Preparation method of TOPCon battery

Abstract

The invention discloses a preparation method of a TOPCon battery, which comprises the following steps of preparing a tunneling oxide layer on the back surface of a silicon wafer through LPCVD and depositing intrinsic amorphous silicon, firstly removing amorphous silicon winding plating on the front surface of the silicon wafer, then coating a liquid dopant on the back surface of the silicon wafer and drying, then annealing the silicon wafer, crystallizing the amorphous silicon through annealing and activating impurities. The method can realize single-sided diffusion without winding expansion, is a process scheme for preparing an n + POLO structure, meets the requirement of high productivity, optimizes a process window, avoids the winding expansion risk, can realize removal of amorphous silicon winding plating before annealing, simplifies process steps, protects the front surface structure of a silicon wafer, improves process controllability, and the contradiction between the diffusion concentration and the tunneling layer effect can be solved.

Description

technical field [0001] The invention relates to the field of photovoltaics, in particular to a method for preparing a TOPCon battery. Background technique [0002] In order to increase the proportion of photovoltaic power generation, cost reduction and efficiency improvement are the two main lines of photovoltaic manufacturing. At present, the mainstream photovoltaic cells are crystalline silicon solar cells. TOPCon technology is highly compatible with traditional PERC cell production lines and its The obvious efficiency gain has become one of the most potential new high-efficiency battery technologies, and its related research is increasing day by day. [0003] With the development and introduction of TOPCon battery technology, the conversion efficiency of industrialized n-type TOPCon batteries has exceeded 24%. The preparation of the n+ POLO structure is the core technology of the battery. There are currently two common preparation methods in the industry: ① thermal oxyge...

AI Technical Summary

Problems solved by technology

[0007]In terms of POLO structure preparation, since the intrinsic deposition rate is much higher than in-situ deposition, the same Poly Si thickness scheme ② has obvious advantages in production capacity, while scheme ① uses annealing for crystallization The crystallization process is simple and controllable, and there is no need to consider the risk of winding expansion. The dewinding plating treatment can be performed before crystallization to reduce the process steps, and there is no etching risk (BSG protection) for the front structure during the alkali polishing process. The two solutions are respectively in terms of production capacity and There are defects in process controllability