Invited Paper TF-WeA4
Mechanisms of Thin Film Growth under Shadowing and Re-Emission Effects

Wednesday, October 17, 2007, 2:40 pm, Room 613/614

Over the last decades, there has been a continuing interest on the mechanisms of the dynamic growth front morphology of thin films. Several competing mechanisms such as noise, surface diffusion, and shadowing have been well known to play roles in the evolution of surface roughness. Based on these effects, various growth models have been developed within the frame work of dynamic scaling theory in order to predict the evolution of thin film morphology. However, many experimentally obtained surfaces have been realized to be much rougher or smoother than the predictions of these models. Especially in processes where the shadowing effect is important due to the existence of obliquely incident particles (such as in sputter deposition, chemical vapor deposition, and plasma etching), the morphological evolution was smoother for deposition, while it was rougher for etched surfaces compared to the expected effect of shadowing. A recently recognized "re-emission" effect that originates from the non-unity sticking probability of incident particles offers a better understanding of morphological growth process. Non-sticking re-emitted particles can lead to a rough surface during etching and a smooth surface during deposition. It is shown that competing effects of shadowing and re-emission can predict many of the experimental results reported in the literature. It is also proposed that shadowing and re-emission effects can lead to a novel "universality class" of dynamic scaling behavior of the surface roughness.