X‐ray photoelectron spectroscopy study of the atomic structure change of amorphous carbon films annealed in vacuum

Abstract

Amorphous carbon films deposited at near room temperature on Si substrates by a direct current plasma chemical vapor deposition technique using CH4 gas have been annealed in vacuum. X‐ray photoelectron spectroscopy measurements show that, as the annealing temperature increases from room temperature to 300 °C, a significant shift (0.5 eV) of the C 1s electron binding energy is observed. The observed shift may be the indication of an atomic structure change of the amorphous films upon the thermal annealing. On the other hand, a large shift in the sp2 bond peaks of the Raman spectra only occurs at annealing temperatures higher than 300 °C, which may be the indication of a structural change of the amorphous carbon films by the annealing. A two stage stress release mechanism is suggested: One for the atomic structure change and one for the film structure change.