Structural investigation of the initial interface region formed by thin titanium films on silicon (111)

A structural study of the initial interface region formed by titanium on silicon (111) was undertaken. Thin films (100 A) of titanium were deposited in ultrahigh vacuum (UHV) conditions onto atomically clean silicon(111) wafers and annealed in situ at 25 °C intervals between 300 and 475 °C. Structural characterization of the evolving interface was performed primarily via extended x-ray absorption fine structure (EXAFS) measurements. Results indicate that a major structural rearrangement takes place between 400 and 425 °C. EXAFS fitting analysis reveals this transition to be from a disordered TiSi-like phase to a more ordered C49-like disilicide state. The results are compared with those previously reported for the zirconium:silicon system.