Preparation method for topcon double-POLO battery structure

Abstract

A preparation method for a TOPCon double-POLO battery structure. The method comprises: forming a double-POLO structure on the front face and back face of a silicon wafer, wherein a local POLO structure is formed on the front face. A coating mask is combined with a laser to form the local POLO structure on the front face, thereby improving a metal contact composite current on the front face and also avoiding a current loss, and thus greatly improving the battery efficiency. An inorganic oxide mask that is used can be easily removed by means of a laser of a conventional SE laser device, and the damage of the laser to a silicon substrate is less. The solution for implementing poly patterning by using a laser has good compatibility with a production line. The remaining mask after texturing is performed can be removed by means of hydrofluoric acid pickling, which can be combined with conventional acid pickling after texturing is performed, without the need for extra cleaning devices and processes. Boron diffusion is performed after local POLO is formed on the front face, and boron doping can be implemented in a front-face POLO area and a suede area at the same time, thereby simplifying the preparation steps for the local POLO structure on the front face.