低エネルギー炭素負イオンビーム蒸着膜の原子間結合状態のエネルギー依存性 Ion Energy Dependence of Inter-atomic Bonding State of Carbon Films Deposited by Low-Energy Carbon-Negative Ion Beam
Atomic bonding state of carbon-negative-ion beam deposited films was investigated. Mass-separated ions of C<SUP>-</SUP> and C<SUP>-</SUP><SUB>2</SUB>were deposited on Si (100) and Si (111) at a low ion energy of 50-400 eV under 1 × 10<SUP>-6</SUP> Pa. Deposited films showed a broad Raman band in 1400-1600 cm<SUP>-1</SUP> similar to diamond-like carbon films. From details of C<SUB>1s</SUB> spectra in X-ray photoelectron spectroscopy (XPS), it was found that the fraction of C-C (sp<SUP>3</SUP>) bonds increased with an increase in ion energy up to 75 eV/atom of ions for both ion species, and then gradually decreased with the further increase in ion energy. The kinetic energy of ions is considered to contribute to the formation of metastable sp<SUP>3</SUP> bonds, but the excessive kinetic energy might destroy the sp<SUP>3</SUP> bonds. As a result of the ion energy dependence of carbon interatomic bonding state, the sp<SUP>3</SUP> bond fraction of more than 80% was obtained at ion energy of 75 eV/atom for both C<SUP>-</SUP> and C<SUP>-</SUP><SUB>2</SUB> depositions.
真空 42(3), 221-224, 1999-03
The Vacuum Society of Japan