We have investigated the states produced at the Si‐SiO2interface by Fowler–Nordheim tunneling and by UV photoinjection at low temperature (90 K). After the interface states are generated, subsequent application of a negative gate bias (5–6 MV/cm) converts them entirely into trapped negative charge. The reverse conversion into interface states occurs if a positive gate bias (5–6 MV/cm) is applied. Cycling of the defects between interface states and trapped negative charge is observed in both experiments. The data strongly suggest that both low‐temperature Fowler–Nordheim tunneling and UV photoinjection generate essentially the same structural defect at the interface between Si and SiO2.