Structural and chemical changes during the growth of Fe nanoparticles in SiO<SUB align="right">2 under low energy ion implantation

Abstract

Low energy (15 keV) Fe implantation into SiO 2 (400 nm) on Si initially leads to the formation of very small Fe nanoparticles. The Fe nanoparticles grow in size and remain crystalline as the fluence is increased. At the same time there is Si and oxygen sputtering that reduces the thickness of the SiO 2 layer. It is this sputtering that leads to Fe nanoparticles that protrude from the surface for high Fe fluences of at least 5 × 10 16 at.cm –2 . The surface nanoparticles develop an oxide layer when exposed to air. Fe silicides (probably FeSi 2 ) also occur for these high fluences. Their formation is likely to occur because sputtering leads to a Si excess near the surface.