FORMATION OF EPI-C49 TISI2/SI(111) BY SOLID-PHASE EPITAXIAL-GROWTH

Abstract

Solid-phase epitaxial growth of TiSi2 with a C49 structure was obtained by depositing an ultra-thin Ti film on a Si(111)-7 X 7 substrate in ultra-high vacuum and in-situ annealing. X-ray diffraction and Auger electron spectroscopy showed that TisSi4 and C49-TiSi2 phases coexisted in the samples annealed at 500-degrees-C and 600-degrees-C. However, at 650-degrees-C, only the C49-TiSi2 phase was detected. When the deposited thickness of the Ti film exceeded 30 ML, agglomeration due to grain boundary grooving took place, which resulted in the formation of silicide islands. The best epitaxial growth of C49-TiSi2 was obtained from the Ti(30 ML)/Si(111)-7 x 7 sample annealed at 650-degrees-C for 20 min. Images of cross-sectional high-resolution transmission electron microscopy showed that the C49-TiSi2/Si(111) interface was clear and that no glassy phase was formed. The orientation relationship between the C49-TiSi2 and the Si(111) substrate was TiSi2[211BAR] parallel-to Si[011BAR], TiSi2(120) parallel-to Si(111) without a misorientation angle. Almost the whole area of the sample was covered with the epitaxial C49 structure.