Ion induced chemical bonding of carbon with Ta as studied by Auger electron spectroscopy and slow electron energy loss spectroscopy

The chemical bonding of contaminants like carbon and oxygen on the surface of Ta and Ta2O5 films due to Ar+ ion bombardment during sputter etching, has been studied using Auger electron spectroscopy and slow electron energy loss spectroscopy. Finger printing of C KLL peak shows that the energy separation between the major positive-going and negative-going excursions, which is 23 eV in the pure graphitic form, reduces to 6 eV indicating the carbide formation after ion bombardment. It is assumed that the chemical reaction is initiated by an increase in π electrons in the graphite due to ion bombardment. The carbide formation is found to be much less effected in Ta2O5 films which has been attributed to the absence of free d electrons of Ta in the oxide.