Novel diffusion process capable of increasing polysilicon open-circuit voltage

Abstract

The invention discloses a novel diffusion process capable of increasing polysilicon open-circuit voltage. The novel diffusion process includes: 1), placing a silicon wafer in a diffusion furnace, and heating to 800 DEG C; 2), feeding a source, namely feeding diffusion nitrogen, oxygen and purging nitrogen into the diffusion furnace at the temperature according to a feeding flow ratio of 3:1:17 for 10-25 minutes; 3), heating for knot pushing, namely, using 10-25 minutes to increase temperature in a diffusion furnace pipe to be 850-860 DEG C, and continuously feeding purging nitrogen and oxygen with a feeding flow ratio of 10:3 into the diffusion furnace pipe in the whole process of heating; 4), using 10-25 minutes to lower temperature in the diffusion furnace pipe to be 750-800 DEG C, and continuously feeding purging nitrogen into the diffusion furnace pipe in the whole process of cooling; 5), taking the silicon wafer out. By the novel diffusion process, surface compositing speed of the silicon wafer can be lowered, knot depth can be increased, width of a polysilicon substrate can be reduced, and open-circuit voltage of a solar cell is increased.

Description

technical field [0001] The invention relates to the field of manufacturing crystalline silicon solar cells, in particular to a diffusion process for solar cells. Background technique [0002] At present, the main manufacturing process of monocrystalline and polycrystalline silicon solar cells has been standardized. The main production steps are: cleaning and preparing the suede on the surface of silicon wafers, diffusion to form PN junctions, dry and wet etching to remove peripheral and back junctions, and PECVD to form anti-reflection nitriding Silicon film, screen printing to form electrodes, and sintering to form ohmic contact resistance. [0003] We use POCl at high temperature 3 Diffusion to form a PN junction. The PN junction formed in the prior art has a low internal doping concentration and a high surface doping concentration, which leads to a high surface recombination speed of the silicon wafer and reduces the open circuit voltage of the solar cell. A low open ci...

AI Technical Summary

Problems solved by technology

The PN junction formed in the prior art has a low internal doping concentration and a high surface doping concentration, which leads to a high surface recombination speed of the silicon wafer, which reduces the open circuit voltage of the solar cell, and a low open circuit voltage will reduce the efficiency of the cell.