TEM analysis of an additional metal-rich component at the C49-C54 transformation in Ti/Si thin films capped with tin

From ex situ transmission electron microscopy observations it is shown that during the C49-C54 TiSi2 transformation in the system Ti/Si capped with (111) oriented TiN film, both phases coexist with a metal-rich third component located beneath TiN. Its metalysilicon ratio is close to 5:3. The high-degree of preferred orientation observed in the TiN and the metal-rich layers has been analyzed in terms of possible structural coherence between TiN (111) and Ti5Si3 (210) planes. In Ti5Si3, (210) planes contain sections where favorable Ti atom organizations exist slightly corrugated and restricted to short-scale areas. In TiN, similar Ti arrangements can be found in (111) planes. They may serve as local contacts between the silicide and nitride structures. The results indicate that the formation of titanium silicide in Ti/Si thin films can also be manipulated by capping the initial metal film with a layer exhibiting favorable nucleation sites for metal-rich silicide.