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The electrical properties of silicon-rich oxide (SRO) films in metal-oxide-semiconductor-like structures were analysed by current versus voltage (I-V) and capacitance versus voltage (C-V) techniques. SRO films were thermally annealed to activate the agglomeration of the silicon excess in the form of nanoparticles (Si-nps). High current was observed at low negative and positive voltages, and then at a certain voltage (V(drop)), the current dropped to a low conduction state until a high electric field again activated a high conduction state. C-V measurements demonstrated a capacitance reduction at the same time as the current dropped, but without appreciable flat-band voltage (V(FB)) shifting. The reduction in capacitance and current was also observed after applying an electrical stress. These effects are ascribed to the annihilation of conductive paths created by Si-nps. An equivalent circuit is used to explain the capacitance and current reductions. Finally, the conduction mechanism is also analysed by making use of trap assisted tunnelling and Fowler-Nordheim tunnelling at low and high electric fields, respectively.

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Charge trapping effect in silicon-rich oxide (SRO) films was investigated using capacitance versus voltage (C–V), current versus voltage (I–V) and current versus time (I–t) measurements in an Al/SRO/Si MOS-like structure. SRO layers with different thicknesses were deposited. The trapped charge density was found to depend on the thickness of the SRO layers. It was shown that the total trapped charges can be divided into two parts: one part is correlated with the Si nanoclusters located near the SRO/Si interface (interface-NCs); another one is correlated with the Si nanoclusters distributed in the bulk of the SRO layers (bulk-NC). A current peak was observed in the I–V curves in the surface inversion condition. The peak position voltage varies with the thickness of the SRO layers. The current peak is attributed to the charging/discharging of the interface-NCs. The charging/discharging process of interface-NCs was evidenced by a fast decay of current in I–t measurements at the current peak voltage. I–t curves recorded at a large positive voltage are associated with the charge trapping effect of the bulk-NCs. The Coulomb blockade effect was suggested to be the reason of current decay at constant voltage.

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