Dome-to-pyramid shape transition in Ge/Si islands due to strain relaxation by interdiffusion
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois (United States)
- Materials Science Division, Argonne National Laboratory, Argonne, Illinois (United States)
- Hewlett-Packard Laboratories, Palo Alto, California 94304 (United States)
Ge islands were grown on Si(001) and then annealed at 650 degree sign C for 0, 20, 40, and 60 min in a chemical-vapor deposition reactor following Ge deposition. This letter confirms the previous observations directly. By combining the ability to quantify strain with the ability to measure island dimensions in a transmission electron microscope, we were able to plot strain versus aspect ratio for the various annealing times. The islands first relax strain because of Si intermixing with the Ge epilayer causes the lattice mismatch to be lowered. Once the mismatch is sufficiently reduced, and thus the strain energy sufficiently reduced, it becomes favorable for the islands to reverse their shape back from domes to pyramids, thus reducing surface energy. This confirms the reversibility of island shape and thus the thermodynamics of the transition. (c) 2000 American Institute of Physics.
- OSTI ID:
- 20217577
- Journal Information:
- Applied Physics Letters, Vol. 77, Issue 11; Other Information: PBD: 11 Sep 2000; ISSN 0003-6951
- Country of Publication:
- United States
- Language:
- English
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