Alkaline cleaning additive used after acid texturing of polycrystalline silicon wafers, and using method thereof

Abstract

The invention relates to an alkaline cleaning additive used after acid texturing of polycrystalline silicon wafers. The alkaline cleaning additive comprises the following components in percentage by weight: 0.1 to 0.5 percent of span-80, 0.6 to 2.5 percent of tween-40, 0.3 to 1.5 percent of dodecyl polyglycol ether and the balance of water. The invention also provides a cleaning liquid for alkaline cleaning of the polycrystalline silicon wafers. The cleaning liquid comprises an alkaline solution and the alkaline cleaning additive used after acid texturing of the polycrystalline silicon wafers, wherein the mass ratio of the alkaline cleaning additive for the polycrystalline silicon wafers to the alkaline solution is (0.2-2):100; the alkaline solution is the alkaline solution of inorganic alkali or organic alkali. The cleaning liquid can be used for cleaning the residual organic matters on the surfaces of the silicon wafers in a texturing process, so that the surfaces of the silicon wafers are hydrophobic and blow-drying of the silicon wafers is facilitated; porous silicon on the surfaces of the silicon wafers can be removed in an alkaline cleaning process, so that the hidden danger that a dispersing process is unstable due to the porous silicon is eliminated and the uniformity of the subsequent silicon nitride coating film is promoted.

Description

technical field [0001] The invention relates to an alkali cleaning additive used for acid texturing of polycrystalline silicon wafers and a using method thereof, belonging to the technical field of polycrystalline silicon solar cells. Background technique [0002] During the development of the photovoltaic industry, polycrystalline silicon solar cells have attracted more and more attention. The reason is that the efficiency of polycrystalline silicon solar cells has been significantly improved while maintaining low prices, and their unit energy consumption ratio and cost performance are significantly better than those of solar cells. Monocrystalline cells, therefore, the current market share of polycrystalline cells has far exceeded that of monocrystalline cells. [0003] The mixed acid of nitric acid and hydrofluoric acid is generally used for texturing of polycrystalline cells. Generally, the reflectance of silicon wafers after texturing is generally higher than 22%, even ...

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Problems solved by technology

[0005] In view of the above problems, the present invention provides a polycrystalline silicon chip alkali cleaning additive and its use method, which can solve the cleaning problem of the silicon chip surface, making polycrystalline texturing The additive can improve the conversion efficiency of the cell while reducing the reflectivity of the silicon wafer

After alkali cleaning, there are still organic residues on the surface of the silicon wafer, which makes it difficult to dry the silicon wafer after texturing, and it is easy to introduce metal pollution; at the same time, porous silicon has an impact on the process links such as diffusion and silicon nitride coating, resulting in parallel resistance and The reduction of open circuit voltage affects the improvement of efficiency, and the present invention can solve this problem well

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