Oxygen adsorption on thin cobalt films. An Auger and work function study

G. BENITEZ; J.M. HERAS; L. VISCIDO

VACUUM

Pergamon

Año: 1997 vol. 48 p. 651 - 653

0042-207X

The adsorption of oxygen by thin cobalt films supported on oxidized Si (100) was studied at 300 K using Auger electron spectroscopy (AES) and work function changes. The films were prepared in separate UHVsystems either by vapor deposition (PVD) or by pulsed laser ablation (PLA). The oxygen saturation exposure depends on the preparation method: in PVD-films at least 100 L are needed, while in films deposited by PLA only 70 L are required. However, films prepared by PLA, but on cleaved muscovite, showed uptake curves saturating at ~ 80 L as in evaporated films. The work function changes upon oxygen adsorption showed an initial increase of 0.2 eV, followed by a steep decrease, saturating at ~ - 1.2 eV. An oxide formation is clearly demonstrated by the AES MVV spectra of Co at exposures above 9 L.Si (100) was studied at 300 K using Auger electron spectroscopy (AES) and work function changes. The films were prepared in separate UHVsystems either by vapor deposition (PVD) or by pulsed laser ablation (PLA). The oxygen saturation exposure depends on the preparation method: in PVD-films at least 100 L are needed, while in films deposited by PLA only 70 L are required. However, films prepared by PLA, but on cleaved muscovite, showed uptake curves saturating at ~ 80 L as in evaporated films. The work function changes upon oxygen adsorption showed an initial increase of 0.2 eV, followed by a steep decrease, saturating at ~ - 1.2 eV. An oxide formation is clearly demonstrated by the AES MVV spectra of Co at exposures above 9 L.