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Preparation method of multicrystalline silicon texture

A technology of polysilicon and polysilicon wafers, applied in chemical instruments and methods, crystal growth, gaseous chemical plating, etc., can solve problems such as low photoelectric conversion efficiency, small short-circuit current, and poor light trapping effect, and achieve improved short-circuit current Isc, The effect of large structure size and reduced reflectivity

Inactive Publication Date: 2012-07-18
BAODING GUANGWEI GREEN ENERGY TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Since the polycrystalline silicon wafer is completely immersed in the chemical solution in the double-sided acid texturing process, the size of the wormhole-like textured surface formed on the damaged layer on the surface of the silicon wafer by the isotropic chemical etching technology is very small. <1um, it is difficult to observe the texture effect with the naked eye before coating and packaging, and the texture is uneven and the light trapping effect is poor, resulting in a reflectivity of about 20% of the silicon wafer before coating, a small short-circuit current Isc, and photoelectric conversion less efficient

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0013] Embodiment 1, a kind of preparation method of polysilicon textured surface, it comprises the following steps:

[0014] 1. Use the PECVD equipment with double deposition chambers to coat the polysilicon raw material with double-layer protective film on one side.

[0015] (1) In the first deposition chamber of the PECVD equipment, the inflatable gas flow ratio is nitrous oxide N of 1.2:1 2 O and silane gas SiH 4 , the deposition temperature is 350 ° C, and a layer of porous silicon dioxide SiO is deposited on the raw material sheet 2 layer, the silicon dioxide layer was deposited with a thickness of 5 nm.

[0016] (2) In the second deposition chamber of the PECVD equipment, the gas flow ratio of the filling gas is 3: 1 ammonia gas NH 3 and silane gas SiH 4 , the deposition temperature is 500°C, and a layer of porous silicon nitride Si is deposited on one side of the polysilicon wafer deposited with a silicon dioxide layer. 3 N 4 layer, the silicon nitride layer was ...

Embodiment 2

[0020] Embodiment 2, a kind of preparation method of polysilicon textured surface, it comprises the following steps:

[0021] 1. Use the PECVD equipment with double deposition chambers to coat the polysilicon raw material with double-layer protective film on one side.

[0022] (1) In the first deposition chamber of the PECVD equipment, the inflatable gas flow ratio is nitrous oxide N of 1.6:1 2 O and silane gas SiH 4 , the deposition temperature is 400 ° C, and a layer of porous silicon dioxide SiO is deposited on the raw material sheet 2 layer, the silicon dioxide layer was deposited with a thickness of 9 nm.

[0023] (2) In the second deposition chamber of the PECVD equipment, the gas flow ratio is 3.5:1 ammonia NH 3 and silane gas SiH 4 , the deposition temperature is 550°C, and a layer of porous silicon nitride Si is deposited on one side of the polysilicon wafer deposited with the silicon dioxide layer. 3 N 4 layer, the silicon nitride layer was deposited with a thi...

Embodiment 3

[0027] Embodiment 3, a kind of preparation method of polysilicon textured surface, it comprises the following steps:

[0028] 1. Use the PECVD equipment with double deposition chambers to coat the polysilicon raw material with double-layer protective film on one side.

[0029] (1) Dinitrogen monoxide N with gas flow ratio of 1.4:1 in the first deposition chamber of PECVD equipment 2 O and silane gas SiH 4 , the deposition temperature is 450 ° C, and a layer of porous silicon dioxide SiO is deposited on the raw material sheet 2 layer, the silicon dioxide layer was deposited to a thickness of 10 nm.

[0030] (2) Ammonia NH with gas flow ratio of 5:1 in the second deposition chamber of PECVD equipment 3 and silane gas SiH 4 , the deposition temperature is 600°C, and a layer of porous silicon nitride Si is deposited on one side of the polysilicon wafer deposited with the silicon dioxide layer. 3 N 4 layer, the silicon nitride layer was deposited with a thickness of 25 nm.

...

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PUM

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Abstract

The invention discloses a preparation method of a multicrystalline silicon texture. The method comprises the following steps: 1. coating a silicon dioxide (SiO2) layer with thickness being 5-10nm and a double-layer silicon nitride (Si3N4) protective film with thickness being 15-25nm on the single surface of a raw multicrystalline silicon wafer by using PECVD (plasma enhanced chemical vapor deposition) equipment with double deposition chambers; 2. using RENA texturing equipment to carry out acid washing on the single surface, on which the double layer films are coated, of the multicrystalline silicon wafer to carry out single surface texturing for 2-3min at the temperature of 5-7 DEG C, wherein the mixed acid liquor is mixed liquor of 65% of HNO3, 40% of HF and deionized water with volume ratio being 2:1:1.6; and 3. carrying out acid washing on the multicrystalline silicon wafer in HF aqueous solution with concentration being 10-20% for 10-15min and washing the multicrystalline siliconwafer with water and drying the multicrystalline silicon wafer after the residual SiO2 film and Si3N4 film completely fall off. The method has the following beneficial effects: the multicrystalline silicon texture prepared by the method has finer wormhole-like structure and large size; the texturing effect can be obviously seen after texturing; and the light trap effect of the cell slices and theshort-circuit current Isc are improved, thus improving the photoelectric conversion efficiency of the cell slices.

Description

technical field [0001] The invention relates to a solar cell manufacturing technology, in particular to a method for preparing a polysilicon textured surface. Background technique [0002] At present, the preparation of polysilicon wafers needs to go through the following processes: double-sided acid texturization of polysilicon raw materials, cleaning process, single-side diffusion process, wet etching process, silicon nitride anti-reflection coating process on PECVD equipment, printing and sintering process and testing and binning process. Since the polycrystalline silicon wafer is completely immersed in the chemical solution in the double-sided acid texturing process, the size of the wormhole-like textured surface formed on the damaged layer on the surface of the silicon wafer by the isotropic chemical etching technology is very small. <1um, it is difficult to observe the texture effect with the naked eye before coating and packaging, and the texture is uneven and the...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C30B33/10C23C16/40C23C16/34
Inventor 金浩张艳芳刘爽
Owner BAODING GUANGWEI GREEN ENERGY TECH CO LTD