Scanning electron microscopy and cathodoluminescence were used to investigate the irradiation-sensitive defect structure of pure and Ge+-implanted amorphous silicon dioxide layers. Cathodoluminescence emission spectra from specimens between liquid N temperatures and room temperature were identified with particular defect centers including the non-bridging O-hole center (Si-O▪) associated with the red luminescence at 650nm (1.9eV), the self trapped exciton with the yellow-green luminescence at 580nm (2.1eV) and the Si-related O-deficient center with the blue (460nm; 2.7eV) and ultra-violet band (295nm; 4.2eV). In Ge doped SiO2 an additional emission band was identified at (410nm; 3.1eV). This band corresponds to the Ge-related O-deficient center. The annealing process of Ge+-implanted layer leads first to a strong increase of the violet luminescence due to formation of Ge dimers, trimers and higher aggregates, finally to destruction of the luminescence centers by further growing to Ge nanoclusters.

Electron Beam Induced Defects in Ge-Implanted SiO2 Layers. R.Salh, A.von Czarnowski, H.J.Fitting: Physica Status Solidi C, 2005, 2[1], 580-3