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Method for preparing polycrystalline silicon ingot, polycrystalline silicon ingot casting furnace and silicon wafer

A polysilicon ingot casting furnace and polysilicon ingot technology, which is applied in the growth of polysilicon materials, chemical instruments and methods, crystal growth, etc., can solve the problems of not being able to effectively reduce the proliferation of dislocations

Active Publication Date: 2017-01-18
GCL POLY SUZHOU NEW ENERGY OPERATION MANAGEMENTCO
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, this method can only suppress the initial dislocation density by increasing the number of grain boundaries, and cannot effectively reduce the dislocation proliferation in the later vertical grain growth process. In addition, too many grain boundaries, such as figure 1 As shown in the PL photo, it limits the continuous improvement of the efficiency of this kind of method to prepare high-efficiency polycrystalline

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  • Method for preparing polycrystalline silicon ingot, polycrystalline silicon ingot casting furnace and silicon wafer
  • Method for preparing polycrystalline silicon ingot, polycrystalline silicon ingot casting furnace and silicon wafer
  • Method for preparing polycrystalline silicon ingot, polycrystalline silicon ingot casting furnace and silicon wafer

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preparation example Construction

[0024] Please refer to figure 2 , The invention provides a method for preparing a polycrystalline silicon ingot, comprising the following steps.

[0025] Step S110, setting molten silicon material in the crucible, wherein the inner bottom surface of the crucible is an inclined surface inclined relative to the horizontal direction, and the thickness of the bottom of the crucible gradually increases in the horizontal direction. The inner bottom surface of the crucible is inclined at a certain angle, and the angle range is 5° to 20°. In this way, the thickness of the bottom of the crucible is inconsistent, and gradually increases in the horizontal direction, so that the crystal grains grow horizontally or obliquely when the subsequent liquid silicon material grows.

[0026] The amount of silicon material in the molten state in the crucible can be obtained in the following ways.

[0027] Method 1: loading solid silicon material in the crucible; heating the crucible to melt the ...

Embodiment 1

[0040] Put 750kg of silicon material into the crucible 160, and one inner surface of the crucible 160 is sprayed with a silicon carbide layer or a quartz sand layer. The inclination angle of the inner bottom surface of the crucible 160 was 5°.

[0041] The heat insulation cage 120 forms a closed cavity with the heat insulation top plate 130 and the heat insulation bottom plate 140 . The top heater 172 is used to heat the silicon material from the top, and the side heaters 174 are used to heat the silicon material from three outer sides of the crucible 160 .

[0042] After the silicon material is melted, the first surface 122 that controls the independent movement of the heat insulation cage 120 rises independently, and after rising by 8 cm, the other parts of the heat insulation cage 120 are controlled to rise together, and the silicon liquid is nucleated under the promotion of silicon carbide, and The polycrystalline silicon ingot is grown from one side of the crucible 160 a...

Embodiment 2

[0045] 700kg of silicon material was put into the crucible 160, and one inner surface of the crucible 160 was sprayed with a layer of quartz sand. The inclination angle of the inner bottom surface of the crucible 160 was 10°.

[0046] The heat insulation cage 120 forms a closed cavity with the heat insulation top plate 130 and the heat insulation bottom plate 140 . The top heater 172 is used to heat the silicon material from the top, and the side heaters 174 are used to heat the silicon material from three outer sides of the crucible 160 .

[0047] After the silicon material is melted, the first surface 122 that controls the independent movement of the heat insulation cage 120 rises independently, and after rising by 8 cmm, controls the other parts of the heat insulation cage 120 to rise together, and the silicon liquid is nucleated under the promotion of silicon carbide, and The polycrystalline silicon ingot is grown from one side of the crucible 160 along a horizontal direc...

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Abstract

The invention relates to a preparation method of a polycrystalline silicon ingot. The preparation method comprises the following steps: arranging molten silicon materials in a crucible, wherein the inner bottom surface of the crucible is an inclined surface arranged obliquely relatively to the horizontal direction, and the thicknesses of the bottom of the crucible is gradually increased in the horizontal direction; controlling the thermal field in crystal growth, so that the horizontal temperature gradient is greater than longitudinal temperature gradient, and silicon material grows along the horizontal direction or in the direction with an acute angle with the vertical direction. During the growth of silicon ingot, a solid-liquid interface is not perpendicular to the axial direction of the crucible (i.e., vertical direction), so that the small-angle grain boundary in the silicon ingot can be reduced, and the dislocation density is grown outside the crystals before high dislocation density is formed. Therefore, silicon wafers with low grain boundary density and low dislocation density can be obtained through cutting, and the conversion efficiency of the silicon wafers can be improved. In addition, the invention further provides a polycrystalline silicon ingot furnace implementing the method.

Description

technical field [0001] The invention relates to the field of solar photovoltaic material preparation, in particular to a method for preparing polycrystalline silicon ingots, a polycrystalline silicon ingot furnace and silicon wafers. Background technique [0002] At present, crystalline silicon cells occupy more than 90% of the market share in the photovoltaic power generation market, among which polycrystalline cells based on polycrystalline silicon wafers as substrates occupy about 70% of the market share of crystalline silicon cells. The solid silicon material is put into the crucible of the ingot furnace, and the silicon material is melted by graphite resistance or induction heating, and then through the temperature gradient constructed by the ingot thermal field, the vertical crystal growth is carried out from the bottom upwards, and then annealed and cooled Preparation of polycrystalline silicon ingots. After the polycrystalline silicon ingot is processed into a small...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C30B28/06C30B29/06
Inventor 孟召标张凤汪晨
Owner GCL POLY SUZHOU NEW ENERGY OPERATION MANAGEMENTCO