On the energy distribution profile of interface states obtained by taking into account of series resistance in Al/TiO 2/p–Si (MIS) structures

Abstract

The energy distribution profile of the interface states ( N ss ) of Al/TiO 2/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 ( ϕ 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 ( ϕ 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/TiO 2 interface. The values of N ss localized at the Si/TiO 2 interface were found with and without the R s at 0.25 -E v in the range between 8.4×10 13 and 4.9×10 13 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.