GRAIN-BOUNDARY DEFECTS IN LASER-CRYSTALLIZED POLYCRYSTALLINE SILICON

Polycrystalline silicon (poly-Si) films were prepared by laser crystal lization of amorphous silicon with various laser energy densities at s ubstrate temperatures of 300 and 673 K. At T-S=300 and 673 K poly-Si f ilms with grain sizes of 1.5 and 1.0 mu m were obtained at laser fluen ces-of 540 and 505 mJ/cm(2), respectively. An increase of the grain si ze results in a decrease of the spin density due to a reduction of the grain-boundary volume. Moreover, the increase in substrate temperatur e resulted in a pronounced decrease of the spin density independent of the laser energy density. Defects are passivated by exposing the poly -Si films to monatomic H at 350 degrees C. This causes the spin densit y to decrease to a residual value of approximate to 9x10(16) cm(-3) in dependent of substrate temperature and laser fluence.