Reducing leakage current in GaN-Schottky diodes by suppressing hollow core nanopipes

The nanopipes in GaN films grown on sapphire substrates using metal-organic chemical vapor deposition were identified as leakage-related defects through investigations by PeakForce tunneling atomic force microscopy. An insertion layer of n-Al0.03Ga0.97N can prevent nanopipes from extending, thereby reducing the leakage current of Schottky diodes. By analyzing the element’s distribution in and out of nanopipes on epitaxial wafers, it is inferred that segregation of Ga around nanopipes may be responsible for the leakage.