scholarly journals Approximate methods for the optical characterization of inhomogeneous thin films: Applications to silicon nitride films

2019 ◽  
Vol 70 (7) ◽  
pp. 16-26
Author(s):  
Ivan Ohlídal ◽  
Jiří Vohánka ◽  
Daniel Franta ◽  
Martin Čermák ◽  
Jaroslav Ženíšek ◽  
...  
Keyword(s):  
Thin Films ◽  
Silicon Nitride ◽  
Optical Characterization ◽  
Point Of View ◽  
Approximate Methods ◽  
Multilayer Systems ◽  
Practical Point ◽  
Advantages And Disadvantages ◽  
Silicon Nitride Films

Abstract In this paper the overview of the most important approximate methods for the optical characterization of inhomogeneous thin films is presented. The following approximate methods are introduced: Wentzel–Kramers–Brillouin–Jeffreys approximation, method based on substituting inhomogeneous thin films by multilayer systems, method based on modifying recursive approach and method utilizing multiple-beam interference model. Principles and mathematical formulations of these methods are described. A comparison of these methods is carried out from the practical point of view, ie advantages and disadvantages of individual methods are discussed. Examples of the optical characterization of three inhomogeneous thin films consisting of non-stoichiometric silicon nitride are introduced in order to illustrate efficiency and practical meaning of the presented approximate methods.

Optical characterization of non-stoichiometric silicon nitride films

2008 ◽  
Vol 5 (5) ◽  
pp. 1320-1323 ◽  
Author(s):  
David Necas ◽  
Vratislav Perina ◽  
Daniel Franta ◽  
Ivan Ohlídal ◽  
Josef Zemek
Keyword(s):  
Silicon Nitride ◽  
Optical Characterization ◽  
Silicon Nitride Films

Preparation and Characterization of N-CdS Thin Films and its Schottky Barrier

2013 ◽  
Vol 665 ◽  
pp. 307-310
Author(s):  
K.D. Patel ◽  
Keyur S. Hingarajiya ◽  
Mayur M. Patel ◽  
V.M. Pathak ◽  
R. Srivastava
Keyword(s):  
Thin Films ◽  
Barrier Height ◽  
Thermionic Emission ◽  
Cadmium Sulphide ◽  
Optical Characterization ◽  
Point Of View ◽  
Flat Band ◽  
Zero Bias ◽  
Cds Thin Films

Cadmium sulphide (CdS), a member of group II-VI semiconductors is one of the promising materials from its applications point of view. The present investigations are about the preparation, structural and optical characterization of CdS thin films and their use as Schottky diode with Aluminum. Thin films of CdS having thickness around 700nm have been deposited by thermal evaporation. The chemical composition of the deposited CdS thin films has been made using EDAX technique. The structural characterization of this films was carried out using XRD. The structure of CdS after the deposition was found to be Cubic. Also, the lattice parameters were evaluated from the XRD data. From TEM of CdS thin films, the polycrystalline nature was confirmed. Optical characterization has been carried out using UV-VIS-IR spectroscopy. The direct as well as indirect band gaps obtained are 1.64eV and 1.48eV respectively. Schottky junctions were formed by a thermal vapor-deposition of 500nm Al films on pre-coated CdS glass substrates. Diode parameters, such as the zero bias barrier height φb0, the flat band barrier height φbf and the ideality factorη, were calculated using thermionic emission theory at room temperature.

scholarly journals Optical Characterization of Non-Stoichiometric Silicon Nitride Films Exhibiting Combined Defects

Coatings ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 416 ◽  
Author(s):  
Jiří Vohánka ◽  
Ivan Ohlídal ◽  
Miloslav Ohlídal ◽  
Štěpán Šustek ◽  
Martin Čermák ◽  
...  
Keyword(s):  
Experimental Data ◽  
Silicon Nitride ◽  
Least Squares Method ◽  
Uniaxial Anisotropy ◽  
Optical Characterization ◽  
Inhomogeneous Layer ◽  
Matrix Formalism ◽  
Random Roughness ◽  
Silicon Nitride Films

The study was devoted to optical characterization of non-stoichiometric silicon nitride films prepared by reactive magnetron sputtering in argon-nitrogen atmosphere onto cold (unheated) substrates. It was found that these films exhibit the combination of three defects: optical inhomogeneity (refractive index profile across the films), uniaxial anisotropy with the optical axis perpendicular to the boundaries and random roughness of the upper boundaries. The influence of the uniaxial anisotropy was included into the corresponding formulae of the optical quantities using the matrix formalism and the approximation of the inhomogeneous layer by a multilayer system consisting of large number thin homogeneous layers. The random roughness was described using the scalar diffraction theory. The processing of the experimental data was performed using the multi-sample modification of the least-squares method, in which experimental data of several samples differing in thickness were processed simultaneously. The dielectric response of the silicon nitride films was modeled using the modification of the universal dispersion model, which takes into account absorption processes corresponding to valence-to-conduction band electron transitions, excitonic effects and Urbach tail. The spectroscopic reflectometric and ellipsometric measurements were supplemented by measuring the uniformity of the samples using imaging spectroscopic reflectometry.

Optical characterization of silicon nitride films deposited by ECR-CVD

Vacuum ◽  
1994 ◽  
Vol 45 (10-11) ◽  
pp. 1027-1028 ◽  
Author(s):  
S García ◽  
JM Maŕtin ◽  
I Mártil ◽  
G González-Díaz
Keyword(s):  
Silicon Nitride ◽  
Optical Characterization ◽  
Silicon Nitride Films

Characterization of Silicon Nitride Thin Films on Si and Overlayer Growth of Si and Ge

2001 ◽  
Vol 40 (Part 1, No. 6B) ◽  
pp. 4292-4298 ◽  
Author(s):  
Xue-Sen Wang ◽  
Zongquan Li ◽  
Lei Wang ◽  
Yanfang Hu ◽  
Guangjie Zhai ◽  
...  
Keyword(s):  
Thin Films ◽  
Silicon Nitride

Structural and Optical Characterization of Zinc Telluride Thin Films

2013 ◽  
Vol 665 ◽  
pp. 254-262 ◽  
Author(s):  
J.R. Rathod ◽  
Haresh S. Patel ◽  
K.D. Patel ◽  
V.M. Pathak
Keyword(s):  
Thin Films ◽  
Extinction Coefficient ◽  
Nir Spectroscopy ◽  
Optical Characterization ◽  
X Ray Diffraction ◽  
X Ray ◽  
Evaporation Technique ◽  
Film Form ◽  
Znte Thin Films

Group II-VI compounds have been investigated largely in last two decades due to their interesting optoelectronic properties. ZnTe, a member of this family, possesses a bandgap around 2.26eV. This material is now a day investigated in thin film form due to its potential towards various viable applications. In this paper, the authors report their investigations on the preparation of ZnTe thin films using vacuum evaporation technique and their structural and optical characterizations. The structural characterization, carried out using an X-ray diffraction (XRD) technique shows that ZnTe used in present case possesses a cubic structure. Using the same data, the micro strain and dislocation density were evaluated and found to be around 1.465×10-3lines-m2and 1.639×1015lines/m2respecctively. The optical characterization carried out in UV-VIS-NIR region reveals the fact that band gap of ZnTe is around 2.2eV in present case. In addition to this, it was observed that the value of bandgap decreases as the thickness of films increases. The direct transitions of the carries are involved in ZnTe. Using the data of UV-VIS-NIR spectroscopy, the transmission coefficient and extinction coefficient were also calculated for ZnTe thin films. Besides, the variation of extinction coefficient with wavelength has also been discussed here.

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