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Wet etching process for improving emitter square resistance

A sheet resistance, wet etching technology, used in circuits, electrical components, sustainable manufacturing/processing, etc., to reduce surface doping concentration, improve battery open circuit voltage and short-wave response, and improve battery efficiency.

Inactive Publication Date: 2012-11-14
TAITONG TAIZHOU IND
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Domestic diffusion furnaces are facing great challenges in terms of uniformity under high square resistance

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment approach 1

[0017] (1) Clean the diffused silicon wafer and square resistance (45Ω / □) with HF with a volume concentration of 1% for 5 minutes, remove the phosphosilicate glass, and then clean it with deionized water for 5 minutes;

[0018] (2) Use HNO to remove the silicon wafer from the phosphosilicate glass 3 , HF, H 2 SO 4 、H 3 PO 4 The mixed solution etches the silicon wafer surface, HNO 3 :HF:H 2 SO 4 :H 3 PO 4 The volume ratio is 3:1:3:1 and the temperature is 5 o C, the time is 5min, then wash with deionized water;

[0019] (3) Clean the silicon chip with a NaOH solution with a concentration of 5%, and the temperature is 5 o C, the time is 5min, removes the porous silicon produced in step (2), further improves square resistance, then cleans with deionized water;

[0020] (4) Clean the silicon wafer with a mixed solution of HF and HCl, the volume ratio of HF:HCl is 1:2, the time is 1min, and the temperature is 5 o C; remove metal ions, then wash with deionized water;

...

Embodiment approach 2

[0023] (1) Wash the diffused silicon wafer and sheet resistance (50Ω / □) with HF with a volume concentration of 2% for 5 minutes, remove the phosphosilicate glass, and then wash it with deionized water for 5 minutes;

[0024] (2) Use HNO to remove the silicon wafer from the phosphosilicate glass 3 , HF, H 2 SO 4 、H 3 PO 4 The mixed solution etches the silicon wafer surface, HNO 3 :HF:H 2 SO 4 :H 3 PO 4 The volume ratio is 4:1:3:1 and the temperature is 5 o C, the time is 7min, then wash with deionized water;

[0025] (3) Clean the silicon chip with a NaOH solution with a concentration of 1%, and the temperature is 5 o C, the time is 10min, removes the porous silicon produced in step (2), further improves square resistance, then cleans with deionized water;

[0026] (4) Clean the silicon wafer with HF and HCl mixed solution, the volume ratio of HF:HCl is 1:3, the time is 1min, and the temperature is 5 o C; remove metal ions, then wash with deionized water;

[0027] ...

Embodiment approach 3

[0029] (1) Clean the diffused silicon wafer and the square resistance (65Ω / □) with HF with a volume concentration of 1% for 5 minutes, remove the phosphosilicate glass, and then clean it with deionized water for 5 minutes;

[0030] (2) Use HNO to remove the silicon wafer from the phosphosilicate glass 3 , HF, H 2 SO 4 、H 3 PO 4 The mixed solution etches the silicon wafer surface, HNO 3 :HF:H 2 SO 4 :H 3 PO 4 The volume ratio is 5:1:3:1 and the temperature is 5 o C, the time is 9min, then wash with deionized water;

[0031] (3) Clean the silicon chip with a NaOH solution with a concentration of 5%, and the temperature is 5 o C, the time is 5min, removes the porous silicon produced in step (2), further improves square resistance, then cleans with deionized water;

[0032] (4) Clean the silicon wafer with a mixed solution of HF and HCl, the volume ratio of HF:HCl is 1:2, the time is 1min, and the temperature is 5 o C; remove metal ions, then wash with deionized water;...

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PUM

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Abstract

The invention discloses a wet etching process for improving emitter square resistance, which comprises the following steps of: (1) cleaning a silicon chip after diffusion by adopting HF (hydrogen fluoride), removing phosphorosilicate glass, and then cleaning by deionized water; (2) etching the surface of the silicon chip with phosphorosilicate glass being removed by a mixed solution of HNO3, HF, H2SO4 and H3PO4, etching off a heavy doped region, and then cleaning by deionized water; (3) cleaning the silicon chip by a NaO solution, and removing porous silicon generated in the step (2), improving the square resistance further, and then cleaning by deionized water; and (4) cleaning the silicon chip by the mixed solution of HF and HCI, removing a metal ion, and then cleaning by deionized water. The wet etching process for improving emitter square resistance reduces the surface doped concentration, removes the surface dead layer, and improves the square resistance as well as battery open circuit voltage and short wave response, thus the battery efficiency is improved.

Description

technical field [0001] The invention relates to the technical field of solar cell etching, in particular to a wet etching process for improving the sheet resistance of an emitter. Background technique [0002] The core of a solar cell is a PN junction, so making high-quality PN junctions is the key to high-efficiency solar energy. For a passivated emitter, it is required to have a low surface doping concentration, less than 10 20 cm 3 . At the same time, to maintain low emitter saturation current Joe, the emitter must be shallow. With the development of the paste, it is no longer difficult to form a good ohmic contact under high square resistance, the bottleneck lies in the diffusion furnace. Domestic diffusion furnaces are facing great challenges in terms of uniformity under high square resistance. After diffusion, a very high surface concentration is often formed. This layer is usually called a dead layer because of the relatively high doping concentration and the ser...

Claims

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Application Information

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IPC IPC(8): C23F1/24H01L31/18
CPCY02P70/50
Inventor 鲁伟明初仁龙
Owner TAITONG TAIZHOU IND
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