Design of antireflection coatings on different substrates

number: 
1906
إنجليزية
Degree: 
Author: 
Fatima Majid Khalil Al-Bahrani
Supervisor: 
Dr. Ziad T. Al-Dahan
year: 
2008
Abstract:

The purpose of this work is to design an antireflection coatings for semiconductor substrate by representation of antireflection coatings simulation programs. Antireflection coatings have been modeled for optical and electro-optical applications in two selected wavelengths of 630 nm, and 870 nm to reduce reflections from the surfaces of three semiconductor materials. There are several cases for designing antireflection coatings which are single, double, and multi-layer thin film deposit into three semiconductor materials of GaAs, AlGaAs, and Si which are widely used in electro-optics and laser applications, such as, detectors, laser sources, LED's, etc. All cases of optical thickness for deposit layers are studied in this work, such as quarter-wavelength coating and non-quarter wavelength coating for all designed number of layers. The reflection profiles of simulated design curves are compared and analyzed to demonstrate the use of these designed number of layers structure. The description of the method for determining the refractive indices of the coated materials determined from the dispersion formula for these materials in the range of the selected wavelengths, there are several coated materials which perform the optimum reflectivity response with the semiconductor surfaces. Multilayer antireflection coatings designed for two wavelengths of 630 nm, 870 nm and the resultant performance depended on the starting multilayer structure, while the simulated designed antireflection coatings had remarkable very good performance over a two designed wavelengths. Finally, the simulation results for the proposed antireflection coating for all types of coating have shown acceptable results.