A brief description of the RST technology

The substrate for the RST technology is a flexible graphite tape, currently produced for other applications. This tape, after being cut, purified, coated with a film of pyrolytic carbon (carbon deposited at high temperature), goes through a crucible which contains liquid silicon. The carbon tape emerging from the melt is coated on both sides by a crystalline silicon film. The silicon-carbon-silicon ribbons thus obtained are then cut by laser, and the carbon substrate is eliminated by a burn-off step in oxygen gas. The wafers thus obtained are finally etched before being transformed into solar cells.

Schema of the Solarforce process

The development of Solarforce™ Technology

For the development of its process, Solarforce has designed, produced and developed all the necessary equipment to implement the various stages up to the silicon wafer. This equipment involves cutting the graphite tape, the high temperature treatment of the carbon ribbon, the growth of the RST ribbon, its laser cutting, burning and etching. The design of the key equipment is the property of Solarforce.

The RST process being modular, these facilities are representative of future industrial machines; they prefigure industrial prototypes. Solarforce now produces multicrystalline silicon flat wafers 60 to 120 μm thick, which are cut into rectangular shape

Characterization tests on cells made from Solarforce wafers are now carried out in partnership with research centers. The results obtained in terms of conversion efficiency are already now around 15% and should continue to increase with the optimization of the material and the use of cell technologies adapted to the characteristics of RST wafers.


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See the Solarforce video

Solarforce video

Discover Solarforce and its technology in this 3’52 minutes-film.