Formation and kinetics of ion-induced yttrium silicide layers

Yttrium layers on amorphous or crystalline silicon substrates were irradiated with 600 keV Ar⁺⁺, Kr⁺⁺, and Xe⁺⁺ ions between liquid-nitrogen temperatures and 265°C. Ion-induced YSi _1.7 formed in those samples irradiated above 205°C and fluence ≥1×10¹⁵ ions/cm². The growth rates were monitored as a function of fluence and nuclear energy deposition at the Y/Si interface. For each ions species investigated, the growth rate varied linearly with the square root of fluence. The apparent activation energy was determined to be 0.6±0.1 eV. The experimental growth rates also exhibited a linear dependence on the nuclear energy deposition. This finding agrees qualitatively with the premise of nonoverlapping subcascades.