Defect investigation in Al0.87In0.13N/AlN/GaN heterostructures by scanning force microscopy methods

AlInN/AlN/GaN heterostructures were characterized by atomic force microscopy (AFM) in semi-contact and conductive mode. These indium-related alloys contain threading dislocations (TDs) with a density around 108 ~109cm-2, originating from the GaN (0001) substrate grown on sapphire. The TDs, with screw or mixed components, terminate at the surface of overgrown layers as V-defects. Using semi-contact AFM (phase-imaging) mode, we traced sites of indium segregation at the V-defects. These sites in V-defects were found to be highly conductive by current-AFM and could be a possible cause for the leakage current in Schottky diodes