The transition between commensurate and incommensurate growth of Ge//xSi//1// minus //x alloys on Si is observed directly by means of ion channeling and x-ray diffraction measurements. Molecular beam epitaxial films of thickness h up to 2500 A thick show commensurate epitaxy for x APP 1STH 50% and h APP GRTH h//c, a critical thickness dependent upon x. The observed values of h//c are discussed in terms of a model invoking the maximum theoretical interfacial shear strength and a barrier to misfit dislocation formation.
ASJC Scopus subject areas
- Physics and Astronomy(all)
- Physics and Astronomy (miscellaneous)