CHARACTERIZATION OF PHASE-TRANSFORMATION IN TITANIUM POLYCIDE FILMS

Silicide formation on polysilicon from deposited titanium films and ef fects of subsequent thermal annealing at different temperatures (600 d egrees C-900 degrees C) have been investigated by grazing-angle XRD, A FM, ESCA and sheet resistance measurements. The results indicated form ation of a high-resistivity isomorphic phase (C49), polymorphic phases (C49 and C54) and low-resistivity isomorphic C54 TiSi2 films at low, medium and high annealing temperatures from 600 degrees C to 900 degre es C. The complete conversion from C49 to isomorphic C54 TiSi2 phase o ccurs at about 850 degrees C. The influence of phase formations and po lymorphic transformation on the surface morphology is studied by estim ating the r.m.s. surface roughness using AFM. Samples annealed at 900 degrees C have the highest surface roughness of 15.47 nm owing to aggl omeration of C54 grains in TiSi2 films. XPS studies showed the formati on of a thin layer of TiO2 on the surface of TiSi2.