Bonding characteristics of Si and Ge incorporated amorphous carbon (a-C) films grown by magnetron sputtering

The bonding configuration and structural evolution of Si and Ge incorporated amorphous carbon (a-C:Six and a-C:Gex) films were studied. The incorporation of Si and Ge to amorphous carbon (a-C) has the advantageous effect of promoting sp3 hybridized bond formation due to smaller energy difference between s and p orbital in Si and Ge than C. The C 1s NEXAFS spectra of Si or Ge incorporated a-C films, the formation of Si (or Ge)–C bond is observed, i.e., the formation of a-SiC or a-GeC networks by the incorporation of Si (or Ge) in sp2 hybridized site and bonding with carbon atoms to generate sp3 hybridization. The important role of the incorporated Si and Ge in modifying the bonding configuration of a-C is revealed by using UV Raman spectroscopy to open up the ring structure of sp2 hybridized bonded C atoms and formation of sp3 hybridized bond with high efficiency.