XPS studies on SiOx thin films

Alfonsetti, R.; Lozzi, L.; Passacantando, M.; Picozzi, P.; Santucci, S.

doi:10.1016/0169-4332(93)90431-a

Cited by 279 publications

(135 citation statements)

References 11 publications

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“…25,26 This parameter can be taken as a measurement of the extra-atomic relaxation energy of photoholes and therefore depends on the electronic properties of the material hosting that element. The exact definition of ␣Ј refers to a given oxidation state of an element and therefore its application to SiO x would imply a precise deconvolution of both the Si 2p photoemission and Si KLL Auger spectra.…”

Section: B Auger Parameter and Thin-film Stoichiometrymentioning

confidence: 99%

Electronic state characterization of SiOx thin films prepared by evaporation

Barranco

Yubero

Espinós

et al. 2005

Journal of Applied Physics

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SiO x thin films with different stoichiometries from SiO 1.3 to SiO 1.8 have been prepared by evaporation of silicon monoxide in vacuum or under well-controlled partial pressures of oxygen ͑P Ͻ 10 −6 Torr͒. These thin films have been characterized by x-ray photoemission and x-ray-absorption spectroscopies, this latter at the Si K and L 2,3 absorption edges. It has been found that the films prepared in vacuum consists of a mixture of Si 3+ and Si + species that progressively convert into Si 4+ as the partial pressure of oxygen during preparation increases. From this spectroscopic analysis, information has been gained about the energy distribution of both the full and empty states of, respectively, the valence and conduction bands of SiO x as a function of the O / Si ratio. The characterization of these films by reflection electron energy-loss spectroscopy ͑REELS͒ has provided further evidences about their electronic structure ͑band gap and electronic states͒ as a function of the oxygen content. The determination of the plasmon energies by REELS has also shown that the films prepared by evaporation in vacuum consist of a single phase which is characterized by a density ͑1.7 g cm −3 ͒ lower than that of SiO 2 ͑i.e., 2.2 g cm −3 ͒ or Si ͑i.e., 2.4 g cm −3 ͒. The optical properties ͑n and k͒ of the films as a function of the O / Si content have been deduced from the analysis of REELS spectra in the energy range from 4 to 20 eV. It has been also shown that the O / Si ratio in the films and several spectroscopic parameters such as the Auger parameter or the energy of bulk plasmons present a linear relationship and that this linear dependence can be used for a rapid characterization of SiO x materials. By contrast, the band-gap energy changes differently with the O / Si ratio, following a smooth linear increase from about 3.8 eV for SiO 1.3 to ca. 5.0 eV for SiO 1.7 and a jump up to 8.7 eV for SiO 2 . These results indicate that the random-bonding model does not apply to thin films prepared by evaporation under our experimental conditions. Other distributions of Si n+ states can be induced if the films are excited with an external source such as heat or photon irradiation. In this case the electronic properties vary and the previous linear correlations as a function of the oxygen content do not hold any longer.

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Section: B Auger Parameter and Thin-film Stoichiometrymentioning

confidence: 99%

Electronic state characterization of SiOx thin films prepared by evaporation

Barranco

Yubero

Espinós

et al. 2005

Journal of Applied Physics

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“…16,17 Once the fits were performed, the area of oxidized Si species ͑the sum of peaks C, D, and E in Fig. 2͒ was divided by the area of the nonoxidized species ͑sum of peaks A and B͒ to give the ratio r required in Eq.…”

Section: A Silicon 2p Core Levelmentioning

confidence: 99%

Stability of cerium oxide on silicon studied by x-ray photoelectron spectroscopy

Preisler¹,

Marsh²,

Beach³

et al. 2001

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

132

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The silicon-cerium oxide interface is studied using x-ray photoelectron spectroscopy. The oxidation and reduction of species at the interface are examined as a function of annealing temperature both in vacuum and oxygen ambient, in order to determine their relative stabilities. By depositing a very thin CeO 2 film ͑ϳ30 Å͒, the cerium and silicon core level peaks can be monitored simultaneously. The presence of characteristic chemical shifts of the Si 2p peak gives information about any SiO x layer that may form at the interface. The oxidation state of the cerium can be probed from three different areas of the spectrum. From this information we can infer the oxidation state of both the silicon and the cerium. For the first time a complete picture of the interface is obtained. The implications of these findings on the utility of CeO 2 in device applications are discussed.

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“…After deconvolution three Gaussians peaked at 103.6, 102.4 and 100.1 eV were resolved. The peaks at 103.6 and 102.4 eV are attributed to Si-O bonds in pure SiO 2 and in Si 2 O 3 compounds, respectively, while the shoulder at lower binding energy could be superposition of signals resulting from Si-O bonds in Si 2 O suboxide and Si-Si bonds in silicon, having binding energies close to each other, 100.7 eV and 99.8 eV, respectively (Alfonsetti et al, 1993). In all spectra of the annealed films (Figs.…”

Section: Si Nanoparticle Growth Oxygen Matrix Densification Interfamentioning

confidence: 99%

“…The main peak in the spectrum of the control sample at both angles (Figs. 6 (a) and 7 (a)) is positioned at 102.4 eV and corresponds to a SiO x film with x = 1.35 (Alfonsetti et al, 1993), a value that is close to the composition set by the deposition conditions. After deconvolution three Gaussians peaked at 103.6, 102.4 and 100.1 eV were resolved.…”

Section: Si Nanoparticle Growth Oxygen Matrix Densification Interfamentioning

confidence: 99%