Tem Investigation of Titanium Silicide Thin Films

Titanium silicide films grown on silicon were analyzed by transmission electron microscopy (TEM), electron diffraction, scanning transmission electron microscopy (STEM), and energy dispersive x-ray spectroscopy. The films were prepared by sequential rapid thermal annealing (RTA) at 675 °C and 850 °C of 16-nm-thick sputtered Ti on Si (001) wafers. In some cases, a 20-nm-thick TiN capping layer was deposited on the Ti film before the RTA procedure and was removed after annealing. TEM and STEM analyses showed that the silicide films were less than 0.1 μm thick; the capped film was more uniform, ranging in thickness from ∼ 25 – 45 nm, while the uncapped film ranged in thickness from ∼ 15 – 75 nm. Electron diffraction was used to determine that the capped film contained C54-TiSi2, C49-TiSi2, Ti5Si3, and possibly TiSi, and that the uncapped film contained C49-TiSi2, TiSi, Ti5Si3, unreacted Ti, and possibly C54-TiSi2.