Nanostructured TiO x film on Si substrate: room temperature formation of TiSi x nanoclusters

We present a morphologic and spectroscopic study of cluster-assembled TiO _x films deposited by supersonic cluster beam source on clean silicon substrates. Data show the formation of nanometer—thick and uniform titanium silicides film at room temperature (RT). Formation of such thick TiSi _x film goes beyond the classical interfacial limit set by the Ti/Si diffusion barrier. The enhancement of Si diffusion through the TiO _x film is explained as a direct consequence of the porous film structure. Upon ultra high vacuum annealing beyond 600 °C, TiSi₂ is formed and the oxygen present in the film is completely desorbed. The morphology of the nanostructured silicides is very stable for thermal treatments in the RT—1000 °C range, with a slight cluster size increase, resulting in a film roughness an order of magnitude smaller than other TiO _x /Si and Ti/Si films in the same temperature range. The present results might have a broad impact in the development of new and simple TiSi synthesis methods that favour their integration into nanodevices.