Interfacial layer thickness dependent electrical characteristics of Au/(Zn-doped PVA)/n-4H-SiC (MPS) structures at room temperature

Abstract

Au/(Zn-doped PVA)/n-4H-SiC metal/polymer/semiconductor (MPS) structures with different interfacial layer thickness values (50, 150, 500 nm) were fabricated and their electrical characteristics were compared. Their electrical parameters (i.e. reverse-bias saturation current (Io), ideality factor (n), zero-bias barrier height (BH) (φbo), series and shunt resistances (Rs, Rsh)) were calculated from the forward bias current-voltage (IF-VF) data whereas other parameters (i.e. Fermi energy level (EF), BH (Fb) and donor concentration (Nd)) were calculated from the linear part of C-2-V characteristics at room temperature. Obtained results confirmed that the values of n, φbo, Rs and Rsh increase with increasing interlayer thickness, and linear correlation between n and φbo was observed. The high values of n for three structures can be ascribed to the presence of an interlayer, surface states (Nss) and barrier inhomogeneities. The energy density distribution profile of Nss was obtained from the IF-VF data by taking into account voltage-dependent effective BH (Fe) and n for each structure. The Ri vs. V plot for these structures was obtained using both Ohm's law and Nicollian-Brews method. All these experimental results show that the interfacial layer and its thickness play an important role in main electric parameters of these structures. © EDP Sciences, 2017.