X-ray photoelectron spectroscopy and structural analysis of amorphous SiO{sub x}N{sub y} films deposited at low temperatures

Journal Article · Tue Nov 01 04:00:00 EST 2005 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.2113415· OSTI ID:20719674

Cova, P; Poulin, S; Masut, R A ^[1]

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1. Departmento de Fisica, Laboratorio de Simulacion de Dispositivos Semiconductores, Universidad de Oriente, Apartado 124, Cumana 6101, Sucre (Venezuela)

We establish, using a tetrahedral model, the bonding properties of amorphous silicon oxynitride (a-SiO{sub x}N{sub y}) 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 SiH{sub 4}+N{sub 2} 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 2p{sub 3/2} region and corroborated by the results obtained from both survey scans and the high-resolution XPS spectra in the N 1s region. The Si{sub 3}N{sub 4} phase is the most important one and the only bonding unit which is incorporated in all our LT ECRCVD SiO{sub x}N{sub y} 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 SiO{sub x}N{sub y} 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-Si{sub 2}O tetrahedron and suggest that N-Si{sub 3-{nu}}O{sub {nu}} tetrahedrons with {nu}{>=}2 are not incorporated in their networks. A correlation is observed between the N-Si{sub 2}O and the Si-O{sub 3}(ON) tetrahedrons whose component peak is localized at (104.0{+-}0.2) eV in the Si 2p{sub 3/2} region of the XPS data, which suggests that both bonding units coexist in these films as some sort of complex bonding configuration.

• OSTI ID: 20719674
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 9 Vol. 98; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
AMORPHOUS STATE
ARGON
CHEMICAL VAPOR DEPOSITION
CRYSTAL GROWTH
DIELECTRIC MATERIALS
ELECTRON CYCLOTRON-RESONANCE
EV RANGE 100-1000
GAS FLOW
MIXTURES
NITROGEN
OXIDATION
OXYGEN
PLASMA DENSITY
SILANES
SILICON NITRIDES
SILICON OXIDES
SUBSTRATES
THIN FILMS
X-RAY PHOTOELECTRON SPECTROSCOPY
X-RAY SPECTRA