Silicon wafer phosphorus and aluminum combined temperature varying and impurity suction method for preparing solar cells

Abstract

A silicon wafer phosphorus and aluminium combined temperature varying and impurity suction method for preparing solar cells comprises the following steps that after damage layer removing and ultrasonic cleaning are sequentially conducted on a substrate silicon wafer, the front face and the back face of the silicon wafer are coated with phosphorus sources first, and then the silicon wafer is plated with aluminium coatings in an evaporated mode; then under protecting of nitrogen atmosphere, thermal treatment is conducted, and primary impurity suction and secondary impurity suction are sequentially conducted; after the silicon wafer is cooled to the room temperature, the silicon wafer is put in a mixed solution of hydrofluoric acid and nitric acid to be corroded, and an impurity suction layer is removed. The silicon wafer phosphorous and aluminium combined temperature varying and impurity suction method for preparing the solar cells has the advantages that a temperature varying process is introduced on the basis of a phosphorus and aluminium impurity suction process, all the processes of impurity suction are effectively controlled through different temperatures, and the respective advantages of phosphorus impurity suction and aluminium impurity suction are fully utilized; the process is simple and easy to achieve, and other equipment is of no need; an impurity suction effect is obvious, after impurity suction treatment, the minority carrier lifetime of the silicon wafer is obviously prolonged, and the process cycle is reduced under the premise that the requirement for impurity suction effect is met.

Description

technical field [0001] The invention relates to a method for preparing a silicon solar cell, in particular to a silicon chip phosphor-aluminum combined temperature-variable gettering method for preparing a solar cell. Background technique [0002] The carrier of photovoltaic power generation is solar cells, and the key to making solar cells an important part of future energy is to reduce the cost of photovoltaic power generation to the same level as conventional energy. Crystalline silicon solar cells have attracted widespread attention due to their high conversion efficiency, abundant raw materials, and relatively cheap production costs. At present, crystalline silicon solar cells have also accounted for more than 80% of the current solar cell market. In order to further enhance the competitiveness of crystalline silicon solar cells, it is necessary to use cheaper substrates on the basis of ensuring the photoelectric conversion efficiency of the cells. The purity of the ...

AI Technical Summary

Problems solved by technology

The phosphorus gettering method is relatively simple and the process cycle is short, but its gettering mechanism determines that its gettering effect is weaker than that of aluminum gettering

Aluminum gettering has a better gettering effect, but it takes a long time to evaporate the aluminum film, which directly leads to a longer process cycle

In addition, since the main mechanism of the gettering process in silicon lies in the three processes of release, diffusion, and capture, the heat treatment temperature required for different gettering methods and processes is also different, which also directly affects the gettering effect.

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