We report a growth front morphology study of thermally evaporated amorphous Si films using atomic force microscopy. Since there are no well-defined atomic steps on an amorphous film surface, there is no Schwoebel barrier effect which would give rise to a moundlike morphology. The dynamic scaling characteristics observed during growth are unambiguously explained by a noise-induced growth mechanism. The roughness and growth exponents measured are consistent with the Mullins diffusion model with noise.

• Received 4 December 1995

DOI:https://doi.org/10.1103/PhysRevLett.76.3774