A RHEED Study of Epitaxial Growth of Iron on a Silicon Surface: Experimental Evidence for Kinetic Roughening

In a molecular beam epitaxy (MBE) chamber, iron thin films are found to grow epitaxially on a (111) silicon surface at a temperature of about 50 °C and thus even at large thicknesses (up to 2400 Å) as checked in situ by reflection high-energy electron diffraction (RHEED). Electron diffraction also provides a clear evidence for a roughness which develops at the surface during the growth of the crystal. Subsequent annealing at about 200 °C clearly induces an irreversible flattening of this surface. Once the iron surface is made flatter, growth is started on this new surface which develops roughness as the iron thickness increases.