Effect of annealing time on the growth, structure, and luminescence of nitride-passivated silicon nanoclusters

Rapid thermal annealing has been used to study the changes in luminescence and structure from silicon-rich silicon nitride films for annealing times ranging from 2 seconds to 1 hour at 600 and 800°C Silicon nanoclusters formed within the silicon nitride host matrix provided the source of the luminescence in the films through quantum confinement effects. Room temperature photoluminescence spectra exhibited a large, abrupt red-shift in emission after only 2 seconds of annealing, indicating early formation and growth of the silicon nanoclusters occurs through a fast transient diffusion mechanism. This initial shift was followed by a slower but steady growth of the nanoclusters as the annealing time was increased further. While the emission intensity of the films annealed at 600°C showed an increasing trend with longer annealing over the time period studied, the intensity peaked after 6 to 30 seconds of annealing at 800°C before decaying at longer times. X-ray absorption near edge structure at the Si K- and L_3,2-edges supported the trends observed in the photoluminescence spectra, providing evidence of silicon nanocluster growth and restructuring of the silicon nitride host matrix over the course of annealing. ©The Electrochemical Society.