Investigation of the surface of P-implanted LPCVD silicon films

The surface morphology and crystallization of amorphous and polycrystalline silicon films, P-implanted at doses between 2 × 1014 and 8 × 1015 cm−2 and annealed at 950 °C, were investigated by scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques. It is found that a secondary grain growth process, dependent on the phosphorus dose, occurs at the film surface. Increasing the implantation dose above 5 × 1015 cm−2 determines the retardation of the grain growth. The mechanisms considered responsible for the structural changes of the films are the phosphorus diffusion on the grain boundary regions, determining the secondary grain growth, and the phosphorus segregation at the grain boundary, which determines the retardation process.