Characterisation of titanium disilicide thin films

Properties of TiN/TiSi2 thin films prepared on phosphorus-doped Si (1 0 0) substrates by sputtering of Ti film followed by a rapid thermal annealing in NH3 atmosphere at different conditions were studied. Thickness of as-deposited Ti layers was 40 and 60 nm and the annealing duration was set to 10 s at temperatures from 750 to 900 °C. Formation of a compact TiN/TiSi2/Si structure by rapid thermal annealing has been analysed by Auger electron spectroscopy and time-of-flight secondary ion mass spectroscopy depth profiling. Different amounts of oxygen in TiN layers and phosphorus redistribution in both TiN and TiSi2 layers have also been detected. Both C54 and C49 TiSi2 phases were identified by micro-Raman spectroscopy in samples annealed at 750 °C, whereas single C54 phase has been observed in samples annealed at higher temperatures. Creation of TiSi2 grains of sub-micrometer size at the TiSi2/Si substrate, explaining the depth dependence of the sheet resistance of silicide layers has been revealed by the scanning electron microscopy.