Vertical GaN PIN Structure with Intrinsic AlGaN Drift Layer Grown Using Metal-Organic Chemical Vapor Deposition

In this study, it is aimed to examine the DC characteristics of a vertical PIN diode featuring AlGaN as the drift layers. In the investigation, observing the changes in DC characteristics with the variation of Al content (0%-4%) in the drift layers as well as its thickness is focused on. By applying AlGaN as the drift layer, the semi-insulating properties are augmented and the detrimental background carbon impurity is reduced, leading to a reduction in the leakage current and an improvement in the breakdown voltage characteristics of the device. Room-temperature and low-temperature photoluminescence measurements confirm a reduction in the intensity of both yellow luminescence and blue luminescence, which can be attributed to the decrease in defect concentration. Furthermore, to minimize the occurrence of premature breakdown voltage, p-type GaN is meticulously etched into a bevel shape, and subsequent confirmation through the utilization of a scanning electron microscope reveals an inclination of 13 degrees. The outcome of the analysis on the DC characteristic indicates an improvement in reverse-bias characteristics with the increase in the Al ratio in the drift layer for the 2 mu m series. Furthermore, for the 20 mu m Al0.04Ga0.96N, a breakdown voltage of 2540 V is recorded. The study examines the impact of aluminum content (0%-4%) and drift layer thickness on DC characteristics and breakdown voltage in vertical GaN-on-GaN PIN diodes. Using PL and AFM, surface and defects of the drift layers are analyzed. A device with a 20 mu m Al0.04Ga0.96N drift layer achieves a breakdown voltage of 2540 V.image (c) 2024 WILEY-VCH GmbH