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.