A Light-Induced Aluminum Plating Tool for Substitution of Silver in Silicon Solar Cells

Today’s silicon solar cells employ screen-printed silver as the front-side electrode. Silver is expensive as the fabrication cost from wafers to cells is ~$0.10/cell today and silver accounts for ~50% of that cost. Replacing silver with aluminum is a critical step to achieve higher solar penetration at affordable prices as the cost of aluminum is a tiny fraction of the silver cost. This SBIR/STTR project aims to develop a new aluminum plating tool for a front-side aluminum electrode in silicon solar cells based on a proprietary technology, light-induced aluminum plating. Our technology enables a simpler aluminum electrode than the competing technology, thus reducing processing costs, improving module reliability and lifetime, while maintaining high cell efficiencies. The objective of this Phase I project is to develop a prototype light- induced aluminum plating tool for commercial-size silicon solar cells. It involves optimization of the light-induced aluminum plating process, demonstration of low contact resistance in the milli-Ohm-centimeter-squared range, and demonstration of reliable and reproducible aluminum plating on silicon solar cells. The deliverable of Phase I is a functional prototype light- induced aluminum plating tool that produces low resistivity, low contact resistance, adherent, and uniform aluminum electrodes on silicon solar cells. In Phase II our plan is to develop a commercial R&D version of this tool and sell it to solar companies so they can try out the new aluminum electrode on their own. This will help the adoption of the technology. A production version of this tool will be developed in partnership with a plating tool company.