Treatment method of oil stains on surface of silicon wafer for efficient N-type heterojunction batteries

Abstract

The invention discloses a treatment method of oil stains on the surface of a silicon wafer for efficient N-type heterojunction batteries, which relates to the technical field of solar cell silicon wafer preparation. The treatment method includes the following steps: S1, inserting an N-type mono-crystalline silicon wafer into a piece of heating equipment before cleaning and texturing; S2, heating the heating equipment to 500-1000 DEG C, and introducing a fixed amount of protective gas, wherein the heating lasts 1-20min; and S3, after heating, taking the N-type mono-crystalline silicon wafer out, cooling the N-type mono-crystalline silicon wafer to room temperature and cleaning the N-type mono-crystalline silicon wafer. The treatment method of the invention has the advantages as follows: theoil stains on the surface of a silicon wafer for N-type mono-crystalline heterojunction batteries can be removed; the yield and conversion efficiency of batteries can be improved; and the productioncost can be saved.

Description

technical field [0001] The invention relates to the technical field of silicon wafer preparation for solar cells, in particular to a method for treating oil stains on the surface of silicon wafers for high-efficiency N-type heterojunction cells. Background technique [0002] High-efficiency N-type monocrystalline heterojunction cells, due to their high conversion efficiency and mature manufacturing process, are likely to become the mainstream technology for next-generation crystalline silicon cells. Heterojunction cells have been setting new world records for mass-produced cell conversion efficiency. The efficiency of heterojunction cells is 1-2% higher than that of P-type monocrystalline silicon cells, and the difference between them is slowly increasing. The conversion efficiency of solar cells can be expressed as the product of three parameters: open circuit voltage, short circuit current and fill factor, where the open circuit voltage depends on the built-in electric fie...

AI Technical Summary

Problems solved by technology

In the production process of cutting single crystal silicon rods into single crystal silicon wafers and then making them into high-efficiency N-type single crystal cells with different structures, there will be a large number of unqualified single crystal silicon wafers with oily stains. These oily silicon wafers are usually used Acidic or alkaline cleaning agents remove oil stains, but these methods have limited ability to remove oil stains. If you directly use acidic cleaning liquid or alkaline cleaning liquid to clean, oily monocrystalline silicon wafers will still have oily stains after acid-base washing Attached to the surface of the silicon wafer, and the production temperature of these processes is below 200°C. Due to the low process temperature, the oil on the surface of the silicon wafer cannot be completely removed. At the same time, the high-efficiency battery with this structure has high requirements for high-efficiency N-type monocrystalline silicon wafers. The process route is sensitive to surface oil pollution, which eventually leads to the presence of oil pollution in the production process of the battery, which affects the EL image of the battery, causing defects such as pitting or foggy blackening, and also causes poor appearance, which leads to the yield of the production line decline, because heterojunction cells require high cleanliness on the surface of silicon wafers, and the performance of heterojunction cells is mainly determined by the properties of the monocrystalline silicon-amorphous silicon interface. Therefore, it is particularly important to obtain a clean monocrystalline silicon surface