CN112899777B - Seed wafer, preparation method thereof and preparation method of crystalline silicon ingot - Google Patents

Seed wafer, preparation method thereof and preparation method of crystalline silicon ingot Download PDF

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CN112899777B
CN112899777B CN201911131667.4A CN201911131667A CN112899777B CN 112899777 B CN112899777 B CN 112899777B CN 201911131667 A CN201911131667 A CN 201911131667A CN 112899777 B CN112899777 B CN 112899777B
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silicon
seed
induction
wafer
crystal
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CN112899777A (en
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熊震
李煜燚
李飞龙
朱军
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Artes Photovoltaic Power Luoyang Co ltd
Luoyang Csi Photovoltaic Technology Co ltd
CSI Cells Co Ltd
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Artes Photovoltaic Power Luoyang Co ltd
Luoyang Csi Photovoltaic Technology Co ltd
CSI Cells Co Ltd
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    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B29/00—Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape
    • C30B29/02—Elements
    • C30B29/06—Silicon
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
    • B23K26/36—Removing material
    • B23K26/362—Laser etching
    • B23K26/364—Laser etching for making a groove or trench, e.g. for scribing a break initiation groove
    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B28/00—Production of homogeneous polycrystalline material with defined structure
    • C30B28/04—Production of homogeneous polycrystalline material with defined structure from liquids
    • C30B28/06—Production of homogeneous polycrystalline material with defined structure from liquids by normal freezing or freezing under temperature gradient
    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B33/00—After-treatment of single crystals or homogeneous polycrystalline material with defined structure

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  • Crystallography & Structural Chemistry (AREA)
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  • Optics & Photonics (AREA)
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  • Mechanical Engineering (AREA)
  • Crystals, And After-Treatments Of Crystals (AREA)

Abstract

The application provides a seed crystal sheet, a preparation method thereof and a preparation method of a crystal silicon ingot. According to the method, the seed crystal slices are laid at the bottom of the crucible, and the crushed silicon materials are replaced by the plurality of induction grooves to induce crystal growth, so that on one hand, the dosage of the monocrystalline silicon slices is far smaller than that of the crushed silicon materials, the output proportion of the whole dosage of the silicon materials is improved, the silicon material loss is relatively reduced, and the cost is relatively reduced; on the other hand, the crystal orientations of the plurality of induction grooves on the first surface are consistent, so that the silicon liquid can be induced to be directionally solidified, and large crystal grains are generated, and therefore a polycrystalline silicon ingot or a monocrystalline silicon-like silicon with a good crystal orientation is obtained.

Description

Seed wafer, preparation method thereof and preparation method of crystalline silicon ingot
Technical Field
The application relates to the technical field of crystalline silicon ingot casting, in particular to a seed crystal sheet capable of reducing silicon material loss and ingot casting cost, a preparation method of the seed crystal sheet and a preparation method of a crystalline silicon ingot.
Background
Solar photovoltaic power generation is rapidly developed as a clean and efficient renewable energy technology. Nowadays, the biggest problem of popularization of the photovoltaic industry is still whether to realize low-price internet surfing. The goal of flat-price internet surfing is realized, and only the cost of photovoltaic power generation is continuously reduced. At present, silicon crystal materials are mainly used for photovoltaic power generation, and most of the silicon crystal materials are polycrystalline silicon wafers. For polycrystalline silicon wafers, the silicon cost accounts for more than 70% of the total silicon wafer cost, and therefore, it is particularly important to reduce the silicon cost of the ingot.
At present, a semi-melting process is widely adopted for polycrystalline ingots, and a silicon scrap material is adopted as an induction material; however, a part of the silicon scrap is not melted and is cut off during ingot processing, so that the silicon scrap cannot be used, the utilization rate of the whole silicon material put into the crucible is reduced, and waste is caused.
In view of the above, it is desirable to provide a seed wafer, a method for preparing the seed wafer, and a method for preparing a silicon ingot, which solve the above problems.
Disclosure of Invention
The invention aims to provide a seed crystal sheet capable of reducing silicon material loss and ingot casting cost, a preparation method of the seed crystal sheet and a preparation method of a crystal silicon ingot adopting the seed crystal sheet to induce crystal growth.
In order to achieve the purpose, the invention adopts the following technical scheme:
a seed wafer comprises a monocrystalline silicon wafer and a plurality of induction grooves located on a first surface of the monocrystalline silicon wafer.
Further, the depth of the induction groove is 1 mm-3 mm, and/or the area of the induction groove is 1mm 2-9 mm 2; and/or the shape of the induction groove is square, round, rhombic or hexagonal; and/or the density of the induction grooves is 500 to 1000 per sheet.
Further, the plurality of induction slots are identical, or the plurality of induction slots include at least two induction slots.
Further, the plurality of induction grooves are uniformly distributed on the first surface.
Further, the seed wafer is also provided with a silicon dioxide film, and the silicon dioxide film is positioned in a region, on the first surface, where the induction groove is not arranged.
Further, the thickness of the silicon dioxide film is 100-200 μm.
Further, the crystal orientation of the monocrystalline silicon piece is a <100> direction; and/or the thickness of the monocrystalline silicon piece is between 1mm and 2 mm.
Further, the seed wafer also comprises a silicon nitride layer located on a second surface of the monocrystalline silicon, wherein the second surface is opposite to the first surface.
Further, the thickness of the silicon nitride layer is 0.2 mm-1.5 mm.
In order to achieve the purpose, the invention also adopts the following technical scheme:
a preparation method of a seed wafer comprises the following steps: a plurality of induction grooves are formed in the first surface of the monocrystalline silicon piece.
Further, the depth of the induction groove is 1 mm-3 mm, and/or the area of the induction groove is 1mm 2-9 mm 2; and/or the shape of the induction groove is square, round, rhombic or hexagonal; and/or the density of the induction grooves is 500 to 1000 per sheet.
Further, the induction groove is formed on the first surface by adopting a laser grooving process.
Further, the method also comprises the step of forming a silicon dioxide film on the first surface in the area where the induction groove is not arranged.
Further, the thickness of the silicon dioxide film is 100-200 μm.
Further, the preparation method of the seed wafer comprises the following steps: firstly, a silicon dioxide film is formed on the first surface, and then a plurality of induction grooves are formed on the first surface.
Further, the method also comprises the step of forming a silicon nitride layer on a second surface of the monocrystalline silicon wafer, wherein the first surface is arranged opposite to the second surface.
Further, the thickness of the silicon nitride layer is 0.2 mm-1.5 mm.
Further, the silicon nitride layer is formed on the second surface by adopting a spraying process.
Further, the method also comprises the step of cleaning the monocrystalline silicon wafer before the induction groove is formed, wherein the cleaning agent is acid liquor; and/or polishing the monocrystalline silicon wafer before the induction groove is formed, wherein the polishing tool is a diamond grinding wheel, and the particle size of diamond is 1-10 microns.
In order to achieve the purpose, the invention also adopts the following technical scheme:
a preparation method of a crystal silicon ingot comprises the following steps:
s1, placing the seed wafer into the bottom of a crucible, wherein the first surface faces away from the bottom of the crucible;
s2, putting a silicon material into the crucible, wherein the silicon material is positioned above the seed wafer;
s3, placing the crucible into an ingot furnace for ingot casting.
Further, in the ingot casting process, when the silicon material is melted to the induction groove, the crystal growth stage is carried out.
Compared with the prior art, the invention has the beneficial effects that: according to the method, the seed crystal slices are laid at the bottom of the crucible, and the crushed silicon materials are replaced by the plurality of induction grooves to induce crystal growth, so that on one hand, the dosage of the monocrystalline silicon slices is far smaller than that of the crushed silicon materials, the output proportion of the whole dosage of the silicon materials is improved, the silicon material loss is relatively reduced, and the cost is relatively reduced; on the other hand, the crystal orientations of the plurality of induction grooves on the first surface are consistent, so that the silicon liquid can be induced to be directionally solidified, and large crystal grains are generated, and therefore a polycrystalline silicon ingot or a monocrystalline silicon-like silicon with a good crystal orientation is obtained.
Drawings
FIG. 1 is a schematic structural diagram of a seed chip according to a preferred embodiment of the present application;
FIG. 2 is a schematic view of a first surface of a seed wafer shown in FIG. 1;
FIG. 3 is a cross-sectional view taken along A-A' of FIG. 2;
FIG. 4 is a schematic view of a seed crystal in another preferred embodiment of the present application from the perspective of FIG. 3;
FIG. 5 is a schematic view of a seed crystal in another preferred embodiment of the present application from the perspective of FIG. 3;
FIG. 6 is a schematic view of a seed crystal in another preferred embodiment of the present application from the perspective of FIG. 3;
FIG. 7 is a schematic view of a crucible for ingot casting used for placing seed wafers and crushed silicon wafers in accordance with a preferred embodiment of the present application;
fig. 8 is a sectional view taken along the direction B-B' of fig. 7.
The silicon-based crystal growth method comprises the following steps of 1-seed wafer, 11-monocrystalline silicon wafer, 12-induction groove, 13-silicon dioxide film, 14-silicon nitride layer, 2-crucible and 3-silicon material.
DETAILED DESCRIPTION OF EMBODIMENT (S) OF INVENTION
The present application will be described in detail below with reference to specific embodiments. These embodiments are not intended to limit the present application, and structural, methodological, or functional changes made by those skilled in the art according to these embodiments are included in the scope of the present application.
Referring to fig. 1 to 6, the present application provides a seed wafer 1, which includes a monocrystalline silicon wafer 11 and a plurality of inducing grooves 12 located on a first surface of the monocrystalline silicon wafer 11. The seed wafer 1 is laid at the bottom of the crucible 2, and the crushed silicon material is replaced by the plurality of induction grooves 12 to induce crystal growth, so that on one hand, the dosage of the monocrystalline silicon wafer 11 is far less than that of the crushed silicon material, the output proportion of the whole dosage of the silicon material serving as seed crystal and the silicon material for ingot casting is improved, the silicon material loss is relatively reduced, and the cost is relatively reduced; on the other hand, the crystal orientations of the plurality of induction grooves 12 on the first surface are consistent, so that the silicon liquid can be induced to be directionally solidified, and large crystal grains are generated, thereby obtaining a polycrystalline silicon ingot or a monocrystalline silicon-like silicon with better crystal orientation.
The crystal orientation of the monocrystalline silicon wafer 11 is the <100> direction, which is the main growth direction in a polycrystalline ingot, and a polycrystalline silicon ingot with a good crystal orientation can be formed.
And/or the thickness of the monocrystalline silicon piece 11 is between 1mm and 2 mm. When a silicon wafer is formed by cutting a monocrystalline silicon square rod by adopting a diamond wire, because the perpendicularity of the end face of the square rod and the splicing gap of the square rod is poor, the diamond wire can slide and pull the end face and the splicing welding seam to cause wire breakage, certain safety distance needs to be reserved at the positions, namely the parts are not sliced, and a thick silicon wafer with the thickness of 1 mm-2 mm is formed; the thick silicon wafer is skillfully used as the monocrystalline silicon wafer 11, waste is avoided, the cost of using the monocrystalline silicon wafer 11 as the seed wafer 1 is not increased, and the conventional monocrystalline square rod cutting process is not influenced. As can be understood by those skilled in the art, the area of the thick silicon wafer is much smaller than that of the crucible 2 for ingot casting, so that a plurality of seed wafers 1 are generally spliced and then placed in the crucible 2, and the splicing manner and the processing method at the splicing seam are the prior art, and are not described herein again.
Referring to fig. 1 to 6, the induction groove 12 has at least one of the following characteristic parameters: the depth of the induction groove 12 is 1 mm-3 mm, and the area of the induction groove 12 is 1mm2~9mm2The shape of the induction groove 12 is square, round, diamond, hexagon and the like, and the density of the induction groove 12 is 500 to 1000 pieces per piece. The depth, area and shape of the induction groove 12 limit the size of the induction groove, and the size of the induction groove is similar to that of a silicon crushed material in the prior art, so that the induction effect on the crystal growth is not influenced; the density of the inducing grooves 12 is preferably such that the inducing grooves 12 can be distributed over the entire single crystal silicon wafer 11, so that the crystal growth in each region is uniform.
Specifically, in an embodiment, the plurality of guiding grooves 12 on the first surface are the same, and the grooving process is simple. Or, in other embodiments, the plurality of induction slots 12 includes at least two induction slots 12, i.e., a portion of the induction slots 12 have at least one different characteristic parameter than other induction slots 12.
Preferably, the inducing grooves 12 are uniformly distributed on the first surface and are distributed on the whole first surface; the induction effect in each area is the same, and the crushed crystal seed material commonly used at present can be well replaced.
In addition, as shown in fig. 4 and 6, the seed wafer 1 is further provided with a silica thin film 13, the silica thin film 13 is located in a region where the induction groove 12 is not provided on the first surface, and the silica thin film 13 serves as a blocking layer, so that impurities in the ingot casting crucible 2 can be further blocked from entering the silicon ingot or the silicon melt, a region with few or short lifetime of few molecules in the formed silicon ingot is greatly reduced, and the utilization rate of the silicon ingot is improved.
In one embodiment, the thickness of the silicon dioxide film 13 is 100 μm to 200 μm.
As shown in fig. 5 and 6, the seed wafer 1 according to any of the above embodiments further includes a second surface disposed opposite to the first surface, and a silicon nitride layer 14 on the second surface. The silicon nitride layer 14 is advantageous for demolding after ingot casting, and can prevent impurities such as oxygen and metal in the crucible 2 from entering the silicon ingot.
In one embodiment, the thickness of the silicon nitride layer 14 is 0.2mm to 1.5 mm.
The present application also provides a method for preparing a seed wafer, comprising: a plurality of induction grooves 12 are formed in a first surface of a single crystal silicon wafer 11. Wherein the monocrystalline silicon wafer 11 is the above-mentioned thick silicon wafer formed in the slicing process of the conventional monocrystalline silicon rod.
In one embodiment, the inducing groove 12 is formed on the first surface by a laser grooving process; specifically, except for the shape, area, depth, density, etc. of the trench, the laser trench process adopts the process parameters of trench on the silicon wafer in the prior art, which are not described herein again. The inducing groove 12 is formed to have the characteristics of the inducing groove 12 in any one of the seed wafers 1, which will not be described herein.
Preferably, the preparation method of the seed wafer further comprises forming a silicon dioxide film 13 on the first surface in the region where the inducing groove 12 is not arranged; for example, the silicon dioxide thin film 13 with a thickness of 100 μm to 200 μm is formed, that is, the thickness of the silicon dioxide thin film 13 is 100 μm to 200 μm; the effect of the barrier layer can be satisfied on the premise that the cost for forming the silicon dioxide film 13 is low.
In a specific embodiment, a silicon dioxide film 13 is formed on the first surface, and then a plurality of induction grooves 12 are formed on the first surface, so that the silicon dioxide film 13 is left in the non-induction groove 12 region. Methods of forming the silicon dioxide thin film 13 include, but are not limited to: and brushing high-purity silicon dioxide slurry.
The preparation method based on any seed wafer further comprises the following steps: a silicon nitride layer 14 is formed on a second surface of the single-crystal silicon wafer 11 disposed opposite to the first surface, and the seed wafer 1 shown in fig. 4 or 6 can be obtained. The silicon nitride layer 14 may be formed on the second surface by a spraying process, which is the same as the spraying process of the silicon nitride layer 14 on the surface of the silicon wafer in the art, and is not described herein again.
In an embodiment, the silicon nitride layer 14 with a thickness of 0.2mm to 1.5mm is formed on the second surface, that is, the thickness of the silicon nitride layer 14 is 0.2mm to 1.5 mm.
The method of preparing the seed wafer of the present invention will be described in detail below with two specific examples.
Example one
A method of preparing a seed wafer, comprising the steps of:
s1.1, using a monocrystalline thick silicon wafer formed by conventional slicing in the industry, wherein the thickness of the monocrystalline thick silicon wafer is 1.5mm +/-0.5 mm, and the crystal orientation is <100 >;
s1.2, cleaning and polishing a single-crystal thick silicon wafer; wherein the cleaning agent is acid liquor, the grinding tool is a diamond grinding wheel, and the particle size of diamond is 1-10 μm; the thickness of the processed thick monocrystalline silicon piece is reduced by 10-30 microns, and the surface of the thick monocrystalline silicon piece is a flat surface;
s1.3, preparing a silicon nitride layer 14 on the second surface of the monocrystalline thick silicon wafer by using a silicon nitride spraying process, wherein the thickness of the silicon nitride layer 14 is 0.2 mm-1.5 mm;
s1.4 preparing an induction groove 12 on the first surface of the monocrystalline thick silicon wafer by using a laser drilling method, wherein the depth of the induction groove 12 is 1 mm-3 mm, and the area of the induction groove 12 is 1mm2~9mm2The density of the induction grooves 12 is 500 to 1000 per piece; the shape of the induction groove 12 may be square, circular, diamond, hexagonal, etc.
Example two
A method of preparing a seed wafer, comprising the steps of:
s2.1, using a monocrystalline thick silicon wafer formed by conventional slicing in the industry, wherein the thickness of the monocrystalline thick silicon wafer is 1.5mm +/-0.5 mm, and the crystal orientation is <100 >;
s2.2, cleaning and polishing the monocrystalline thick silicon wafer; wherein the cleaning agent is acid liquor, the grinding tool is a diamond grinding wheel, and the particle size of diamond is 1-10 μm; the thickness of the processed thick monocrystalline silicon piece is reduced by 10-30 microns, and the surface of the thick monocrystalline silicon piece is a flat surface;
s2.3, preparing a silicon nitride layer 14 on the second surface of the monocrystalline thick silicon wafer by using a silicon nitride spraying process, wherein the thickness of the silicon nitride layer 14 is 0.2 mm-1.5 mm;
s2.4, brushing high-purity silicon dioxide slurry on the first surface of the thick monocrystalline silicon wafer to form a layer of silicon dioxide film 13, wherein the thickness of the silicon dioxide film is 100-200 microns; preparing an induction groove 12 on the silicon dioxide film 13 by using a laser hole-opening method, wherein the depth of the induction groove 12 is 1 mm-3 mm, and the area of the induction groove 12 is 1mm2~9mm2The density of the induction groove 12 is 500 to 1000 pieces per piece; the shape of the induction groove 12 may be square, circular, diamond, hexagonal, etc.
The application also provides a preparation method of the crystal silicon ingot, which comprises the following steps:
s1, placing the seed crystal sheet 1 into the bottom of a crucible 2, wherein the first surface faces away from the bottom of the crucible 2, namely the second surface arranged opposite to the first surface faces the bottom of the crucible 2, so that the induction groove 12 opens upwards to the inner side of the crucible 2;
s2, charging a silicon material 3 into the crucible 2, the silicon material 3 being located above the seed wafer 1;
s3, placing the crucible 2 into an ingot furnace for ingot casting; the ingot casting process can refer to the prior art, and is not described in detail herein.
The crystal silicon wafer prepared by the method is prepared into a battery under the same battery process, and the conversion efficiency is consistent with that of a battery prepared by preparing a polycrystalline silicon wafer by a conventional method; the cost of the silicon chip is reduced by 0.01 yuan/chip.
In a reference embodiment, in the ingot casting process, when it is detected that the silicon material 3 melts to the inducing groove 12, the heating is stopped and the crystal growth stage is started, in the process, the seed wafer 1 does not melt, and the inducing groove 12 can play a good inducing role.
The method for producing a silicon ingot according to the present invention will be described in detail below with reference to two specific examples.
EXAMPLE III
A preparation method of a crystal silicon ingot comprises the following steps:
s3.1, placing any seed wafer 1 into a crucible 2 for crystal ingot casting, wherein the crucible 2 is a quartz crucible 2 for common polycrystalline silicon ingot casting, the inner surface of the quartz crucible 2 is provided with a silicon dioxide film 13, the first surface of the seed wafer 1 is opposite to the bottom of the crucible 2, and the induction groove 12 is opened towards the inside of the crucible 2;
s3.2, putting the silicon material 3 on the seed wafer 1, and putting the seed wafer into an ingot furnace for ingot casting.
In summary, the seed wafer 1 is laid at the bottom of the crucible 2, and the crushed silicon material is replaced by the plurality of induction grooves 12 to induce crystal growth, so that on one hand, the dosage of the monocrystalline silicon wafer 11 is far less than that of the crushed silicon material 3, the output proportion of the whole dosage of the silicon material 3 is improved, the loss of the silicon material 3 is relatively reduced, and the cost is reduced; on the other hand, the crystal orientations of the plurality of induction grooves 12 on the first surface are consistent, so that the silicon liquid can be induced to be directionally solidified, and large crystal grains are generated, thereby obtaining a polycrystalline silicon ingot or a monocrystalline silicon-like silicon with better crystal orientation.
It should be understood that although the present description refers to embodiments, not every embodiment contains only a single technical solution, and such description is for clarity only, and those skilled in the art should make the description as a whole, and the technical solutions in the embodiments can also be combined appropriately to form other embodiments understood by those skilled in the art.
The above list of details is only for the concrete description of the feasible embodiments of the present application, they are not intended to limit the scope of the present application, and all equivalent embodiments or modifications that do not depart from the technical spirit of the present application are intended to be included within the scope of the present application.

Claims (21)

1. The seed wafer is characterized by comprising a monocrystalline silicon wafer and a plurality of induction grooves positioned on the first surface of the monocrystalline silicon wafer, wherein the crystal orientations of the induction grooves are consistent.
2. A seed wafer according to claim 1, wherein: the depth of the inducing groove is 1 mm-3 mm,
and/or the area of the induction groove is 1mm2~9mm2；
And/or the shape of the induction groove is square, round, rhombic or hexagonal;
and/or the density of the induction grooves is 500 to 1000 per sheet.
3. A seed wafer according to claim 2, wherein: the plurality of induction grooves are the same, or the plurality of induction grooves comprise at least two induction grooves.
4. A seed wafer according to claim 1, wherein: the plurality of induction grooves are uniformly distributed on the first surface.
5. A seed wafer according to claim 1, wherein: the seed wafer is further provided with a silicon dioxide film, and the silicon dioxide film is located in a region, on the first surface, where the induction groove is not formed.
6. A seed wafer according to claim 5, wherein: the thickness of the silicon dioxide film is 100-200 μm.
7. The seed wafer of claim 1, wherein: the crystal orientation of the monocrystalline silicon piece is a <100> direction; and/or the thickness of the monocrystalline silicon piece is between 1mm and 2 mm.
8. A seed wafer according to any one of claims 1 to 7, wherein: the seed wafer also includes a silicon nitride layer on a second surface of the single crystal silicon, the second surface being disposed opposite the first surface.
9. The seed wafer of claim 8, wherein: the thickness of the silicon nitride layer is 0.2 mm-1.5 mm.
10. A method for preparing a seed wafer is characterized by comprising the following steps: a plurality of induction grooves are formed in the first surface of the monocrystalline silicon piece, and the crystal directions of the induction grooves are consistent.
11. A method for producing a seed sheet according to claim 10, characterized in that: the depth of the induction groove is 1 mm-3 mm;
and/or the area of the induction groove is 1mm2~9mm2；
And/or the shape of the induction groove is square, round, rhombic or hexagonal;
and/or the density of the induction grooves is 500 to 1000 per sheet.
12. A method for producing a seed sheet according to claim 10, characterized in that: and forming the induction groove on the first surface by adopting a laser grooving process.
13. A method for producing a seed sheet according to claim 10, characterized in that: and forming a silicon dioxide film on the first surface in the region where the induction groove is not arranged.
14. A method of preparing a seed wafer according to claim 13, wherein: the thickness of the silicon dioxide film is 100-200 μm.
15. A method of preparing a seed wafer according to claim 13, wherein: the preparation method of the seed wafer comprises the following steps: firstly, a silicon dioxide film is formed on the first surface, and then a plurality of induction grooves are formed on the first surface.
16. A method of preparing a seed wafer according to any one of claims 10 to 15, wherein: the method also comprises the step of forming a silicon nitride layer on the second surface of the monocrystalline silicon wafer, wherein the first surface and the second surface are arranged oppositely.
17. A method of preparing a seed wafer according to claim 16, wherein: the thickness of the silicon nitride layer is 0.2 mm-1.5 mm.
18. A method of preparing a seed wafer according to claim 16, wherein: and forming the silicon nitride layer on the second surface by adopting a spraying process.
19. A method for producing a seed sheet according to claim 10, characterized in that: cleaning the monocrystalline silicon wafer before the induction groove is opened, wherein the cleaning agent is acid liquor;
and/or polishing the monocrystalline silicon wafer before the induction groove is formed, wherein the polishing tool is a diamond grinding wheel, and the particle size of diamond is 1-10 microns.
20. A preparation method of a crystal silicon ingot is characterized by comprising the following steps: the method comprises the following steps:
s1 placing the seed crystal wafer of any claim 1-9 into the bottom of a crucible, wherein the first surface faces away from the bottom of the crucible;
s2, putting a silicon material into the crucible, wherein the silicon material is positioned above the seed wafer;
s3, placing the crucible into an ingot furnace for ingot casting.
21. The method of preparing a crystal silicon ingot according to claim 20, characterized in that: and in the ingot casting process, when the silicon material is melted to the induction groove, entering a crystal growth stage.
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