Published online by Cambridge University Press: 11 February 2011
Random surface roughness very often can occur during the growth or etching of films under non-equilibrium conditions. Several competing mechanisms such as noise, surface diffusion, and shadowing all play a role in the evolution of surface roughness. However, recent results obtained in many growth and etching processes exhibit an unusual tendency: the morphology is very rough where it is expected to be smooth and vice versa. The origin, we believe, is due to the fact that during the deposition and etching processes the atoms very often do not stick to the surface upon their first strikes. Atoms actually bounce around before all settle on surface sites. This non-unity sticking probability can lead to a very rough surface during etching and a very smooth surface during sputter or chemical vapor deposition that cannot be explained by the conventional mechanisms.