The analysis of leakage current in MIS Au/SiO$_2$/$n$-GaAs at room temperature

The aim of this study is to determine the reverse-bias leakage current conduction mechanisms in Au/SiO$_2$/$n$-GaAs metal–insulator–semiconductor type Schottky contacts. Reverse-bias current-voltage measurements (I–V) were performed at room temperature. The using of leakage current values in SiO$_2$ at electric fields of 1.46–3.53 MV/cm, $\ln(J/E)$ vs. $\sqrt{(E)}$ graph showed good linearity. From this plot, dielectric constant of SiO$_2$ was calculated as 3.7 and this value is perfect agreement with 3.9 which is value of SiO$_2$ dielectric constant. This indicates, Poole–Frenkel type emission mechanism is dominant in this field region. On the other hand, electric fields between 0.06–0.73 and 0.79–1.45 MV/cm, dominant leakage current mechanisms were found as ohmic type conduction and space charge limited conduction, respectively.