Diffusion of silicon in Pd₂Si during growth

The diffusion of silicon in Pd₂Si during silicide formation has been studied with the aid of radioactive ³¹Si. Annealing samples with the structure Si〈 〉/³¹Si/Pd at 350 °C produces Pd₂Si in which the ³¹Si is broadly distributed throughout the silicide, thereby indicating a very high silicon self‐diffusion in Pd₂Si during silicide formation. Since silicon self‐diffusion in Pd₂Si in the absence of growth is low at these temperatures, this suggests that silicon diffuses by a vacancy mechanism during polycrystalline Pd₂Si growth. If samples with the structures Si〈111〉/epitaxial Pd₂Si/³¹Si/Pd are annealed at the same temperature, the ³¹Si is found to be broadly distributed throughout the subsequently grown Pd₂Si, but very little diffusion of ³¹Si back into the epitaxial region is observed. It is argued that a silicon vacancy mechanism is the most probable diffusion mechanism to have produced the observed ³¹Si distribution and it is therefore proposed that silicon diffuses by a vacancy mechanism in both polycrystalline and epitaxial Pd₂Si growth.