Inducing rapid epitaxy of polycrystalline silicon films deposited on 〈100〉 silicon by arsenic ion implantation

Abstract

Alignment of undoped polycrystalline silicon deposited on 〈100〉 single-crystal silicon is known to occur for temperatures higher than 1000 °C. In this paper we provide evidence of a greatly enhanced epitaxy occurring in the polycrystalline silicon film after arsenic ion implantation, which amorphizes the surface layer of this film, followed by rapid thermal processing. The significantly enhanced epitaxy over that of undoped polycrystalline silicon is attributed to the mechanisms of solid phase epitaxial growth of the amorphized surface layer and alignment and realignment and coalescence, which are thought to be enhanced by arsenic segregation to the film grain boundaries and its interface with the silicon substrate via grain boundary diffusion. During this rapid epitaxy the arsenic atoms distribute themselves throughout the film, presumably with a considerable fraction occupying substitutional sites and electrically active.