Funct. Mater. 2013; 20 (3): 332-339.

The influence of Pt  on solid state reactions in Ni  (30  nm)/Pt(x)  /Si_ep.(50  nm)/ Si  (001) (x=2  nm, 6  nm) nanodimensional films has been investigated. The layers of Pt  and Ni  were produced by magnetron sputtering technique on the epitaxially grown 50  nm Si  layer on the top of the monocrystalline Si  (001) substrate at the room temperature. Isochronal rapid thermal annealing of the samples was carried out in nitrogen atmosphere for 30  s in (450—900)°  C temperature range. In the as-deposited films no phase formations were observed. During heat treatments thermally activated solid state reactions began by formation of intermediate silicide phase of Ni₂Si  for x=2  nm, but the formation of this Ni  reach phase was hindered for x=6  nm. Increasing the annealing temperature up to 600°  C, independently from the thickness of the intermediate Pt  layer, NiSi  , PtSi  compounds as well as Ni_1—xPt_xSi  solid solution have been formed. Two-layered heterostructure has been observed for x=6  nm: complex polycrystalline Ni_1—xPt_xSi  phase formed close to the surface, below which the NiSi  phase was situated. Decomposition of Ni_1—xPt_xSi  silicide to the NiSi  (and PtSi  ) phases was observed after annealing above 650°  C and 850°  C. Si  enrichment at the surface of the Ni_1—xPt_xSi  , NiSi  and NiSi₂ phases is clearly observed on secondary neutral mass spectrometry depth profiles, which is interpreted as a consequence of the fast diffusion of Si  along the grain boundaries.