Effects of X-ray Irradiation on Vertical GaN-on-GaN Schottky Barrier Diode Biased on the Applied Voltage

The radiation characteristics of vertical GaN-on-GaN Schottky barrier diodes (SBD) by the bias of +0.8 V and -5.0 V have been investigated with four different doses of the total ionizing dose irradiation for the first time. The off-state current decreases by ~99 % for X-ray doses of 80 krad due to the trapping of electrons at the nitrogen vacancies and the barrier height increases. The off-state current for X-ray doses above 160 krad increases owing to the effects of X-ray radiation induced carrier generation over occupation of defect sites. The leakage current still reduces compared with that of the pristine device even after 400 krad X-ray doses. Moreover, the effect of X-ray irradiation on the physical characteristics has been analysed by X-ray diffraction (XRD), Micro-raman, and photoluminescence (PL) measurements. This study provides an evidence for improved performance of GaN SBD devices by using a certain dosage treatment of X-ray.