Electrical characteristics of Au/n-GaAs Schottky barrier diodes with and without SiO2 insulator layer at room temperature

In this study, our main goal is fabricated with and without insulator layer Au/n-GaAs Schottky barrier diodes (SBDs) to explain whether or not the insulator layer is effective on some electric parameters such as ΦB, n, Nss, and Rs. The current–voltage (I–V) and capacitance–voltage (C–V) characteristics of metal–semiconductor (Au/n-GaAs) are investigated and compared with metal–insulator–semiconductor (Au/SiO2/n-GaAs) Schottky diodes. From the room temperature I–V characteristics of these devices, the main electrical parameters such as, ideality factor (n) and zero bias barrier height (Φbo) values of 1.25 and 0.73 eV for Au/n-GaAs, and 1.51 and 0.75 eV for Au/SiO2/n-GaAs, were obtained. The interface distribution profile (Nss) as a function of (Ec − Ess) was extracted from the forward-bias I–V measurements by taking into account the bias dependence of the effective barrier height (Φe) and series resistance (Rs) for the Schottky diodes. The Nss values obtained taking into account the series resistance values are lower than those obtained without considering the series resistance. The diodes show non-ideal I–V behavior with ideality factor greater than unity. This behavior is attributed to the interfacial insulator layer and the interface states. The I–V characteristics confirmed that the distribution of Nss, Rs, and interfacial insulator layer are important parameters that influence the electrical characteristics of metal–semiconductor and metal–insulator–semiconductor Schottky diodes.