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:Si_x and a-C:Ge_x) 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 sp ² hybridized bonded C atoms and formation of sp³ hybridized bond with high efficiency.