In the SDS process (see flow diagram in Fig. 1) a bed of silicon dust, obtained from high purity gaseous feedstock, is prepared, acting both as a cheap substrate and as a “sacrificial detachment layer”. A thick film is then deposited on this bedding layer by fast CVD, at low temperature and atmospheric pressure. Finally, the detached free standing ribbon is recrystallised by a floating molten zone (ZMR — Zone Melting Recrystallization) technique.

The advantages of the SDS process are: (i) no substrate and therefore no associated cost and no contamination; (ii) low energy and thermal budget by use of atmospheric pressures and low temperature CVD; (iii) high quality, free standing, crystalline silicon sheet by float zone crystallisation, with no contact with foreign materials.