Highly Conformal Deposition of Pure Co Films by MOCVD Using Co[sub 2](CO)[sub 8] as a Precursor

Highly conformal Co thin films were deposited on trenches with an aspect ratio of 13 by metallorganic chemical vapor deposition (MOCVD) using as a precursor in a low-temperature regime of where the growth rate was . Lowering the pressure of the process reduces the number of collisions in the gas phase and, thus, widens the temperature regime in which the surface reaction controls the growth rate. A processing pressure of allows for conformal deposition only at , whereas deposition at a reduced pressure of widens the temperature regime in which excellent conformality can be obtained. The conformal Co thin film, produced at and , showed a resistivity of and contained 1.0 atom % oxygen and less than 1.0 atom % carbon. After annealing this film at , its resistivity was reduced to , which is close to the bulk resistivity of Co. Therefore, this low-temperature process, which allows for the excellent conformal deposition of pure Co films, can be utilized to produce silicided contacts for advanced devices which require a low contact resistance and good electrical performance.