First phase nucleation of metal-rich silicide in Ta/Si systems

Solid-phase reactions in the interfacial region of Ta/(100)Si systems have been studied by x-ray diffraction and Auger electron spectroscopy. The metal-rich silicide of Ta5Si3, which has never been observed in Ta/Si systems so far, is first nucleated at annealing temperatures of 600–650 °C in the first stage of the reaction. Subsequent annealing at 700 °C leads to the formation of a TaSi2 phase, and the metal-rich phase is replaced by TaSi2 at annealing temperatures over 700 °C by the out-diffusion of Si.