Effect of nitrogen incorporation on electrical properties of Ti/Au/GaAsN Schottky diodes

Abstract Electrical I – V and C – V – F measurements have used to investigate the behaviour of Ti/Au/GaAsN Schottky diodes, deposited by Molecular Beam Epitaxy, with various nitrogen percent contents. Ideality factor and series resistance were found to increase with increasing N% dilution in GaAs. This was accompanied by a decrease in Schottky barrier height ( I – V ). The discrepancy found between Schottky barrier heights estimated from I – V and C – V measurements is attributed to a difference in measurements methods and inhomogeneities in barrier height. The peak capacitance behaviour and its dependence on frequency for Schottky diodes with 0.8% N and 1.2% N content was attributed to annihilation of trap levels below midgap. These traps levels associated with those above midgap are responsible for the nondependence of peak capacitance on frequency for Schottky diodes with 0.2% N content. A compensation effect between traps below and above midgap is believed to be taking place. The dependency reappears for Schottky diodes without nitrogen content and is attributed to trap levels below midgap. Capacitance and conductance at high frequency were corrected to eliminate series resistance effect. Interface states density significantly increased when we increased dilute nitride concentration and may play an important role in Ti/Au/GaAsN Schottky diodes at low frequency.