Electron Trap Activation in Thermal SiO2

The charge accumulation in oxide of silicon MOS-structures is studied under monopolar injection and electron–hole injection cycling. The hole injection is found to result in new electron trap generation with cross section (4 ± 1) × 10−15 cm2. The effect observed is due to the precursor state activation in the bulk of oxide. Annealing experiments reveal the irreversible precursor reconstruction under hole capture and the thermal stability of activated traps up to 500 °C. The results of the activation effect study after neutron and proton bombardment and under chlorine incorporation are also presented. Strained bonds, e.g. SiO, are considered as possible precursor centers. The activation effect reported seems to be the first stage of oxide degradation under ionization. In view of trap thermal stability the activation can be responsible for the gate oxide degradation under lithography with electron beams, synchrotron radiation, or X-rays and under other radiation technologies used.