Forward and reverse bias current–voltage characteristics of Au/n-Si Schottky barrier diodes with and without SnO 2 insulator layer

Abstract

The effects of interfacial insulator layer, interface states ( N ss) and series resistance ( R s) 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 SnO 2 layer to explain the effect of insulator layer on main electrical parameters. The values of ideality factor ( n), R s and barrier height ( Φ Bo) 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 ( Φ e) and R s into account for MS and MIS SBDs. It was found that N ss values increase from at about mid-gap energy of Si to bottom of conductance band edge of both SBDs and the MIS SBD’s N ss 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 R s into account.