Soft x-ray photoreactions of CF{sub 3}Cl adsorbed on Si(111)-7x7 studied by continuous-time photon-stimulated desorption spectroscopy near F(1s) edge

Journal Article · Fri Sep 21 04:00:00 EDT 2007 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.2772257· OSTI ID:21024188

Wen, C -R; Jang, C -Y; Chou, L -C; Chen, J; Wu, Y -H; Chang, S -C; Tsai, W -C; Liu, C -C; Wang, S -K; Shai, Y ^[1]

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1. Department of Physics, National Cheng Kung University, Tainan 70101, Taiwan (China)

The continuous-time core-level photon-stimulated desorption (PSD) spectroscopy was employed to monitor the monochromatic soft x-ray-induced reactions of CF{sub 3}Cl adsorbed on Si(111)-7x7 near the F(1s) edge (681-704 eV). Sequential F{sup +} PSD spectra were measured as a function of photon exposure at the CF{sub 3}Cl-covered surface (dose=0.3x10{sup 15} molecules/cm{sup 2}, {approx}0.75 ML). The F{sup +} PSD and total electron yield (TEY) spectra of molecular solid CF{sub 3}Cl near the F(1s) edge were also measured. Both F{sup +} PSD and TEY spectra show two features at the energy positions of 690.2 and 692.6 eV, and are attributed to the excitations of F(1s) to 11a{sub 1}[(C-Cl)*] and (8e+12a{sub 1})[(C-F)*] antibonding orbitals, respectively. Following Auger decay, two holes are created in the F(2p) lone pair and/or C-F bonding orbitals forming the 2h1e final state which leads to the F{sup +} desorption. This PSD mechanism, which is responsible for the F{sup +} PSD of solid CF{sub 3}Cl, is employed to interpret the first F{sup +} PSD spectrum in the sequential F{sup +} PSD spectra. The variation of spectrum shapes in the sequential F{sup +} PSD spectra indicates the dissipation of adsorbed CF{sub 3}Cl molecules and the formation of surface SiF species as a function of photon exposure. From the sequential F{sup +} PSD spectra the photolysis cross section of the adsorbed CF{sub 3}Cl molecules by photons with varying energy (681-704 eV) is determined to be {approx}1.0x10{sup -17} cm{sup 2}.

• OSTI ID: 21024188
• Journal Information: Journal of Chemical Physics, Journal Name: Journal of Chemical Physics Journal Issue: 11 Vol. 127; ISSN JCPSA6; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
ABSORPTION SPECTROSCOPY
ADSORPTION
AUGER ELECTRON SPECTROSCOPY
CHLORINATED ALIPHATIC HYDROCARBONS
CROSS SECTIONS
DESORPTION
ELECTRONS
EV RANGE 100-1000
FLUORINATED ALIPHATIC HYDROCARBONS
FLUORINE IONS
MONOCHROMATIC RADIATION
PHOTOCHEMISTRY
PHOTOLYSIS
PHOTONS
SOFT X RADIATION
SPECTRA
SURFACES
X-RAY PHOTOELECTRON SPECTROSCOPY
X-RAY SPECTROSCOPY