Effects of trichloroethane during oxide growth on radiation-induced interface traps in Metal/SiO2/Si capacitors

Abstract

The radiation‐induced interface traps in Metal/SiO₂/Si capacitors where the oxides are grown in dry O₂+1.1.1.‐trichloroethane (TCA) have been studied. Among all the samples tested, a peak in the interface trap distribution above midgap (centered at ∼E_ν +0.70–0.75 eV) appears immediately after irradiation, and the magnitude of this peak is a function of the amount of TCA during oxide growth. After the termination of the irradiation, this peak will either increase or decrease with time at room temperature for a few hours, followed by a continuous decrease over a long period of time (up to several months) before saturation, and this time‐dependent behavior also appears to be a function of the TCA concentration. In the case when this peak decreases with time, a second peak located below midgap (centered at ∼E_ν +0.35 eV) will develop, and the rate of growth of the second peak is correlatable to the reduction of the first peak. A closer examination of the data reveals that it is the initial damage level that determines the post‐radiation time‐dependent behavior, and the apparent dependence on the TCA concentration arises from its effect on the radiation sensitivity of the SiO₂/Si interface.