Crystal growth method

Abstract

The present invention discloses a crystal growth method, which includes: determining conditions for adding a dopant into a crucible; bonding the dopant to the lower end of a seed crystal through silicone gel, so that the seed crystal moves downward and extends into the molten soup of the crucible and the dopant and silicone gel are completely located in the molten soup. According to the crystal growth method of the present invention, dopants are added to the crucible to ensure the stability of the resistivity of the grown crystal rod. At the same time, the silicone gel is used as the raw material of the crystal rod after being dehydrated and fused with the molten soup. While effectively utilizing the silicone gel, it will not cause chemical or physical effects on the molten soup in the crucible, effectively ensuring the purity and uniformity of the raw material of the crystal rod. In addition, the operation of adding a dopant into the crucible is simple, avoiding a complicated material hanging process, reducing the operation steps, thereby improving work efficiency, and reducing unnecessary waste of silicon materials, effectively reducing costs.

Description

Technical Field

[0001] The invention relates to the technical field of crystal growth, and in particular to a crystal growth method. Background Art

[0002] In the current field of semiconductor photovoltaic crystal pulling technology, the Czochralski method is widely used as the mainstream technology. By accurately adding dopants to maintain the stability of the resistivity of the crystal rod, the quality of the crystal rod is improved to meet the needs of subsequent processes of photovoltaic cells. However, when the crystal growth equipment is continuously operating and the dopant antimony needs to be supplemented to keep the resistivity of the crystal rod constant, the existing technology generally uses the hanging material method to add dopants. In this process, a part of the silicon material in the crucible needs to be consumed in advance before adding the dopant to meet the weight requirements of the standard feed and dopant addition. This operation process is relatively cumbersome and causes some waste of silicon material, increasing costs. Summary of the invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides a crystal growth device, wherein the crystal growth method is simple to add a dopant into a crucible, avoids a complicated material hanging process, reduces the operation steps, improves work efficiency, reduces unnecessary waste of silicon materials, and effectively reduces costs.

[0004] A crystal growth method according to an embodiment of the present invention is used to grow a crystal rod, comprising: determining conditions for adding a dopant into a crucible; bonding the dopant to the lower end of a seed crystal through silicone gel, so that the seed crystal moves downward into the molten metal of the crucible and the dopant and the silicone gel are completely located in the molten metal.

[0005] According to the crystal growth method of the embodiment of the present invention, the conditions for adding dopants into the crucible are determined, and the dopants are bonded to the lower end of the seed crystal through silicone gel, so that the seed crystal moves downward and extends into the molten soup of the crucible, and the dopants and silicone gel are completely located in the molten soup, thereby realizing the addition of dopants into the crucible to ensure the stability of the resistivity of the grown crystal rod. At the same time, the silicone gel is used as the raw material of the crystal rod after being dehydrated and fused with the molten soup. While effectively utilizing the silicone gel, it will not cause chemical or physical effects on the molten soup in the crucible, effectively ensuring the purity and uniformity of the raw material of the crystal rod. In addition, the operation of adding dopants into the crucible is simple, avoiding the complicated material hanging process, reducing the operation steps, thereby improving work efficiency, and reducing unnecessary waste of silicon materials, effectively reducing costs.

[0006] In some embodiments of the present invention, the conditions for adding dopants into the crucible are determined to be met, including: at least one of the following: a crystal rod being prepared has broken edges, the resistivity of the prepared crystal rod exceeds a preset range, and the volume of the molten metal in the crucible is less than a preset value.

[0007] In some embodiments of the present invention, after the crystal rod being prepared has broken edges or the volume of the molten metal in the crucible is less than a preset value, the seed crystal is controlled to rise and the crystal rod being prepared is taken out.

[0008] In some embodiments of the present invention, before preparing the crystal rod, the crystal growth method includes: placing the silicon material and the dopant in the crucible and melting them to obtain the molten soup; or placing the silicon material in the crucible and melting them to obtain the molten soup, and bonding the dopant to the lower end of the seed crystal through the silicone gel, so that the seed crystal moves downward and extends into the molten soup of the crucible and the dopant and the silicone gel are completely located in the molten soup.

[0009] In some embodiments of the present invention, the dopant is As, P or Sb.

[0010] In some embodiments of the present invention, the silicone gel is bonded to the outer peripheral wall of the seed crystal.

[0011] In some embodiments of the present invention, the silicone gel is one or more along the axial direction of the seed crystal; and / or the silicone gel is in a ring shape extending along the circumferential direction of the seed crystal or is in a plurality of shapes spaced apart along the circumferential direction of the seed crystal.

[0012] In some embodiments of the present invention, the silicone gel is bonded to the lower end surface of the seed crystal.

[0013] In some embodiments of the present invention, the silica gel has a first receiving cavity, and the dopant is located in the first receiving cavity; and / or, the silica gel and the outer surface of the seed crystal form a second receiving cavity, and the dopant is located in the second receiving cavity.

[0014] In some embodiments of the present invention, the thickness of the silicone gel is 3 mm-8 mm.

[0015] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0017] Figure 1 is a flow chart of a crystal growth method according to one embodiment of the present invention;

[0018] Figure 2 is a flow chart of a crystal growth method according to a specific embodiment of the present invention;

[0019] Figure 3 is a front view of a seed crystal and a silicone gel according to an embodiment of the present invention;

[0020] Figure 4 is a front view of a seed crystal and a silicone gel according to another embodiment of the present invention;

[0021] Figure 5 is a front view of a seed crystal and silicone gel according to yet another embodiment of the present invention.

[0022] Reference numerals:

[0023] 1. Seed crystal;

[0024] 2. Silicone gel. DETAILED DESCRIPTION

[0025] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0026] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0027] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0028] The crystal growth method according to an embodiment of the present invention will be described below with reference to the accompanying drawings.

[0029] like Figure 1 As shown, the crystal growth method according to an embodiment of the present invention is used to grow a crystal rod, and the crystal growth method includes determining the conditions for adding a dopant into a crucible; bonding the dopant to the lower end of a seed crystal 1 through a silicone gel 2, so that the seed crystal 1 moves downward into the molten soup of the crucible and the dopant and the silicone gel 2 are completely located in the molten soup.

[0030] It is understandable that the crystal growth device using the crystal growth method may include a crucible, a seed crystal 1 and a driving assembly, wherein the driving assembly is used to drive the seed crystal 1 to be movably arranged above the crucible in the up-down direction, the seed crystal 1 is used as a growth carrier of the crystal rod, and the crystal rod grows along the seed crystal 1. When the seed crystal 1 is used to prepare a single crystal silicon rod, the molten metal in the crucible is a silicon melt. Specifically, when preparing the crystal rod, the seed crystal 1 is first immersed in the molten metal, and the driving assembly drives the seed crystal 1 to rotate around its own central axis and move upward in the up-down direction, so that the molten metal in the crucible crystallizes along the movement direction of the seed crystal 1 to generate a crystal rod.

[0031] Therefore, when it is determined that the conditions for adding dopants into the crucible are met, dopants need to be added into the crucible to ensure the stability of the resistivity of the grown crystal rod, thereby ensuring the quality of the crystal rod.

[0032] The dopant is bonded to the lower end of the seed crystal 1 through the silica gel 2, so that the seed crystal 1 moves downward and extends into the molten soup of the crucible, and the dopant and the silica gel 2 are completely located in the molten soup. It can be understood that after determining that the conditions for adding the dopant to the crucible are met, since the silica gel 2 has a certain viscosity, the dopant can be bonded to the lower end of the seed crystal 1 through the silica gel 2, and the seed crystal 1 is movably arranged above the crucible in the up and down directions, so that the seed crystal 1 can move downward and extend into the molten soup of the crucible, and the dopant and the silica gel 2 are completely located in the molten soup. Since the temperature of the molten soup in the crucible is relatively high, the silica gel 2 and the dopant are directly fused with the molten soup in the crucible, thereby realizing the addition of the dopant to the crucible to ensure the stability of the resistivity of the grown crystal rod. At the same time, the silica gel 2 is used as the raw material of the crystal rod after being dehydrated and fused with the molten soup. While the silica gel 2 is effectively utilized, it will not cause chemical or physical effects on the molten soup in the crucible, effectively ensuring the purity and uniformity of the raw material of the crystal rod.

[0033] Compared with the prior art method of adding dopants by hanging materials, the crystal growth method of the present application connects the dopant to the lower end of the seed crystal 1 through the silicone gel 2, so that the seed crystal 1 moves downward into the molten soup of the crucible and the dopant and the silicone gel 2 are completely located in the molten soup. While achieving the supplement of dopants, it has the following advantages: 1. There is no need to reopen the furnace, which provides greater operational flexibility; 2. The operation of supplementing dopants is simple, avoiding the complicated hanging process, reducing the operating steps, and thus improving work efficiency; 3. Reducing unnecessary waste of silicon materials and effectively reducing costs.

[0034] It should be noted that the amount of dopant added needs to be precisely controlled based on experimental data or theoretical calculations to avoid crystal performance problems caused by excess or deficiency.

[0035] According to the crystal growth method of the embodiment of the present invention, the conditions for adding dopants into the crucible are determined, and the dopants are bonded to the lower end of the seed crystal 1 through the silicone gel 2, so that the seed crystal 1 moves downward and extends into the molten soup of the crucible, and the dopants and the silicone gel 2 are completely located in the molten soup, thereby realizing the addition of dopants into the crucible to ensure the stability of the resistivity of the grown crystal rod. At the same time, the silicone gel 2 is used as the raw material of the crystal rod after being dehydrated and fused with the molten soup. While the silicone gel 2 is effectively utilized, it will not cause chemical or physical effects on the molten soup in the crucible, and the purity and uniformity of the raw material of the crystal rod are effectively ensured. In addition, the operation of adding dopants into the crucible is simple, avoiding the complicated material hanging process, reducing the operation steps, thereby improving work efficiency, and reducing unnecessary waste of silicon materials, effectively reducing costs.

[0036] In some embodiments of the present invention, Figure 1 and Figure 2 As shown, determining that the conditions for adding dopants into the crucible are met includes: at least one of the following conditions is met: the crystal rod being prepared has broken edges, the resistivity of the prepared crystal rod exceeds a preset range value, and the volume of the molten soup in the crucible is less than a preset value.

[0037] It can be understood that broken edges are defects that occur during the crystal growth process. When broken edges appear in the prepared crystal rod (detected by the system or observed by the human eye), the conditions for adding dopants to the crucible are met, and the dopants are bonded to the lower end of the seed crystal 1 through the silicone gel 2, so that the seed crystal 1 moves downward and extends into the melt of the crucible, and the dopants and silicone gel 2 are completely located in the melt, thereby adding dopants to the crucible and improving the structure of the crystal to ensure the stability of the resistivity of the grown crystal rod.

[0038] Resistivity is an important indicator to measure the conductive properties of crystals. For photovoltaic cells, the resistivity needs to be within a certain range to ensure conversion efficiency and long-term stability. When the resistivity of the prepared crystal rod exceeds the preset range, the condition for adding dopants to the crucible is met, and the dopants are bonded to the lower end of the seed crystal 1 through the silicone gel 2, so that the seed crystal 1 moves downward and extends into the melt of the crucible, and the dopants and silicone gel 2 are completely located in the melt, thereby adding dopants to the crucible and changing the resistivity of the crystal to ensure that the grown crystal rod meets product requirements.

[0039] The volume of the melt directly affects the growth rate and final size of the crystal. A too small volume of the melt may cause uneven crystal growth or even fail to complete the growth process. Therefore, when the volume of the melt in the crucible is less than the preset value, it is necessary to add silicon material and dopants to the crucible, and the dopants are bonded to the lower end of the seed crystal 1 through the silicone gel 2, so that the seed crystal 1 moves downward and extends into the melt of the crucible, and the dopants and silicone gel 2 are completely located in the melt, thereby adding dopants to the crucible to ensure that the grown crystal rods meet product requirements.

[0040] In some embodiments of the present invention, Figure 2 As shown, after the crystal rod being prepared has broken edges or the volume of the molten metal in the crucible is less than a preset value, the seed crystal 1 is controlled to rise and the crystal rod being prepared is taken out.

[0041] It is understandable that after the crystal rod being prepared has broken edges, the crystal rod being prepared is waste, and it is necessary to control the seed crystal 1 to rise, take out the crystal rod being prepared, and bond the dopant to the lower end of the seed crystal 1 through the silicone gel 2, so that the seed crystal 1 moves downward and extends into the molten soup of the crucible, and the dopant and silicone gel 2 are completely located in the molten soup, thereby adding dopants to the crucible and changing the resistivity of the crystal to ensure that the grown crystal rod meets product requirements.

[0042] After the volume of the melt in the crucible is less than the preset value, it is necessary to add silicon material and dopant into the crucible, control the seed crystal 1 to rise, take out the crystal rod being prepared, and bond the dopant to the lower end of the seed crystal 1 through the silicone gel 2, so that the seed crystal 1 moves downward and extends into the melt in the crucible, and the dopant and silicone gel 2 are completely located in the melt, thereby realizing the addition of dopant into the crucible.

[0043] In some embodiments of the present invention, before preparing the crystal rod, the crystal growth method includes placing silicon material and dopant in a crucible for melting to obtain a molten metal. Thus, by placing silicon material and dopant in a crucible for melting to obtain a molten metal, the molten metal meets the raw material requirements for crystal pulling, thereby ensuring the stability of the resistivity of the grown crystal rod.

[0044] Alternatively, silicon material is placed in a crucible for melting to obtain a molten metal, and the dopant is bonded to the lower end of the seed crystal 1 through the silicone gel 2, so that the seed crystal 1 moves downward into the molten metal of the crucible and the dopant and the silicone gel 2 are completely located in the molten metal, so that the molten metal meets the raw material requirements for crystal pulling and ensures the stability of the resistivity of the grown crystal rod.

[0045] In some embodiments of the present invention, the dopant is As, P or Sb. It is understood that when preparing N-type single crystals, the dopant is As (arsenic), P (phosphorus) or Sb (antimony) to ensure the stability of the resistivity of the grown crystal rod.

[0046] In some embodiments of the present invention, Figure 3 and Figure 4 As shown, the silicone gel 2 is bonded to the outer peripheral wall of the seed crystal 1; or, as Figure 5 As shown, the silicone gel 2 is bonded to the lower end surface of the seed crystal 1. Thus, the silicone gel 2 can be bonded to the outer peripheral wall or the lower end surface of the seed crystal 1 according to different requirements, thereby improving the versatility of the crystal growth method.

[0047] In some embodiments of the present invention, Figure 3 and Figure 4 As shown, when the silicone gel 2 is bonded to the outer peripheral wall of the seed crystal 1, there are one or more silicone gels 2 along the axial direction of the seed crystal 1. Therefore, according to the need to supplement the dopant, the dopant can be connected to the outer peripheral wall of the seed crystal 1 through one silicone gel 2, or the dopant can be connected to the outer peripheral wall of the seed crystal 1 through multiple silicone gels 2 along the axial direction of the seed crystal 1, thereby improving versatility.

[0048] Figure 4 The figure shows two silicone gels 2 along the axial direction of the seed crystal 1 for illustrative purposes, but after reading the following technical solution, an ordinary technician can obviously understand that the solution can be applied to the technical solution in which there are three or more silicone gels 2 along the axial direction of the seed crystal 1, which also falls within the scope of protection of the present invention.

[0049] In some embodiments of the present invention, when the silicone gel 2 is bonded to the peripheral wall of the seed crystal 1, the silicone gel 2 is in the form of a ring extending along the circumferential direction of the seed crystal 1 or a plurality of silicone gels spaced apart along the circumferential direction of the seed crystal 1. Thus, the dopant can be connected to the peripheral wall of the seed crystal 1 through one ring-shaped silicone gel 2 or through a plurality of silicone gels 2 along the circumferential direction of the seed crystal 1, respectively, according to the need to supplement the dopant, thereby improving versatility.

[0050] In some embodiments of the present invention, the silica gel 2 has a first receiving cavity, and the dopant is located in the first receiving cavity. Therefore, by locating the dopant in the first receiving cavity, the silica gel 2 is coated with the dopant and then bonded to the seed crystal 1, thereby avoiding leakage of the dopant and improving the reliability of the crystal growth method.

[0051] In some embodiments of the present invention, the outer surfaces of the silica gel 2 and the seed crystal 1 form a second receiving cavity, and the dopant is located in the second receiving cavity. Thus, by the dopant being located in the second receiving cavity formed by the outer surfaces of the silica gel 2 and the seed crystal 1, leakage of the dopant is avoided, and the reliability of the crystal growth method is improved.

[0052] In some embodiments of the present invention, the thickness of the silicone gel 2 is 3mm-8mm. It is understandable that if the thickness of the silicone gel 2 is small, the viscosity may be small or the dopant may not be covered, while if the thickness of the silicone gel 2 is large, when the seed crystal 1 moves downward into the molten soup of the crucible and the dopant and the silicone gel 2 are completely in the molten soup, the melting time of the silicone gel 2 is long, which is not conducive to the mixing of the dopant and the molten soup. Therefore, by limiting the thickness of the silicone gel 2 to 3mm-8mm, while ensuring that the dopant is reliably connected to the lower end of the seed crystal 1 through the silicone gel 2, the mixing of the dopant and the molten soup is guaranteed, thereby improving the overall reliability.

[0053] The crystal growth method according to the embodiment of the present invention and other structures and operations of the crystal growth equipment are well known to those skilled in the art and will not be described in detail here.

[0054] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0055] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A crystal growth method for growing a crystal rod, characterized in that: include: Determining that conditions are met for adding a dopant into the crucible; The dopant is bonded to the lower end of the seed crystal through the silicone gel, so that the seed crystal moves downward and extends into the molten soup of the crucible, and the dopant and the silicone gel are completely located in the molten soup.

2. The crystal growth method according to claim 1, characterized in that The conditions for adding dopants to the crucible include: at least one of the following: a crystal rod being prepared has broken edges, a resistivity of the prepared crystal rod exceeds a preset range, and a volume of the molten metal in the crucible is less than a preset value.

3. The crystal growth method according to claim 2, characterized in that: After the crystal rod being prepared has broken edges or the volume of the molten metal in the crucible is less than a preset value, the seed crystal is controlled to rise and the crystal rod being prepared is taken out.

4. The crystal growth method according to claim 1, characterized in that: Before preparing the crystal rod, the crystal growth method includes: Putting silicon material and the dopant into the crucible to melt to obtain the molten soup; Alternatively, silicon material is placed in the crucible for melting to obtain the molten soup, and the dopant is bonded to the lower end of the seed crystal through the silicone gel, so that the seed crystal moves downward into the molten soup of the crucible and the dopant and the silicone gel are completely located in the molten soup.

5. The crystal growth method according to claim 1, characterized in that: The dopant is As, P or Sb.

6. The crystal growth method according to claim 1, characterized in that: The silicone gel is bonded to the outer peripheral wall of the seed crystal.

7. The crystal growth method according to claim 6, characterized in that: Along the axial direction of the seed crystal, the silicone gel is one or more; And / or, the silicone gel is in a ring shape extending along the circumferential direction of the seed crystal or is in a plurality of shapes spaced apart along the circumferential direction of the seed crystal.

8. The crystal growth method according to claim 1, characterized in that: The silicone gel is bonded to the lower end surface of the seed crystal.

9. The crystal growth method according to claim 1, characterized in that: The silica gel has a first containing cavity, and the dopant is located in the first containing cavity; And / or, the outer surfaces of the silica gel and the seed crystal form a second receiving cavity, and the dopant is located in the second receiving cavity.

10. The crystal growth method according to claim 1, characterized in that: The thickness of the silicone gel is 3mm-8mm.

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