RESUMO
It is shown that a simple metal-oxide-semiconductor (MOS) structure with highly doped silicon substrate can exhibit current-voltage hysteresis effects related to sudden rises and drops in the flowing electric current. Experimental current-voltage characteristics of Al-SiO2-(n++Si) structures are presented and discussed. Their analysis shows that the ohmic and shallow traps assisted space-charge limited conduction (SCLC) are the dominating transport mechanisms. Sudden rises and drops in the flowing current, leading to the current-voltage hysteresis effects, are attributed to tunneling through deep traps in the oxide. Based on inelastic electron tunneling spectroscopy (IETS), the energy levels of the deep traps and their position in the oxide are evaluated.
RESUMO
In this study, the resistive switching phenomenon in Al/SiO2/n++-Si structures is observed and studied by means of DC, small-signal admittance, and complex impedance spectroscopy measurements. Possible transport mechanisms in the high and low resistance states are identified. Based on the results of the applied measurement techniques, an electrical equivalent circuit of the structure is proposed. We discuss the effect of parasitic elements influencing the measurement results and show that a proper model can give useful information about the electrical properties of the device. A good agreement between the characteristics of the proposed equivalent circuit and the experimental data, based on different measurement procedures, confirms the validity of the used methodology and its applicability to the electrical characterization of RRAMs.
