Recent research on point defects in thin films of these materials on Si was reviewed. In the case of SiO2, it was considered to be clear that no single type of E center was the lone source of radiation-induced positive charge. Hydrogenous moieties or other types of E’ were proposed. Molecular orbital theory, and the easy passivation of E’ by H2, suggested that released H might depassivate interface Pb sites. A charged Eb’ center had been seen in Cl-free, separation by implantation of O structures, and in thermal oxide films, and had been attributed to an electron which was delocalized over four O3Si units around a fifth Si atom. In the case of Si3N4, a new model for the amphoteric charging of •SiN3 moieties was based upon local shifts in defect energy, with respect to the Fermi level, that arose from a non-uniform composition. It did not assume a negative-U electron correlation. A new defect, NN20, was identified; with dangling orbitals on a 2-coordinated N atom that was bonded to another N atom.

E.H.Poindexter, W.L.Warren: Journal of the Electrochemical Society, 1995, 142[7], 2508-16