Preparation method for silicon nitride film, solar cell with silicon nitride film and preparation method for solar cell

Abstract

The invention discloses a preparation method for a silicon nitride film, a solar cell with the silicon nitride film and a preparation method for the solar cell. The preparation method for the silicon nitride film includes following steps: S1, placing a silicon wafer into a tubular furnace; S2, feeding nitrogen into the tubular furnace, heating the tubular furnace under the atmosphere of nitrogen to 340 DEG C to 360 DEG C, and maintaining the temperature for 500 seconds to 2000 seconds; and S3, utilizing the PECVD (plasma enhanced chemical vapor deposition) method to sequentially form a first silicon nitride film layer and a second silicon nitride film layer on the silicon wafer. The first silicon nitride film layer is arranged on the silicon wafer before the temperature of the tubular furnace is maintained, so that temperatures around and in the middle of the silicon wafer are uniform after the step of temperature maintaining of the silicon wafer, growth rate of the silicon nitride film around and in the middle of the silicon wafer is guaranteed, overhigh growth rate caused by higher temperature at the edge of the silicon wafer is improved, the problem of color deviation caused by different thicknesses and refractive indexes of the silicon nitride film at various positions on the surface of the silicon wafer is solved, grade of the silicon wafer is lowered, and acceptance rate of the silicon wafer is improved.

Description

technical field [0001] The invention relates to the field of solar cells, in particular to a method for preparing a silicon nitride film, a solar cell with a silicon nitride film and a method for preparing the same. Background technique [0002] A solar cell, also called a photovoltaic cell, is a semiconductor device that converts the sun's light directly into electrical energy. Because it is a green product, does not cause environmental pollution, and is a renewable resource, solar cells are an energy source with broad development prospects in today's energy shortage situation. The manufacturing process of solar cells generally has the following steps: chemical cleaning and surface texture treatment, diffusion junction, peripheral etching, silicon nitride film deposition, screen printing, and sintering. In the silicon nitride film deposition step, plasma-enhanced chemical vapor deposition (PECVD) is a commonly used method for preparing silicon nitride films. [0003] Plas...

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Problems solved by technology

There are some defects in the existing preparation process, such as pushing the graphite boat equipped with silicon wafers into the furnace tube of the tube furnace and starting to heat, because the heat conduction speed of solid is greater than the heat conduction speed of air, so the silicon wafers close to the graphite boat will There is a temperature difference with the middle part of the silicon wafer that is not in contact with the graphite boat, which eventually leads to inconsistent growth rates between the silicon nitride film deposited around the silicon wafer and the silicon nitride film deposited on the middle part of the silicon wafer, and the fast growth rate around the silicon nitride film leads to The thickness of the film is large, and the internal growth rate is slow, resulting in a thinner silicon nitride film. Therefore, due to the inconsistency of the thickness and refractive index of the silicon nitride film on the surface of the silicon wafer, the color of the silicon nitride film seen in the appearance has chromatic aberration.

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