We have compared the generation of radiation‐inducedPb(‘‘trivalent silicon’’) centers at the Si/SiO2interface with the radiation‐induced buildup of interface states. We observe a strong correlation between the density ofPbcenters and radiation‐induced interface state density (Dit) and similar annealing behavior of radiation‐inducedPbandDit. Furthermore, thePbresonance intensity is strongly bias dependent; this indicates that the charge state of thePbdefect is bias dependent. We conclude thatPbdefects account for a very large portion of radiation‐induced interface states.