Analysis of Ti-silicide formation with a thin Ta interlayer on Si (100)

The phase formation of Ti-silicide with a Ta interlayer deposited on Si (100) substrates has been studied. The Ti layer of 100 Å was deposited on top of a 5 Å Ta interlayer on a Si (100) substrate. After metal deposition, the Si substrate was in-situ annealed at temperatures between 580 and 830 °C. Ti-silicides were formed and analyzed with using X-ray diffractometer (XRD), scanning electron microscope (SEM), Auger electron spectroscopy (AES), and transmission electron microscope (TEM) to verify the phase transition and the surface and interface morphologies. The change in the temperature of the phase transition from C49 to C54 TiSi₂ was observed. The C49 to C54 TiSi₂ phase transition temperature was below 630 °C for the samples with the Ta interlayer and was about 830 °C for the samples without the Ta interlayer. The temperature of the phase transition from C49 to C54 TiSi₂ with the Ta interlayer was observed to be lowered by about 200 °C. The AES data showed a 1:2 ratio of Ti:Si in the Ti-silicide layer and indicated that the Ta layer remained at the interface between TiSi₂ and the Si (100) substrate. A retarded agglomeration of Ti-silicide was observed with the Ta interlayer. The present results for Ti-silicide with a Ta interlayer confirmed that the areal coverage and island morphologies of TiSi₂ on Si (100) were uniform and smooth.