The formation of mosaics during the reactive growth of MgO films on Ag(100)

The morphology of ultra-thin MgO films has been studied using Spot-Profile Analysis Low-Energy Electron Diffraction (SPA-LEED). The films are deposited at 350 K on a Ag(100) substrate oxidizing Mg in an O-2 atmosphere during deposition. The intensity oscillations of the specular beam prove that the smooth film grows almost flat in the layer-by-layer growth mode. After depositing 1 ML, MgO satellites appear in the diffraction pattern, which can be attributed to mosaics with (100) planes tilted in the [010] directions. The tilt angle theta has been obtained from analysing the satellite positions at various scattering conditions. It decreases with increasing MgO coverage Theta. The mosaic coverage equilibrates at 7 ML. (C) 1998 Elsevier Science B.V. All rights reserved.