Analysis of interface states and series resistance of MIS Schottky diodes using the current–voltage (I–V) characteristics

The purpose of this paper is to analyze interface states in Al/SiO2/p-Si (MIS) Schottky diodes and determine the effect of SiO2 surface preparation on the interface state energy distribution. The current–voltage (I–V) characteristics of MIS Schottky diodes were measured at room temperature. From the I–V characteristics of the MIS Schottky diode, ideality factor (n) and barrier height (ΦB) values of 1.537 and 0.763 eV, respectively, were obtained from a forward bias I–V plot. In addition, the density of interface states (Nss) as a function of (Ess–Ev) was extracted from the forward bias I–V measurements by taking into account both the bias dependence of the effective barrier height (Φe), n and Rs for the MIS Schottky diode. The diode shows non-ideal I–V behaviour with ideality factor greater than unity. In addition, the values of series resistance (Rs) were determined using Cheung’s method. The I–V characteristics confirmed that the distribution of Nss, Rs and interfacial insulator layer are important parameters that influence the electrical characteristics of MIS Schottky diodes.