On the segregation of metals during low-energy oxygen bombardment of silicon

Segregation of metal impurities in Si under oxygen ion bombardment has been studied using secondary ion mass spectrometry. A strong evidence has been found for the thermodynamic driving force for segregation. This includes segregation of metal atoms at both interfaces of a buried SiO2 layer and the `antisegregationʹ behaviour of metal atoms having lower heats of oxide formation than Si. Segregation is enhanced at elevated temperatures when the metal diffusivity in amorphous Si is higher.