Effect of implantation and annealing regimes on ion-beam synthesis of InAs nanocrystals

Abstract

We reported the formation of nanosized InAs crystallites in silicon wafers by means of As (245 keV, 4.1⋅10¹⁶ cm^–2) and In (350 keV, 3.7⋅10¹⁶ cm^–2) implantation. The implantation was carried out at 25 and 500 ^∘C. In order to verify the effect of getter on precipitates growth an additional procedure was carried out for the samples implanted with As and In species at the room temperature. This procedure included the implantation of H₂⁺ ions with the energy of 100 keV at 1.2⋅10¹⁶ cm^–2.
Afterwards, the samples were annealed at 900 ^∘C for 60 min in inert ambient. In order to characterize the implanted layers, Rutherford backscattering spectrometry in combination with the channelling (RBS / C) and transmission electron microscopy (TEM) techniques were used. TEM has revealed InAs nanocrystals in implanted samples after the annealing. It has been shown that average size and size distribution of InAs clusters depend on implantation temperature and annealing duration. Signicant diffusional redistribution of implanted species has been revealed after hot implantation and post-implantation annealing. We have suggested that it is caused by non-equilibrium diffusion. The radiation-enhanced diffusivities at hot implantation have been determined for the abovementioned experimental conditions.
Keywords: crystalline silicon, high-fluence implantation of As and In ions, InAs nanocrystals
PACS: 61.46.-w, 61.72.Tt, 68.37.Lp, 78.67.Bf