Scanning tunneling microscopy and spectroscopy characterization of ion-beam-induced dielectric degradation in ultrathin SiO2 films and its thermal recovery process

Abstract
We have investigated dielectric degradation in ultrathin SiO 2 films induced by ion-beam irradiation and its thermal recovery by using scanning tunneling microscopy(STM) and spectroscopy. Our STM results showed that although the ion-beam-induced damage uniformly spreads on the oxide, the dielectric properties are locally recovered by thermal annealing. We found that the tunneling spectra obtained from the ultrathin SiO 2 films are sensitive to the process-induced damage, and observed both a leakage current through the damaged oxide film and the thermal recovery of the insulating features. In addition, we confirmed a local charging phenomena of the damaged oxide caused by electron traps around the STM tip.