Effects of the GaN layers and the annealing on the electrical properties in the Schottky diodes based on nitrated GaAs

This work attempts to characterize the Au/GaN/GaAs Schottky diode. The thin GaN film is realized by nitridation of GaAs substrates with different thicknesses (0.7-2.2 nm). We propose a study of the electrical quality of the components after the elaboration of the Au/GaN/GaAs systems; first without annealing and the second with annealing at 620 °C. Analysis of the current voltage I-V and capacitance voltage C-V characteristics of the Au/heated GaN/GaAs and Au/GaN/GaAs samples with 2.2 nm of GaN thickness allows the determination of the electrical parameter variations. Then, the ideality factor increases after the annealing at 620 °C and becomes equal to 2.86 and 2.77 for the 5 min and 30 min of nitridation, respectively. The calculated states density Nss shows less defects and traps in the Au/GaN/GaAs structure (not heated). It is seen that the electrical parameters of the Au/heated GaN/GaAs diode are significantly different from the conventional Au/GaAs Schottky diode. The improvement of the parameters may be attributed to the passivation of the GaAs surface with the formation of the GaN interfacial layer.