Master Degree / Yüksek Lisans Tezleri

Permanent URI for this collectionhttps://hdl.handle.net/11147/3008

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Language: search.filters.language.enSubject: search.filters.subject.Silicon wafers

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  • Master Thesis
    Investigation of the Silicon Nitride Coating Thickness on Silicon Wafer Substrates for Enhanced Sensitivity in Dried Nano-Droplet Analysis by Laser Induced Breakdown Spectroscopy
    (01. Izmir Institute of Technology, 2021) Durkan Kaplan, Dilara; Yalçın, Şerife; Yalçın, Şerife Hanım; 04.01. Department of Chemistry; 04. Faculty of Science; 01. Izmir Institute of Technology
    Laser Induced Breakdown Spectroscopy (LIBS) is an atomic emission spectroscopic technique that uses laser beam to generate plasma for detection. Also, LIBS is a fast and non-destructive methodology with the advantage of no sample preparation requirement and easy usage. Surface Enhanced LIBS (SENLIBS) is recently developed version of the LIBS technique that uses some kinds of surface materials for supporting liquids and for the enhancement of LIBS signal intensity. It has been previously shown that silicon nitride coated silicon wafer substrates have some properties to enhance LIBS signal of several metal solutions by dried-droplet analysis methodology. Within the scope of this thesis study, silicon wafers coated with silicon nitride of several thicknesses were utilized for investigating the effect of coating thickness on sensitivity of the LIBS technique for liquids analysis. Heavy metals above a certain concentration have a significant negative impact on the environment and human health. In this context, the chromium, copper and lead metal liquid samples was loaded on 75 nm, 300 nm, 450 nm and 1000 nm silicon nitride coated wafers and dried, then analyzed by LIBS. As a result of this study, it was seen that the 1000 nm coating increased the LIBS signal intensity at the highest degree. The LOD value of the chromium element was improved as 0.56 pg, the lead element as 0.7 pg, and the copper element as 0.42 pg with 1000 nm Si3N4 coated wafers.
  • Master Thesis
    Exploiting Second Harmonic Generation for Microelectronics Interface Characterization
    (Izmir Institute of Technology, 2016) Soylu, Gizem; Yüksel Aldoğan, Kıvılcım; Dinleyici, Mehmet Salih; Yüksel Aldoğan, Kıvılcım; Dinleyici, Mehmet Salih; 03.05. Department of Electrical and Electronics Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    This thesis aims to develop a technique to characterize microelectronic interfaces based on Second Harmonic Generation (SHG) method. In the experiment part of this study, silicon wafers with thermal and native oxide, silicon-on-insulator (SOI), pure glass and glass with TiO2 thin film samples were used to observe Second Harmonic (SH) signal. The experiments have been performed in IMEP-LAHC laboratory in Grenoble, France. In addition, the measurements were carried out with “Harmonic F1X” which is a femtosecond laser developed by the company FemtoMetrix based in California/USA (FemtoMetrix). Three contributions to SHG were investigated experimentally: the electric dipole approximation due to symmetry breaking at the surface/interface, a dc electric field because of the charge separation at the interface, and lastly bulk contributions. Then, the phenomenological model of surface SHG (Mizrahi & Sipe, 1988) was simulated in MATLAB, and the ratios of the elements of second order nonlinear susceptibility (χzzz/χzii and χizi/χzii) for the silicon wafers were identified with comparing the model with the experimental results. In addition, it was shown that surface and bulk contributions can be separated by using specific polarization states and azimuthal orientations. To show this separation, Fourier coefficients, which describes the crystal facial orientations of the total SHG, were determined for the silicon wafers. Furthermore, it was observed that there are some critical parameters which have an effect to SHG: the polarization states of the incident light and second harmonic light, the angle of incidence of the incoming light and the oxidation types of silicon. Finally, SOI has been used to check whether the effecting factors are same for silicon wafers. The findings demonstrate that SHG is a powerful technique to characterize the surface/interface and the bulk of the sample in microelectronic industry.