Plasma damage mechanisms in low k organosilicate glass and their inhibition by Ar ion bombardment
In-situ x-ray photoelectron spectroscopy and ex-situ Fourier transform infrared spectroscopy studies of vacuum ultraviolet (VUV) photons with or without O{sub 2}, and O radicals point to distinct mechanisms of carbon abstraction in nanoporous organosilicate glass (OSG) films. VUV alone in the absence of O{sub 2} results in Si-CH{sub 3} bond scission and recombination preferentially at silicon monomethyl sites, obeying diffusion kinetics. In contrast, the presence of O{sub 2} interferes with recombination, resulting in diffusion-dominated carbon loss kinetics, enhanced Si oxidation, and greatly accelerating the rate of carbon loss in both the near surface and bulk regions of the OSG, at both monomethyl and dimethyl sites. Carbon abstraction due to exposure to (O({sup 3}P)) does not follow diffusion kinetics, and such interactions yield a SiO{sub 2}-like surface layer inhibiting further O diffusion. Results indicate that diffusion-dominated carbon abstraction kinetics previously observed for OSG exposure to O{sub 2} plasma damage is primarily attributable to the diffusion of O{sub 2} down OSG nanopores, reacting at photoactivated sites, rather than the diffusion of O radicals. OSG pretreatment by 900 eV Ar{sup +} bombardment effectively inhibits both VUV + O{sub 2} and O damage mechanisms by formation of ∼1 nm thick SiO{sub 2}-like surface region that inhibits both O and O{sub 2} diffusion.
- OSTI ID:
- 22258683
- Journal Information:
- Journal of Vacuum Science and Technology. A, Vacuum, Surfaces and Films, Vol. 32, Issue 2; Other Information: (c) 2014 American Vacuum Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0734-2101
- Country of Publication:
- United States
- Language:
- English
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