of silicon liquid during blanking in secondary feeding in the prior art.

FIG. 2 is a schematic diagram of a secondary feeding method provided in the examples of this specification.

Fig. 3 is a schematic diagram of blanking in a secondary feeding method provided in an embodiment of the present specification.

FIG. 4 is a schematic diagram of the appearance of surface crystalline structure in a secondary feeding method provided in the examples of this specification.

FIG. 5 is a schematic diagram of a secondary feeding operation in a secondary feeding method provided in an embodiment of the present disclosure.

Fig. 6 is a schematic structural diagram of a secondary feeding device provided in an embodiment of the present specification.

Fig. 7 is a schematic diagram of a method for growing single crystal silicon provided in the embodiments of the present disclosure.

Fig. 8 is a schematic structural diagram of a single crystal silicon growth apparatus provided in an embodiment of the present specification.

Detailed Description

The embodiments of the present application will be described in detail below with reference to the accompanying drawings.

The following description of the embodiments of the present application is provided by way of specific examples, and other advantages and effects of the present application will be readily apparent to those skilled in the art from the disclosure herein. It is to be understood that the embodiments described are only a few embodiments of the present application and not all embodiments. The present application is capable of other and different embodiments and its several details are capable of modifications and/or changes in various respects, all without departing from the spirit of the present application. It is to be noted that the features in the following embodiments and examples may be combined with each other without conflict. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

It is noted that various aspects of the embodiments are described below within the scope of the appended claims. It should be apparent that the aspects described herein may be embodied in a wide variety of forms and that any specific structure and/or function described herein is merely illustrative. Based on the present application, one skilled in the art should appreciate that one aspect described herein may be implemented independently of any other aspects and that two or more of these aspects may be combined in various ways. For example, an apparatus may be implemented and/or a method practiced using any number and aspects set forth herein. Additionally, such an apparatus may be implemented and/or such a method may be practiced using other structure and/or functionality in addition to one or more of the aspects set forth herein.

It should be noted that the drawings provided in the following embodiments are only for illustrating the basic idea of the present application, and the drawings only show the components related to the present application rather than the number, shape and size of the components in actual implementation, and the type, amount and ratio of the components in actual implementation may be changed arbitrarily, and the layout of the components may be more complicated.

In addition, in the following description, specific details are provided to facilitate a thorough understanding of the examples. However, it will be understood by those skilled in the art that the aspects may be practiced without these specific details.

In conventional methods, for example, in the growth of high-end semiconductor single-crystal silicon, a magnet (i.e., a device for generating a magnetic field) is disposed in a semiconductor single-crystal silicon growth furnace device, and thus, in the steps of crystal pulling, for example, seeding, shouldering, etc., a magnetic field is applied to a silicon melt, so that a lorentz force is generated in the silicon solution having conductive properties in a high-temperature solution, and the convection motion of the melt is inhibited, thereby suppressing the thermal convection of the silicon melt and growing a high-quality crystal.

In the melting step, the melting is performed in order to sufficiently transfer heat between the silicon liquid and the silicon solid (i.e., the unmelted silicon raw material), and thus no magnetic field is applied in the melting step.

However, in an attempt to solve the problem of splashing of the silicon liquid, the inventors have conducted extensive analysis and verification on the thermal convection condition of the silicon liquid under the action of a magnetic field, for example, when the magnetic field is applied to the silicon liquid in the melting material in the crucible, when the melt (i.e., the silicon liquid) in the crucible is suppressed by the magnetic field, i.e., the melt flows under the magnetic field of the silicon liquid to generate lorentz force, which hinders the flow, and at this time, the convection heat transfer of the silicon liquid is significantly weakened, so that the temperature of the silicon liquid at the surface in the center of the crucible is reduced, and the solidification phenomenon occurs at the surface, and in addition, the flow resistance of the silicon liquid is greatly increased when the temperature of the silicon liquid at the surface.

Therefore, if a magnetic field is applied to the secondary feeding process, for example, the magnetic field acts on the silicon liquid in the secondary feeding, not only the solidification phenomenon can occur on the surface of the silicon liquid, but also the temperature of the silicon liquid at the surface is reduced, and simultaneously, the silicon liquid at the surface flows under the magnetic field to generate the Lorentz force to block the flow, so that the viscosity is obviously improved, therefore, if the secondary feeding is carried out at this time, namely, the silicon raw material in the feeding pipe (such as a quartz pipe) falls onto the silicon liquid again at this time, in view of the solidification of the silicon liquid at the surface and the improvement of the viscosity, the splashing of the silicon liquid can not occur or can be extremely reduced.

Based on this, the embodiments of the present disclosure provide a secondary feeding scheme in silicon single crystal growth, wherein after a primary feeding, a material melting state in a crucible may be monitored, when a silicon raw material in the crucible is melted to a predetermined degree, for example, a nearly melted state, a central region is not completely melted or completely melted, and the like, the magnetic field strength is raised according to a predetermined magnetic field strength raising strategy, for example, the magnetic field strength is raised rapidly, so that the magnetic field strength reaches a target strength when a secondary feeding is performed, for example, the magnetic field strength is raised to 3000G within 30 minutes, and then the silicon raw material is dropped into the crucible within a predetermined feeding time period, for example, within 30 minutes or within 15 minutes, so as to implement a secondary feeding process without splashing of silicon liquid.

Through introducing the magnetic field and acting on the reinforced silicon liquid of secondary in the reinforced process in the secondary, make the reinforced silicon liquid before the blanking of secondary, for example the silicon liquid of crucible central part, its surface temperature reduces fast, take place crystallization solidification phenomenon, thereby form certain thickness and great crystallization layer of radius, and the viscidity of surface silicon liquid also greatly increased, throw in silicon raw materials this moment again, silicon raw materials will fall on the crystallization layer, along with blanking weight increase, the crystallization layer sinks, and the viscidity effect of silicon liquid, make the reinforced silicon liquid of secondary can not taking place to splash of secondary, the silicon liquid who has solved the reinforced secondary well splashes, can prolong the life-span of each part of thermal field, still can improve the crystal pulling success rate of monocrystalline silicon in growing.

The technical solutions provided by the embodiments of the present description are described below with reference to the accompanying drawings.

Referring to fig. 2, an embodiment of the present description provides a secondary feeding method.

As shown in fig. 2, the secondary feeding method provided in the embodiment of the present specification may include:

step S202, the melting state of the silicon raw material in the crucible is monitored.

In practice, during the secondary feeding operation, it is possible to monitor whether the silicon raw material in the crucible has been melted to a certain extent, thereby determining whether the blanking operation is possible.

It should be noted that the monitoring can be performed by a conventional monitoring means, and the monitoring method is not limited herein.

And step S204, judging according to the monitoring result, and determining whether the melting state enters a preset state.

In practice, the preset state may be a melting state suitable for the secondary charging and blanking operation, such as that the silicon raw material in the center of the crucible starts to melt, such as that the silicon raw material in the crucible is melted by a certain ratio (e.g. half), such as that the silicon raw material in the crucible is completely melted, etc., so that the preset state may be preset according to the actual application requirement, and is not limited herein.

By monitoring and judging the melting state of the silicon raw material in the crucible, the time point suitable for blanking in the secondary charging process can be judged in time, so that when the silicon raw material in the crucible is judged to be melted to be in a state suitable for secondary charging and blanking, subsequent secondary charging step operations are executed in time for blanking, such as steps S206 and S208; and when the silicon raw material in the crucible is judged not to be melted to be in a state suitable for secondary feeding for blanking, other operations can be performed, such as continuously heating the material, for example, returning to the step S202 to continuously monitor the material, and the like.

And S206, applying a magnetic field with target intensity to the silicon liquid in the crucible according to a preset magnetic field applying strategy.

On the basis of step S204, that is, when it is monitored and determined that the granular or block-shaped silicon raw material can be added to the crucible, a magnetic field action may be performed on the silicon liquid in the crucible, that is, a magnetic field with a target intensity may be applied to the silicon liquid in the crucible according to a preset magnetic field application strategy, so that the temperature of the surface of the silicon liquid is lowered, the viscosity of the silicon liquid is increased, the flow resistance is increased, and a crystalline layer appears on the surface of the silicon liquid under the action of the magnetic field.

In implementation, the preset magnetic field applying strategy may be an applying strategy corresponding to a magnetic field for controlling the silicon liquid acting in the crucible, that is, an excitation control strategy, such as a magnetic field start control strategy, such as a magnetic field strength setting strategy, such as a magnetic field strength variation strategy, and the like, so that the preset magnetic field applying strategy may be preset according to application needs, for example, the magnetic field strength reaches 3000 gauss in 30 minutes, which is not limited herein.

In practice, the target intensity corresponding to the magnetic field can be preset according to actual needs, and the target intensity can correspond to a numerical point (of course, the numerical point can be added with a numerical point of an error range), for example, the target intensity is set to 3000G ± 50G.

In some embodiments, the target intensity may be set to correspond to a range of values, such as 500G-4000G, and more preferably a range of magnetic field strengths, such as between 2000G-3000G.

And S208, after the magnetic field is applied, dropping the silicon raw material in the feeding pipe into the crucible within a preset time.

And applying a magnetic field to enable the temperature of the silicon liquid in the crucible to be reduced, so that the viscosity of the silicon liquid at the surface is increased, and a crystallization layer is formed at the surface, therefore, the silicon raw material in the feeding pipe can be dropped into the crucible within a preset time, and the blanking operation in secondary feeding is implemented.

In some embodiments, the preset time may be preset according to an actual application scenario, so as to facilitate operations of material melting, blanking of secondary feeding, or excitation, for example, 30 minutes, 15 minutes, and the like.

In the secondary feeding method provided by the embodiment of the specification, by monitoring the melting state of the silicon raw material in the crucible and timely applying a magnetic field to act on the silicon liquid when monitoring the melting state suitable for the secondary feeding and blanking operation in the crucible, the temperature on the surface of the silicon liquid is reduced, so that the viscosity is increased, and a crystallization layer is formed on the surface, at the moment, the silicon raw material in the feeding pipe falls on the crystallization layer, and along with the increase of the blanking weight, the crystallization layer slowly sinks, and the viscosity of the silicon liquid is increased, so that the splashing of the silicon liquid does not occur in the secondary feeding, the splashing of the silicon liquid in the secondary feeding is well solved, the service life of each part of a thermal field can be prolonged, and the crystal pulling success rate of the monocrystalline silicon in the growth process can be improved.

As shown in fig. 3 and 4, under the action of the magnetic field, the silicon liquid in the crucible appears a crystallization area at the central surface, the crystallization area gradually expands under the continuous action of the magnetic field, then the silicon raw materials in the feeding pipe can fall onto the crystallization layer, and further the silicon raw materials slowly sink into the silicon liquid under the bedding action of the crystallization layer and the flow resistance of the silicon liquid under the magnetic field, so that the splashing of the silicon liquid is not seen in the whole process of blanking.

Through the secondary feeding method provided by the embodiment of the specification, namely, the problem of splashing of the silicon liquid in the secondary feeding process can be effectively solved at low cost by simply improving the feeding process.

In some embodiments, a superconducting magnetic field or a conductive magnetic field can be selected to act on the crucible to form a desired magnetic field according to the actual application.

In addition, the apparatus for generating the superconducting magnetic field and the conductive magnetic field is not limited herein.

In some embodiments, the direction of the magnetic field may include one of the following magnetic field directions, as required by the actual application scenario: the direction of a hook-shaped magnetic field formed by an upper coil and a lower coil is used in the horizontal direction and the vertical direction so as to conveniently act on the silicon liquid by using the magnetic field in the monocrystalline silicon growth procedure.

In some embodiments, after the preset time, the strength of the magnetic field can be reduced, and even the magnetic field is turned off, so that the influence of the magnetic field is removed in the material melting process, which is beneficial to shortening the material melting time.

In some embodiments, upon monitoring that the melting state enters a preset state, the output power of the heater may be adjusted to a first power value according to a preset power variation strategy.

When it needs to be explained, the preset power variation strategy may be a strategy for adjusting the output power, and may be preset according to the actual application requirement, for example, the output power is reduced by 20%, so that the temperature of the silicon liquid is reduced more, and a crystallization layer is formed better when a magnetic field is applied.

In some embodiments, the first power value may be set according to practical application requirements, and may preferably be 10% to 40% of the original output power, for example, when a higher silicon liquid temperature needs to be maintained, for example, the second feeding time is shorter, the power of the heater may be reduced by a little, for example, 10%, for example, when a larger crystallization area or a thicker crystallization area needs to be maintained, for example, the second feeding time is longer, and the power of the heater may be reduced by a little, for example, 40%.

In some embodiments, the output power of the heater may be adjusted to a second power value after the preset time, for example, the output power before the drop is restored.

For ease of understanding, the timing diagram for the second addition can be as shown in FIG. 5.

In the material melting process, by monitoring the melting state of silicon liquid in the crucible, when the melting state suitable for secondary feeding is monitored, on one hand, the total power P of the heater can be reduced, on the other hand, the magnetic field can be opened to enable the magnetic field intensity to reach the target intensity M, the blanking operation of secondary feeding can be carried out within the preset time, and after the blanking operation is finished or the preset time is passed, the magnetic field is reduced or even closed, the total power P of the heater is recovered, and the material melting process is continued. In addition, when the secondary feeding is needed for multiple times, the power of the heater, the magnetic field intensity and the like can be repeatedly adjusted, and the description is not repeated.

The following is a comparison of the secondary feeding scheme provided in the examples of the present specification with the prior art scheme, by way of example.

For example, in the growth process of a 300mm large silicon single crystal, after 280kg of polycrystalline silicon raw material is initially charged using a 32-inch thermal field and a 32-inch quartz crucible, 70kg of polycrystalline silicon raw material is additionally charged each time using a quartz feeder, and the charging is divided into 2 times.

In the conventional secondary feeding scheme, during each additional feeding process, granular or blocky polycrystalline silicon slides out of the quartz feeder and falls into the silicon liquid in the quartz crucible, and more silicon liquid is often splashed (see the schematic illustration of fig. 1), and when the furnace cleaning after crystal pulling is finished, the silicon liquid is found to be attached to the crucible wall, the heater, the draft tube and other parts along the upper edge of the quartz crucible.

According to past experience, under the condition of silicon liquid adhesion, the service life of a thermal field component and the stability of the process are influenced, and the success rate of crystal pulling is reduced.

The secondary feeding is carried out by adopting the secondary feeding scheme provided by the embodiment of the specification, namely in each feeding process, when the temperature of the temperature sensor of the side heater reaches 1650 ℃, the diameter of the unmelted silicon material in the center of the crucible is about 200-300mm, the power of the side heater can be reduced by 20 percent, the magnetic field intensity is started and increased, after about 30 minutes, the magnetic field intensity reaches 3000 gauss, the edge of the unmelted silicon material in the center of the crucible starts to crystallize and gradually expands to form a silicon liquid surface crystallization area, when the diameter of the surface crystallization area is 1.5-2.0 times larger than the diameter of the feeding pipe, the silicon raw material can be started to be fed, namely, the granular or blocky polycrystalline silicon slides out from the quartz feeder, the silicon raw material falls on the crystallization layer, and the crystallization layer sinks along with the increase of the blanking weight, and the splashing of the silicon liquid does not occur. And then, after the feeding is finished, reducing the magnetic field intensity to zero, increasing the power of the side heater to the power of the raw material, and continuously melting the material.

After the secondary feeding scheme provided by the embodiment of the specification is adopted, when the furnace cleaning is finished after crystal pulling, no splashing of silicon liquid is found, for example, no silicon liquid is attached to the crucible wall on the upper edge of a quartz crucible, a heater, a guide cylinder and other parts, the usable frequency of the guide cylinder is increased by 30%, and the success rate of crystal pulling is relatively increased by 20%.

Based on the same inventive concept, the embodiment of the present specification further provides a secondary feeding device, so as to implement the secondary feeding method described in any one of the foregoing embodiments.

In practice, a control unit for executing the steps of the secondary feeding method may be added to the single-crystal silicon growth apparatus, that is, the control unit is a unit configured to execute the secondary feeding method shown in any one of the foregoing embodiments, so that the secondary feeding scheme provided by the embodiments of the present specification can be implemented on the existing apparatus by simply modifying the existing apparatus.

As shown in fig. 6, in the existing single crystal silicon growth system (such as a growth furnace), the function of the control unit can be added to the existing secondary feeding device, and the secondary feeding operation can be performed together through the interaction of the function of the control unit and other equipment units.

It should be noted that, the control units here may be virtual control units, for example, virtual function units that execute one or more steps in the secondary charging method described in the foregoing embodiments, and the virtual function units may be virtual function units that are correspondingly presented when an existing equipment unit executes one or more steps in the secondary charging method, so that the control units at this time may be virtual units; of course, the control unit may also be a new equipment unit for performing one or more steps of the secondary feeding method described in the previous embodiments.

It should be noted that other equipment units may be the equipment units existing in the single crystal silicon growth furnace, including but not limited to, a heater in a crucible, a magnet, a feed tube, a guide cylinder, and the like.

Based on the same inventive concept, the embodiment of the specification further provides a monocrystalline silicon growth method.

The single crystal silicon growth method provided in the embodiments of the present specification may include the secondary charging method described in any one of the foregoing embodiments, so as to implement the secondary charging function described in any one of the foregoing embodiments in the single crystal silicon growth process.

As shown in fig. 7, in the single crystal silicon growth process scheme, the following procedures may be included, but not limited to: a primary feeding and material melting process, a secondary feeding process, a crystal pulling process and the like.

It should be noted that the secondary feeding process is a process using the secondary feeding method described in any one of the foregoing embodiments, and the remaining processes are not limited herein.

Based on the same inventive concept, the embodiment of the specification further provides a monocrystalline silicon growing device.

The monocrystalline silicon growing device (such as a growing furnace) provided by the embodiment of the specification can comprise the secondary feeding device in any one of the embodiments.

As shown in fig. 8, in the conventional single-crystal silicon growth apparatus (for example, growth furnace), the existing secondary charging process apparatus may include the secondary charging apparatus according to any of the above-described embodiments, and further, the function of the new secondary charging apparatus and the other process apparatuses cooperate with each other to realize the above-described blanking operation of the secondary charging, thereby performing the single-crystal silicon growth process together and improving the single-crystal silicon crystallization rate.

The embodiments in the present specification are described in a progressive manner, and the same and similar parts among the embodiments can be referred to each other, and each embodiment focuses on the differences from the other embodiments. In particular, for the method embodiments described later, since they correspond to the system, the description is simple, and for the relevant points, reference may be made to the partial description of the system embodiments.

The above description is only for the specific embodiments of the present application, but the scope of the present application is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present application should be covered within the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A secondary feeding method is characterized by comprising the following steps:

monitoring the melting state of the silicon raw material in the crucible;

when the melting state is monitored to enter a preset state, applying a magnetic field with target intensity to the silicon liquid in the crucible according to a preset magnetic field applying strategy;

after the magnetic field is applied, the silicon raw material in the feeding tube is dropped into the crucible for a preset time.

2. The secondary charging method as claimed in claim 1, wherein said magnetic field comprises a superconducting magnetic field or a conductive magnetic field;

3. The secondary feeding method according to claim 1, wherein the range of the target intensity comprises a range of 500 gauss to 4000 gauss, or the range of the target intensity comprises a range of 2000 gauss to 3000 gauss.

4. The secondary feeding method according to claim 1, wherein the preset time comprises 30 minutes or 15 minutes.

5. The secondary charging method as claimed in claim 1, further comprising: after the preset time has elapsed, the magnetic field is turned off.

6. The secondary charging method as claimed in claim 1, further comprising: and when the melting state is monitored to enter a preset state, adjusting the output power of the heater to a first power value according to a preset power change strategy.

7. The secondary charging method as claimed in claim 6, further comprising: and after the preset time, adjusting the output power of the heater to a second power value.

8. A secondary feeding device, comprising:

a control unit configured to perform the secondary charging method as claimed in any one of claims 1 to 7.

9. A single-crystal silicon growth method comprising the secondary charging method according to any one of claims 1 to 7.

10. A single-crystal silicon growth apparatus comprising the secondary charging apparatus according to claim 9.