Revival of Smooth MgO(100) Surface: Ar Ion-Beam Milling and Postvacuum Annealing in Oxygen Atmosphere

A recreation procedure for achieving the smooth and clean surface morphology of the degraded MgO(100) substrates is presented. The surfaces of the degraded MgO(100) substrates are treated with Ar ion-beam milling (IBM) and annealing in O-2 atmosphere. After each treatment, the changes in the MgO(100) substrate surface morphology are characterized using X-ray diffraction (XRD), a 3D optical profilometer, atomic force microscopy, and Fourier-transform infrared (FTIR) spectroscopy and compared with a fresh MgO substrate. It is shown that before any treatment, XRD and FTIR spectra show peaks corresponding to hydroxyl and carbonate groups in the degraded samples, whereas after treatment, XRD and FTIR spectra are comparable with the fresh sample. Further, after treatment, the surface roughness R-av value for two used/degraded samples reduces from 129 and 186 nm to 3.96 and 7.91 nm, respectively, after combined Ar IBM and annealing treatment. It is shown that the surface quality of the treated MgO(100) substrate improves in comparison with as it was before any treatment and can be reused for the good quality thin-film deposition.