Formation of cobalt silicide from filter metal vacuum arc deposited films

The thermal reaction of Co film deposited on Si(1 1 1) surfaces by a high current filter metal vacuum arc (FMEVAD) system has been studied. After deposition the films were annealed over the 400–900 °C temperature range for 30 min. Rutherford backscattering spectrometry (RBS) was used to characterize the elemental depth distributions in the films subjected to different annealing temperatures. Ordered chemical phases were determined by glancing-incidence X-ray diffraction (GIXRD) and the morphology was determined by cross section transmission electron microscopy (TEM). The results show that the phases formed are Co2Si at 400 °C, CoSi + CoO at 500 °C, CoSi + CoSi2 at 600 °C and CoSi2 at (700–800 °C). At 900 °C, CoSi2 was formed with a mixture of cubic cobalt and probably an amorphous cobalt oxide surface layer. The interface morphology was a rough cusp-like crenelation at 600 °C which became less pronounced after annealing at 800 °C.