Inline fast CVD sysyem for continuous production of silicon ribbons for solar cells by the SDS process

The silicon wafer accounts for about half of the photovoltaic module cost. We believe two aspects are essential to reduce considerably the "wafer" costs: the feedstock issue and ribbon technology. In the SDS process the pre-ribbons are grown directly from silane by fast CVD process and followed by zone melting recrystallization (ZMR). In this paper a new generation of fast CVD reactor to grow silicon ribbons in a continuous mode by the SDS process is presented along with results on the CFD modeling that led to the reactor design. To perform the CVD, halogen lamps with elliptical mirrors are used. Due to the existing optics the radiation is focused on the deposition surface, promoting the creation of well defined convection flow cells inside the reactor. The need to increase both the pre-ribbon deposition homogeneity and recrystallization success and the adaptation of the reactor to an inline process, are the reasons for this new generation of the SDS reactor.