Layer Formation and Surface Roughness in Films Obtained by Alternate Deposition
Abstract
Our 3D Monte Carlo model has been used to explore layer formation and surface roughness in films obtained by alternate deposition of two components. The effect of the alternation period on these characteristics has been studied. The main results are: 1) As the period of alternation increases, two transitions occur: Alloy - Ring Structure - Discrete Multilayer Structure. In the simulated films, good layering and layer uniformity have been achieved starting at 2+2 ML alternation periods. 2) In films with negative mixing energy, the surface roughness is lower and in films with positive mixing energy it is higher than in films with zero mixing energy. This is contrary to the usual belief that stronger coupling between two films deposited onto each other always leads to smoother film growth. 3) The surface roughness shows non-monotonic dependence on the alternation period. For films with positive mixing energy (hindering the component mixing), the smoothest surface has been obtained at approximately 1+1 ML periods. In the case of negative mixing energy the roughest surfaces has been obtained at 0.5+0.5-ML period. 4) In the case of positive mixing energy, for 2+2-ML and larger periods, the dependence of roughness on film thickness shows a zigzag behavior. This is due to collars of the newly deposited atoms that form around islands and act as an artificial Ehrlich-Schwoebel barrier before they are burried.
- Publication:
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APS March Meeting Abstracts
- Pub Date:
- March 2000
- Bibcode:
- 2000APS..MARK31002S