MORPHOLOGY DEPENDENT PLATINUM SILICIDE FORMATION IN OXYGEN AMBIENT

The temperature induced silicide growth of thin (50 nm) platinum films after room temperature deposition on Si(100) is studied by scanning e lectron microscopy methods (Auger crater edge depth profiling and tran smission techniques) and scanning tunneling microscopy (STM). The pres ence of oxygen is known to slow down or even to stop this reaction bef ore all metal is consumed by the silicide formation process. We found the influence of oxygen during the annealing of the system to be stron gly dependent on the morphology of the as-deposited Pt film. Based on the results obtained for processing Pt films with different grain size s in UHV and 10 Pa oxygen ambient, respectively, a model for the oxyge n induced inhibition of the silicide formation is proposed suggesting a grain boundary diffusion mechanism of oxygen in the unreacted platin um.