On the energy distribution profile of interface states obtained by taking into account of series resistance in Al/TiO2/p-Si (MIS) structures

The energy distribution profile of the interface states (N_ss) of Al/TiO₂/p-Si (MIS) structures prepared using the sol-gel method was obtained from the forward bias current-voltage (I-V) characteristics by taking into account both the bias dependence of the effective barrier height (?_e) and series resistance (R_s) at room temperature. The main electrical parameters of the MIS structure such as ideality factor (n), zero-bias barrier height (?_b0) and average series resistance values were found to be 1.69, 0.519 eV and 659 Ω, respectively. This high value of n was attributed to the presence of an interfacial insulator layer at the Al/p-Si interface and the density of interface states (N_ss) localized at the Si/TiO₂ interface. The values of N_ss localized at the Si/TiO₂ interface were found with and without the R_s at 0.25-E_v in the range between 8.4×10¹³ and 4.9×10¹³ eV⁻¹ cm⁻². In addition, the frequency dependence of capacitance-voltage (C-V) and conductance-voltage (G/ω-V) characteristics of the structures have been investigated by taking into account the effect of N_ss and R_s at room temperature. It can be found out that the measured C and G/ω are strongly dependent on bias voltage and frequency.