Dome-to-pyramid shape transition in Ge/Si islands due to strain relaxation by interdiffusion

William L. Henstrom, Chuan Pu Liu, J. Murray Gibson, T. I. Kamins, R. Stanley Williams

Research output: Contribution to journalArticle

40 Citations (Scopus)

Abstract

Ge islands were grown on Si(001) and then annealed at 650°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.

Original languageEnglish
Pages (from-to)1623-1625
Number of pages3
JournalApplied Physics Letters
Volume77
Issue number11
DOIs
Publication statusPublished - 2000 Sep 11

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy (miscellaneous)

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