Nucleationless island formation in SiGe/Si(100) heteroepitaxy

The formation of faceted three-dimensional (3-D) islands during growth of Si1−xGex alloys on Si(100) has been investigated by low-energy electron microscopy (LEEM). The formation of the islands in this alloy system does not involve 3-D nucleation, but rather proceeds continuously via a precursor array of shallow, stepped mounds on the surface that result from the inherent morphological instability of the strained alloy film.