Growth instabilities in the deposition of amorphous films

TLDR: In this paper, the attractive forces between the oncoming atoms and those deposited become important in determining the growth of the film when surface diffusion and many atom rearrangement processes are suppressed (precisely the conditions that lead to the formation of amorphous films).

Abstract: It is proposed that during the atom-by-atom deposition of a film, the attractive forces between the oncoming atoms and those deposited become important in determining the growth of the film when surface diffusion and many atom rearrangement processes are suppressed (precisely the conditions that lead to the formation of amorphous films). The trajectories of the oncoming atoms are distorted in such a way that the formation and growth of surface irregularities are favored. Since the deflection depends inversely upon the incident kinetic energy of the atoms, sputtered films should be smoother than evaporated films for equal substrate temperatures. It is also argued that this mechanism can lead to the formation of voids.