Progress on laser assisted nickel seed layer deposition for front contact copper plating

The high price of silver has motivated the search for new paths in regard to the front metallization of crystalline silicon solar cells. Copper is a suitable material from the conductivity and cost point of view; however, contact resistivity and long term stability are still issues that must be addressed. The present work describes the results obtained in the improvement of frontal metallization of textured crystalline silicon solar cells. Laser chemical metal deposition has been used in the creation of nickel seed layers for subsequent copper plating. Conditions have been optimized to reduce the number of laser scan repetitions, and consequently the processing time per cell. The average finger width is below 80 microns, thus reducing the shaded area. In-depth chemical and morphological characterization results of the seed layers are presented and related with laser settings and cell performance. The produced solar cells show viability of the process, leading to pseudoe fficiencies exceeding 15%.