Nucleation rate reduction through stress relief of thermally annealed hydrogenated amorphous silicon films

摘要

The effect of film stress on crystallite nucleation is investigated in 0.11 μm thick, thermally annealed hydrogenated amorphous silicon films. Using a recently developed optical method, the crystallite density is measured as the films are isochronally annealed at 600 ℃, which enables the determination of the crystallite nucleation rate. This rate is significantly suppressed around scratches, cleaved film edges, and laser ablated areas, extending laterally as much as 100-150μm from these regions where the film connectivity is disrupted. μ-Raman measurements of the transverse optical mode of Si demonstrate an accompanying reduction in tensile stress in the regions where nucleation is suppressed. The first measurements of nucleation rate in stress and in stress relieved areas in the same film are presented.