Kinetics of titanium silicide formation by rapid thermal processing

Summary Auger electron spectroscopy (depth profiling and line shape analysis), X-ray diffraction, and cross-sectional transmission electron microscopy were employed to investigate the kinetics of titanium silicide formation by rapid thermal annealing in N₂ and Ar ambients. A silicide is formed within only a few seconds at 620°–700°C. All the analysis techniques utilized reveal that the silicides primarily consist of sequential TiSi₂ and TiSi phases. The TiSi₂ is the metastable, poorly-conducting C49 modification. The TiSi₂ growth was evaluated quantitatively and was shown to be limited by diffusion of Si through the silicide. For annealing in N₂, the TiSi phase is stabilized compared to Ar annealing; additionally a titanium nitride forms near the surface and grows inward by another diffusion-limited process. When the TiSi and TiN reaction fronts approach the available Ti is consumed for these reactions; further silicide growth can only occur via complex phase transformations. The ratio of the activation energies for both diffusion processes was measured to be , in approximate agreement with literature data. The role of impurities for silicide growth will be discussed.

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Kinetik der Titansilizidbildung durch Kurzzeittempern