Effect of elastic anisotropy on surface pattern evolution of epitaxial thin films

INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES

卷:46

Article

Pang, Yaoyu¹  Huang, Rui¹ 

[1] Univ Texas Austin, Dept Aerosp Engn & Engn Mech, Austin, TX 78712 USA

关键词: Surface pattern;    Epitaxial film;    Anisotropic elasticity;    Surface diffusion;   

DOI  :  10.1016/j.ijsolstr.2009.03.009

来源: Elsevier

【 摘 要 】

Stress-induced surface instability and evolution of epitaxial thin films leads to formation of a variety of self-assembled surface patterns with feature sizes at micro-and nanoscales. The anisotropy in both the surface and bulk properties of the film and substrate has profound effects on the nonlinear dynamics of surface evolution and pattern formation. Experimentally it has been demonstrated that the effect of anisotropy strongly depends on the crystal orientation of the substrate surface on which the film grows epitaxially. In this paper we develop a nonlinear model for surface evolution of epitaxial thin films on generally anisotropic crystal substrates. Specifically, the effect of bulk elastic anisotropy of the substrate on epitaxial surface pattern evolution is investigated for cubic germanium (Ge) and SiGe films on silicon (Si) substrates with four different surface orientations: Si(001), Si(111), Si(110), and Si(113). Both linear analysis and nonlinear numerical simulations suggest that, with surface anisotropy neglected, ordered surface patterns form under the influence of the elastic anisotropy, and these surface patterns clearly reflect the symmetry of the underlying crystal structures of the substrate. It is concluded that consideration of anisotropic elasticity reveals a much richer dynamics of surface pattern evolution as compared to isotropic models. (C) 2009 Elsevier Ltd. All rights reserved.

【 授权许可】

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