Method for making a crystalline silicon solar cell substrate utilizing flat top laser beam

摘要

A method for making a crystalline silicon solar cell substrate is provided. A doped dielectric layer is deposited over the backside surface of a crystalline silicon substrate, the doped dielectric layer having a polarity opposite the polarity of the crystalline silicon substrate. Portions of the backside surface of the crystalline substrate are exposed through the doped dielectric layer. An overlayer is deposited over the doped dielectric layer and the exposed portions of the backside surface of the crystalline silicon substrate. Pulsed laser ablation of the overlayer is performed with a flat top laser beam on the silicon substrate to form continuous base openings nested within the exposed portions of the backside surface of the crystalline silicon substrate, the flat top laser beam having a beam intensity profile flatter as compared to a Gaussian beam intensity profile and having a rectangular beam cross section. Doped base regions are formed in the crystalline silicon substrate through the continuous base openings.