الفهرس 
Theoretical BackgroundOnly 14 pages are availabe for public view
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Abstract
The solid state reaction between Cu and a-Si films was investigated at
200 °C by depth profiling with secondary neutral mass spectrometry. Intermixing was observed leading to the formation of a homogeneous Cu3Si layer at the interface. The growth of the crystalline silicide follows a parabolic law at 200 °C. The parabolic kinetics can be estimated. The Cu3Si phase can play an interesting role in the field of power sources. But in silicon integrated circuits (ICs) the diffusion of Cu into the Si at rather low temperatures leads to degradation of devices. So, a suitable barrier material is required to prevent Cu from diffusing into the dielectric layer. ZnO and Al2O3 can be considered as candidates for these barriers. So, in this work we focus on fabrication and characterization of these oxides.
Highly transparent zinc oxide thin films with varied layer thicknesses have been prepared on microscopic glass substrates at 200 °C. Films thickness was measured by stylus profilometer. The films have been investigated for their structure using X-Ray diffraction; the patterns showed their amorphous nature. The dispersion parameters i.e. refractive index (n) and extinction coeffcient (k) are computed in the wavelength range (350–2500 nm). The Tauc model was used to determine the optical band gap and Urbach tail with direct allowed transitions. The real and imaginary parts of the high frequency dielectric constant were discussed. Other parameters such as penetration depth, cut-off wavelength, dissipation factor, volume and surface energy loss functions, reflection loss factor, optical, electrical and thermal conductivities have also been determined. A systematic study of a wide range of optical parameters of ALD prepared ZnO films can serve as a valuable data source and can enrich the knowledge of the studied material.
II
Also, In the present work we focus on how the stacking of Al2O3 and ZnO layers affects the optical properties of Al2O3/ ZnO thin films (Al2O3/ ZnO bilayer and Al2O3/Al2O3-ZnO mixed oxide/ZnO trilayer) prepared by ALD. The total thickness of the films and the thickness ratio of the pure Al2O3 and ZnO layers are the same. The extracted results from the X-ray diffraction suggested structural transformation as a function of the number of layers of pure and mixed Al2O3/ZnO. Analysis was performed to investigate the physical, optical and nonlinear optical properties. The dispersion parameters were investigated in the wavelength range of 280 – 2500 nm. The absorption coefficient, optical, electrical and thermal conductivities, furthermore penetration depth have also been determined. The absorption mechanism of the prepared samples obeys the rule of allowed indirect optical transitions. The value of the optical band gap was found to increase from 3.205 eV for bilayered to 3.229 eV for trilayered samples. The dispersion of the refractive index is described and discussed in terms of the single oscillator model proposed by Wemple – DiDomenico. Moreover, the phase velocity, electric susceptibility, reflection loss, and dispersion of nonlinear parameters such as third order nonlinear optical susceptibility and nonlinear refractive index are presented. Overall, from on the basis of these results several applications could be suggested for the layer samples obtained in this work.