A kind of monocrystalline silicon crystal growth method and thermal field structure

Abstract

A silicon-like crystal growth method and a thermal field structure, the invention relates to the technical field of solar crystal silicon materials. A single plate-shaped seed crystal is used to grow a quasi-square crystal whose height is slightly equal to the width from silicon melt from top to bottom along the thickness direction of the seed crystal under the induction of the seed crystal. In order to realize the crystal growth method, the thermal field structure of the present invention includes main and auxiliary furnace chambers, seed crystal loading chambers, ingot unloading chambers, crystal pulling mechanisms, crucibles, heaters, heat preservation baskets, heat insulation plates and other components, auxiliary The crystal pulling mechanism in the furnace chamber mounts the seed crystal to induce crystal growth. During the crystal growth process, the preparation of the seed crystal module and the removal of the crystal rod are carried out in the seed crystal loading chamber and crystal rod unloading chamber. After the crystal rod growth is completed, The crystal pulling mechanism can quickly unload and remount the seed crystal block to grow the next crystal. The quasi-monocrystalline silicon crystal grown in the invention has the characteristics of uniform crystal orientation, low proportion of edge leather, high product pass rate, low defect density and high production efficiency.

Description

technical field

[0001] The invention relates to the technical field of solar silicon materials, in particular to a method for growing silicon-like crystals and a thermal field structure. Background technique

[0002] Solar photovoltaic power generation is the main way of solar photovoltaic application because of its environmental friendliness, high conversion efficiency, and convenient installation. In the past ten years, the cost of photovoltaic power generation has dropped rapidly to the on-grid electricity price close to that of traditional thermal power, which provides strong support for the further large-scale application of photovoltaic power generation.

[0003] Monocrystalline silicon wafers and polycrystalline silicon wafers are two basic materials for making photovoltaic cells. Monocrystalline silicon wafers are grown and cut by pulling (Cz) crystals. They are characterized by less defects, high minority carrier life, and stable quality, so they are favored by hig...

Examples

Embodiment 1

[0065] In order to match the subsequent ingot slicing equipment, the size of the seed crystal 51 is (length*width*thickness) 650mm*165mm*25mm, and the crystal orientation in the thickness direction is the direction. A polycrystalline high-purity crucible 16 purchased from the market is used, and 480 kg of silicon material is charged. The crucible 16 is connected to the furnace bottom 11 and can be opened for loading and unloading operations of the crucible 16 . After the crucible 16 is loaded into the main furnace chamber, the main furnace chamber 1 is closed, and the main furnace chamber 1 and the auxiliary furnace chamber 2 partition plates (21 and 22). The main furnace chamber 1 is vacuumed (atmospheric pressure less than 0.01mbar) and then heated, and a protective gas (argon) is introduced. The pressure in the furnace is 600mbar, and the gas flow rate is 50SLPM. The insulation board 18 is set to a horizontal state, such as figure 2 Shown, in order to reduce the heat lo...

Embodiment 2

[0076] Using the same production process as that of Example 1, the size of the seed crystal 51 is (length*width*thickness) 900mm*165mm*25mm, and the charge amount is 510kg. Since the ingot only becomes longer and the width remains unchanged, the crystal growth rate remains unchanged. The weight of a single crystal rod is about 60kg, and the weight of the rear rod (size: 159mm*159mm*900mm) is about 53kg. Eight times of growth are carried out with one feeding, the melting time of silicon material is 10 hours, and the total cycle is 42 hours. Each seed crystal is recycled 2 to 3 times, and a total of 3 new seed crystals are used, each seed crystal is 8.65kg, and the total weight is 26kg. Then the effective output of the final square rod is 424kg, the total input of silicon material is 536kg, and the qualified rate of output is 79%. The 24-hour square rod output of a single device is 242kg, and the monthly (30 days) output is 7260kg.

Embodiment 3

[0078] Adopt the same technological process as embodiment 1. In order to increase the output per unit time, a seed crystal with a size of 650mm*330mm*25mm is used, the weight of a single block is 12.5kg, and the loading capacity is 800kg. As the ingot becomes wider, the growth rate decreases, and the growth cycle of the single crystal ingot is increased to 5 hours. The weight of a single ingot is about 85kg, and two square ingots with a size of 159mm*159mm*650mm can be produced at one time, with a total weight of about 76.6kg. 9 times of growth are carried out with one feeding, the melting time of silicon material is 15 hours, and the total cycle is 60 hours.

[0079] Each seed crystal is recycled 2 to 3 times, and a total of 4 new seed crystals are used, with a weight of 50 kg. Then the final square bar output is 690kg, the total input of silicon material is 850kg, and the qualified rate of the product (square bar) is 81%. The 24-hour square rod output of a single device i...

technical field

[0001] The invention relates to the technical field of solar silicon materials, in particular to a method for growing silicon-like crystals and a thermal field structure. Background technique

[0002] Solar photovoltaic power generation is the main way of solar photovoltaic application because of its environmental friendliness, high conversion efficiency, and convenient installation. In the past ten years, the cost of photovoltaic power generation has dropped rapidly to the on-grid electricity price close to that of traditional thermal power, which provides strong support for the further large-scale application of photovoltaic power generation.

[0003] Monocrystalline silicon wafers and polycrystalline silicon wafers are two basic materials for making photovoltaic cells. Monocrystalline silicon wafers are grown and cut by pulling (Cz) crystals. They are characterized by less defects, high minority carrier life, and stable quality, so they are favored by hig...

Examples

Embodiment 1

[0065] In order to match the subsequent ingot slicing equipment, the size of the seed crystal 51 is (length*width*thickness) 650mm*165mm*25mm, and the crystal orientation in the thickness direction is the direction. A polycrystalline high-purity crucible 16 purchased from the market is used, and 480 kg of silicon material is charged. The crucible 16 is connected to the furnace bottom 11 and can be opened for loading and unloading operations of the crucible 16 . After the crucible 16 is loaded into the main furnace chamber, the main furnace chamber 1 is closed, and the main furnace chamber 1 and the auxiliary furnace chamber 2 partition plates (21 and 22). The main furnace chamber 1 is vacuumed (atmospheric pressure less than 0.01mbar) and then heated, and a protective gas (argon) is introduced. The pressure in the furnace is 600mbar, and the gas flow rate is 50SLPM. The insulation board 18 is set to a horizontal state, such as figure 2 Shown, in order to reduce the heat lo...

Embodiment 2

[0076] Using the same production process as that of Example 1, the size of the seed crystal 51 is (length*width*thickness) 900mm*165mm*25mm, and the charge amount is 510kg. Since the ingot only becomes longer and the width remains unchanged, the crystal growth rate remains unchanged. The weight of a single crystal rod is about 60kg, and the weight of the rear rod (size: 159mm*159mm*900mm) is about 53kg. Eight times of growth are carried out with one feeding, the melting time of silicon material is 10 hours, and the total cycle is 42 hours. Each seed crystal is recycled 2 to 3 times, and a total of 3 new seed crystals are used, each seed crystal is 8.65kg, and the total weight is 26kg. Then the effective output of the final square rod is 424kg, the total input of silicon material is 536kg, and the qualified rate of output is 79%. The 24-hour square rod output of a single device is 242kg, and the monthly (30 days) output is 7260kg.

Embodiment 3

[0078] Adopt the same technological process as embodiment 1. In order to increase the output per unit time, a seed crystal with a size of 650mm*330mm*25mm is used, the weight of a single block is 12.5kg, and the loading capacity is 800kg. As the ingot becomes wider, the growth rate decreases, and the growth cycle of the single crystal ingot is increased to 5 hours. The weight of a single ingot is about 85kg, and two square ingots with a size of 159mm*159mm*650mm can be produced at one time, with a total weight of about 76.6kg. 9 times of growth are carried out with one feeding, the melting time of silicon material is 15 hours, and the total cycle is 60 hours.

[0079] Each seed crystal is recycled 2 to 3 times, and a total of 4 new seed crystals are used, with a weight of 50 kg. Then the final square bar output is 690kg, the total input of silicon material is 850kg, and the qualified rate of the product (square bar) is 81%. The 24-hour square rod output of a single device i...

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