Preparation method of solar cell silicon oxide layer and solar cell

Abstract

The invention provides a preparation method of a silicon oxide layer. The preparation method comprises the following steps: putting a silicon chip in mixed acid liquid for oxidation treatment, wherein the mixed acid liquid is nitric acid-sulfuric acid mixed liquid which is prepared by mixing 68% concentrated nitric acid and 98% concentrated sulfuric acid in a volume ratio of (1:1)-(10:1). The preparation method of the silicon oxide layer has the following advantages: 1) a more efficient oxidation effect can be realized on the silicon surface, the silicon of the silicon oxide layer is oxidized more thoroughly, and the proportion of high-valence silicon is raised; 2) the preparation temperature is low, a silicon oxide layer with thickness of greater than 1.4nm can be prepared at a temperature of as low as 20 DEG C, and the need for preparing a solar cell is met; 3) the treatment time is short, for example, the silicon oxide layer with thickness of greater than 1.4nm can be prepared within 2-4min; and 4) the thickness of the oxide layer is appropriate, the prepared silicon oxide layer can be controlled at 1.0-3.0nm, and the thickness of the silicon oxide layer can completely meet the thickness requirements of devices.

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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