Microstructral and charge-trap properties of single Hf-silicate dielectric films are presented versus annealing treatment. The as-grown films were found to be homogeneous and amorphous. It is shown that annealing treatment results in the formation of alternated Hf-rich and Si-rich layers. The mechanism responsible for this phenomenon is found to be surface directed spinodal decomposition. The increase of annealing temperature up to 1000-1100°C resulted in the crystallization of Hf-rich phase. The stability of its tetragonal phase caused an enhancement of film permittivity was observed. The evolution of charge trapping properties of the films results in the memory effect which nature was discussed.

The effect of thermal annealing on the optical properties of Al2O3 films with different Si content was investigated by the photoluminescence method. Si-rich Al2O3 films were prepared by RF magnetron co-sputtering of the silicon and alumina targets on long quarts glass substrates. Photoluminescence (PL) spectra of freshly prepared Si-rich Al2O3 films are characterized by three PL bands with the peak positions at 2.97-3.00, 2.25-2.29 and 1.50 eV. The thermal annealing of the films at 1150 °C during 30 min stimulates the formation of Si nanocrystals (NCs) in the film area with Si content exceeded 60%. After the thermal annealing the PL intensity of all mentioned PL bands decreases and the new PL band appears with the peak position at 1.67 eV. The new PL band is attributed to the photo currier recombination inside of Si NCs. The size of NCs estimated from the PL peak position 1.67 eV of Si NC emission is about ∼-4.5-5.0 nm.

The temperature dependences of PL spectra of Si-rich Al2O3 films have been studied in the range of 10-300K with the aim to reveal the mechanism of recombination transitions for mentioned above PL bands 2.97-3.00, 2.25-2.29 and 1.50 eV in freshly prepared films. The thermal activation of PL intensity and permanent PL peak positions in the temperature range 10-300K permit to assign these PL bands to defect related emission in Al2O3 matrix.

The present work deals with the comparative investigation of Si-ncs embedded in SiO2 and Al2O3 dielectrics grown by RF magnetron sputtering on fused quarts substrate. The effect of post-deposition processing on the evolution of microstructure of the films and their optic and luminescent properties was investigated. It was observed that photoluminescence (PL) spectra of Six(SiO2)1-x films showed one PL band, which peak position shifts from 860 nm to 700 nm when the x decreases from 0.7 to 0.3. It is due to exciton recombination in Si-ncs. For Six(Al2O3)1-x films, several PL bands peaked at about 570-600 nm and 700-750 nm and near-infrared tail or band peaked at about 800 nm were found. Two first PL bands were ascribed to different oxygen-deficient defects of oxide host, whereas near-infrared PL component is due to exciton recombination in Si-ncs. The comparison of both types of the samples showed that the main radiative recombination channel in Six(SiO2)1-x films is exciton recombination in Si-ncs, while in Six(Al2O3)1-x films the recombination via defects prevails due to higher amount of interface defects in the Six(Al2O3)1-x caused by stresses.