Structure and property of magnetron sputtered ternary cobaltnickel silicide films
Ternary cobaltnickel silicide films were prepared using magnetron sputtering from an equiatomic cobaltnickel alloy target on Si substrate. The effect of post-deposition annealing on the phase formation, structural properties and resistivity of the resultant films has been studied. The results of XRD show that the annealing temperature and impurity level of oxygen play a crucial role in controlling the phase transformation of ternary silicide. Silicide phases are absent in the as-deposited film due to the amorphous nature. At relatively low annealing temperature, the phase of CoNi3Si (220) and CoNiSi (220) coexist. With the increase of annealing temperature, the phase of CoNi3Si (220) begins to transform into CoNiSi (220). At high annealing temperature (800C), only the phase of CoNiSi2 (222) is formed. For CoNi silicide film annealed in pure argon gas ambient, two Raman peaks at 1357cm?1 and 1591cm?1 are attributed to the vibrational mode of CoSi2 and NiSi2 compounds. For ternary silicide annealed in atmosphere ambient, two Raman peaks located at 538cm?1 and 690cm?1 were observed and may be related to Si oxide or CoNi oxide. The 3D views of AFM images show that the surface roughness is relatively low when the silicidation temperature is smaller than 550C. After silicidation in 800C, the surface roughness increases abruptly. The resistance initially decreases with the increase of annealing temperature, and achieves minimum value (19??cm) in temperature ranges 500550C. When the annealing temperature increases from 600C to 800C, the resistivity was found to increase slightly to 26??cm. The ternary silicide shows a temperature window for low resistivity as compared to binary NiSi.
magnetron sputtering ternary cobaltnickel silicides annealing resistivity