Method for producing polysilicon ingots

Abstract

The invention provides a method for producing polysilicon ingots. The method comprises the following steps: (a) mixing nanoscale silicon powder and absolute ethyl alcohol, and coating the bottom surface inside a crucible with the mixture; and (b) adding silicon into the crucible, and performing ingot casting production, thereby obtaining the polysilicon ingots. Compared with the prior art, the method for producing the polysilicon ingots provided by the invention has the advantages that the nanoscale silicon powder serves as a nucleating agent; and because the body surface area of the nanoscale silicon powder is large, more nucleating points are uniformly induced, and macroscopic crystal defects such as crystal boundary and dislocation due to spontaneous disordered growth of the crystal are reduced, so that the number of sub-load centers in the crystal is further reduced, and the photoelectric conversion efficiency of the polysilicon is greatly improved.

Description

technical field

[0001] The invention relates to the technical field of polysilicon, and more specifically, relates to a production method of a polysilicon ingot. Background technique

[0002] Polycrystalline silicon ingot technology has surpassed monocrystalline silicon produced by the Czochralski method to a large extent because of its large amount of material, simple operation, and low cost, and has become the main technology for producing solar cell materials in the photovoltaic industry. The process flow of polysilicon ingot mainly includes four steps: crucible spraying, crucible baking, crucible charging and ingot production; in the ingot production process, it needs to go through five stages of heating, melting, crystal growth, annealing and cooling. Through the optimization of the traditional polysilicon ingot process, the production of low-defect, high-quality polysilicon ingots is an important means to improve the level of competition in the industry.

[0003] At p...

Examples

Embodiment 1

[0058] (1) Take a G5 type common crucible with a bottom surface size of 890mm×890mm, firstly, clean, wipe and purge the inner bottom surface and inner wall of the above-mentioned crucible in sequence; secondly, heat the above-mentioned crucible at 85°C to obtain a hot crucible ; Again, the silicon nitride aqueous solution obtained by mixing 500g of silicon nitride and 1000mL of water is evenly sprayed on the inner bottom surface and inner wall of the above-mentioned hot crucible; finally, the above-mentioned sprayed crucible is baked at 200°C for 2.5h to obtain the inner A crucible with a silicon nitride coating on the bottom and inner walls.

[0059] (2) After mixing 500g of nano-scale silicon powder with a median particle size of 150nm and 500mL of absolute ethanol evenly under stirring conditions, evenly coat it on the inner bottom surface of the above-mentioned crucible provided with a silicon nitride coating.

[0060] (3) Add crushed silicon chips into the above-mentioned...

Embodiment 2

[0063] (1) Take a G6 type common crucible with a bottom surface size of 1040mm×1040mm, firstly, clean, wipe and purge the inner bottom surface and inner wall of the above-mentioned crucible in sequence; secondly, heat the above-mentioned crucible at 90°C to obtain a hot crucible ; again, the silicon nitride aqueous solution obtained by mixing 650g of silicon nitride and 1500mL of water is evenly sprayed on the inner bottom and inner wall of the above-mentioned hot crucible; finally, the above-mentioned sprayed crucible is baked at 250°C for 3 hours to obtain the inner bottom and a crucible with a silicon nitride coating on the inner wall.

[0064] (2) After mixing 690g of nano-scale silicon powder with a median particle size of 100nm and 690mL of absolute ethanol under stirring conditions, evenly coat it on the inner bottom surface of the above-mentioned crucible with a silicon nitride coating.

[0065] (3) Add crushed silicon chips into the above-mentioned crucible, place it ...

Embodiment 3

[0068](1) Take a G5 type common crucible with a bottom surface size of 890mm×890mm, firstly, clean, wipe and purge the inner bottom surface and inner wall of the above-mentioned crucible in sequence; secondly, heat the above-mentioned crucible at 85°C to obtain a hot crucible ; Again, the silicon nitride aqueous solution obtained by mixing 500g of silicon nitride and 1000mL of water is evenly sprayed on the inner bottom surface and inner wall of the above-mentioned hot crucible; finally, the above-mentioned sprayed crucible is baked at 200°C for 2.5h to obtain the inner A crucible with a silicon nitride coating on the bottom and inner walls.

[0069] (2) After mixing 500g of nano-scale silicon powder with a median particle size of 200nm and 500mL of absolute ethanol under stirring conditions, evenly coat it on the inner bottom surface of the above-mentioned crucible with a silicon nitride coating.

[0070] (3) Add crushed silicon chips into the above-mentioned crucible, place ...

technical field

[0001] The invention relates to the technical field of polysilicon, and more specifically, relates to a production method of a polysilicon ingot. Background technique

[0002] Polycrystalline silicon ingot technology has surpassed monocrystalline silicon produced by the Czochralski method to a large extent because of its large amount of material, simple operation, and low cost, and has become the main technology for producing solar cell materials in the photovoltaic industry. The process flow of polysilicon ingot mainly includes four steps: crucible spraying, crucible baking, crucible charging and ingot production; in the ingot production process, it needs to go through five stages of heating, melting, crystal growth, annealing and cooling. Through the optimization of the traditional polysilicon ingot process, the production of low-defect, high-quality polysilicon ingots is an important means to improve the level of competition in the industry.

[0003] At p...

Examples

Embodiment 1

[0058] (1) Take a G5 type common crucible with a bottom surface size of 890mm×890mm, firstly, clean, wipe and purge the inner bottom surface and inner wall of the above-mentioned crucible in sequence; secondly, heat the above-mentioned crucible at 85°C to obtain a hot crucible ; Again, the silicon nitride aqueous solution obtained by mixing 500g of silicon nitride and 1000mL of water is evenly sprayed on the inner bottom surface and inner wall of the above-mentioned hot crucible; finally, the above-mentioned sprayed crucible is baked at 200°C for 2.5h to obtain the inner A crucible with a silicon nitride coating on the bottom and inner walls.

[0059] (2) After mixing 500g of nano-scale silicon powder with a median particle size of 150nm and 500mL of absolute ethanol evenly under stirring conditions, evenly coat it on the inner bottom surface of the above-mentioned crucible provided with a silicon nitride coating.

[0060] (3) Add crushed silicon chips into the above-mentioned...

Embodiment 2

[0063] (1) Take a G6 type common crucible with a bottom surface size of 1040mm×1040mm, firstly, clean, wipe and purge the inner bottom surface and inner wall of the above-mentioned crucible in sequence; secondly, heat the above-mentioned crucible at 90°C to obtain a hot crucible ; again, the silicon nitride aqueous solution obtained by mixing 650g of silicon nitride and 1500mL of water is evenly sprayed on the inner bottom and inner wall of the above-mentioned hot crucible; finally, the above-mentioned sprayed crucible is baked at 250°C for 3 hours to obtain the inner bottom and a crucible with a silicon nitride coating on the inner wall.

[0064] (2) After mixing 690g of nano-scale silicon powder with a median particle size of 100nm and 690mL of absolute ethanol under stirring conditions, evenly coat it on the inner bottom surface of the above-mentioned crucible with a silicon nitride coating.

[0065] (3) Add crushed silicon chips into the above-mentioned crucible, place it ...

Embodiment 3

[0068](1) Take a G5 type common crucible with a bottom surface size of 890mm×890mm, firstly, clean, wipe and purge the inner bottom surface and inner wall of the above-mentioned crucible in sequence; secondly, heat the above-mentioned crucible at 85°C to obtain a hot crucible ; Again, the silicon nitride aqueous solution obtained by mixing 500g of silicon nitride and 1000mL of water is evenly sprayed on the inner bottom surface and inner wall of the above-mentioned hot crucible; finally, the above-mentioned sprayed crucible is baked at 200°C for 2.5h to obtain the inner A crucible with a silicon nitride coating on the bottom and inner walls.

[0069] (2) After mixing 500g of nano-scale silicon powder with a median particle size of 200nm and 500mL of absolute ethanol under stirring conditions, evenly coat it on the inner bottom surface of the above-mentioned crucible with a silicon nitride coating.

[0070] (3) Add crushed silicon chips into the above-mentioned crucible, place ...