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Project Name: Sound Assisted Low Temperature Spalling for Low Cost Silicon
Funding Opportunity: PVRD-SIPS
SETO Subprogram: Photovoltaics
Location: Tempe, AZ
Award Amount: $179,284
Awardee Cost Share: $19,930
Project Investigator: Mariana Bertoni

This project is evaluating and developing a method for sound-assisted low temperature (SALT) spalling to enable low-cost silicon wafers. This disruptive technology cuts silicon wafers without kerf losses, which results in high-quality silicon wafers at twice the yield and half of the cost of traditional wafering methods.


The new research technique, SALT spalling, peels a wafer from a silicon block by applying stress and acoustic waves at low temperatures. This method would eliminate kerf loss, which is the amount of material “lost” in the process of cutting silicon. SALT technology, combined with state-of-the-art manufacturing, has the potential to achieve highly efficient, lightweight, and inexpensive solar modules at prices far below the current industry standard.


The SALT process eliminates traditional abrasive slurries, wires, and multiple cleaning steps during spalling, while doubling the yield of a silicon ingot. The technique precisely engineers the stress applied to layers to spall thicker wafers, controlling the fracture front to ensure high-quality surfaces, and relying on low-temperature processes to minimize unwanted decrease of carrier lifetime. By maintaining the silicon quality during spalling and controlling the motion of the fracture front, the SALT process can dramatically reduce costs and be applied to a wide variety of solar technologies.