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We establish, using a tetrahedral model, the bonding properties of amorphous silicon oxynitride (a-SiOxNy) films deposited at low temperatures (LTs) by electron-cyclotron resonance chemical-vapor deposition (ECRCVD) on several substrates and under various conditions of gas flows and total gas pressure in a dilute mixture of SiH4+N2 in Ar. The atomic percentage of each tetrahedral unit incorporated in the film network is calculated from the deconvolution of the high-resolution x-ray photoelectron spectroscopy (XPS) spectra in the Si 2p3/2 region and corroborated by the results obtained from both survey scans and the high-resolution XPS spectra in the N 1s region. The Si3N4 phase is the most important one and the only bonding unit which is incorporated in all our LT ECRCVD SiOxNy films. The incorporation of all the other component tetrahedrons depends strongly on growth conditions. The threshold values of the N/Si atomic ratio for which intrinsic defects, such as Si–Si bonds, are not incorporated in the network depend on the O/Si ratio incorporated in the films, mainly due to the competition between oxygen and nitrogen atoms in their reaction with silicon dangling bonds. The effect of the total gas pressure on the atomic percentages of the oxidation states present in the LT ECRCVD SiOxNy films is qualitatively similar to the effect of the ion bombarding energy or the plasma density. O–N bonds are present only in samples having high amount of oxygen and nitrogen in their networks. For these films, our results show unambiguously the presence of the N–Si2O tetrahedron and suggest that N–Si3-νOν tetrahedrons with ν>=2 are not incorporated in their networks. A correlation is observed between the N–Si2O and the Si–O3(ON) tetrahedrons whose component peak is localized at (104.0±0.2) eV in the Si 2p3/2 region of the XPS data, which suggests that both bonding units coexist in these films as some sort of complex bonding configuration. [ABSTRACT FROM AUTHOR]

We establish the role of oxygen atoms on the structural, chemical, and mechanical properties of SiO[sub X]N[sub Y] films grown on Si and InP substrates by electron-cyclotron resonance chemical-vapor deposition (ECR CVD) using a diluted SiH[sub 4] and N[sub 2] mixture in Ar, under controlled conditions. The mechanical and chemical properties of ECR-CVD SiN[sub X] films depend on the oxygen contamination even when this element is present in low concentrations. The compressive stress of SiN[sub X] films deposited with a low (and constant) content of oxygen (less than 12%) is shown to be in qualitative agreement with a model of repulsive Coulomb forces related mainly to polar [sup -]N-H[sup +] units in the SiN[sub X] network. We observe a decrease of the film compressive stress when the N[sub 2]/SiH[sub 4] flow ratio increases, which is due to the increase of Si-N bonds in detriment of N-H bonds. Films deposited with high oxygen content in the plasma show a decrease of nitrogen incorporation. Oxygen radicals species compete with those of nitrogen in their reaction with silicon dangling bonds, which has as a consequence a decrease in the incorporation of nitrogen. Additional creation of oxygen radicals, with no hydrogen dilution, is more effective in decreasing the number of N-H bonds, or the compressive stress in the SiN[sub X] films, than the corresponding creation of nitrogen radicals. The mechanical properties of SiN[sub X] films contaminated with oxygen are controlled, in general, by the total number of both nitrogen plus oxygen atoms relative to silicon. The buffered HF (BHF) film etch rate is enhanced and thus is mainly controlled by the oxygen content. Low values of the compressive stress do not necessarily imply low values of BHF etch rate or a high N/Si ratio. We also present a discussion of the origin of the unintentional incorporation of oxygen in a ECR-CVD system designed for industrial production. [ABSTRACT FROM AUTHOR]