Polycrystalline black silicon wafer diffusion method through MCCE etching

Abstract

The invention discloses a polycrystalline black silicon wafer diffusion method through MCCE etching, which is applicable to a black silicon diffusion process prepared by adopting a metal catalytic chemical etching method. A process of first deposition-first propulsion-second deposition-second propulsion is adopted. The oxygen flow rate in the first deposition process is larger than the nitrogen flow rate with a phosphorus source; the first propulsion is anaerobic propulsion, and the pure nitrogen flow rate in the first propulsion process is larger than that in the first deposition process; thenitrogen flow rate with a phosphorus source in the second deposition process is larger than that in the first deposition process; the pure nitrogen flow rate in the second deposition process is smaller than that in the first deposition process; the temperature of the second deposition process is larger than that of the first deposition process; the second propulsion is oxygen-enriched propulsion;the first propulsion time is smaller than the first deposition time; and the second propulsion time is larger than the second deposition time. Photocarrier recombination can be effectively reduced, the silicon wafer diffusion uniformity is enhanced, and the black silicon cell efficiency is enhanced.

Description

Technical field

[0001] The invention relates to a diffusion method for MCCE texturing polycrystalline black silicon wafers. The polycrystalline black silicon wafers can be used to manufacture solar cells and belong to the field of solar cells. Background technique

[0002] At present, the preparation methods of black silicon mainly include the following: laser etching, reactive ion etching (RIE) and metal catalyzed chemical etching (MCCE). The specific surface area of ​​black silicon prepared by these methods becomes larger. The surface is in the shape of holes, which is good for trapping light and increasing the utilization rate of light. The suede structure is as follows figure 1 Shown. However, the porous surface is difficult to diffuse under the production line process conditions, the junction is shallow after diffusion, the square resistance uniformity is poor, it is easy to burn through during sintering, and the source concentration is high. The porous surface structure mak...

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