Characterization and modeling of antireflective coatings of SiO2, Si3N4, and SiOxNy deposited by electron cyclotron resonance enhanced plasma chemical vapor deposition

Abstract

In this work the optical transmission spectra of silicon oxide (SiO2), silicon nitrides (Si3N4), silicon-rich oxynitrides (SiOxNy), and antireflective coatings (ARCs), deposited by the electron cyclotron resonance enhanced plasma chemical vapor deposition onto a silicon substrate at room temperature, are studied. Simulations carried out with the MATHEMATICA program, from 0to1000nm thick coatings, showed maximum transmittance in the three basic colors at 620, 480, and 560nm for the SiO2, Si3N4, and SiOxNy ARCs, respectively. However, a highly significant transmittance over a broad spectral range from visible (VIS) to near the infrared region, with optical gain in the three basic colors above 20%, is observed only at thicknesses of 80, 70, and 60nm, respectively, for SiO2, Si3N4, and SiOxNy ARCs. Among the three evaluated films, the highest transmittance in the broad spectral band in the VIS range was observed for 60nm thick Si3N4 films. The Fourier transform infrared spectroscopy of these films reveal high structural quality and the presence of Si–O, Si–H, N–H, and Si–N bonds, independent of thickness and deposition parameters.