Chemical characterization and optical properties of SiO

• Published in: Materials express 2016-06, Vol.6 (3), p.295-299
• Main Authors: Vanegas, Henry S, Pinzon, Manuel, Alfonso, Jose E, Olaya, Jhon J, Pineda-Vargas, C
• Format: Article
• Language: English
• Subjects: Chemical composition; Energy gaps (solid state); Rutherford backscattering spectroscopy; Silicon dioxide; Silicon nitride; Silicon oxynitride; Stoichiometry; Transmittance
• ISSN: 2158-5849
• DOI: 10.1166/mex.2016.1306

SiO sub(x)N sub(y) films have been widely studied due to their physicochemical properties, which have allowed them to be used in microelectronics, as an alternative for silicon dioxide and silicon nitride as a dielectric layer, with the advantages of low leakage currents, and in optical components such as graded index fibers and antireflection coatings, due to the fact that the films exhibit refractive indices between 1.5 and 2.0 and high visible light transparency. In the present paper, we deposited SiO sub(x) N sub(y) thin films from a Si sub(3)N sub(4) target via RF magnetron sputtering technique varying the power supply to the target in order to characterize the chemical composition and relate it to the optical response of the films. Structural analysis was carried out through X-ray diffraction (XRD), stoichiometry of the phase composition was obtained through Rutherford Backscattering Spectroscopy (RBS), and the optical response was evaluated via transmittance measurements. The Swanepoel method was used to calculate the refractive index and the average thickness of the films. Additionally, the energy bandgap was determined using the Tauc method. The results show the possibility of obtaining a chemical composition of SiON in the films via sputtering. XRD analysis showed that all the films were amorphous, RBS results indicated that the films are composed of one phase of a Si-O-N network, and optics measurements revealed that between 750 and 1100 nm there is an average transmittance of about 83%. In addition, the energy bandgap was 3.22 eV for the films deposited at 300 W with a stoichiometry: Si = 34.4 at.%, N = 33.0 at.%, and O = 32.6 at.%. These results could be important for optical applications such as designing efficient light emitting devices.