GROWTH-KINETICS OF COSI FORMED BY ION-BEAM IRRADIATION AT ROOM-TEMPERATURE

Growth kinetics of cobalt silicide layers formed by ion beam irradiati on was investigated at a temperature between room temperature and 100 degrees 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 x 10(15) c m(-2). The number of intermixed silicon atoms in the CoSi layers was e valuated as a function of dose, dose rate, and nuclear energy depositi on rate at the Co/Si interface for samples irradiated with 40 keV focu sed 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 pr oportional 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. (C) 1997 American Institute of Physics.