Process applied to single-surface corroded p-n junction or suede structure of crystalline silicon solar cell

Abstract

The invention discloses a process applied to a single-surface corroded p-n junction or suede structure of a crystalline silicon solar cell, which comprises the steps of: firstly, chemically preprocessing a silicon sheet to form a suede structure; secondly, carrying out high-temperature phosphorus diffusion or boron diffusion on the silicon sheet to form a p-n junction; thirdly, removing phosphorosilicate glass or borosilicate glass with an acid chemical liquid; fourthly, carrying out dielectric film protection on the p-n junction of a non-corroding surface of the silicon sheet; fifthly, removing a naturally oxidizing layer of a non-protecting surface, i.e. a corroding surface, or a dielectric film material of the corroding surface with the acid chemical liquid; sixthly, carrying out chemical reaction corrosion on the p-n junction or suede structure of the corroding structure by adopting an alkali chemical liquid; and finally, effectively cleaning the dielectric film on the silicon sheet and the corroding surface of the silicon sheet, and remaining the dielectric film as a functional film of the crystalline silicon solar cell. According to the invention, the process of re-preparing the functional film is avoided, the production cost of the crystalline silicon solar cell is effectively lowered, the low-cost single-surface corroded p-n junction or suede structure is realized, the open-circuit voltage and the short-circuit current of the crystalline silicon solar cell are effectively improved, and the photoelectric conversion efficiency of the cell is finally improved.

Description

technical field [0001] The invention belongs to the technical field of solar cells, and in particular relates to a process for single-sided etching of p-n junctions or textured structures applied to crystalline silicon solar cells. Background technique [0002] With the development of human society, the demand for energy continues to increase. However, conventional fossil energy has the disadvantages of limited resources and non-renewable resources. At the same time, it causes serious pollution to the environment and changes the characteristics of the earth's climate. Therefore, solar energy, as one of the environmentally friendly renewable energy sources, has received more and more attention and support from all countries in the world in recent years. . Solar cell photovoltaic power generation is a form of utilization of solar energy, and its basic principle is to use the photovoltaic effect to directly convert light into electricity. In order for solar cell photovoltaic ...

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Problems solved by technology

However, for the plasma edge etching p-n junction method, since the gas commonly used to generate plasma is carbon tetrafluoride (CF 4 ) or sulfur hexafluoride (SF 6 ) gases, they are not only highly toxic gases, but also one of the harmful gases that produce the greenhouse effect. At the same time, the fluorine element in the gas will destroy the ozone layer of the earth and deteriorate the human living environment. In addition, this method will destroy the p-n at the edge of the light-receiving surface of the solar cell, Reduce the effective area of ​​the p-n junction on the light-receiving surface and reduce the photoelectric conversion efficiency of the solar cell; for the laser isolation edge p-n junction method, the local high-temperature action of the laser is mainly used to melt and isolate the p-n junction at the edge of the light-receiving surface of the solar cell, cutting off the front and The electrical connection of the p-n junction on the back achieves the purpose of leakage prevention, but this process has high requirements for the accuracy of the laser, high requirements for the stability of the long-term working state, and high cost of laser equipment. In addition, this process also reduces the p-n junction on the light-receiving surface. The disadvantage of the effective area, and the silicon wafer is prone to thermal damage after high-temperature laser treatment, which reduces the photoelectric conversion efficiency; for HNO 3 / HF mixed etching solution backside corrosion p-n junction method is also one of the methods commonly used to prevent edge leakage in the mass production of crystalline silicon solar cells. This method mainly uses HNO 3 Oxidation reaction of p-n junction silicon material to generate SiO 2 , HF then on SiO 2 The cyclic process of corrosion and stripping realizes the corrosion of the p-n junction on the back, but due to the chemical reaction, the main component of the corrosion solution is HNO 3 Both HF and HF are volatile strong acids, and the reaction process is an exothermic process, so it is very difficult to control the composition stability of the corrosive solution, and the volatilization of the acidic corrosive solution poses a great threat to the life safety of process operators; Difficulty, improper handling will seriously damage the ecological environment, and the use of HNO 3 / HF mixed etching solution backside etching p-n junction process equipment is expensive, which increases the manufacturing cost of solar cells

Therefore, these methods all have their own disadvantages