Published online by Cambridge University Press: 25 February 2011
A KrF (248 nm) pulsed laser was used to melt 90-, 190-, and 440-nm thickamorphous silicon layers produced by Si ion implantation into (100)crystalline Si substrates. Time-resolved reflectivity measurements at twodifferent probe wavelengths (633 nm and 1.15 μm) and post-irradiation TEMmeasurements were used to study the formation of an undercooled liquid Siphase and the subsequent solidification processes. The time-resolvedmeasurements provide new experimental information about the nucleation offine-grained Si crystallites in undercooled liquid Si, at low laser energydensities (Eℓ), and about the growth of large-grained Si in thenear-surface region at higher Eℓ. Measurements with the infraredprobe beam reveal the presence of a buried, propagating liquid layer at low??. Model calculations indicate that this liquid layer is generated in partby the release of latent heat associated with the nucleation and growthprocess.
Research sponsored by the Division of Materials Sciences, . S.Department of Energy under contract DE-ACO5-840R21400 with MartinMarietta Energy Systems,Inc.