Evolution of coherent islands in Si{sub 1{minus}x}Ge{sub x}/Si(001)
- Sandia National Laboratories, Albuquerque, New Mexico 87185-1415 (United States)
- Division of Engineering, Brown University, Providence, Rhode Island 02912 (United States)
- Center for Microanalysis of Materials, University of Illinois, Urbana, Illinois 61801-2985 (United States)
- Sandia National Laboratories, Livermore, California 94551 (United States)
- Department of Materials Science and Engineering, Lehigh University, Bethlehem, Pennsylvania (United States)
The evolution of strain driven coherent islands is examined using sensitive real time stress measurements during heteroepitaxial growth of Si{sub 1{minus}x}Ge{sub x}/Si(001), combined with {ital ex situ} microscopy. We show that the sequence of morphological transitions at low mismatch strain is qualitatively identical to that for pure Ge heteroepitaxy on Si(001). In particular, films with strains less than 1{percent} undergo Stranski-Krastanov-like island-on-layer growth, followed by an extended regime of [501]-faceted hut clusters that eventually transform into higher aspect ratio dome clusters. The hut and dome islands are fully coherently strained and do not exhibit lateral composition modulation. Quantitatively, the relevant island length scales are significantly increased at low strain. Scaling of the morphological transitions with strain is directly demonstrated using the real time stress data. We further show that the apparent formation of a ripplelike surface morphology at low strain is actually a consequence of kinetic limitations on adatom diffusion, and does not necessarily signify the presence of a surface instability. {copyright} {ital 1999} {ital The American Physical Society}
- OSTI ID:
- 295543
- Journal Information:
- Physical Review, B: Condensed Matter, Vol. 59, Issue 3; Other Information: PBD: Jan 1999
- Country of Publication:
- United States
- Language:
- English
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