Growth kinetics of CoSi formed by ion beam irradiation at room temperature

Growth kinetics of cobalt suicide layers formed by ion beam irradiation was investigated at a temperature between room temperature and 100 °C. The CoSi phase was identified by x-ray diffraction of Co/Si samples irradiated with 25 keV argon ions to a dose of 2.0×10¹⁵ cm^-2. The number of intermixed silicon atoms in the CoSi layers was evaluated as a function of dose, dose rate, and nuclear energy deposition rate at the Co/Si interface for samples irradiated with 40 keV focused silicon ion beams. The growth is shown to be diffusion-limited and attributed to radiation-enhanced diffusion with an activation energy of 0.16 eV. The number of intermixed silicon atoms is approximately proportional to the nuclear energy deposition rate at the initial Co/Si interface, while it is independent of dose rate, which shows that the CoSi phase is formed without contribution of the sample heating caused by irradiation.