Planar solidification of multicrystalline silicon for photovoltaic applications

Crystalline Solar Silicon has reached a 95 percent market penetration in outdoor applications meanwhile. Cost studies for a high volume (500 MW) plant (EU - APAS) have proven that multicrystalline (mc) Silicon has the best potential to get to the lowest wafer costs. Planar solidified mc - Silicon (SOPLIN Process) has shown up meanwhile to be nearly as good as monocrystalline CZ - Si. An industrial production of mc - Si with a defect density of only 10(4) to 10(5)/cm(2), negligible electrical activity of grain boundaries, high lifetimes in processed wafers and about three times lower Oxygen contents compared to CZ - Si is possible. Special characterisation techniques will be mentioned. Efficiencies well above 16 % have been achieved by several independent laboratories with low cost, industrial production suited processes. The new Bayer Solar Company in Freiberg, designed for 16 million wafers/year, and their casting process is being introduced. The next generation of Solar Silicon Wafers may be manufactured from cheap ribbon foils. The status of the RGS process development at Bayer will be presented shortly.