Abstract
The first nucleated phase in ultrahigh vacuum deposited Ti thin films on silicon has been unambiguously identified utilizing high-resolution transmission electron microscopy (HREM) in conjunction with optical diffractometry. Ti 5 Si 3 was found to form first at the interface of the Ti overlayer and the amorphous interlayer. For plan-view specimens of the samples annealed at 450°C for 30 min, 1 and 2 h, all 15 silicide diffraction rings corresponding to interplanar spacings longer than 0.098 nm could be attributed to Ti 5 Si 3 . Ti 5 Si 3 was also the only silicide phase that could match the symmetry and lattice spacings of the HREM images. The observation is consistent with a kinetic model which predicts that the crystalline phase with composition and structure nearest to that of the amorphous interlayer will be first nucleated.