The Effect of Nanopipes and an Inserted n-AlGaN Interlayer on GaN Avalanche Photodiodes Performance

The effect of nanopipe defects on the device performance of Gallium nitride (GaN) avalanche photodiodes (APDs) is investigated and the influence mechanism is analyzed. It is discovered that nanopipes can incorporate more carbon impurities, resulting in the introduction of more deep energy level defects into the epitaxial layers. This causes an increase in device leakage and challenges in distinguishing between light current and dark current. It is found that an inserted n-AlGaN interlayer can effectively block nanopipes and improve device performance significantly. The n-AlGaN interlayer in Gallium nitride (GaN) avalanche photodiodes (APD) devices effectively blocks nanopipes, preventing the incorporation of carbon impurities and the formation of deep energy level defects during GaN material growth. Consequently, the reduction of nanopipes and carbon impurities in GaN materials has made a significant improvement in reducing leakage and optimizing the gain of GaN APD devices.image (c) 2023 WILEY-VCH GmbH