In this paper the surface roughness and topography of low-pressure chemical vapor deposition amorphous silicon films grown on (001) silicon substrates after phosphorus/argon/arsenic ion implantation, after annealing at 850 degreesC in an ambient N-2 environment and after further annealing to 1070 degreesC in O-2 environment have been investiaated. The influence of the different treatments on the sample surface topography was examined by atomic force microscopy in the noncontact mode. The surface composition of the films was analyzed by x-ray photoelectron spectroscopy for annealed and unannealed phosphorus implanted wafers. It was found that the surface roughness of the films is affected by implantation and annealing and mostly by implantation followed by annealing. Only implantation reduced the surface roughness while only annealing results in an increase of surface roughness. Implantation followed by annealing results in a drastic increase of surface roughness. "Bumps" which appeared following annealing seem to consist of a polysilicon structure. The evolution of surface roughness with annealing temperature is accompanied by a concurrent formation of silicon oxide. Implanted wafers annealed at 850 degreesC in an ambient N-2 grow a thin substochiometric silicon oxide layer which has a higher roughness than the as-deposit amorphous silicon layer. Further annealing to 1070 degreesC in a O-2 environment results in an increase in roughness and formation of a stochiometric SiO2 layer.