Effects of hydrogen irradiation on the electrical properties of dilute nitride GaAsN Schottky diodes

Electrical characteristics of as-grown and hydrogen-irradiated GaAsN Schottky diodes having different contents of nitrogen (N = 0–1.2%) have been investigated. In this work, the effect of hydrogen irradiation on the electrical properties of Schottky diodes has been studied. Current–Voltage, Capacitance–Voltage and Capacitance–Voltage–Frequency measurements were analysed along with the previously reported DLTS and Laplace results. It was found that the reverse saturation current for all hydrogen-irradiated Schottky diodes increased as compared to the as-grown devices, which is attributed to high densities of several trap levels that have activation energies higher than 0.50 eV. The density of ionized donors N_d in as-grown samples (0.2% N) has been found to decrease from 1.52 × 10¹⁶ cm⁻³ to 1.12 × 10¹⁶ cm⁻³ in hydrogen-irradiated samples. An unexpected behaviour of conductance is observed along with a drastic increase of capacitance due to the high leakage current. The analysis for the existence of higher densities of deep trap levels which leads to higher peak values of capacitance at low frequencies is presented in this investigation.