Charging/discharging of silicon nanocrystals embedded in anSiO2 matrix inducing reduction/recovery in the total capacitance and tunneling current

Abstract

In this work, we have found that the charging of Si nanocrystals (nc-Si) distributedthroughout a thin gate oxide can induce a reduction in the total gate oxide capacitance andtunneling current. The capacitance can be reduced to an extremely low value if thenanocrystals are charged up. The gate oxide current is also found to decrease dramaticallyif the nanocrystals are charged up. The reduction in both the capacitance and the currentcaused by the charging in the nanocrystals is found to be fully recoverable underultraviolet (UV) light illumination for 5 min or a thermal annealing at a temperature of100 °C for 10 min. The reduction and recovery of the capacitance due to the charging anddischarging in the nanocrystals are explained with an equivalent circuit model.