Auger lineshape analysis of carbon bonding in sputtered metal-carbon thin films

Abstract

The Auger spectrum for carbon corresponds to the KLL group of transitions in which the L states are the 2s and 2p valence states, and as a consequence each type of carbon bond is associated with a distinctive Auger lineshape in d N(E)/ d E mode which acts as a fingerprint for the chemical bonding state of the carbon. Transition metal-carbon composite layers with carbon-carbon and carbon-metal bonding states have carbon Auger lineshapes which are intermediate linear combinations of the amorphous carbon and transition metal-carbide lineshapes. In this work a simple mathematical technique based on peak height relationships has been used to separate the carbon-carbon (C-C) and carbon-metal (C-M) bonding state components of the carbon Auger lineshapes of sputtered stainless steel-carbon composite layers. Application of a value of 3.5 for the Auger sensitivity factor of carbon in C-M states relative to carbon in C-C states allowed relative numbers of C-M and C-C bonding states in thh stainless steel-carbon composite layers to be determined. Heat treatment (at 500°C) of the composite layers resulted in alterations in the bonding coniguration of the carbon atoms which were reflected in changes in the carbon Auger lineshapes. The association of changes in carbon atom bonding configuration with changes in optical extinction coefficient and electrical resistance of the stainless steel-carbon composite layers is also discussed.