XPS study of ion‐beam‐assisted formation of Si nanostructures in thin SiO ₂ layers

Abstract

Abstract Thin thermally grown SiO 2 layers have been enriched with Si up to ∼15 at.% by Si ion implantation at room temperature. X‐ray photoelectron spectroscopy (XPS) was used to monitor the composition changes caused in the layers by bombardment with 3 keV Ar ions at elevated temperatures. Argon ion irradiation of pure SiO 2 does not lead to the formation of Si nanoprecipitates. That was the case also for room‐temperature Ar bombardment of Si‐rich layers. Their ‘hot’ irradiation with Ar ions was found to enhance considerably the formation of segregated Si nanophase inclusions. The process starts at ∼500°C and becomes strongly pronounced at 650°C. At this temperature ion‐beam‐induced crystallization of Si nanoprecipitates may be achieved. The results obtained are explained in the framework of the physical model, based on the irradiation‐enhanced diffusion of excess Si atoms. Copyright © 2002 John Wiley & Sons, Ltd.