LEE- Fizik Mühendisliği Lisansüstü Programı

Bu topluluk için Kalıcı Uri

http://hdl.handle.net/11527/19275

Gözat

Yazar "Aşar, Muharrem" ile LEE- Fizik Mühendisliği Lisansüstü Programı'a göz atma
  • Öge
    Development and application of imaging ellipsometry for optical characterization and defect analysis of advanced thin films
    (ITU Graduate School, 2025) Yıldız, Furkan ; Zayim, Esra ; Aşar, Muharrem ; 509221110 ; Physics Engineering
    This study is based on a research conducted under the title of " Development and Application of Imaging Ellipsometry for Optical Characterization and Defect Analysis of Advanced Thin Films ". The research covers substrate materials such as GaN and SiC, which are critical in power electronics within the scope of the PowerElec project, and different materials in the ATMOC project. The main purpose of the study is to perform both defect analysis and determination of optical constants of these materials and to contribute to these processes with measurements in the visible and infrared (IR) bands. Classical ellipsometry methods have various limitations, especially in terms of defect analysis. The disadvantages of these systems, such as low spatial resolution, narrow angular measurement range and complex sample preparation, have led to significant deficiencies in studies conducted in this field in the literature. Against this background, instead of assuming that Imaging Ellipsometry implies a totally new principle, the current thesis puts its essential ideas to work to correct particular inadequacies found in traditional ellipsometry. Though traditional ellipsometry has already served, at one time or other, as a highly effective and precise technique for measuring optical constants and thin-film thicknesses, it necessarily supplies a macroscopic average of reflected light, consequently restricting its usefulness in surface investigation when lateral inhomogeneities or microscale structure attributes are concerned. To overcome this limitation, Imaging Ellipsometry has proven to be a highly effective auxiliary technique, allowing for spatially resolved surface and thin-film characterization. Here, unlike in usual dual-arm imaging ellipsometry systems, a small but easy-to-operate imaging ellipsometry instrument has been conceived and put in place. This tool unites optical microscopy principles and ellipsometric measurement, seeking to improve usability while, at the same time, maintaining high spatial resolution and clear imagery. Accordingly, it holds much potential for microscale surface defects analysis, besides surface and bulk substance characterization. The system consists of optical components such as a single wavelength tunable laser source (633 nm, 612 nm, 604 nm, 594 nm and 543 nm), and other ligth sources, motorized compensator and analyzer units, high NA (0.75) Nikon Plan Fluorite objective, a beam splitter on the light path and a Retiga-R6 CCD camera. The data of the optical system is processed with a high-performance analysis infrastructure. In this context, CUDA-based software was developed to increase the parallel processing capacity and obtain faster analysis results. In the software development process, C++ programming language was used to optimize both system control and data analysis processes. This choice provided a performance-oriented and efficient infrastructure. Empirical analysis has proven that the Imaging Ellipsometer system can be optimally applied for defect analysis and for determining optical constants for materials like GaN, SiC, and others. Moreover, this system has proven to offer higher accuracy and resolution compared to conventional ellipsometry methods described in published work elsewhere. The study provides significant contributions in areas like material science and power electronics in terms of creating an innovative Imaging Ellipsometer. This research presents itself as a relevant resource for researchers, teachers, and professionals who encourage a wide-ranging use of the technology in processes that evaluate material quality.