Spectroscopic Ellipsometry And Its Characterization On The Properties Of Functional Thin Films

Since the development and perfection of automatic ellipsomyters, an effort that began nearly three decades ago, spectroscopic ellipsometry (SE) has increased in popularity as a non-destructive tool for characterizing the optical properties and layered structure of bulk solids and thin films. Compared with other conventional methods, SE is very powerful, non-destructive, non-rigorous, and high precise. By using SE, one can obtain the full spectra of the ellipsometric parameters Ψ and △ as a function of wavelength from near ultraviolet to near infrared in a few seconds. After processing Ψ and △, many parameters like dielectric functions, optical constants, layer thickness, fraction of the every composition and etc. can be determined. So SE can be used to characterize surfaces, interfaces, inhomogeneous films and multiplayer structures. In order to understand SE deeply and widely, the study will be carried out from several aspects as follow.First, Chapter 1 is devoted to tell SE's developmental history, characteristics and applications in many kinds of functional film materials. Second, Chapter 2 mainly introduces the principle of dynamic reflecting spectroscopic ellipsometry. Then in Chapter 3, the elements of two kinds of SE are introduced, and at the same time the automatization of the SE is also discussed. Many important windows and functions of the SE data processing software are introduced in Chapter 4.Finally, in Chapter 5, the application of SE is studied in three parts. The first part is the application of SE in ultrathin silver films. Ultrathin silver films (4.0, 6.2, 12.5, 26.2, 30.0nm) were successfully prepared by direct current sputtering deposition. The samples of which thicknesses are lower than 30nm were found to be discontinuous by transmission electron microscope. The thicknesses and optical constants of the films were studied by spectroscopic ellipsometry. The results show that surface plasma resonance peaks appeared in the spectra of extinction coefficient k of Ag1, Ag2, Ag3 and Ag4 samples. In the same time, another absorption peaks in the position of 288nm are also found for the Agl and Ag2 films. The reasons are discussed. The second part is the application of SE in transparent and conductive ITO thin films. ITO film with thickness of 140.5nm, grown on Si substrate by sputtering method, was studied with reflecting spectroscopic ellipsometry in the energy range 1.5-4.5 eV. Parameterized analysis, based on Lorentz Oscillators combined with Drude model, along with Bruggeman effective-medium approximation model and Graded model, was used to...