AFM and TEM study for surface morphology and grain growth of rapid thermal annealed dichlorosilane based CVD tungsten silicide

Surface morphology and grain size of dichlorosilane (DCS) based CVD WSix films of different thickness are investigated by AFM and TEM. The experimental result shows that the grain size and surface roughness increases with the film thickness. It means that the thicker WSix film has higher background noise level which may add particles to a scatterometer measurement. In addition, film stress deviation induced by rapid thermal annealing (1000°C, 30 sec, in N₂) decreases with the film thickness because of a different degree of recrystallization. Furthermore, the surface roughness has no significant changes during rapid thermal annealing which indicates that phase transition or silicon precipitation is the dominant factor to effect film reflectivity