Cobalt disilicide formed by rapid thermal annealing and throughmetal arsenic implantation

Abstract

Cobalt disilicide CoSi₂ of a specific resistivity of 23 μω was formed by the solid phase reaction of cobalt and silicon in the phase sequence of Co₂Si, CoSi, and CoSi₂ by use of rapid thermal annealing. The through-metal arsenic implantation caused the mixing of cobalt with the silicon substrate and the formation of cobalt silicides. A significant lateral growth of cobalt silicides was observed in samples subjected to one-step rapid thermal annealing process at 900 °C without through-metal ion implantation. Ion beam mixing reduced this lateral silicide growth efficiently, but resulted in a higher density of cobalt atoms remaining in the silicon oxide film than after rapid thermal annealing, as revealed by vapor phase decomposition atomic absorption spectroscopy.