Elastic constants and thermal expansion coefficient of metastable C49 TiSi2

The elastic constants and thermal expansion coefficient of C49 TiSi2 thin films have been investigated by in situ curvature measurement during heat treatment and ex situ x-ray diffraction measurements. The C49 TiSi2 compound was formed from Ti-Si multilayers deposited on monocrystalline silicon and sapphire substrates. The films were polycrystalline without any evident texture. Young’s modulus (142 GPa), Poisson’s ratio (0.27), and the thermal expansion coefficient (10.9×10−6 K−1) have been determined. Note that these values are averages over random crystal orientations. Directly after formation C49 TiSi2 films exhibit tensile stress. This stress relaxes considerably above 375 °C. Below this temperature the thermal expansion is found to be independent of the state of relaxation of the C49 TiSi2 film.