Project Name: Low Cost Tool Design for Cell and Module Fabrication with Thin, Free-Standing Silicon Wafers
Funding Opportunity: PVRD
SunShot Subprogram: Photovoltaics
Location: Cambridge, MA
SunShot Award Amount: $1,125,003
Awardee Cost Share: $131,276
Project Investigator: Tonio Buonassisi

This project aims to reduce the barriers to inexpensive photovoltaic (PV) module manufacturing by de-risking key technology elements necessary to enable manufacturing with lower capital costs. The project team will focus its efforts on the tools needed to enable high yield wafer, cell, and module fabrication with thin, free-standing silicon wafers. Thin wafers dramatically reduce the amount of polysilicon required and increase growth-system productivity, thereby reducing the capital expenditures associated with silicon refining and wafer fabrication, which together are more than half of the total capital costs of silicon module manufacturing.


The research team will work to reduce the failures associated with handling thin wafers by developing manufacturing approaches that prevent cracks that develop on wafer edges. The work will center on detection and measurement of edge cracks, safe handling of stand-alone thin wafers, and multi-wire cell stringing and interconnects for thin cells. This project will create a prototype crack-detection tool capable of detecting the presence of cracks, as well as a wafer-handling tool that places the wafer edges in compressive strain, which reduces cracks in the wafer. Stringing of thin cells will be enabled by the development of a multi-wire busbar prototype design to replace traditional tabbing.


This project will enable free-standing thin silicon wafers, while also enhancing manufacturing yield and reducing variable costs of line-of-sight silicon solar cells. The new tools developed in this project for crack detection and wafer handling will improve manufacturing yields. Robust and efficient silicon PV cells enabled by this project will have significantly lower capital expenditures than the current silicon cells, leading to significant reduction in silicon PV module costs.