Investigation of optical properties of silicon oxynitride films deposited by RF PECVD method

In this study, the authors deposited silicon oxynitride films by Radio Frequency Plasma Enhanced Chemical Vapour Deposition (RF PECVD) method. The research explores the relationship between the deposition process parameters and the optical properties of the deposited SiO_xN_y films. The optical constants of SiO_xN_y films were measured and calculated by spectroscopic ellipsometry method. Additionally, the authors investigated the possibility of controlling the deposited film composition by the flow ratio of different gaseous precursors: ammonia (NH₃), diluted silane (2%SiH₄/98%N₂), nitrous oxide (N₂O) and nitrogen (N₂). The gas mixture introduced to the working chamber during the growth of the film has the influence on the Si–O and Si–N bonds formation and the ratio between these bonds determines the refractive index of the deposited film.