Full composition range silicon oxynitride films deposited by ECR-PECVD at room temperature

• Published in: Thin solid films Vol. 343; pp. 437 - 440
• Main Authors: del Prado, A., Mártil, I., Fernández, M., González-Díaz, G.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.04.1999
• Subjects: Fourier transform infrared spectroscopy; Plasma processing and deposition; Silicon oxynitride; Fourier transform infrared spectroscopy; Plasma processing and deposition; Silicon oxynitride
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/S0040-6090(98)01701-5

Silicon oxynitride films were deposited at room temperature using the ECR-PECVD technique. Precursor gases were O 2, N 2 and SiH 4. The composition of the films can be controlled by regulating the gases flow ratio. R = (O 2 + N 2)/SiH 4 and R′ = O 2/SiH 4 have proved to be the key deposition parameters. FTIR spectroscopy, AES and ellipsometric measurements were performed in order to characterise the films. A single Si O/Si N stretching band is observed in the FTIR spectrum for all compositions, indicating single-phase homogeneous SiO x N y films. FWHM of the stretching band shows a maximum for the composition corresponding to the same number of Si O and Si N bonds. Samples cover the whole composition range from silicon nitride to silicon oxide including nitrogen-rich films, even though the gas flow ratio R″ = N 2/O 2 during deposition was small (from r″ = 1.0 for SiO 1.9N 0.04 to R″ = 6.7 for SiO 0.26N 1.2). Silicon oxide composition samples (SiO 2.0) show essentially the same IR features as the thermal oxide: Si O stretching band located at 1072 cm −1, with a FWHM of 96 cm −1 and a shoulder/peak ratio of 0.30, while nitrogen-rich samples (SiO 0.26N 1.2) show a total bonded hydrogen content below 2 × 10 22 cm −3.