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Boron-gallium co-doped single crystal silicon wafer and its preparation method and solar cell

A technology for solar cells and monocrystalline silicon wafers, applied in the direction of single crystal growth, single crystal growth, chemical instruments and methods, etc., can solve the problem of crystal resistivity, silicon lattice distortion, and hinder the large-scale application of gallium-doped single crystals, etc. problem, to achieve the effect of easy operation and simple preparation method

Active Publication Date: 2016-11-02
JA SOLAR +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] In order to solve the problem of battery LID, a patent 200710058315 proposes to use gallium as the acceptor impurity instead of boron. Since the energy required for the combination of gallium and oxygen is higher than that of boron and oxygen, the performance of photodefects is suppressed to a certain extent, and the LID is greatly reduced. , but because the atomic radius of gallium is larger than that of silicon, it mainly exists in the form of substitution in the silicon lattice, causing silicon lattice distortion. Usually, the average conversion efficiency of gallium-doped single crystal cells is 0.1%-0.2% lower than that of boron-doped single crystal cells. Moreover, the segregation coefficient of gallium in silicon (0.008) is much lower than that of boron (0.9), and the crystal resistivity is difficult to control, which hinders the large-scale application of gallium-doped single crystals in practice.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0029] Put polysilicon material, 5.6g of borosilicate alloy, 2.7g of gallium-silicon alloy in total 66kg into the quartz crucible, and put them neatly. The initial concentration of gallium in the melt is expected to be 1.85×10 15 atoms / cm3, the boron concentration is expected to be 3.95×10 15 atoms / cubic centimeter, target resistivity 2~4.5Ω. cm, put the above-mentioned raw materials in the Czochralski single crystal furnace, vacuumize the system, heat the furnace body, control the temperature in the furnace to gradually increase to 1450°C, melt the raw materials and alloys completely, and stabilize the melt after fully mixing The temperature is at 1420°C, and the seed crystal is slowly put in, and the temperature gradient in the furnace is adjusted to be constant. After seeding, necking, shouldering, equal-diameter growth, and finishing stages, the crystal rotation speed is controlled at 5 rpm throughout the process, and the quartz The rotation speed of the crucible is 5rpm,...

Embodiment 2

[0033] Put polysilicon material, 0.4g of borosilicate alloy, 6.6g of gallium-silicon alloy, 66kg in total into the quartz crucible, and put them neatly. The initial concentration of gallium in the melt is expected to be 3.0×10 15 atoms / cm3, the boron concentration is expected to be 3.0×10 15atoms / cubic centimeter, the target resistivity is 1.1~2.9Ω. cm. Put the above-mentioned raw materials in a Czochralski single crystal furnace, vacuumize the system, heat the furnace body, control the temperature in the furnace to gradually increase to 1460°C, melt all the raw materials and alloys, and stabilize the melt temperature at 1430°C, slowly put in the seed crystal, adjust the temperature gradient in the furnace to be constant, go through seeding, necking, shouldering, equal diameter growth, and finishing stages, keep the crystal rotation speed at 10rpm during the whole process, and the quartz crucible rotation speed The crystal growth rate is 10rpm, and the crystal growth rate is...

Embodiment 3

[0037] Put polysilicon material, 5.6g of borosilicate alloy, 0.09g of gallium metal in total 80kg into the quartz crucible, put them neatly, and the concentration of gallium in the initial melt is expected to be 1.0×10 16 atoms / cm3, the boron concentration is expected to be 5.0×10 15 atoms / cubic centimeter, the target resistivity is 0.9~3.5Ω. cm. Put the above-mentioned raw materials in a Czochralski single crystal furnace, vacuumize the system, heat the furnace body, control the temperature in the furnace to gradually rise to 1480°C, melt all the raw materials and alloys, and stabilize the melt temperature at 1450°C, slowly put in the seed crystal, adjust the temperature gradient in the furnace to be constant, after seeding, necking, shouldering, equal diameter growth, and finishing stages, keep the crystal rotation speed at 15rpm throughout the process, and the quartz crucible The rotation speed is 15rpm, the crystal growth rate is reduced from 100mm / h to 45mm / h after neck...

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Abstract

The invention discloses a boron-gallium codoping monocrystalline silicon piece which contains boron and gallium, wherein the concentration of the boron is 10<14>-<16> atoms / cm<3> and the concentration of the gallium is 10<13>-6*10<16> atoms / cm<3> so that the concentration of a boron oxide composite caused by single boron doping is reduced. The invention also discloses a boron-gallium codoping monocrystalline silicon solar cell made of the boron-gallium codoping monocrystalline silicon piece. The cell has a conversion efficiency at the same level with that of conventional boron doping cell and has a lower LID level. The invention further discloses the boron-gallium codoping monocrystalline silicon piece and a preparation method of the cell. The method is simple in process, easy in operation, capable of large-scale production and free from a problem of cost rise.

Description

technical field [0001] The invention belongs to the photovoltaic industry, and specifically relates to a boron-gallium co-doped single-crystal silicon wafer, a preparation method thereof, and a solar cell. Background technique [0002] With the decrease of fossil energy reserves, the thirst for renewable energy has made the current large-scale photovoltaic industry. At the same time, in order to reduce the cost per watt of products and improve the competitiveness of products, technical workers of various companies are constantly proposing new solutions. Technical solutions to continuously improve product performance. [0003] At present, single crystal silicon is mainly grown by the Czochralski (Chai's) method or the zone melting method. For cost considerations, the single crystal silicon for photovoltaic applications uses the former, and the single crystal is doped with boron as the acceptor impurity to form p-type. , In battery processing, an n-type layer is formed by dif...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01L31/0288C30B15/00C30B29/06
CPCC30B15/04C30B29/06H01L31/0288H01L31/1804Y02E10/547
Inventor 杨伟强魏红军冯立军曹建民
Owner JA SOLAR