We have examined fluctuations in the tunneling current of 3.5 nm SiO2barriers for voltages in the direct tunneling regime. We find a 1/fpower law for the spectral density of the fluctuations wherefis the frequency. This 1/fnoise can be attributed to fluctuations of a trap assisted tunneling current through the oxide that causes current noise but is not evident in theI–Vcurves. We suggest that this noise may be a more sensitive probe of trap assisted tunneling and degradation in thin oxides than other measures. At voltages above a threshold of 2.5 V, we observe the reversible onset of non‐Gaussian current transients in the noise. The onset of these current transients can be related to a transition in the spacial uniformity of the tunneling current density that may result in eventual breakdown of the oxide. ©1996 American Institute of Physics.