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We investigate the effect of Ar-ion-beam irradiation during the deposition of SiOx films by dual-ion-beam deposition system. Ion-beam irradiation effectively increases the oxygen content, x, in SiOx films indicative of the preferential sputtering of Si phase as compared to SiO2 phase in SiOx films. We observe the intense photoluminescence from nonirradiated sample after postdeposition annealing at 1100°C indicating the formation of Si nanocrystals as shown by a cross-sectional transmission electron microscope. However, the increased oxygen content in ion-beam-irradiated sample results in small optical volume of small Si nanocrystals not sufficient for yielding appreciable photoluminescence intensity after postdeposition annealing. The property is utilized for achieving the area-selective formation of Si nanocrytals by inserting a shadow mask in assist ion beam during deposition. [ABSTRACT FROM AUTHOR]

We observe a completely different growth regime of silicon-rich oxide (SRO) layers by rapid thermal chemical vapor deposition for the formation of luminescent nanocrystals. The growth regime is characterized by low [N[sub 2]O]/[SiH[sub 4]] ratios (<1) and high growth temperatures (>700 °C). High-resolution cross-sectional transmission electron microscopy (XTEM) shows the bimodal distribution of large polycrystals and nanocrystals after post-deposition annealing. The luminescence is attributed to the nanocrystals. Fourier transform infrared spectroscopy in conjunction with XTEM and energy-dispersive x-ray studies show the phase separation and bonding reconfiguration in as-deposited SRO layers. The effectively increased oxygen content in the oxide matrix by phase separation and bonding reconfiguration reduces the diffusion coefficient of Si in the matrix, resulting in the formation of nanocrystals during post-deposition annealing. © 2003 American Institute of Physics. [ABSTRACT FROM AUTHOR]