Creation of Si nanocrystals from SiO2/Si by He and H ion implantation

Cz (1 0 0)-oriented n-type Si wafers with a 220 nm SiO2 surface layer were sequentially implanted with He and H ions at two different energy combinations, and subjected to furnace annealing in the temperature range from 400 to 1000 °C. Si nanocrystals have been created by sequentially He and H ions implanted Si/SiO2 and thermal annealing. High-resolution transmission electron microscopy and atomic force microscopy reveal the formation of Si nanocrystals (NCs) in the SiO2 layer. Photoluminescence (PL) measurements show a broad ultraviolet light emission band, which is mainly made up of two peaks situated at about 300 and 370 nm, respectively. The formation mechanism of Si NCs in the SiO2 layer by sequential implantation of He and H ions and annealing has been proposed in view of the results on surface damage and defect microstructures.