Diffusion technology for preparing Se battery by using etching process

Abstract

The invention discloses a diffusion technology for preparing a Se battery by using an etching process. According to the diffusion technology, the gradient diffusion temperature, the source flow and the oxygen flow are adopted; and the diffusion technology specifically comprises the following steps of: a, putting a silicon sheet into a diffusion furnace; b, rising the temperature to 840-850 DEG C, introducing nitrogen and oxygen from a carrying source, keeping the temperature, gradually reducing the flow of a diffusion source, adding the flow of the oxygen and lasting the whole process for 10-30min; c, increasing the temperature to 860-870 DEG C, and keeping for 5-15min; and d, reducing the temperature and finishing the diffusion. By utilizing the diffusion technology for preparing the Se battery by using the etching process, high enough surface concentration and phosphorosilicate glass thickness are ensured with very good phosphorus concentration distribution curves, and a very low emitter saturation current and a very wide process window are ensured for a later etching method in etching a high sheet resistor.

Description

technical field [0001] The invention relates to a diffusion process for solar cells, in particular to a diffusion process for preparing Se cells by etching. Background technique [0002] A solar cell is a device that converts light energy directly into electricity. The selective emitter structure is heavily doped at the contact between the metal gate line and the silicon chip, and lightly doped between the electrodes. Such a structure can reduce the recombination of the emitter, thereby improving the short-wave response of the battery, reducing the contact resistance between the front metal grid line and silicon, and improving the short-circuit current, open-circuit voltage, and fill factor, thereby improving the conversion efficiency. [0003] In the process of preparing the Se battery, the heavy diffusion area can be etched into the light diffusion area by means of etching slurry. However, this diffusion step requires a good junction depth distribution and surface concen...