Tetraethoxyorthosilicate (TEOS) based silicon oxide films were deposited by plasma enhanced chemical vapor deposition and subsequently annealed in an oxidizing ambient at 950 and 1070 degrees C. Carbon atoms were found to segregate at the SiO2/Si interface inducing interfacial charges in excess of 1 X 10(11) cm(-2) in the presence of hydrogen. The interfacial carbon and charge concentrations were dependent on the annealing temperature and film thickness. A mechanism based on the rapid diffusion of carbon toward the interface during the early stages of annealing followed by oxygen diffusion toward the interface and the subsequent oxidation of interfacial carbon is proposed as an explanation for the charge dependence on the film thickness and annealing temperature. Additional data are presented concerning the composition of interfacial carbon species as well as hydrogen diffusion through the TEOS based oxide layer. (c) 2005 American Vacuum Society.