Electrical properties of tisi2 clusters in poly-Si

Clusters of TiSi were formed in a polysilicon matrix by thermal annealing of a Ti-Si multilayer structure. The silicide grain size was varied by suitable thermal treatments. The DC electrical resistivity of the composite material has been measured in the 4-500 K temperature range by van der Pauw technique. Structural characterisation was performed by transmission electron microscopy equipped with an electron energy loss spectrometer. The dependence of resistivity on temperature indicated that at low temperature the electric transport occurs by percolation through connected TiSi grains, whilst at high temperature hopping between insulated grain dominates. The volume fraction of percolating grains and the hopping probability has been derived from the fit of the experimental data.