Stress-driven surface evolution in heteroepitaxial thin films: Anisotropy of the two-dimensional roughening mode
- Process Development Group, Applied Micro Circuits Corporation, San Diego, California 92121 (United States)
- Materials Science and Engineering Department, Stanford University, Stanford, California 94305 (United States)
- Mechanical Engineering Department, Stanford University, Stanford, California 94305 (United States)
We have analyzed the anisotropic behavior of surface roughening in Si{sub 1{minus}x}Ge{sub x}/Si(001) heterostructures by use of methods of elastic analysis of undulated surfaces and perturbation analysis on the basis of global energy variations associated with surface evolution. Both methods have shown that the two-dimensional stage of surface roughening preferentially takes place in the form of ridges aligned along the two orthogonal {l_angle}100{r_angle} type directions. This prediction has been confirmed by {ital ex situ} experimental observations of surface evolution by use of atomic force microscopy and transmission electron microscopy in both subcritically and supercritically thick Si{sub 1{minus}x}Ge{sub x} films grown on Si(001) substrates. Further experiments in supercritically thick films have revealed a remarkable interplay between defect formation and surface evolution: the formation of a network of {l_angle}110{r_angle} misfit dislocations in the latter stages alters the evolution process by rotating the ridge formations toward the {l_angle}110{r_angle} type directions. {copyright} {ital 1999 Materials Research Society.}
- OSTI ID:
- 686525
- Journal Information:
- Journal of Materials Research, Journal Name: Journal of Materials Research Journal Issue: 8 Vol. 14; ISSN JMREEE; ISSN 0884-2914
- Country of Publication:
- United States
- Language:
- English
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