Metal catalytic texturing method for decreasing reflectance of polycrystalline silicon wafer cut with diamond wire

Abstract

The invention relates to a metal catalytic etching method for decreasing a reflection rate of a polycrystalline silicon wafer cut with a diamond wire. The method comprises the following steps: soaking a polycrystalline silicon wafer cut with a diamond wire in an alkaline solution, and removing a mechanically damaged layer on the surface of the silicon wafer in an etching manner; and integrally treating the treated polycrystalline silicon wafer by virtue of metal catalysis, chemical etching and silver plating and hole digging, and forming a nano porous silicon structure on the surface of the polycrystalline silicon wafer; soaking the polycrystalline silicon wafer treated in the step II in a second mixed solution, performing the etching treatment, so that a honeycomb-shaped suede-like structure is formed on the surface of the silicon wafer; alkaline washing and desilverizing the polycrystalline silicon wafer treated by the last step in an alkaline mixed solution; and cleaning the treated polycrystalline silicon wafer successively with an acid mixed solution and deionized water, and finally drying. By adopting the method, cut marks of the diamond wire can be eliminated, the reflection rate of the polycrystalline silicon etched surface can be effectively decreased to 15 percent, the compatibility with a conventional etching process is good, and the conversion efficiency of a solar cell can be increased.

Description

technical field [0001] The invention belongs to the field of manufacturing polycrystalline silicon solar cells, and in particular relates to a metal-catalyzed texturing method for reducing the reflectivity of polycrystalline silicon slices cut by diamond wires. Background technique [0002] With the rapid development of the industrialized economy and the deterioration of the ecological environment, traditional non-renewable energy sources such as coal, oil, and natural gas are facing a crisis of depletion, and it is imminent to find new renewable energy sources. Among them, solar energy has become a new type of energy to replace traditional petrochemical energy because of its inexhaustibility and inexhaustibility. Solar photovoltaic power generation is the conversion of light energy into electrical energy. Photovoltaic modules have the characteristics of green environmental protection, long service life, low cost, high efficiency and convenience, and have become the focus of...

AI Technical Summary

Problems solved by technology

The polysilicon textured sheet prepared by this method has a low reflectivity, which has laid a necessary foundation for further improving the photoelectric conversion efficiency, but the preparation process of this method is complicated, the cost of equipment and loss is expensive, and sulfuration will be emitted during the process. substances, halogen compounds, etc., especially Cl 2 , the gas is highly toxic and will pollute the environment

[0005] Patent No. 201610310040.5 discloses a diamond wire-cut polysilicon wafer texturing method using HF-HNO 3 -H 2 O Two-step texturing process, first use the traditional HF-HNO 3 -H 2 The O texturing system etches micron-scale larger wormhole structures on the surface of diamond-wire-cut polysilicon, and then uses H 2 o 2 -HF-H 2 The O system etches a micro-hole structure with a smaller size, and reduces the reflectivity of the silicon wafer surface through two-step acidity, but this texturing process cannot obtain a textured structure with uniform corrosion on the entire surface, and micron-sized insects on the surface of the textured surface Etching a smaller-sized micro-hole structure on the hole structure will also cause too many recombination centers to be formed on the surface of the silicon wafer, which is detrimental to improving the photoelectric performance of the battery

[0006] In recent years, some manufacturers have also tried to reduce the reflectivity of diamond wire-cut polysilicon wafers by wet chemical methods of metal ion assisted etching of polysilicon. For example, in the application number 201410652553.5, in the traditional HF-HNO 3 -H 2 O acidic system forms micro-textured surface after texturing, and then deposits metal nanoparticles on the micro-textured surface, and then puts it in an etching solution for etching to obtain a polycrystalline silicon wafer with a micro-nano composite textured structure. Metal-catalyzed chemical etching The etching adopts a two-step method to first deposit a layer of silver on the textured surface and then place it in an etching solution for etching. The surface area and uniformity of the prepared textured surface need to be improved, and more textured textures are added on the basis of the traditional production line. Process steps, and the high concentration of silver ions will increase the burden on the treatment of peripheral sewage and waste gas

Images