Method for local modification of etching resistance in a silicon layer, use of this method in the production of passivation contact solar cells and thus-created solar cell

A method for local structuring of a silicon layer to produce locally structured polycrystalline layers (301,1301,1302),

• characterized in that
• the method comprises a step of local modification of the etching resistance within said silicon layer (301,1301,1302) and a subsequent step of removing unmodified regions of said silicon layer (301,1301,1302) by etching,
• wherein the local modification of the etching resistance of the silicon layer (301,1301,1302) is brought about at least partly by application of a laser to those regions of the silicon layer (301,1301,1302) in which the etching resistance is increased,
• wherein the local modification of the etching resistance is brought about at least partly by inducing a local increase in the crystallinity of the silicon layer (301,1301,1302) in the modified regions to produce locally structured polycrystalline layers, and
• wherein the laser that is used is a short pulse ultraviolet light excimer laser, and wherein the pulse energy is being selected such that a local increase in the crystallinity of the silicon layer (301,1301,1302) and diffusion or activation of dopants, in case dopants are present, occurs, but an underlying layer remains unaffected.