Characteristics of SiOxNy Thin Films

Different films of silicon oxynitride (SiOxNy) were grown using a glass-assisted CO2 laser technique. The samples were prepared on P- type silicon substrates (111) at temperatures from (750, 800, 850 oC) using two different gases of NH3 and O2 as the source of nitrogen and oxygen in open air. Fourier Transform Infrared (FTIR) Spectroscopy, Reflectometry, Spectroscopic Ellipsometry and C-V measurements were used for films characterization. FTIR spectra shows a strong stretching bond of Si-N at wave number range from (700-1000 cm-1) depending on the films composition, and Si-O stretching bond at wave number around (1088 cm1). The peak position and the corresponding full width at half maxima (FWHM) for Si-O stretching bond have been also analyzed. The Reflectometry was used to measure the refractive index which is equal to 1.66 for SiOxNy film growing at 750 oC. It was found that the samples are non uniform in their thickness (16-142 nm) and the refractive index of the films is graded (1.44-1.97) through the Spectroscopic Ellipsometry. The C-V characterization, dielectric constant and flat band voltage (VFB) were determined at high frequency of 1MHz.