Thermal growth/removal steps of SiO2 films are largely used in the fabrication of electronic devices. The effect on the SiO2 thermal growth rate and on the SiO2/SiC interfacial region thickness of samples submitted to sequential steps of removal/growth of (SiO2)-O-18 on 4H-SiC was investigated, using nuclear reaction analyses, in the Si and C faces interspersed or not with a H2O2 thermal treatment. In the Si face structures the H2O2 treatment lead to a reduction of the SiO2/SiC interfacial region and to an increase in the SiO2 growth rate. Results of additional experiments performed to investigate the effects of the H2O2 treatment are also reported. (C) 2011 The Electrochemical Society. [DOI: 10.1149/1.3600635] All rights reserved.