Method for preparing texture on surface of silicon wafer

Abstract

The invention discloses a method for preparing texture on the surfaces of silicon wafers. The method comprises the following steps: the surfaces of the silicon wafers are cleaned and purified, each two cleaned and purified silicon wafers are overlapped and placed in a vapor deposition reacting furnace; when the temperature of the vapor deposition reacting furnace is controlled to 1050 to 1200 DEG C and the vacuum degree is controlled in the range of 1*10<-2>Pa to 1*10<-4>Pa, trichlorosilane and hydrogen are mixed according to the required reaction molar ratio of the chemical equation, the mixture is introduced in the vapor deposition reacting furnace to ensure that crystalline silicon deposits on the exposed surfaces of each two overlapped silicon wafers and silicon grain texture surfaces are formed; and nitrogen is introduced after the deposition, the temperature of the vapor deposition reacting furnace is reduced to the room temperature, the pressure of the furnace is increased to the atmospheric pressure, and the silicon wafers with the deposited silicon grain texture surfaces are taken out. The thickness of the texture layers of the silicon grain texture surfaces which are prepared on the surfaces of the silicon wafers by the texture-preparing method of the invention is 5mu m-8mu m, and the average reflectivity of the surfaces of the silicon wafers to the light with the wavelength of 300nm-1100nm is 7.5%-8.5%. The silicon grain texture surface layers can be controlled, the reflectivity of the silicon grain texture surface is reduced, the production process is simple, and the speed of the batch production is fast.

Description

technical field [0001] The invention relates to a solar cell production technology, in particular to a method for making texture on the surface of a silicon wafer. Background technique [0002] At present, in the production process of silicon solar cells, the texture of the surface of the silicon wafer directly affects the absorption of solar energy. The reflectivity of the textured surface of the prior art is basically between 10% and 20%, which cannot meet the requirements of smaller solar cells. There is a need for the development of solar cells that generate greater power in terms of area. [0003] There is a Chinese patent application publication that discloses a method for reactive ion etching to prepare the textured surface of silicon wafers for solar cells, which discloses that the reactive ion etching gas containing at least two halogen-containing gases and oxidizing gases is used to process crystalline silicon Suede preparation, although the disclosed embodiment p...

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Problems solved by technology

In fact, under uncertain conditions, the silicon wafer is transported to the LPCVD furnace tube for processing, which may not necessarily achieve the desired purpose of "the size and orientation of the hemispherical silicon grains formed on the surface of the silicon wafer". Even if it is specified in the published specification that "silane" is used as the vapor phase material for chemical vapor deposition, according to conventional knowledge, it will produce an amorphous silicon film, rather than a thin layer of hemispherical silicon grains, so whether the published information can To achieve the purpose of the invention in industrial production, it has yet to be proved by practice

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