Solar cell boron diffusion method capable of improving efficiency and reducing cost

Abstract

The invention relates to a solar cell boron diffusion method capable of improving efficiency and reducing cost. The method improves the problem of high maintenance cost of tubular boron diffusion while improving efficiency, and specifically comprises the following steps: step 1, growing boron-doped amorphous silicon on the front surface of an N-type silicon wafer; and step 2, performing high-temperature crystallization on the amorphous silicon and completing boron doping. The crystal silicon surface boron-doped activation rate is improved, the efficiency is improved, and meanwhile, the problems that in the conventional tubular boron diffusion pre-deposition process, due to the fact that the boiling point of a reaction product B2O3 is 1600 DEG C or above, a reaction product B and the B2O3 which is always in a liquid state severely corrode a quartz device in the diffusion process, and are rapidly cooled and solidified outside a constant-temperature area after diffusion is finished, a tail pipe is prone to being blocked, the adhesion of a quartz furnace door of a diffusion machine and a quartz furnace tube is caused, and the maintenance cost is high.

Description

technical field [0001] The invention belongs to the technical field of solar cells, and in particular relates to a boron diffusion method for solar cells that improves efficiency and reduces costs. Background technique [0002] At present, P-type crystalline silicon batteries occupy an absolute share of the crystalline silicon battery market. However, the constant pursuit of efficiency improvement and cost reduction is an eternal theme in the photovoltaic industry. Compared with conventional P-type single crystal silicon, N-type single crystal silicon has the advantages of high minority carrier lifetime and small light-induced attenuation, and has greater room for efficiency improvement. At the same time, N-type single crystal modules have good weak light response and low temperature coefficient. advantage. Therefore, the N-type single crystal system has the dual advantages of high power generation and high reliability. [0003] Boron diffusion is the core process of N-ty...

AI Technical Summary

Problems solved by technology

Compared with phosphorus diffusion, the diffusion rate of boron atoms in silicon is lower, so to achieve the expected doping concentration and depth, the temperature of boron diffusion process is higher and the time is longer, and the phenomenon of "dead layer" is more likely to appear in the shallow surface layer of silicon. The activation rate of boron doping directly affects the efficiency performance

Furthermore, during the boron diffusion process, due to the direct action on the B of the silicon wafer 2 o 3 The boiling point of silicon reaches 1860°C, while the diffusion process temperature is generally between 900°C and 1000°C, B 2 o 3 Contact with solar cells in liquid form during the process, resulting in poor process uniformity of solar cells

On the other hand, due to the existence of the by-product BSG (borosilicate glass), there is a sticking phenomenon in the quartz parts, which leads to the short maintenance period and high cost of the boron diffusion equipment, which seriously restricts the development of N-type batteries.

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