Effect of preamorphization implantation on C54–TiSi2 formation in salicided narrow lines

The effect of the preamorphization implantation (PAI) process on TiSi2 phase transformation has been investigated by using arrays of submicron TiSi2 lines. The C49–C54 transformation of TiSi2 during annealing is promoted by the PAI process. The promotion of phase transformation cannot be explained only by the difference in grain size of the C49–TiSi2; hence, the nucleation site density for the phase transformation was estimated. The epitaxial relation with the Si substrate also retards the C49–C54 phase transformation. The epitaxial growth of C49–TiSi2 on the Si substrate is observed in a large portion of C49–TiSi2 grains in the sample without PAI, whereas orientation of C49–TiSi2 in the sample with PAI has no relation to that of the Si substrate. Epitaxial C49–TiSi2 is more stable and is difficult to phase transform. After phase transformation, the C54–TiSi2 oriented to the 〈004〉 direction is predominant in the samples without PAI. The strong orientation of C54〈004〉 resulted from one-dimensional growth along submicron lines enhanced by the low density of the nucleation site. On the other hand, in the sample with PAI, an increase in the nucleation site leads to two-dimensional growth, and C54–TiSi2 films exhibit a random orientation with a weak dominant C54〈311〉 orientation.