MICROVOID FORMATION IN LOW-TEMPERATURE MOLECULAR-BEAM-EPITAXY-GROWN SILICON

In a study of (100) Si growth by molecular-beam epitaxy, we have observed an interesting growth phenomenon associated with epitaxial growth at low temperatures. Electron-microscope imaging reveals that the growth surface no longer remains planar but develops a series of cusps with {111}-oriented facets that generate linear arrays of spherical defects. Both electron microscopy and variable-energy positron-annihilation spectroscopy have been used to determine that the defects are in fact microvoids.