Recent research on point defects in thin films of silicon dioxide, silicon nitride, and silicon oxynitride on Si is presented and reviewed. In SiO2, it now clear that no one type of E’ center is the sole source of radiation-induced positive charge; hydrogenous moieties or other types of E’ are proposed. Molecular orbital theory and easy passivation of E’ by H-2 suggest that released H might depassivate interface P-b sites. A charged E(delta)’ center has been seen in Cl-free SIMOX (separation by implantation of oxygen) and thermal oxide films, and it is reassigned to an electron delocalized over four O-3=Si units around a fifth Si. In Si3N4, a new model for the amphoteric charging of . Si=N-3 moieties is based on local shifts in defect energy with respect to the Fermi level, arising from nonuniform composition; it does not assume negative U electron correlation. A new defect NN20 has been identified, with dangling orbital on a two-coordinated N atom bonded to another N. Silicon oxynitride defects are briefly presented.