Optimization of Light-Induced Al Plating on Si for Substitution of Ag in Si Solar Cells

This paper focuses on optimization of the light-induced Al plating process to promote a dense adherent film to the Si solar cell as the front electrode. Electrochemical capacitance-voltage and sheet resistance measurements were used to optimize the laser patterning process for the SiNx layer. A recipe to remove contaminants and laser damage on the Si surface after SiNx patterning was developed. Atomic force microscopy revealed the minimum etch time to remove all the original Si surface which was damaged and contaminated. Various plating conditions including temperature, plating voltage, and light intensity were investigated. The lowest Al resistivity obtained is $4\times 10^{-6}\ \mathrm{\Omega}-\mathrm{cm}$, which is comparable to that of electroplated Cu.