It is shown that for semiconductor memory devices utilizing charge storage in localized states it is possible to achieve a high degree of immunity to soft errors. This is accomplished by the application of an electric field which is strong enough to efficiently remove carriers produced by radiation from the region where charge is stored in localized states but not so strong as to remove readily by field ionization charge already stored in localized states. Tests of this concept have been performed using energetic Compton electrons produced by gamma rays.