Automatic overturning method suitable for single crystal flat interface growth of Czochralski method resistance furnace

Abstract

The invention discloses an automatic overturning method suitable for single crystal flat interface growth of a Czochralski method resistance furnace, and belongs to the technical field of crystal preparation. Comprising the following steps: charging a furnace, vacuumizing, inflating, heating and melting materials, lifting a pot position, sinking seed crystals, seeding the crystals, automatically turning over, ending, discharging embryos and the like. Through an automatic overturning process that the rotating speed and the pulling speed are gradually increased under the control of a program, the problem that in an original overturning process, conversion from a convex interface to a flat interface is completed on a single section is solved; due to the fact that crystals on the cross section grow in different periods (crystals at different radiuses on the cross section perpendicular to the growth axis do not grow at the same time), point defects, line defects and dislocation are formed in the diameter amplification process, and it is verified that the point defects, line defects and dislocation performance in the crystals are greatly reduced through the technology.

Description

Technical Field

[0001] This invention relates to the field of crystal preparation technology, and in particular to an automatic flipping method suitable for single crystal planar interface growth in a Czochralski resistance furnace. Background Technology

[0002] The Czochralski method is a technique for growing high-quality single-crystal materials. In this method, the raw materials constituting the crystal are placed in a crucible, heated, and melted. A seed crystal is then placed on the surface of the melt, and the melt is pulled up. Under controlled conditions, the atoms or molecules at the interface between the seed crystal and the melt continuously rearrange, gradually solidifying as the temperature decreases, thus growing a single crystal. In the process of growing laser crystals using a Czochralski single-crystal furnace, if the solid-liquid interface is convex, it is called a convex interface; if the solid-liquid interface is relatively flat, it is called a flat interface. Crystals grown with convex interfaces have a core, while crystals grown with flat interfaces do not, resulting in higher utilization rates. Due to the radial temperature gradient of the melt within the crucible, the melt spontaneously rises from the edge of the crucible and flows towards the center, sinking thereafter. This process is called natural convection. Crystals grown under natural convection have convex interfaces. The flipping process, however, increases the crystal rotation speed, affecting melt convection and making the solid-liquid surface more flat. In this case, the melt within the crucible undergoes forced convection. The traditional flipping process involves turning off the pulling mechanism after the crystal has grown to a certain size, raising it to a predetermined speed and holding it at a constant temperature for a period of time, and then adjusting the temperature by observing the convection of the liquid surface through an opening above the hot zone. This process is repeated, and the crystal is melted back to 2mm before being pulled again.

[0003] The current drawbacks of this process are: 1. The judgment of the liquid level and the adjustment of the temperature are too subjective and rely too heavily on experience, making it impossible to establish a standardized operating procedure. 2. Manual execution of the process involves many uncertainties and variables, resulting in low repeatability and high production costs due to heavy reliance on manual labor. 3. This process completes the transition from a convex to a flat interface in a single cross-section. After the transition at a certain point, the crystals on that cross-section have grown from different periods (crystals at different radii on a cross-section perpendicular to the growth axis do not grow simultaneously), which can introduce defects formed during the diameter enlargement process, resulting in poor quality single crystals. 4. When reaching the flipping position, operators cannot flip each single crystal furnace on time, and there are also errors in the isothermal time during the flipping process for each single crystal furnace. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide an automatic flipping method suitable for the growth of single crystal planar interfaces in a Czochralski resistance furnace.

[0005] The objective of this invention is achieved through the following technical solution: an automatic flipping method for single crystal planar interface growth in a Czochralski resistance furnace, comprising the following steps: Step 1: Place the raw materials into the single crystal resistance furnace; Step 2: Evacuate the single crystal resistance furnace to the first vacuum level and heat it to the first temperature; Step 3: Stop heating and fill the single crystal resistance furnace with protective gas; Step 4: Heat the single-crystal resistance furnace to the melting temperature of the raw materials; Step 5: After the raw material begins to melt, raise the crucible a first distance; after the raw material melts a first volume, raise the crucible to the seed crystal pot position; then release the gas pressure to the first gas pressure; before the raw material is completely melted, the seed crystal is close to the surface of the raw material liquid but not in contact, which is used to preheat the seed crystal; Step 6: Once the raw material has completely melted, set the rotation speed and lower the seed crystal to contact the surface of the liquid raw material; Step 7: Perform crystal pulling. When the temperature reaches the second temperature, set the pulling speed to start pulling and give a cooling command to make the raw material grow from the seed crystal. Step 8: After successful crystal introduction, crystal growth is performed using an automatic flipping method, which includes a shoulder formation stage, a shoulder rotation stage, a flipping stage, and a constant diameter stage. Step 9: After crystal growth is complete, raise the crystal by a second distance, lower it by a third distance, and reduce the rotation speed to give a cooling command; Step 10: Remove the crystal after it has cooled down.

[0006] Preferably, the shoulder-forming stage, shoulder-turning stage, flipping stage, and constant-diameter stage are performed by changing the shape parameters and motion parameters; the shape parameters include the initial diameter, growth length, termination diameter, and growth shape of the crystal, the heating slope and cooling slope of the single-crystal resistance furnace, and the growth shape includes a straight shape and a rear half-wedge shape; the motion parameters include the pulling speed and rotation speed.

[0007] Preferably, the shoulder-relaxing stage includes the following steps: S1: Set the initial diameter to the first diameter, the growth length to the first length, the termination diameter to the second diameter, the growth shape to a straight line, the heating slope not exceeding the first heating slope, the cooling slope not exceeding the first cooling slope, the lifting speed to keep the first lifting speed constant, and the rotation speed to keep the first rotation speed constant. S2: Set the initial diameter to the second diameter, the growth length to the first length, the termination diameter to the third diameter, the growth shape to a semi-wedge shape, the heating slope not exceeding the first heating slope, the cooling slope not exceeding the first cooling slope, the lifting speed to keep the first lifting speed constant, and the rotation speed to keep the first rotation speed constant; the first diameter is smaller than the second diameter, and the second diameter is smaller than the third diameter.

[0008] Preferably, after the shoulder relaxation phase, the shoulder rotation phase begins, which includes the following steps: F1: Set the initial diameter to the third diameter, the growth length to the second length, the termination diameter to the third diameter, the growth shape to a straight line, the heating slope not exceeding the first heating slope, the cooling slope not exceeding the first cooling slope, the lifting speed to keep the first lifting speed constant, and the rotation speed to keep the first rotation speed constant; the second length is less than the first length.

[0009] Preferably, after the shoulder turning stage, the flipping stage begins, which includes the following steps: F2: Set the initial diameter to the third diameter, the growth length to the third length, the termination diameter to the third diameter, the growth shape to a straight line, the heating slope not exceeding the first heating slope, the cooling slope not exceeding the second cooling slope, the lifting speed to be uniformly increased from the first lifting speed to the second lifting speed, and the rotation speed to be uniformly increased from the first rotation speed to the second rotation speed. F3: Set the initial diameter to the third diameter, the growth length to the fourth length, the termination diameter to the third diameter, the growth shape to a straight line, the heating slope not exceeding the first heating slope, the cooling slope not exceeding the third cooling slope, the lifting speed to be uniformly increased from the second lifting speed to the third lifting speed, and the rotation speed to be uniformly increased from the second rotation speed to the third rotation speed. F4: Set the initial diameter to the third diameter, the growth length to the fifth length, the termination diameter to the third diameter, the growth shape to a straight line, the heating slope not exceeding the first heating slope, the cooling slope not exceeding the second cooling slope, the pulling speed to uniformly increase from the third pulling speed to the fourth pulling speed, and the rotation speed to uniformly increase from the third rotation speed to the fourth rotation speed; the third length is less than the second length, the second length is less than the fifth length, the fifth length is less than the fourth length, and the fourth length is less than the first length; the second cooling slope is less than the first cooling slope, and the third cooling slope is less than the second cooling slope; the first pulling speed is less than the second pulling speed, the second pulling speed is less than the third pulling speed, and the third pulling speed is less than the fourth pulling speed; the first rotation speed is less than the second rotation speed, the second rotation speed is less than the third rotation speed, and the third rotation speed is less than the fourth rotation speed. Preferably, after the flipping stage, the equal diameter stage begins, which includes the following steps: B1: Set the initial diameter to the third diameter, the growth length to the sixth length, the termination diameter to the third diameter, the growth shape to a straight line, the heating slope not exceeding the first heating slope, the cooling slope not exceeding the second cooling slope, the lifting speed to keep the fourth lifting speed constant, and the rotation speed to keep the fourth rotation speed constant. B2: Set the initial diameter to the third diameter, the growth length to the seventh length, the termination diameter to the third diameter, the growth shape to a straight line, the heating slope not exceeding the first heating slope, the cooling slope not exceeding the first cooling slope, the lifting speed to keep the fourth lifting speed constant, and the rotation speed to keep the fourth rotation speed constant. B3: Set the initial diameter to the third diameter, the growth length to the eighth length, the termination diameter to the third diameter, the growth shape to be linear, the heating slope not exceeding the first heating slope, the cooling slope not exceeding the first cooling slope, the lifting speed to keep the fourth lifting speed constant, and the rotation speed to keep the fourth rotation speed constant; the eighth length is greater than the fourth length but less than the first length, the sixth length is greater than the first length, and the seventh length is greater than the sixth length.

[0010] Preferably, the protective gas is argon and carbon dioxide.

[0011] The beneficial effects of this invention are: 1) The automatic flipping process, which uses program-controlled gradual increase in rotation speed and lifting speed, solves the problem that the original flipping process, when converting a convex interface to a flat interface on a single cross section, caused point defects, line defects, and dislocations during diameter enlargement because the crystals on the cross section grew at different times (crystals at different radii on a cross section perpendicular to the growth axis did not grow at the same time). Verification has shown that this process greatly reduces the occurrence of point defects, line defects, and dislocations inside the crystal. Attached Figure Description

[0012] Figure 1 A flowchart of an automated flipping method for single crystal planar interface growth in a Czochralski resistance furnace; Figure 2 This is a schematic diagram of crystal defects. Detailed Implementation

[0013] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. 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.

[0014] This invention automates the entire flipping process, improving product quality and process stability. It achieves automatic flipping through programmatic programming by segmenting the flipping process and setting corresponding programs for each segment.

[0015] See Figures 1-2 This invention provides a technical solution: an automatic flipping method for single crystal planar interface growth in a Czochralski resistance furnace, comprising the following steps: Step 1: Place the raw materials into the single crystal resistance furnace; Step 2: Evacuate the single crystal resistance furnace to the first vacuum level and heat it to the first temperature; Step 3: Stop heating and fill the single crystal resistance furnace with protective gas; Step 4: Heat the single-crystal resistance furnace to the melting temperature of the raw materials; Step 5: After the raw material begins to melt, raise the crucible a first distance; after the raw material melts a first volume, raise the crucible to the seed crystal pot position; then release the gas pressure to the first gas pressure; before the raw material is completely melted, the seed crystal is close to the surface of the raw material liquid but not in contact, which is used to preheat the seed crystal; Step 6: Once the raw material has completely melted, set the rotation speed and lower the seed crystal to contact the surface of the liquid raw material; Step 7: Perform crystal pulling. When the temperature reaches the second temperature, set the pulling speed to start pulling and give a cooling command to make the raw material grow from the seed crystal. Step 8: After successful crystal introduction, crystal growth is performed using an automatic flipping method, which includes a shoulder formation stage, a shoulder rotation stage, a flipping stage, and a constant diameter stage. Step 9: After crystal growth is complete, raise the crystal by a second distance, lower it by a third distance, and reduce the rotation speed to give a cooling command; Step 10: Remove the crystal after it has cooled down.

[0016] In this embodiment, a mechanical pump is used to evacuate the furnace to a low vacuum, then a diffusion pump is activated, the Eurotherm temperature controller is heated to 6 mV, and the pressure is evacuated to less than or equal to 9.9 x 10⁻³ Pa. After the protective gas is filled, the furnace pressure is slightly higher than atmospheric pressure. When the raw material begins to melt, the crucible is slowly raised a certain distance. After a portion of the raw material has melted, the crucible continues to rise, ensuring that the raw material does not reach the upper screen or overflow from the crucible, until it reaches the crystal-seeding pot. At this point, due to the increased heating pressure, the pressure needs to be reduced to approximately 0.02 MPa. When lowering the seed crystal, the seed crystal must not come into contact with the raw material before it has completely melted. During the seed crystal lowering process, the temperature is maintained for a period of time before temperature adjustment begins, and each temperature adjustment requires maintaining a constant temperature. The second distance is 10 mm, and the third distance is 5 mm. The first vacuum degree, first pressure, first temperature, second temperature, first volume, first distance, second distance, and third distance are preset values ​​based on the working environment and requirements, and are not limited to any specific value. In step 4, the heating slope of the single crystal resistance furnace to the melting temperature of the raw materials is 1.8 mv / h, and the heating process is uniform; in step 5, complete melting means that all raw materials have changed from solid to liquid; in step 7, the cooling slope of the cooling command is -0.03 mv / h.

[0017] In some embodiments, the shoulder-forming stage, shoulder-turning stage, flipping stage, and constant-diameter stage are performed by changing shape parameters and motion parameters; the shape parameters include the initial diameter, growth length, termination diameter, and growth shape of the crystal, the heating slope and cooling slope of the single-crystal resistance furnace, and the growth shape includes a straight shape and a rear half-wedge shape; the motion parameters include the pulling speed and the rotation speed.

[0018] In some embodiments, the shoulder-relaxing stage includes the following steps: S1: Set the initial diameter to the first diameter, the growth length to the first length, the termination diameter to the second diameter, the growth shape to a straight line, the heating slope not exceeding the first heating slope, the cooling slope not exceeding the first cooling slope, the lifting speed to keep the first lifting speed constant, and the rotation speed to keep the first rotation speed constant. S2: Set the initial diameter to the second diameter, the growth length to the first length, the termination diameter to the third diameter, the growth shape to a semi-wedge shape, the heating slope not exceeding the first heating slope, the cooling slope not exceeding the first cooling slope, the lifting speed to keep the first lifting speed constant, and the rotation speed to keep the first rotation speed constant; the first diameter is smaller than the second diameter, and the second diameter is smaller than the third diameter.

[0019] In some embodiments, after the shoulder relaxation phase, a shoulder rotation phase begins, which includes the following steps: F1: Set the initial diameter to the third diameter, the growth length to the second length, the termination diameter to the third diameter, the growth shape to a straight line, the heating slope not exceeding the first heating slope, the cooling slope not exceeding the first cooling slope, the lifting speed to keep the first lifting speed constant, and the rotation speed to keep the first rotation speed constant; the second length is less than the first length.

[0020] In some embodiments, after the shoulder turning phase ends, a flipping phase begins, which includes the following steps: F2: Set the initial diameter to the third diameter, the growth length to the third length, the termination diameter to the third diameter, the growth shape to a straight line, the heating slope not exceeding the first heating slope, the cooling slope not exceeding the second cooling slope, the lifting speed to be uniformly increased from the first lifting speed to the second lifting speed, and the rotation speed to be uniformly increased from the first rotation speed to the second rotation speed. F3: Set the initial diameter to the third diameter, the growth length to the fourth length, the termination diameter to the third diameter, the growth shape to a straight line, the heating slope not exceeding the first heating slope, the cooling slope not exceeding the third cooling slope, the lifting speed to be uniformly increased from the second lifting speed to the third lifting speed, and the rotation speed to be uniformly increased from the second rotation speed to the third rotation speed. F4: Set the initial diameter to the third diameter, the growth length to the fifth length, the termination diameter to the third diameter, the growth shape to a straight line, the heating slope not exceeding the first heating slope, the cooling slope not exceeding the second cooling slope, the pulling speed to uniformly increase from the third pulling speed to the fourth pulling speed, and the rotation speed to uniformly increase from the third rotation speed to the fourth rotation speed; the third length is less than the second length, the second length is less than the fifth length, the fifth length is less than the fourth length, and the fourth length is less than the first length; the second cooling slope is less than the first cooling slope, and the third cooling slope is less than the second cooling slope; the first pulling speed is less than the second pulling speed, the second pulling speed is less than the third pulling speed, and the third pulling speed is less than the fourth pulling speed; the first rotation speed is less than the second rotation speed, the second rotation speed is less than the third rotation speed, and the third rotation speed is less than the fourth rotation speed. In some embodiments, after the flipping stage is completed, a constant diameter stage is entered, which includes the following steps: B1: Set the initial diameter to the third diameter, the growth length to the sixth length, the termination diameter to the third diameter, the growth shape to a straight line, the heating slope not exceeding the first heating slope, the cooling slope not exceeding the second cooling slope, the lifting speed to keep the fourth lifting speed constant, and the rotation speed to keep the fourth rotation speed constant. B2: Set the initial diameter to the third diameter, the growth length to the seventh length, the termination diameter to the third diameter, the growth shape to a straight line, the heating slope not exceeding the first heating slope, the cooling slope not exceeding the first cooling slope, the lifting speed to keep the fourth lifting speed constant, and the rotation speed to keep the fourth rotation speed constant. B3: Set the initial diameter to the third diameter, the growth length to the eighth length, the termination diameter to the third diameter, the growth shape to be linear, the heating slope not exceeding the first heating slope, the cooling slope not exceeding the first cooling slope, the lifting speed to keep the fourth lifting speed constant, and the rotation speed to keep the fourth rotation speed constant; the eighth length is greater than the fourth length but less than the first length, the sixth length is greater than the first length, and the seventh length is greater than the sixth length.

[0021] In this embodiment, the program is set to a total of 9 segments, namely S1, S2, F1, F2, F3, F4, B1, B2, and B3. Among them, the shoulder formation stage is S1 and S2, which mainly control the process of the crystal growing from the moment it is introduced by the seed crystal to the diameter increasing to the required size. F1 is the shoulder turning stage, which changes the diameter growth from the diameter increase during the shoulder formation process to the diameter growth remaining constant. Natural convection occurs naturally, caused by density changes due to internal temperature differences within the fluid. Forced convection, on the other hand, is caused by external forces. In this invention, natural convection manifests as deposition from the periphery of the airflow towards the center, while forced convection manifests as airflow from the center outwards. From F2, F3, and F4 onwards, the process enters a transition phase. The crystal pulling and rotation speeds are gradually increased through automatic control. When the rotation speed is between 15-25 rpm, the critical value has not yet been reached, and natural convection still dominates, requiring no high cooling slope. Between 25-65 rpm, natural convection transitions to forced convection, necessitating a larger cooling slope to prevent crystal diameter shrinkage. At 65-100 rpm, forced convection dominates, again requiring no large cooling slope. Therefore, the cooling slope needs to be increased during the transition from natural to forced convection to address the diameter reduction that occurs during this transition. In this invention, all heating and cooling slopes are upper limits, restricting the program's heating and cooling rates from exceeding these values. The remaining values ​​are controlled by the computer; the human operator only limits the maximum value. B1, B2, and B3 represent equal-diameter stages. The first diameter, second diameter, third diameter, first length, second length, third length, fourth length, fifth length, sixth length, seventh length, eighth length, first heating slope, first cooling slope, second cooling slope, third cooling slope, first drawing speed, second drawing speed, third drawing speed, fourth drawing speed, first rotation speed, second rotation speed, third rotation speed, and fourth rotation speed are preset values ​​based on the working environment and requirements, and are not limited to any specific value.

[0022] In some embodiments, the protective gas is argon and carbon dioxide.

[0023] In this embodiment, argon gas is first purged to 0.2 MPa, and then carbon dioxide gas is purged to 0.275 MPa.

[0024] The following are specific values ​​for the shape parameters and motion parameters in a particular implementation: External parameters: S1: Initial diameter 6mm, growth length 20mm, termination diameter 28mm, linear shape, heating slope 0.02mv / h, cooling slope -0.04mv / h, initial pulling speed 1.2mm / h, initial rotation speed 15 rpm, termination pulling speed 1.2 mm / h, termination rotation speed 15 rpm; S2: Initial diameter 28mm, growth length 20mm, termination diameter 42mm, rear half-wedge shape, heating slope 0.02 mv / h, cooling slope -0.04 mv / h, initial pulling speed 1.2mm / h, initial rotation speed 15 rpm, termination pulling speed 1.2 mm / h, termination rotation speed 15 rpm; F1: Initial diameter 42 mm, growth length 5 mm, termination diameter 42 mm, linear growth, heating slope 0.02 mv / h, cooling slope -0.04 mv / h, initial pulling speed 1.2 mm / h, initial rotation speed 15 rpm, termination pulling speed 1.2 mm / h, termination rotation speed 15 rpm; F2 has an initial diameter of 42 mm, a growth length of 2 mm, a termination diameter of 42 mm, a linear growth pattern, a heating slope of 0.02 mv / h, a cooling slope of -0.06 mv / h, an initial pulling speed of 1.2 mm / h, an initial rotation speed of 15 rpm, a termination pulling speed of 1.25 mm / h, and a termination rotation speed of 25 rpm. F3 has an initial diameter of 42 mm, a growth length of 10 mm, a termination diameter of 42 mm, a linear growth pattern, a heating slope of 0.02 mv / h, a cooling slope of -0.1 mv / h, an initial pulling speed of 1.25 mm / h, an initial rotation speed of 25 rpm, a termination pulling speed of 1.4 mm / h, and a termination rotation speed of 65 rpm. F4 has an initial diameter of 42 mm, a growth length of 6 mm, a termination diameter of 42 mm, a linear growth pattern, a heating slope of 0.02 mv / h, a cooling slope of -0.06 mv / h, an initial pulling speed of 1.4 mm / h, an initial rotation speed of 65 rpm, a termination pulling speed of 1.5 mm / h, and a termination rotation speed of 100 rpm. B1 has an initial diameter of 42 mm, a growth length of 30 mm, a termination diameter of 42 mm, a linear growth pattern, a heating slope of 0.02 mv / h, a cooling slope of -0.04 mv / h, an initial pulling speed of 1.5 mm / h, an initial rotation speed of 100 rpm, a termination pulling speed of 1.5 mm / h, and a termination rotation speed of 100 rpm. B2 has an initial diameter of 42 mm, a growth length of 70 mm, a termination diameter of 42 mm, a linear growth pattern, a heating slope of 0.02 mv / h, a cooling slope of -0.04 mv / h, an initial pulling speed of 1.5 mm / h, an initial rotation speed of 100 rpm, a termination pulling speed of 1.5 mm / h, and a termination rotation speed of 100 rpm. B3 has an initial diameter of 42 mm, a growth length of 15 mm, a termination diameter of 42 mm, a linear growth pattern, a heating slope of 0.02 mv / h, a cooling slope of -0.04 mv / h, an initial pulling speed of 1.5 mm / h, an initial rotation speed of 100 rpm, a termination pulling speed of 1.5 mm / h, and a termination rotation speed of 100 rpm.

[0025] The above description is merely a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in various other combinations, modifications, and environments, and can be altered within the scope of the concept described herein through the above teachings or related technologies or knowledge. Modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention should be within the protection scope of the appended claims.

Claims

1. An automatic flipping method suitable for single crystal planar interface growth in a Czochralski resistance furnace, characterized in that: Includes the following steps: Step 1: Place the raw materials into the single crystal resistance furnace; Step 2: Evacuate the single crystal resistance furnace to the first vacuum level and heat it to the first temperature; Step 3: Stop heating and fill the single crystal resistance furnace with protective gas; Step 4: Heat the single-crystal resistance furnace to the melting temperature of the raw materials; Step 5: After the raw material begins to melt, raise the crucible a first distance; after the raw material melts a first volume, raise the crucible to the seed crystal pot position; then release the gas pressure to the first gas pressure; before the raw material is completely melted, the seed crystal is close to the surface of the raw material liquid but does not contact it, which is used to preheat the seed crystal; Step 6: Once the raw material has completely melted, set the rotation speed and lower the seed crystal to contact the surface of the liquid raw material; Step 7: Perform crystal pulling. When the temperature reaches the second temperature, set the pulling speed to start pulling and give a cooling command to make the raw material grow from the seed crystal. Step 8: After successful crystal introduction, crystal growth is performed using an automatic flipping method, which includes a shoulder formation stage, a shoulder rotation stage, a flipping stage, and a constant diameter stage. Step 9: After crystal growth is complete, raise the crystal by a second distance, lower it by a third distance, and reduce the rotation speed to give a cooling command; Step 10: Remove the crystal after it has cooled down.

2. The automatic flipping method for single crystal planar interface growth in a Czochralski resistance furnace according to claim 1, characterized in that: The aforementioned shoulder-growing stage, shoulder-turning stage, flipping stage, and constant-diameter stage involve crystal growth by changing shape parameters and motion parameters. The shape parameters include the initial diameter, growth length, termination diameter, and growth shape of the crystal, as well as the heating and cooling slopes of the single-crystal resistance furnace. The growth shape includes a straight shape and a rear half-wedge shape. The motion parameters include the pulling speed and rotation speed.

3. The automatic flipping method for single crystal planar interface growth in Czochralski resistance furnace according to claim 2, characterized in that: The shoulder-relaxation stage includes the following steps: S1: Set the initial diameter to the first diameter, the growth length to the first length, the termination diameter to the second diameter, the growth shape to a straight line, the heating slope not exceeding the first heating slope, the cooling slope not exceeding the first cooling slope, the lifting speed to keep the first lifting speed constant, and the rotation speed to keep the first rotation speed constant. S2: Set the initial diameter to the second diameter, the growth length to the first length, the termination diameter to the third diameter, the growth shape to a semi-wedge shape, the heating slope not exceeding the first heating slope, the cooling slope not exceeding the first cooling slope, the lifting speed to keep the first lifting speed constant, and the rotation speed to keep the first rotation speed constant; the first diameter is smaller than the second diameter, and the second diameter is smaller than the third diameter.

4. The automatic flipping method for single crystal planar interface growth in a Czochralski resistance furnace according to claim 3, characterized in that: After the shoulder relaxation phase, the shoulder rotation phase begins, which includes the following steps: F1: Set the initial diameter to the third diameter, the growth length to the second length, the termination diameter to the third diameter, the growth shape to a straight line, the heating slope not exceeding the first heating slope, the cooling slope not exceeding the first cooling slope, the lifting speed to keep the first lifting speed constant, and the rotation speed to keep the first rotation speed constant; the second length is less than the first length.

5. The automatic flipping method for single crystal planar interface growth in a Czochralski resistance furnace according to claim 4, characterized in that: After the shoulder rotation phase, the flipping phase begins, which includes the following steps: F2: Set the initial diameter to the third diameter, the growth length to the third length, the termination diameter to the third diameter, the growth shape to a straight line, the heating slope not exceeding the first heating slope, the cooling slope not exceeding the second cooling slope, the lifting speed to be uniformly increased from the first lifting speed to the second lifting speed, and the rotation speed to be uniformly increased from the first rotation speed to the second rotation speed. F3: Set the initial diameter to the third diameter, the growth length to the fourth length, the termination diameter to the third diameter, the growth shape to a straight line, the heating slope not exceeding the first heating slope, the cooling slope not exceeding the third cooling slope, the lifting speed to be uniformly increased from the second lifting speed to the third lifting speed, and the rotation speed to be uniformly increased from the second rotation speed to the third rotation speed. F4: Set the initial diameter to the third diameter, the growth length to the fifth length, the termination diameter to the third diameter, the growth shape to a straight line, the heating slope not exceeding the first heating slope, the cooling slope not exceeding the second cooling slope, the pulling speed to uniformly increase from the third pulling speed to the fourth pulling speed, and the rotation speed to uniformly increase from the third rotation speed to the fourth rotation speed; the third length is less than the second length, the second length is less than the fifth length, the fifth length is less than the fourth length, and the fourth length is less than the first length; the second cooling slope is less than the first cooling slope, and the third cooling slope is less than the second cooling slope; the first pulling speed is less than the second pulling speed, the second pulling speed is less than the third pulling speed, and the third pulling speed is less than the fourth pulling speed; the first rotation speed is less than the second rotation speed, the second rotation speed is less than the third rotation speed, and the third rotation speed is less than the fourth rotation speed.

6. The automatic flipping method for single crystal planar interface growth in Czochralski resistance furnace according to claim 5, characterized in that: After the flipping stage is completed, the equal diameter stage begins, which includes the following steps: B1: Set the initial diameter to the third diameter, the growth length to the sixth length, the termination diameter to the third diameter, the growth shape to a straight line, the heating slope not exceeding the first heating slope, the cooling slope not exceeding the second cooling slope, the lifting speed to keep the fourth lifting speed constant, and the rotation speed to keep the fourth rotation speed constant. B2: Set the initial diameter to the third diameter, the growth length to the seventh length, the termination diameter to the third diameter, the growth shape to a straight line, the heating slope not exceeding the first heating slope, the cooling slope not exceeding the first cooling slope, the lifting speed to keep the fourth lifting speed constant, and the rotation speed to keep the fourth rotation speed constant. B3: Set the initial diameter to the third diameter, the growth length to the eighth length, the termination diameter to the third diameter, the growth shape to be linear, the heating slope not exceeding the first heating slope, the cooling slope not exceeding the first cooling slope, the lifting speed to keep the fourth lifting speed constant, and the rotation speed to keep the fourth rotation speed constant; the eighth length is greater than the fourth length but less than the first length, the sixth length is greater than the first length, and the seventh length is greater than the sixth length.

7. The automatic flipping method for single crystal planar interface growth in a resistance furnace using the Czochralski method according to any one of claims 1-6, characterized in that: The protective gases are argon and carbon dioxide.

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