Real-time monitoring of silicon oxide deposition processes

Multi-wavelength ellipsometry in Vis–far UV energy range has been applied for the study and the monitoring of the stoichiometry (x) and optical properties of SiOx films, grown on c-Si substrates by electron-beam evaporation technique, using different source materials (SiO2, SiO or SiOx). The ellipsometric data collected in real-time correspond to 32 different wavelengths covering the range from 1.5 up to 6.5 eV, and are fitted by applying the Tauc–Lorentz model. The calculated optical parameters, such as Penn Gap ω0 and the fundamental band gap ωg, are directly correlated to x values. In addition, the close monitoring of the deposition processes provides the ability to study the growth mechanisms that are discussed in terms of the source material and the predominant precursors during deposition. Therefore, this methodology reveals the potential for real-time control of SiOx films’ growth of desirable stoichiometry or a functionally graded one, meeting specific demands for microelectronics or other industrial applications.