We employ surface-enhanced Raman spectroscopy (SERS) to investigate the effect of nitridation on interfacial carbon at the SiO2/4H-SiC interface. These results demonstrate that the interfacial carbon clusters are strongly modified by post-nitridation process and the nitrogen take-up correlates with the reduction in the interface state density. (C) 2006 Elsevier B.V. All rights reserved.