Electrochemical Processes for Metallization of Novel Silicon Solar Cells

Within this work electrochemical processes for manufacturing of novel silicon solar cells are investigated. Direct plating of Ni and Al on n- and p-silicon is demonstrated by making use of solar cell characteristics. Homogenous Ni/Cu stacks are realized for bifacial and back contact solar cells, forming an excellent mechanical and electrical contact to silicon. For metallization of HIT solar cells, the plating behavior on ITO layers is studied. Additionally, plating processes on evaporated Al layers are developed and applied to back contact solar cells.

By means of process optimization the plated metal stack on Al features sufficient adhesion and increases the lateral conductivity of the metal grid resulting in increased solar cell efficiency. An advanced metallization route for back contact solar cells which purposefully utilizes the different characteristics of the deposited metals (Al, Ni, Cu) is developed. The resulting metal stacks are characterized in detail using SEM, EDX and AES methods.

Besides plating processes, local oxidizing processes for Al are established and combined with printing technologies to realize the metal contact separation for back contact solar cells.