Adhesion strength of plated Ni/Cu metallization in Si solar cells

Abstract

Replacing silver paste contacts in silicon solar cells by electroplated nickel and copper (Ni/Cu) connections offer potential advantages of more exceptional grid lines, lower series resistance, and reduced costs in industrial silicon solar cell manufacturing. To achieve acceptance in the market for an electroplated Ni/Cu contacts sufficient contact adhesion has become the significant issue. In this work, a thin nickel layer was deposited on textured (001) silicon by an electroless plating method and form silicides by annealing treatment—this substrate designed as Ax–Si. Afterward, the Cu(15µ m)/Ni(240–1440 nm)/Ax–Si were prepared by electroplating techniques. The structures of Cu/Ni/Ax–Si characterized by scanning electron microscopy, transmission electron microscope and powder X-ray diffraction. Peel force tests were conducted using a universal testing machine. The peel force tests performed at an angle of 90° with a constant speed of 30 mm/min. Excellent adhesion force with 5.2 N/mm achieved.