Forward and reverse bias current–voltage characteristics of Au/n-Si Schottky barrier diodes with and without SnO2 insulator layer

The effects of interfacial insulator layer, interface states (Nss) and series resistance (Rs) on the electrical characteristics of Au/n-Si structures have been investigated using forward and reverse bias current–voltage (I–V) characteristics at room temperature. Therefore, Au/n-Si Schottky barrier diodes (SBDs) were fabricated as SBDs with and without insulator SnO2 layer to explain the effect of insulator layer on main electrical parameters. The values of ideality factor (n), Rs and barrier height (ΦBo) were calculated from ln(I) vs. V plots and Cheung methods. The energy density distribution profile of the interface states was obtained from the forward bias I–V data by taking bias dependence of ideality factor, effective barrier height (Φe) and Rs into account for MS and MIS SBDs. It was found that Nss values increase from at about mid-gap energy of Si to bottom of conductance band edge of both SBDs and the MIS SBD’s Nss values are 5–10 times lower than those of MS SBD’s. An apparent exponential increase from the mid-gap towards the bottom of conductance band is observed for both SBDs’ (MS and MIS) interface states obtained without taking Rs into account.