Preparation method of silicon oxide layer for solar cell and solar cell

Abstract

The invention provides a method for preparing a silicon oxide layer. The preparation method includes the following steps: placing a silicon chip in a mixed acid solution for oxidation treatment, and the mixed acid solution is a mixed solution of nitric acid and sulfuric acid; wherein the nitric acid 1. The sulfuric acid mixture is formed by mixing 68% concentrated nitric acid and 98% concentrated nitric acid at a volume ratio of 1:1 to 10:1. The preparation method of the above-mentioned silicon oxide layer, 1) can achieve a more efficient oxidation effect on the silicon surface, the silicon in the silicon oxide layer is oxidized more thoroughly, and the proportion of silicon in a high-valence state increases; 2) the preparation temperature is low, and can be obtained at as low as A silicon oxide layer with a thickness greater than 1.4nm is prepared under the condition of 20°C, which meets the needs of preparing solar cells; 3) The processing time is shortened, for example, a silicon oxide layer with a thickness greater than 1.4nm can be prepared in 2 to 4 minutes; 4) The oxide layer The thickness is appropriate, the prepared silicon oxide layer can be controlled within 1.0-3.0 nm, and the thickness of the silicon oxide layer can completely cover the thickness requirement required by the device.

Description

technical field [0001] The invention relates to the field of solar cells, in particular to a method for preparing a silicon oxide layer of a solar cell and the solar cell. Background technique [0002] The Tunneling Oxide Passivation Contact (TOPCon) solar cell is a new type of silicon solar cell proposed by the Fraunhofer Institute in Germany in the past two years. The battery uses an n-type silicon wafer, and the back of the silicon wafer is covered with a silicon oxide layer with a thickness of less than 2nm, and then covered with a doped polysilicon or amorphous silicon layer. The back structure of the battery is n-type silicon wafer / ultra-thin silicon oxide layer / n+ polysilicon layer / metal electrode layer. When the battery is working, electrons tunnel from the n-type silicon slice through the silicon oxide layer through the silicon oxide into the doped polysilicon layer / amorphous silicon layer. The silicon oxide layer therein can have an excellent passivation effect o...

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Problems solved by technology

[0007] Based on this, it is necessary to provide a method for preparing a silicon oxide layer of a solar cell and its preparation for the problems that the thickness and quality of the silicon oxide layer are not easy to control in the prior art, or the thickness of the prepared silicon oxide layer is small, and the content of high-valence silicon is low. silicon oxide layer and solar cells

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