Demonstration of High-Volume Substrate Reuse for Inverted Metamorphic Solar Cells

The substrate of a III-V solar cell typically contributes more than 50% of the materials cost for production. The substrate cost can be mitigated by reuse. Active solar cell layers are removed from the substrate after each growth cycle via epitaxial lift-off. The substrate is then repolished for reuse, while the solar cell layers are transferred to a temporary carrier for processing. The effective substrate cost with reuse is sensitive to yield rate and costs through growth, solar cell fabrication, and reclaim processing. We report on efforts to reduce effective substrate cost at high volume with a focus on minimizing the substrate processing required to optimize yield.