Antimony dopant redistribution during copper silicide formation

In the present work, copper silicide formation and the redistribution of implanted Sb⁺ ions were studied by means of Rutherford backscattering spectrometry (RBS) and X-ray diffraction (XRD). Copper thin films, of 500 Å thickness, were evaporated, at room temperature, onto Sb implanted Si(111) wafers. Two doses, 5×10¹⁴ and 5×10¹⁵ Sb⁺ cm⁻², were used at 130 keV. The samples were heat treated in vacuum by conventional thermal annealing in the temperatures range 500–700°C for various times. It was observed that, independent of Sb implant dose, two silicides (Cu₃Si and Cu₄Si) were formed in the considered temperature range. Antimony ions implanted initially in the Si substrates were found to redistribute towards the sample free surface.