Effect of a substrate on the phase transformations of amorphous TiSi2thin films

摘要

The crystallization of an amorphous TiSi2evaporated film has been studied on both poly‐Si and SiO2substrates. A metastable form of TiSi2(base‐centered orthorhombic;a=3.62 A,b=13.76 A, andc=3.605 A) P. G. Cotter, J. H. Kohn, and R. A. Potter, J. Am. Ceram. Soc.39,11 (1956) is formed first at a temperature of approximately 350 °C on both substrates. This phase consumes the entire amorphous layer before undergoing a polymorphic transformation to face‐centered orthorhombic TiSi2(a=8.24 A,b=4.78 A, andc=8.54 A) F. Laves and H. J. Wallbaum, Z. Kristallogr.101,78 (1979) at 600 and 800 °C on poly‐Si and SiO2, respectively. These transformations were investigated usinginsituresistivity, x‐ray diffraction, and transmission electron microscopy. The room‐temperature resistivities observed were 96 and 20 mgr;OHgr; cm for the base‐centered and face‐centered TiSi2, respectively. The enhanced polymorphic transformation on poly‐Si over SiO2is explained by a lowering of surface energy barrier to nucleation.