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-Pro file Analysis Low-Energy Electron Diffraction (SPA-LEED). The films ar e deposited at 350 K on a Ag(100) substrate oxidizing Mg in an O-2 atm osphere during deposition. The intensity oscillations of the specular beam prove that the smooth film grows almost flat in the layer-by-laye r growth mode. After depositing 1 ML, MgO satellites appear in the dif fraction pattern, which can be attributed to mosaics with (100) planes tilted in the [010] directions. The tilt angle theta has been obtaine d from analysing the satellite positions at various scattering conditi ons. It decreases with increasing MgO coverage Theta. The mosaic cover age equilibrates at 7 ML. (C) 1998 Elsevier Science B.V. All rights re served.