Characteristics of the nanoscale titanium film deposited by plasma enhanced chemical vapor deposition and comparison of the film properties with the film by physical vapor deposition

Abstract

TiSi2 film was grown by plasma enhanced chemical vapor deposition (PECVD) method for lower contact resistance. We obtained a uniform TiSi2 film on Si substrate. The growth rate of TiSi2 on Si substrate is four times higher than that of Ti on silicon dioxide. The thickness ratio of TiSi2∕Si is very high at the early stage of growth. The high ratio, 8.8, results from a long incubation time before the formation of Ti film on silicon dioxide and ignoring the incubation time, thickness ratio is almost constant in the given thickness range. The average of thickness ratio is determined as 4.25. C49 (060) phase was formed on Si substrate by PECVD method and C49 TiSi2 phase was not changed into C54 one by rapid thermal annealing (RTA) at 900°C. We could not observe boron segregation at the TiSi2∕Si interface. On the contrary, we observed inward diffusion of boron into Si substrate during the silicide formation. We obtained 1.21×103Ω of contact resistance by PECVD method. When Ti thickness is less than 1nm, the contact resistance is comparable with that by physical vapor deposition method or lower.