Origin of the C49-C54 volume anomaly in TiSi2 thin films: An in-situ XRD and TEM analysis

To analyze the origin of the C49-C54 volume anomaly in TiSi2 thin films, accurate thermal expansion coefficients were determined for both TiSi2 phases using in-situ X-ray diffraction. Between room temperature and 900 K, the C49 coefficients exhibit a clear anisotropy and the volume expansion is found to be larger in C54. This contributes to reduce the 2.0% volume difference usually observed at room temperature to 1.6% at the transformation temperature. The magnitude of the volume discontinuity during transformation is an indication of a first-order transition. At the C49-C54 transformation, TEM observations of annealed Ti/Si film capped with (111) TiN have shown that both phases coexist with a metal-rich third component indexed as Ti5Si3 and located beneath TiN. © 2002 Elsevier Science B.V. All rights reserved.