Redistribution of phosphorus during NiPtSi formation on in-situ doped Si

Abstract

This study focuses on silicide formation on phosphorus in-situ doped samples, the phosphorus diffusion and its distribution during the solid-state reaction. The silicidation is achieved with a 16 nm thin film of Ni0.9Pt0.1 followed by a two steps annealing process using rapid thermal annealing, selective etching and dynamic surface annealing. Silicide formation is investigated thanks to in-situ X-ray diffraction and X-ray reflectivity, while the phosphorus concentration profiles after silicidation are obtained by Time-of-Flight Secondary Ion Mass Spectroscopy. Based on these profiles, simulation of the phosphorus redistribution is achieved. The latter is linked to a fast diffusion in the silicide and at its grain boundaries. This feature is put forward to explain how doping may influence the phase sequence of silicide formation.