Formation of Several-Micrometer-Thick Polycrystalline Silicon Films on Soda Lime Glass by Flash Lamp Annealing

We have succeeded in forming polycrystalline silicon (poly-Si) films with thicknesses of over 4 μm on soda lime glass by flash lamp annealing (FLA) of precursor amorphous Si (a-Si) films deposited by catalytic chemical vapor deposition (Cat-CVD). The insertion of Cr thin films between glass substrates and a-Si significantly improves the adhesion of Si films to the glass substrates, resulting in uniform crystallization of a-Si in 20 × 20 mm^2 area. Several types of substrate, such as quartz substrates, are also used instead of soda lime glass to elucidate the effects of the properties of glass substrates on formation of the poly-Si films. A-Si films tend to be crystallized under lower irradiance than those on quartz glass substrates, which can be described by the lower thermal conductivity and the thermal diffusion length of soda lime glass. Raman spectra of the poly-Si films on soda lime glass show high crystallinity close to unity. The utilization of soda lime glass with poor thermal resistivity is of great importance for the cost-effective mass production of thin-film poly-Si solar cells