Reversible charging effects in SiO2 films containing Si nanocrystals

Reversible charging effects are observed in metal-insulator-semiconductor structures which have been ion implanted and annealed to produce Si nanocrystals in the insulating SiO2 layer. The shifts in current-voltage (I-V) and capacitance-voltage (C-V) curves are induced by forward constant voltage stress or UV light exposure, and can be explained by hole charging of the nanocrystals in the insulator layer. A reverse constant voltage stress is shown to recover the original I-V curve and partially recover the original C-V curve. For a sample implanted with a Si dose of 3x10(16) Si cm(-2), the voltage shift of the I-V curve produced by a forward voltage stress of V=-10 V for 5 s is 1.2 V, which is shown to be in reasonable agreement with simple estimates based on nanocrystal charging. (C) 1999 American Institute of Physics. [S0003-6951(99)02133-6].