Amorphous Ta2O5 films were deposited by sputtering Ta onto silicon substrates with reactive ion beam. Electron energy loss spectroscopy measurements on the film found that the plasma oscillation energy is 23.1 eV. The refractive index and the extinction coefficient were measured with spectroscopic ellipsometry over the spectral range of 1.9–4.9 eV. The optical band gap is found to be 4.2 ± 0.05 eV. The valence band consists of three bands separated by ionic gaps. The values of electron effective masses were estimated with DFT quantum-chemical calculation. Experiments on injection of minority carriers from silicon into oxide were also conducted and we found that the electron component of conduction current governed by the electron current in the amorphous Ta2O5. 2008 Elsevier B.V. All rights reserved. PACS: 68.49.Uv; 71.15.Mb; 71.20. b; 72.20. i; 78.20. e

Amorphous Ta2O5 films were deposited by sputtering Ta onto silicon substrates with reactive ion beam. Electron energy loss spectroscopy measurements on the film found that the plasma oscillation energy is 23.1 eV. The refractive index and the extinction coefficient were measured with spectroscopic ellipsometry over the spectral range of 1.9–4.9 eV. The optical band gap is found to be 4.2 ± 0.05 eV. The valence band consists of three bands separated by ionic gaps. The values of electron effective masses were estimated with DFT quantum-chemical calculation. Experiments on injection of minority carriers from silicon into oxide were also conducted and we found that the electron component of conduction current governed by the electron current in the amorphous Ta2O5.

We demonstrate the growth of potential barriers, wells and periodic nanostructures on the basis of Hg1-xCdxTe by molecular beam epitaxy. In situ single wavelength ellipsometry is used for control of thickness and variation of Hg1-xCdxTe composition. The behavior of ellipsometric parameters measured during the growth of potential barriers, wells and periodic structures are in good agreement with the numerical calculated of variation of ellipsometric parameters psi and Delta. The thickness and composition of Hg1-xCdxTe nanolayers were determined from comparison of experimental and calculated psi and Delta. The accuracy of nanolayer thickness determination reaches the value of 0.1 nm and composition +/- 0.002 mole fraction.

Single wavelength ellipsometry with high time resolution was used for in situ control of MCT structures growth. Potential barriers and wells were grown with ellipsometric control of composition and thickness. Accuracy of barrier (well) thickness determination depends on the absolute value of the thickness and typically amounts to 0.1 nm. For MCT layers with continuously varying composition a simple interpretation of ellipsometric data was suggested allowing a control over composition profile in real time. Using this approach, MCT structures were grown with a top gradient barrier layer, preventing carriers surface recombination.

Systematization of major fields of laser ellipsometry. application is given and basic ways of its development are considered. A series of industrially oriented laser ellipsometers have been developed. These are a scanning. high-spatial resolution microellipsometer and a high-time resolution in-situ ellipsometer. The partial accuracy chart of the laser ellipsometers and the issues of their metrological certification are described. The possibilities of laser ellipsometry are illustrated by experimental measurements performed on equipment designed.

The integrated analytical equipment has been developed for in-situ measuring growth rate and film composition by the ultra-fast ellipsometer, surface temperature by the polarization-type pyrometer and for precise control over the epitaxial processes by automatic control system. This complex was used to control the mercury cadmium telluride heteroepitaxial structure growth on GaAs substrate with various composition distributions throughout the thickness. The maintenance accuracy of Hg1−xCdxTe composition during growth was up to ΔXCdTe=±0.0005. The maintenance accuracy of substrate temperature was found to be up to ±1°C.