APPLICATION OF ETCHING PASTE ON METALLIZATION OF INTERDIGITATED BACK-CONTACT NTYPE SILICON SOLAR CELLS

摘要

Metallization of interdigitated back-contact n-type c-Si solar cells has been fabricated by the application ofscreen-printing processes with etching paste for contact hole opening. The contact holes are formed by using etchingpaste to remove SiNx passivation layers on diffused silicon surface. Different contact open ratios of metallization are thenapplied to the back side of solar cells by either extending the size of each contact opening or the number of contact holes.Details of cell processing and related cell parameters are clearly shown and discussed in this paper. By increasing thecontact open ratio from 1.1% to 4.3%, Jsc of solar cells shows a great enhancement with ΔJsc~+7.7% while F.F. isslightly improved and Voc has not varied much (Δefficiency~+13.5%). Interdigitated back-contact solar cells with anappropriate contact open ratio can increase the probability of carrier collection to electrodes in the lateral direction andthus have higher Jsc as compared with those of low contact open ratios, e.g., 1.1% in our case. Besides, we also find thatoptimization of SiNx etching processes with etching paste is needed to prevent the over-etching of diffused siliconunderneath and lateral etching of SiNx thin films, especially for cells with large contact open opening and/or with a lowpitch distance between contact holes.