Current–voltage characteristics of a GaAs Schottky diode accounting for leakage paths

Many fabricated Schottky diodes exhibit significant deviations from the theoretically calculated current–voltage (I–V) characteristics of ideal Schottky diodes. Attempts have been made to account for this deviation using interface states or surface state densities. Previous models have used the interfacial layer model to analyze the nonideal I–V characteristics of a GaAs Schottky barrier. We show here how nonideal behavior can be explained by considering surface leakage currents and material resistance. The standard figure of merit of Schottky diodes is the ideality factor, which can be obtained from measurements of δV/δ ln(I). By taking into account device resistance and shunt leakage paths with physically appropriate parameters, a relationship between δV/δ ln(I) and voltage can be established, which yields a better understanding of transport across the interface(s) of real Schottky diodes. © 2000 American Institute of Physics.