Czochralski single crystal magnetic control device and crystal pulling method using same

Abstract

The invention provides a Czochralski single crystal magnetic control device and a crystal pulling method using the same. The Czochralski single crystal magnetic control device comprises a shell, a coil assembly and an electrode interface movably connected with the coil assembly. The shell forms a hollow closed accommodating cavity; the coil assembly is fixedly installed in the closed containing cavity of the shell and comprises multiple sets of coils, and the multiple sets of coils are oppositely arranged in the closed containing cavity. Each group of coils comprises a plurality of coils, and the plurality of coils in each group of coils are arranged at intervals up and down along the axis of the shell side by side in pairs; and the electrode interface is movably arranged on the coil assembly so as to control the current direction in the coil assembly. And switching of different magnetic fields is realized by adjusting the magnitude and direction of the current accessed to the coil.

Description

Technical Field

[0001] The present invention belongs to the technical field of single crystal manufacturing, and in particular, relates to a Czochralski single crystal magnetron device, and also relates to a crystal pulling method using the Czochralski single crystal magnetron device. Background Art

[0002] 12-inch semiconductor-grade single crystal silicon is mainly prepared by the Czochralski method. When growing large-size (such as 12-inch) single crystal silicon, this method makes the melt flow unstable due to the large amount of crystal feed. In order to improve this instability, the magnetically controlled Czochralski (MCZ) technology was introduced to use an external magnetic field to influence and control the flow of the melt, thereby reducing crystal defects and improving the crystal formation rate and crystal quality. At present, the magnetic fields used for the growth of single crystal silicon by the Czochralski method are mainly divided into axial magnetic fields, transverse magnetic fields, and hook-shaped magnetic fields. The axial magnetic field mainly suppresses the lateral convection of the crystal, and has limited suppression of natural convection. At the same time, it will cause poor radial uniformity of the crystal, and is now almost not used.

[0003] Some patents have disclosed relevant technical solutions for the application of transverse magnetic field and hook-shaped magnetic field in the preparation of single crystal silicon by Czochralski method. For example, Chinese patent 201922393861.1 discloses a quadrangular coil distributed superconducting magnet for magnetically controlled Czochralski single crystal, including superconducting coils, coil bearing frames, cryostat, external iron, current leads, service components and GM refrigerator; the superconducting magnet used for magnetically controlled Czochralski single crystal is distributed in a quadrangular coil, which can provide a background magnetic field with high field strength and large uniform area, and can effectively reduce the leakage field to solve the preparation of single crystal silicon with a specification of 300mm. However, this technology can only generate a single transverse magnetic field, and cannot generate the hook-shaped magnetic field required for the growth of heavily doped crystals, and the transverse magnetic field generated by this technology can only adjust the magnetic field strength and the axial position of the magnetic field, and cannot adjust the relative distribution of the magnetic field, and has poor flexibility. Chinese patent 202020168794.3 discloses a hook-shaped magnetic field device for silicon single crystal growth, including two parallel coil assemblies connected to two DC power supplies, and direct currents in opposite directions are respectively passed into the coil assemblies to form the required hook-shaped magnetic field. However, this technology can only generate a single hook-shaped magnetic field, and cannot generate the lateral magnetic field required for the growth of crystals such as storage and logic, and has poor flexibility.

[0004] In summary, there are currently problems such as the non-adjustable relative spatial distribution of the transverse magnetic field, the poor flexibility of the transverse magnetic field and hook-shaped magnetic field equipment, and the inability to switch between the two magnetic fields. Summary of the invention

[0005] The purpose of the present invention is to provide a CZ single crystal magnetostrictive device and a crystal pulling method using the device, so as to solve the problem that the relative spatial distribution of the transverse magnetic field in the prior art is not adjustable, and the current magnetostrictive device cannot realize the mutual switching between the transverse magnetic field and the hook-shaped magnetic field. The CZ single crystal magnetostrictive device provided by the present invention comprises:

[0006] A shell, wherein the shell is formed as a hollow closed cavity;

[0007] A coil assembly is fixedly installed in the sealed cavity of the housing, the coil assembly includes a plurality of coil groups, the plurality of coil groups are arranged relatively in the sealed cavity; each coil group includes a plurality of coils, and the plurality of coils in each coil group are arranged side by side in pairs and spaced apart vertically along the axis of the housing;

[0008] The electrode interface is movably mounted on the coil assembly to control the direction of current in the coil assembly.

[0009] Optionally, the shell may be a cylindrical shell or a square cylindrical shell.

[0010] Optionally, the coil is a superconducting coil, and each coil in the coil assembly has the same shape, winding method, number of winding turns, and conductor area.

[0011] Optionally, when the shell is a cylindrical shell, the shape of the coil is a saddle shape; when the shell is a square cylindrical shell, the shape of the coil is a rectangle or a square.

[0012] Optionally, the spacing distance between the two coils in each group of coils along the axial direction of the cylindrical shell is greater than or equal to 20 mm.

[0013] Optionally, the arc length of a coil in the cylindrical shell is greater than or equal to 1 / 3 of the circumference of the cylindrical shell, and less than 1 / 2 of the circumference of the cylindrical shell.

[0014] Optionally, the spacing distance between the coils in the cylindrical shell in the circumferential direction of the cylindrical shell is greater than 0 and less than or equal to 1 / 6 of the circumference of the cylindrical shell.

[0015] Optionally, the coil assembly includes two groups of coils, wherein each group of coils includes two coils.

[0016] Optionally, a power source is further included, and the power source is connected to the electrode interface to provide current to the coil assembly. The number of the power sources is the same as the number of the coil groups, or the same as the number of the coils.

[0017] Optionally, a lifting device is also included, which is arranged on the cylindrical outer shell so that the outer shell can move axially along the outer circumference of the vertical pulling single crystal furnace.

[0018] Another embodiment of the present invention provides a Czochralski single crystal device, comprising:

[0019] A Czochralski single crystal furnace, comprising a crucible, wherein the crucible is located inside the Czochralski single crystal furnace;

[0020] The Czochralski single crystal magnetron device is coaxially sleeved on the outer periphery of the Czochralski single crystal furnace. The Czochralski single crystal magnetron device can be any one of the Czochralski single crystal magnetron devices described above.

[0021] Another embodiment of the present invention provides a method for pulling a single crystal, comprising the following steps:

[0022] A Czochralski single crystal device is provided, wherein a crucible of the Czochralski single crystal device contains molten silicon material;

[0023] Providing a seed crystal, and placing the seed crystal on the surface of the molten silicon material in the crucible;

[0024] Adjusting the axial position of the CZ single crystal magnetron device in the CZ single crystal device so that the coil assembly in the CZ single crystal magnetron device is arranged opposite to the crucible;

[0025] Providing a power source, and connecting the power source to the electrode interface of the CZ single crystal magnetron device;

[0026] An electric current is applied to the CZ single crystal pulling device, and the coil generates a magnetic field acting on the crucible. The current and / or direction are adjusted to control the growth of the single crystal.

[0027] Optionally, adjusting the magnitude and / or direction of the current includes:

[0028] Passing currents of equal magnitude and same direction through all coils in the coil assembly, so that the coils generate a transverse magnetic field acting on the crucible;

[0029] The magnitude of the current passed through the coil is adjusted to change the relative distribution of the transverse magnetic field in space.

[0030] Optionally, adjusting the magnitude and / or direction of the current includes:

[0031] Passing currents of equal magnitude through all coils in the coil assembly, wherein the currents passed through the same group of coils have the same direction and the currents passed through different groups of coils have opposite directions, so that the coil assembly generates a hook-shaped magnetic field acting on the crucible;

[0032] The magnitude of the current passed through the coil is adjusted to change the relative distribution of the hook-shaped magnetic field in space.

[0033] Compared with the prior art, the technical effects of the present invention include at least:

[0034] The magnetic field shape is adjustable: through the designed four-coil layout, the present invention can achieve the adjustability of the transverse magnetic field in spatial distribution, and can achieve the switching and dynamic adjustment between other magnetic fields such as the transverse magnetic field, the hook-shaped magnetic field, and the hook-shaped magnetic field. This is crucial for controlling the temperature gradient, convection pattern and impurity distribution during the growth of single crystals, and helps to improve the purity, oxygen content, uniformity and crystal quality of single crystal materials, thereby meeting the stringent requirements of high-end electronic devices, optoelectronic devices and semiconductor materials.

[0035] High equipment compatibility: The coil layout is compact and has good compatibility. It is equipped with a lifting device, which can be flexibly adjusted according to the height and layout of different single crystal growth furnaces to meet the growth requirements of single crystals of different materials and sizes.

[0036] Environmental protection and sustainability: The coil is made of superconducting materials, which reduces energy consumption and greenhouse gas emissions, and meets the current global requirements for green manufacturing and sustainable development. At the same time, the promotion and application of this technology will also help enhance the competitiveness of related industries and promote industrial upgrading and transformation. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 Shown is a schematic structural diagram of the CZ single crystal magnetron device of the present invention.

[0038] Figure 2 Display as Figure 1 The cross-sectional view of the CZ single crystal magnetron device in the XY plane is shown.

[0039] Figure 3 A schematic diagram showing the magnetic field intensity distribution and coil current flow direction generated by the CZ single crystal magnetron device in current configuration 1.

[0040] Figure 4 A schematic diagram showing the magnetic field intensity distribution and coil current flow direction generated by the CZ single crystal magnetron device in current configuration 2.

[0041] Figure 5 A schematic diagram showing the magnetic field intensity distribution and coil current flow direction generated by the CZ single crystal magnetron device in current configuration 3.

[0042] Figure 6 A schematic diagram showing the magnetic field intensity distribution and coil current flow direction generated by the CZ single crystal magnetron device in current configuration 4.

[0043] Figure 7 Shown is a flow chart of the Czochralski single crystal method provided in Example 3.

[0044] Figure 8 It shows a schematic diagram of the structure in which a Czochralski single crystal magnetic control device is mounted on a Czochralski single crystal furnace.

[0045] Fig. 9 It shows the morphology of melt flow without magnetic field.

[0046] Fig.10 It shows the influence of the magnetic field generated by the CZ single crystal magnetron device in the current configuration 1 state in Example 1 on the melt convection morphology.

[0047] Fig.11 It shows the influence of the magnetic field generated by the CZ single crystal magnetron device in the current configuration 3 state in Example 1 on the melt convection morphology.

[0048] Reference numerals

[0049] 010, CZ single crystal furnace; 011, crucible;

[0050] 100, cylindrical shell; 101, first coil; 102, second coil; 103, third coil; 104, fourth coil. DETAILED DESCRIPTION

[0051] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0052] It should be noted that the illustrations provided in this embodiment only illustrate the basic concept of the present invention in a schematic manner. Although the illustrations only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation, the form, quantity, positional relationship and proportion of each component in actual implementation can be changed at will under the premise of realizing the technical solution of this party, and the component layout form may also be more complicated.

[0053] Embodiment 1

[0054] This embodiment provides a CZ single crystal magnetron device, such as Figure 1 As shown, the CZ single crystal magnetron device includes a housing, a coil assembly, and an electrode interface movably connected to the coil assembly. The housing is a hollow, sealed cavity. Optionally, the housing can be a cylindrical housing, a square cylindrical housing, or a housing of other shapes. The housing used in this embodiment is a cylindrical housing 100. The cylindrical housing 100 is sleeved on the outer periphery of the CZ single crystal furnace 010 (see Figure 7). The coil assembly is fixedly installed in the closed cavity of the cylindrical shell 100, and the coil assembly includes multiple groups of coils, and the number of coil groups is greater than or equal to two groups. Optionally, the number of coil groups is two, three, four, or other groups. Each group of coils includes multiple coils, and the number of coils in each group of coils is greater than or equal to two. Optionally, the number of coils in each group of coils can be two, three, four, or more. Specifically, the number of coils in the coil assembly of the direct-pull single crystal magnetic control device is greater than or equal to 4, and the number of coils can be four, six, eight, ten, or the like. Specifically, the present embodiment adopts two groups of coils, and each group of coils includes two coils. The coil assembly of the present embodiment includes a first coil 101, a second coil 102, a third coil 103, and a fourth coil 104. The first coil 101 and the second coil 102 are arranged in a vertically spaced manner with their sides facing each other, and the third coil 103 and the fourth coil 104 are arranged in a vertically spaced manner with their sides facing each other. As Figure 2 As shown, it is shown as Figure 1 In the cross-sectional view on the XY plane, the first coil 101 is arranged above the second coil 102, the third coil 103 is arranged above the fourth coil 104, and the first coil 101 and the second coil 102, the third coil 103 and the fourth coil 104 are coaxially arranged at relative positions of the cylindrical shell 100. The coils are all superconducting coils, and the shapes, winding methods, winding turns, wire areas, etc. of all coils are equal. The electrode interface is movably installed on the four coils to flexibly control the current direction connected to each coil.

[0055] In an optional embodiment, the diameter of the cylindrical shell 100 is greater than the diameter of the outer circumference of the CZ single crystal furnace 010, and the diameter of the cylindrical shell 100 may be 1.5m to 2.4m. In this embodiment, the diameter of the cylindrical shell 100 is 1.6m. Optionally, the material of the cylindrical shell 100 may be made of high-performance non-magnetic materials such as pure copper, aluminum alloy or non-magnetic stainless steel to ensure the magnetic field is closed and prevent magnetic leakage. Optionally, the shape of the coil in the cylindrical shell is a saddle shape, and the shape of the coil in the square cylinder shell is a rectangle or a square. In this embodiment, the coils are all saddle-shaped. Optionally, the number of turns of the coil can be adjusted according to actual conditions. In this embodiment, the number of turns of the coil is 2000 turns. Optionally, the arc length of each coil is greater than or equal to 1 / 3 of the circumference of the cylindrical shell 100, and less than 1 / 2 of the circumference of the cylindrical shell. The axial spacing distance of each coil in the cylindrical shell is greater than 0, and less than or equal to 1 / 6 of the circumference of the cylindrical shell. The spacing distance between two adjacent coils in each group of coils along the axial direction of the cylindrical shell is greater than or equal to 20 mm. In this embodiment, the arc length of each coil is equal to 1 / 3 of the circumference of the cylindrical shell 100, and the spacing distance between two coils in each group of coils along the axial direction of the cylindrical shell is equal to 20 mm. Optionally, the superconducting coil can be made of materials such as niobium-titanium alloy and bismuth series high-temperature superconducting materials. The connection methods of the electrode interface and the coil assembly include threaded connection, plug-in and snap-on connection.

[0056] The CZ single crystal magnetic control device also includes a power supply. The power supply is connected to the electrode interface to provide current to the coil, so that the coil assembly generates a magnetic field acting on the CZ single crystal furnace 010. In an optional embodiment, the number of power supplies is the same as the number of coil groups, or the same as the number of coils. In this embodiment, the number of power supplies can be set to 2 or 4. The number of power supplies is 2, that is, the first coil 101 and the second coil 102 share a power supply, and the third coil 103 and the fourth coil 104 share a power supply; the number of power supplies is 4, that is, four power supplies are respectively connected to four coil assemblies to respectively pass current to the four coils. Specifically, the magnitude and direction of the current can be determined according to the required magnetic field strength and direction.

[0057] By providing different current configurations, that is, changing the magnitude and direction of the current connected to the coil assembly, the CZ single crystal magnetron device can generate different types of magnetic fields and realize conversion between different magnetic fields, such as axial magnetic field, transverse magnetic field, hook-shaped magnetic field, non-uniform transverse magnetic field, hook-shaped magnetic field, etc.

[0058] like Figures 3 to 6 As shown, several common current configurations were selected and connected to the coil assembly to study the magnetic field morphology generated by the CZ single crystal magnetron device:

[0059] Current configuration 1: The four coils of the CZ single crystal magnetron device are supplied with currents of the same magnitude and direction. Specifically, the magnitude of the current is determined by the required magnetic field strength and the number of coil turns used. For example, the current magnitude can be Furthermore, Etc. The current size of this embodiment is like Figure 3 As shown, it is a schematic diagram showing the magnetic field intensity distribution and coil current flow direction generated by the CZ single crystal magnetron device in the current configuration 1 state. Figure 3 It can be seen that under current configuration 1, the magnetic field generated by the CZ single crystal magnetron device is a symmetrical transverse magnetic field, and the magnetic field intensity on both sides close to the CZ single crystal magnetron device is greater than the magnetic field intensity in the middle. The transverse magnetic field is mainly aimed at the growth process that needs to suppress temperature fluctuations and slow down the melt flow to obtain high-quality single crystals. This includes but is not limited to high-temperature alloy single crystals, semiconductor single crystals (such as silicon single crystals), etc.

[0060] Current configuration 2: Currents of different magnitudes but the same direction are passed through the four coils of the CZ single crystal magnetic control device. Specifically, the current magnitudes of the first coil 101 and the third coil 103 are equal, the current magnitudes of the second coil 102 and the fourth coil 104 are equal, and the current magnitudes of the first coil 101 and the third coil 103 are smaller than the current magnitudes of the second coil 102 and the fourth coil 104. Generally, the ratio of the current magnitudes of the first coil 101 and the third coil 103 to the current magnitudes of the second coil 102 and the fourth coil 104 can be selected according to actual conditions, such as 1 / 10-1 / 2. Specifically, in this embodiment, the ratio of the current magnitudes of the first coil 101 and the third coil 103 to the current magnitudes of the second coil 102 and the fourth coil 104 is 1 / 2, and the current magnitudes of the first coil 101 and the third coil 103 are The current magnitudes of the second coil 102 and the fourth coil 104 are: Depend on Figure 4 It can be seen that the magnetic field generated by the CZ single crystal magnetron device in the state of current configuration 2 is an asymmetric transverse magnetic field. In the Y-axis direction, the magnetic field strength of the asymmetric transverse magnetic field coil center upward is weaker than the magnetic field strength of the coil center downward, and the magnetic field strength on both sides close to the CZ single crystal magnetron device is greater than the magnetic field strength in the middle. Due to its uneven spatial distribution, the asymmetric transverse magnetic field is used to solve the growth that is difficult to solve with traditional magnetic fields under specific conditions, such as growing single crystal materials with specific morphological structures.

[0061] Current configuration 3: Currents of equal magnitude and opposite directions are passed through the four coils of the CZ single crystal magnetron device. Specifically, the current magnitude is The current directions of the first coil 101 and the second coil 102 are the same, the current directions of the third coil 103 and the fourth coil 104 are the same, and the current directions of the first coil 101 and the second coil 102 are opposite to the current directions of the third coil 103 and the fourth coil 104. Figure 5 It can be seen that the magnetic field generated by the CZ single crystal magnetron device in the state of current configuration 4 is a hook-shaped magnetic field. The hook-shaped magnetic field has its own special magnetic field distribution characteristics: the magnetic lines are symmetrical about the longitudinal axis and the central plane is symmetrical up and down, with a divergent magnetic field with radial and longitudinal components. Therefore, the hook-shaped magnetic field is widely used in single crystal growth processes that require efficient suppression of melt convection and improvement of crystal growth stability. It is particularly suitable for the growth of large-diameter single crystals, such as the growth of semiconductor-grade single crystal silicon larger than 8 inches. The hook-shaped magnetic field can suppress melt convection in three dimensions, reduce the oxygen content of silicon rods, and improve uniformity, thereby improving the quality of single crystals.

[0062] Current configuration 4: Currents of different magnitudes and opposite directions are passed through the four coils of the CZ single crystal magnetic control device. Specifically, the magnitudes of the currents of the first coil 101 and the third coil 103 are equal, the magnitudes of the currents of the second coil 102 and the fourth coil 104 are equal, the magnitudes of the currents of the first coil 101 and the third coil 103 are smaller than the magnitudes of the currents of the second coil 102 and the fourth coil 104, and the directions of the currents of the first coil 101 and the second coil 102 are the same, the directions of the third coil 103 and the fourth coil 104 are the same, and the directions of the currents of the first coil 101 and the second coil 102 are opposite to the directions of the currents of the third coil 103 and the fourth coil 104. Specifically, in this embodiment, the magnitude of the current is equal to that of configuration 1, the ratio of the magnitude of the current of the first coil 101 and the third coil 103 to the magnitude of the current of the second coil 102 and the fourth coil 104 is 1 / 2, and the magnitude of the current of the first coil 101 and the third coil 103 is The current magnitudes of the second coil 102 and the fourth coil 104 are: Depend on Figure 6 It can be seen that the magnetic field generated by the CZ single crystal magnetron device in the current configuration 4 is an asymmetric quasi-hook-shaped magnetic field. Along the Y direction, the magnetic field intensity of the asymmetric quasi-hook-shaped magnetic field coil center upward is weaker than the magnetic field intensity of the coil center downward. The asymmetric quasi-hook-shaped magnetic field is suitable for a specific crystal growth process due to its particularity in spatial distribution.

[0063] The CZ single crystal magnetron device further includes a lifting mechanism (not shown in the figure). The lifting mechanism is connected to the cylindrical shell 100 and is used to adjust the height of the CZ single crystal magnetron device so that the CZ single crystal magnetron device can move axially along the outer side of the CZ single crystal furnace 010 so that the coil assembly is correspondingly arranged around the periphery of the crucible 100 in the CZ single crystal furnace 010.

[0064] In summary, the direct-pull single crystal magnetic control device provided in this embodiment solves the non-adjustability of the spatial distribution of the transverse magnetic field by adjusting the magnitude of the current connected to the coil, and realizes the switching between different magnetic fields by adjusting the magnitude and direction of the current connected to the coil, and the height of the single crystal growth furnace can be flexibly adjusted according to the height of the single crystal growth furnace.

[0065] Embodiment 2

[0066] This embodiment provides a Czochralski single crystal device. Figure 7 The cross-sectional view of a Czochralski crystal device is shown. The Czochralski crystal device includes a Czochralski crystal furnace 010 and a Czochralski crystal magnetocontrol device coaxially sleeved on the outer periphery of the Czochralski crystal furnace 010. The Czochralski crystal furnace 010 includes a crucible 011. The Czochralski crystal magnetocontrol device is the Czochralski crystal magnetocontrol device provided in the first embodiment of the present application. Figure 1 The CZ single crystal magnetron device includes a housing, a coil assembly, an electrode interface, a power supply and a lifting device. The housing is a hollow sealed cavity. Optionally, the housing can be a cylindrical housing, a square cylindrical housing or a housing of other shapes. The housing used in this embodiment is a cylindrical housing 100. The coil assembly is fixedly installed in the sealed cavity of the cylindrical housing 100, and the coil assembly includes four completely equal coils. The coil assembly includes a first coil 101, a second coil 102, a third coil 103 and a fourth coil 104. The electrode interface is movably installed on the coil assembly to control the direction of the current connected to the coil assembly. The power supply is connected to the electrode interface to provide current to the coil assembly. The lifting device is connected to the cylindrical housing 100 to adjust the height of the CZ single crystal magnetron device. Generally, the material of the cylindrical housing 100 can be made of high-performance non-magnetic materials such as pure copper, aluminum alloy or non-magnetic stainless steel, and the diameter of the cylindrical housing 100 can be 1.5m to 2.4m. In this embodiment, the diameter of the cylindrical shell 100 is 1.6 m. In this embodiment, the coils are made of superconducting materials, the arc length is equal to 1 / 3 of the circumference of the cylindrical shell 100, the shape is saddle-shaped, and the number of winding turns is 2000 turns. Optionally, the number of power supplies can be set to 2 or 4. In this embodiment, two power supplies are set, the first coil 101 and the second coil 102 share one power supply, and the third coil 103 and the fourth coil 104 share one power supply.

[0067] By adjusting the size and direction of the current connected to the coil, the device can provide different magnetic fields required for vertical pulling of single crystals, and can achieve mutual conversion between different magnetic fields; in addition, the height of the coil assembly in the device can be flexibly adjusted according to the height of the single crystal growth furnace.

[0068] Embodiment 3

[0069] This embodiment provides a method for pulling a single crystal directly. The method uses the single crystal pulling device provided in the second embodiment. Figure 8 , which is a flow chart of the CZ single crystal pulling method of this embodiment, comprising the following steps:

[0070] A Czochralski single crystal device is provided, wherein a crucible of the Czochralski single crystal device contains molten silicon material;

[0071] Providing a seed crystal, and placing the seed crystal on the surface of the molten silicon material in the crucible;

[0072] Adjusting the axial position of the CZ single crystal magnetron device in the CZ single crystal device so that the coil assembly in the CZ single crystal magnetron device is arranged opposite to the crucible;

[0073] Providing a power source, and connecting the power source to the electrode interface of the CZ single crystal magnetron device;

[0074] An electric current is applied to the CZ single crystal pulling device, and the coil generates a magnetic field acting on the crucible. The current and / or direction are adjusted to control the growth of the single crystal.

[0075] The specific steps are as follows:

[0076] See also Figure 7 , a Czochralski single crystal device is provided, a Czochralski single crystal magnetron device is sleeved on the outer periphery of the Czochralski single crystal furnace 010, and a lifting device is used to move the Czochralski single crystal magnetron device axially relative to the Czochralski single crystal furnace 010, so that the coil assembly in the Czochralski single crystal magnetron device moves to the relative position of the crucible 011. The Czochralski single crystal device in this embodiment can be a type of Czochralski single crystal device provided in Example 2. The device can realize the adjustability of the spatial distribution of the transverse magnetic field, can realize the conversion between other magnetic fields such as the transverse magnetic field and the hook-shaped magnetic field, has high flexibility, and can significantly improve the quality of the single crystal rod.

[0077] A seed crystal is provided and placed on the surface of the molten silicon material in the crucible 011 .

[0078] Using the lifting device of the CZ single crystal magnetron device, the height of the single crystal magnetron device is adjusted, and the position of the coil assembly in the single crystal magnetron device is set at a height relative to the crucible to ensure that the magnetic field generated by the CZ single crystal magnetron device can act on the melt in the crucible;

[0079] Provide power supplies, connect the power supplies to the electrode interface, and the number of power supplies can be set to be equal to the number of coil groups or the number of coils. In this embodiment, two power supplies are provided.

[0080] The current of the power supply is adjusted to change the current in the coil. The current is adjusted according to actual conditions.

[0081] Changing the position of the electrode interface to control the direction of the current connected to the coil;

[0082] An electric current is applied to the Czochralski single crystal device, and the coil generates a magnetic field acting on the crucible to control the growth of the single crystal.

[0083] Next, a more representative current configuration is selected and connected to the CZ single crystal magnetron device to observe the influence of the magnetic field generated by the CZ single crystal magnetron device on the convection morphology of the melt in the CZ single crystal furnace 010 under different current configurations.

[0084] Please continue reading Figure 3 , provide current configuration 1, the magnitude and direction of the current connected to the coil assembly of the CZ single crystal magnetron device are the same. The current magnitude is determined by the required magnetic field strength and the number of coil turns. When other conditions remain unchanged, the current magnitude is proportional to the magnetic field strength and the number of coil turns. The current range can be Furthermore, Specifically, the current in this embodiment is Depend on Figure 3 It can be seen that the magnetic field generated by the CZ single crystal magnetron device is a symmetrical transverse magnetic field.

[0085] The distribution of the transverse magnetic field in space can be changed by changing the current connected to the coil assembly. For example, the current can be adjusted to: the currents of the first coil 101 and the third coil 103 are equal, the currents of the second coil 102 and the fourth coil 104 are equal, and the currents of the first coil 101 and the third coil 103 are smaller than the currents of the second coil 102 and the fourth coil 104. Figure 4It can be seen that the magnetic field generated by the CZ single crystal magnetron device is an asymmetric transverse magnetic field. In the Y-axis direction, the magnetic field strength of the asymmetric transverse magnetic field coil center upward is weaker than the magnetic field strength of the coil center downward, and the magnetic field strength on both sides close to the CZ single crystal magnetron device is greater than the magnetic field strength in the middle. Similarly, the current magnitude may also be: the current magnitudes of the first coil 101 and the third coil 103 are equal, the current magnitudes of the second coil 102 and the fourth coil 104 are equal, and the current magnitudes of the first coil 101 and the third coil 103 are greater than the current magnitudes of the second coil 102 and the fourth coil 104, and the magnetic field generated by the CZ single crystal magnetron device is an asymmetric transverse magnetic field, and in the Y-axis direction, the magnetic field intensity of the asymmetric transverse magnetic field coil center upward is stronger than the magnetic field intensity of the coil center downward; the current magnitude may also be: the current magnitudes of the first coil 101 and the second coil 102 are equal, the current magnitudes of the third coil 103 and the fourth coil 104 are equal, and the current magnitudes of the first coil 101 and the second coil 102 are greater than or less than the current magnitudes of the third coil 103 and the fourth coil 104. In this way, the magnetic field generated by the CZ single crystal magnetron device is also an asymmetric transverse magnetic field, and in the X-axis direction, the distribution of the transverse magnetic field is uneven.

[0086] In addition, there are many situations in which the current magnitude of the access coil is adjusted, for example, the current magnitudes of the first coil 101 and the fourth coil 104 are equal, the current magnitudes of the second coil 102 and the third coil 103 are equal, and the current magnitudes of the first coil 101 and the fourth coil 104 are greater than or less than the current magnitudes of the second coil 102 and the third coil 103; the current magnitudes of the four coils are all different, etc., which are not listed here one by one. In short, the distribution of the transverse magnetic field in space can be adjusted by changing the current magnitude of the access coil assembly. This asymmetric transverse magnetic field is used to solve the growth that is difficult to solve with traditional magnetic fields under specific conditions, such as the growth of single crystal materials with specific morphological structures, due to its uneven spatial distribution.

[0087] See also Fig. 9 , showing the morphology of melt flow without magnetic field. Fig. 9 It can be seen that in the absence of a magnetic field, the melt has obvious convection and the flow direction is chaotic. The oxygen content in the melt is unevenly distributed, with the oxygen content of the entire melt being 14-34ppma and the oxygen content of the melt near the crucible wall being 32-36ppma.

[0088] See also Fig.10, showing the effect of the magnetic field generated by the CZ single crystal magnetron device on the melt convection morphology in current configuration 1. Current configuration 1 is that the magnetic field generated by the CZ single crystal magnetron device is a symmetrical transverse magnetic field, and the magnetic field intensity on both sides of the CZ single crystal magnetron device is greater than the magnetic field intensity in the middle. Fig. 9 ,from Fig.10 It can be seen that under the magnetic field state generated by current configuration 1, the axial melt convection or the melt convection at a certain angle to the axial direction in the melt is significantly suppressed, that is, the convection at the contact position between the melt and the crystal and the convection at the middle position of the melt are significantly reduced. The convection of the melt is closely related to the transport of oxygen. The oxygen content in the entire melt is below 10ppma, the oxygen content is generally low, and the oxygen content at the contact position between the melt and the crystal is 6-8ppma. The transverse magnetic field can effectively improve the uniformity of the radial oxygen content in the single crystal rod, but it has no inhibitory effect on the thermal convection in the direction parallel to the magnetic lines of force, that is, the thermal convection cannot be completely suppressed in the melt, and the longitudinal oxygen content of the single crystal rod is uneven.

[0089] Please continue reading Figure 5 , providing current configuration 3, the currents connected to the coils of the CZ single crystal magnetron device are of the same magnitude and opposite directions. The current directions of the first coil 101 and the second coil 102 are the same, the current directions of the third coil 103 and the fourth coil 104 are the same, and the current directions of the first coil 101 and the second coil 102 are opposite to the current directions of the third coil 103 and the fourth coil 104. Figure 5 It can be seen from the figure that the magnetic field generated by the CZ single crystal magnetron device is a hook-shaped magnetic field.

[0090] The distribution of the hook-shaped magnetic field in space can be changed by changing the current connected to the coil assembly. For example, the current can be adjusted to: the current of the first coil 101 and the third coil 103 are equal, the current of the second coil 102 and the fourth coil 104 are equal, and the current of the first coil 101 and the third coil 103 is smaller than the current of the second coil 102 and the fourth coil 104. Figure 6It can be seen from the figure that the magnetic field generated by the CZ single crystal magnetron device is an asymmetric hook-shaped magnetic field. Along the Y direction, the magnetic field strength of the asymmetric hook-shaped magnetic field from the center of the coil upward is weaker than the magnetic field strength of the coil from the center downward. Similarly, the current magnitude can also be that the current magnitudes of the first coil 101 and the second coil 102 are equal, the current magnitudes of the third coil 103 and the fourth coil 104 are equal, and the current magnitudes of the first coil 101 and the second coil 102 are greater than or less than the current magnitudes of the third coil 103 and the fourth coil 104. In this way, the magnetic field generated by the CZ single crystal magnetron device is also an asymmetric hook-shaped magnetic field. In addition, there are many ways to adjust the current magnitude of the connected coil, which will not be listed one by one here. In short, by changing the current magnitude of the connected coil assembly, the distribution of the hook in space can be adjusted to solve the specific crystal growth process under specific conditions, for example, the oxygen content of the crystal in the longitudinal and transverse directions can be adjusted to face the growth of heavily doped crystals.

[0091] See also Fig.11 , showing the effect of the magnetic field generated by the CZ single crystal magnetron device in current configuration 3 on the melt convection morphology. Specifically, the current magnitude of all coils is The current directions of the first coil 101 and the second coil 102 are the same, the current directions of the third coil 103 and the fourth coil 104 are the same, and the current directions of the first coil 101 and the second coil 102 are opposite to the current directions of the third coil 103 and the fourth coil 104. The magnetic field generated by the CZ single crystal magnetron device is a hook-shaped magnetic field, and the magnetic lines of force are symmetrical about the longitudinal axis and the center plane is vertically symmetrical. Fig.11 It can be seen that under the magnetic field state generated by current configuration 3, the convection suppression in the melt is not obvious, and the overall oxygen content of the melt is relatively high. Fig.10 The melt shown has a high oxygen content, with the oxygen content at the contact point between the melt and the crystal being above 10 ppma, and the melt flow rate below the interface being faster, the melt is evenly mixed, and the oxygen content is uniform, which can effectively improve the overall uniformity of the crystal rod and improve the quality of the crystal rod.

[0092] In summary, the Czochralski single crystal method described in Example 3 has simple equipment: only one Czochralski single crystal magnetron device is needed; simple operation: by adjusting the magnitude and direction of the current connected to the coil assembly, the magnetic field distribution acting on the melt in the crucible 010 can be effectively changed; high flexibility: it can be flexibly adjusted according to the height and layout of different single crystal growth furnaces, and can meet the needs of single crystal growth of different sizes and materials. The Czochralski single crystal method can accurately control the oxygen content of the single crystal rod in the longitudinal and radial directions, thereby significantly improving the quality of the single crystal rod.

[0093] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A Czochralski single crystal magnetron device, sleeved on the outer periphery of a Czochralski single crystal furnace, characterized in that: include: A shell, wherein the shell is formed as a hollow closed cavity; A coil assembly is fixedly installed in the sealed cavity of the housing, the coil assembly includes a plurality of coil groups, the plurality of coil groups are arranged relatively in the sealed cavity; each coil group includes a plurality of coils, and the plurality of coils in each coil group are arranged side by side in pairs and spaced apart vertically along the axis of the housing; The electrode interface is movably mounted on the coil assembly to control the direction of current in the coil assembly.

2. The Czochralski single crystal magnetron device according to claim 1, characterized in that: The shell can be a cylindrical shell or a square cylindrical shell.

3. The Czochralski single crystal magnetron device according to claim 1, characterized in that: The coil is a superconducting coil, and each coil in the coil assembly has the same shape, winding method, number of winding turns, and conductor area.

4. The Czochralski single crystal magnetron device according to claim 2 or 3, characterized in that: When the shell is a cylindrical shell, the shape of the coil is a saddle shape; when the shell is a square cylindrical shell, the shape of the coil is a rectangle or a square.

5. The Czochralski single crystal magnetron device according to claim 1, characterized in that: The spacing distance between two adjacent coils in each group of coils along the axial direction of the shell is greater than or equal to 20 mm.

6. The Czochralski single crystal magnetron device according to claim 4, characterized in that: The arc length of a coil in the cylindrical shell is greater than or equal to 1 / 3 of the circumference of the cylindrical shell and less than 1 / 2 of the circumference of the cylindrical shell.

7. The Czochralski single crystal magnetron device according to claim 4, characterized in that: The spacing distance between the coils in the cylindrical shell in the circumferential direction of the cylindrical shell is greater than 0 and is less than or equal to 1 / 6 of the circumference of the cylindrical shell.

8. The Czochralski single crystal magnetron device according to claim 1, characterized in that: The coil assembly includes two groups of coils, wherein each group of coils includes two coils.

9. The Czochralski single crystal magnetron device according to claim 1, characterized in that: It also includes a power source, which is connected to the electrode interface to provide current to the coil assembly. The number of the power sources is the same as the number of the coil groups, or the same as the number of the coils.

10. The Czochralski single crystal magnetron device according to claim 1, characterized in that: It also includes a lifting device, which is arranged on the shell so that the shell can move axially along the outer circumference of the CZ single crystal furnace.

11. A Czochralski single crystal device, characterized in that: include: A Czochralski single crystal furnace, comprising a crucible, wherein the crucible is located inside the Czochralski single crystal furnace; The Czochralski single crystal magnetron device is coaxially sleeved on the outer periphery of the Czochralski single crystal furnace. The Czochralski single crystal magnetron device can be the Czochralski single crystal magnetron device according to any one of claims 1 to 10.

12. A method for producing a single crystal by pulling a single crystal, comprising the following steps: A Czochralski single crystal device is provided, wherein a crucible of the Czochralski single crystal device contains molten silicon material; Providing a seed crystal, and placing the seed crystal on the surface of the molten silicon material in the crucible; Adjusting the axial position of the CZ single crystal magnetron device in the CZ single crystal device so that the coil assembly in the CZ single crystal magnetron device is arranged opposite to the crucible; Providing a power source, and connecting the power source to the electrode interface of the CZ single crystal magnetron device; An electric current is applied to the CZ single crystal pulling device, and the coil generates a magnetic field acting on the crucible. The current and / or direction are adjusted to control the growth of the single crystal.

13. The method for pulling a single crystal according to claim 12, characterized in that: Adjusting the magnitude and / or direction of current flow includes: Passing currents of equal magnitude and same direction through all coils in the coil assembly, so that the coils generate a transverse magnetic field acting on the crucible; The magnitude of the current passed through the coil is adjusted to change the relative distribution of the transverse magnetic field in space.

14. The method for pulling a single crystal according to claim 12, characterized in that: Adjusting the magnitude and / or direction of current flow includes: Passing currents of equal magnitude through all coils in the coil assembly, wherein the currents passed through the same group of coils have the same direction and the currents passed through different groups of coils have opposite directions, so that the coil assembly generates a hook-shaped magnetic field acting on the crucible; The magnitude of the current passed through the coil is adjusted to change the relative distribution of the hook-shaped magnetic field in space.

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