A model to describe the humplike feature observed in the accumulation branch of capacitance-voltage characteristics of MOS capacitors with oxide-hosted silicon nanoparticles

Abstract

A model is proposed for description of a humplike feature that was previously observed in the lowfrequency capacitance-voltage (C-U) characteristics of MOS capacitors with oxide layers containing silicon nanoparticles. The formation of this feature is related to variation (at the frequency of measurements) of a charge accumulated in the oxide due to injection of charge carriers from electrodes and their migration by tunneling through oxide along linear chains formed by Si nanoparticles (with a certain spread of tunneling distances in the chain). The adequacy of the model is illustrated with the simple example of metal-oxidesilicon (MOS) capacitor with a planar array of Si nanoparticles in the oxide and a monopolar injection of holes from the accumulation layer of the p-type semiconductor. A C-U curve measured on an MOS capacitor with amorphous Si clusters is presented, which closely resembles curves with a two-hump feature predicted by the proposed model.