Radiation damage in silicon dioxide films exposed to reactive ion etching (RIE) in has been investigated. Capacitance‐voltage ((C‐V) and photo‐current‐voltage (photo I‐V) techniques were used to monitor charge trapping and location after the films were incorporated into MOS capacitors. Blanket etched films were used to study the trapping characteristics of bulk, neutral, radiation‐induced traps as a function of position in the reactor, rf peak‐to‐peak voltage, and pre‐RIE high temperature annealing. The trapping characteristics of films etched in a mixture were also studied. Oxide films etched in show reduced trapping when compared with oxides etched in . The ability of gate electrode materials to shield an underlying oxide during RIE was also tested. It was determined that aluminum and n+ polysilicon are effective in shielding oxide from RIE induced radiation damage.