The thickness dependence of thin silicon oxide wearout has been measured. The flatband voltages, bulk oxide trap densities, and low-level leakage currents were measured on oxides in the 5 to Il nm thickness range before and after high-voltage stressing. In oxides that had been stressed at equivalent electric fields for equivalent times, the measured flatband voltage shifts and stress-generated bulk oxide trap densities dropped as the oxide thicknesses dropped and were negligible for oxides thinner than 6 nm. The low-level pretunneling leakage currents increased as the oxide thicknesses decreased. In addition to the transient, 1/time, tunnel charge/discharge component, a de component to this current appeared as the oxide thicknesses decreased. A model based on uniform trap generation throughout the oxide during the high-voltage stressing and subsequent tunnel charging and discharging of the traps within approximately 3 nm of either interface after the stress voltages were removed has been used to explain and accurately fit all of the thickness dependences of the trap generation and flatband voltage shifts. The thickness dependences of the transient and de low-level leakage currents were explained on the basis of electrons tunneling both into, out of, and between the stress-generated traps. Both components of stress-induced leakage currents were proportional to the stress-generated trap densities when the thickness dependences of these currents were analyzed.