In situ x-ray diffraction analysis of the C49-C54 titanium silicide phase transformation in narrow lines

The transformation of titanium silicide from the C49 to the C54 structure was studied using x-ray diffraction of samples containing arrays of narrow lines of preformed C49 TiSi2. Using a synchrotron x-ray source, diffraction patterns were collected at 1.5-2°C intervals during sample heating at rates of 3 or 20°C/s to temperatures of 1000-1100°C. The results show a monotonic increase in the C54 transition temperature by as much as 180°C with a decreasing linewidth from 1.0 to 0.1 μm. Also observed is a monotonic increase in (040) preferred orientation of the C54 phase with decreasing linewidth. The results demonstrate the power of in situ x-ray diffraction of narrow line arrays as a tool to study finite size effects in thin-film reactions.© 1995 American Institute of Physics.