METHOD FOR FABRICATING BI-FACIAL SOLAR CELL

摘要

A method for fabricating a bi-facial solar cell comprises the steps of: respectively stacking a BSG layer and a PSG layer on a front surface and rear surface of an n-type crystal silicon substrate; irradiating laser on a portion of the BSG layer or PSG layer to form a localized doped layer on one surface among a front surface or rear surface of the substrate; completing a selectively doping layered structure on one surface of the substrate by performing a diffusion process and also forming a doped layer on the other rear surface; and removing the BSG and PSG layers. The order of the laser doping process and the diffusion process can be inverted. The BSG and PSG layers can be artificially formed at a sufficient thickness by using a constant chemical vapor deposition method or the like and be used as an etching prevention layer. Also, the BSG and PSG layers can function as a diffusion protection film without forming a separate diffusion protection film by performing a simultaneous diffusion process after forming all of the BSG and PSG layers. Hence, since the forming process of the diffusion protection film or the etching prevention film can be omitted, the number of processes can be reduced to improve process efficiency. Also, by combining and applying the laser doping process and the diffusion and heat-treatment process, a defect generated by the irradiation of the laser can be irradiation alleviated and an efficient and selective emitter structure can be formed.