Electrical measurements on titanium-Schottky diodes were used to evaluate the effects of reactive ion etching (RIE) processing and various post-RIE treatments on silicon substrates. Based on a model for the Schottky barrier with an interfacial layer, the measurements allow one to estimate the effect of an oxygen treatment or an O2-RIE clean-up with a wet chemical etch on the C- and F-containing insulator layer and the residual damage to a silicon surface by different RIE systems. It was shown that the oxygen treatment reduced the thickness of the "polymeric" layer, and decreased the density of surface states. A significant residual damage after O2 clean-up with HF dip was found for the CF4/H2 system. Lastly, the effect of thermal annealing at 950°C was investigated, and it was found that it gives rise to an increased density of surface states. © 1986.