Atomic force microscopy study of growth kinetics: Scaling in TiN–TiB2 nanocomposite films on Si(1 0 0)

We used the reactive unbalanced close-field dc-magnetron sputtering growth of TiN–TiB2 on Si(1 0 0) at room temperature to determine if scaling theory provides insight into the kinetic mechanisms of two-phase nanocomposite thin films. Scaling analyses along with height-difference correlation functions of measured atomic force microscopy (AFM) images have shown that the TiN–TiB2 nanocomposite films with thickness ranging from 70 to 950 nm exhibit a kinetic surface roughening with the roughness increasing with thickness exponentially. The roughness exponent a and growth exponent b are determined to be 0.93 and 0.25, respectively. The value of dynamic exponent z, calculated by measurement of the lateral correlation length j, is 3.70, agreeing well with the ratio of a to b. These results indicate that the surface growth behavior of sputter-deposited TiN–TiB2 thin films follows the classical Family-Vicseck scaling and can be reasonably described by the noisy Mullins diffusion model, at which surface diffusion serves as the smoothing effect and shot noise as the roughening mechanism