Structure and orientation of epitaxial titanium silicide nanowires determined by electron microdiffraction

The crystal structure and epitaxial orientation of self-assembled titanium silicide nanowires (NWs) on Si (111) is determined using transmission electron microdiffraction. The NWs are formed by deposition of ∼1 monolayer Ti on Si(111) at ∼850 °C. Type 1 NWs are oriented with long axis along Si〈2-20〉 and are identified as C49 TiSi2. The most common orientation is C49 [01-3] || Si [112] and C49 (200) || Si (2-20), but several other orientations are also found. Type 2 NWs are oriented with long axis along Si〈224〉 and are identified as B27 TiSi, with orientation B27 [02-1] || Si [111] and B27 (-312) || Si (22-4) + 4°. Most of the NWs are incommensurate and fully strain relaxed. They generally extend below the surface with inclined incoherent interfaces.