Texturing method of polycrystalline silicon wafer cut by diamond wire

Abstract

The invention discloses a texturing method of a polycrystalline silicon wafer cut by a diamond wire. The method comprises the following steps: firstly, immersing the polycrystalline silicon wafer cut by the diamond wire into a mixed water solution of an alkaline solution and an alkaline reaction control agent, removing a surface damage layer of the silicon wafer and immersing the polycrystalline silicon wafer into a hydrofluoric acid solution containing inorganic ions and organic molecules for reaction; secondly, carrying out pretreatment on the polycrystalline silicon surface by a mixed solution of a hydrofluoric acid and hydrogen peroxide and simultaneously adding a pore-forming regulator; and finally texturing the silicon wafer surface by a mixed acid solution of the hydrofluoric acid and a nitric acid. The texturing method has the advantages that the prepared polycrystalline textured wafer is uniform in suede, small in color difference and consistent in etching depth, and has low surface reflectivity and relatively high conversion efficiency; the preparation method is simple and feasible; the reagent cost is relatively low; the reaction conditions are easy to implement; and the texturing method is relatively good in compatibility with an existing industrial production procedure and is suitable for popularization and application.

Description

technical field [0001] The invention belongs to the field of manufacturing polycrystalline silicon solar cells, and in particular relates to a method for making texture of diamond wire cut polycrystalline silicon wafers. Background technique [0002] At present, the cutting of crystalline silicon wafers used in the photovoltaic industry mainly adopts the mortar multi-wire cutting technology, but this technology has many problems such as low cutting efficiency, high cost, and discharge pollution of waste mortar after cutting. In contrast, the slicing method of diamond wire cut polysilicon ingot has attracted much attention because of its advantages of low processing cost, high cutting efficiency and clean environment. However, compared with mortar-cut silicon wafers, diamond wire-cut polycrystalline silicon wafers have a thinner surface damage layer and insufficient reactivity. The acid texturing process used in traditional mortar-cut polycrystalline silicon wafers cannot sol...

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Problems solved by technology

This method can effectively reduce the reflectivity of silicon wafers and improve efficiency, but there are also obvious shortcomings: firstly, it cannot form uniform and small color difference on the surface of polycrystalline silicon wafers with [100], [110], [111] and other crystal planes. 1. The suede surface with high light conversion efficiency can not solve the problem of uniform appearance in mass production; secondly, in this method, the silicon wafer is placed in a mixed solution containing metal ions, oxidant hydrogen peroxide and hydrofluoric acid to form a porous layer on the surface. It is easy to cause the instability of the solution, the suede fluctuates greatly during the batch reaction, and the life of the solution is insufficient

Patent No. 201310127230.X discloses a textured structure of crystalline silicon solar cells and its preparation method. The method coats a layer of metal nanoparticles on the surface, then corrodes the surface of the silicon wafer, and finally corrects the surface of the silicon wafer. Etching, this method can effectively obtain polysilicon textured sheet with low reflectivity, but its textured structure is limited to 100-500nm, and the obtained textured sheet also has problems of uneven textured surface and large color difference

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