Formation mechanism and relative stability of the {112¯0} stacking fault atomic configurations in wurtzite (Al,Ga,In) nitrides

The formation of the {12¯10} stacking fault, which has two atomic configurations in wurtzite (Ga,Al,In)N, has been investigated by high-resolution electron microscopy and energetic calculations. It originates from steps at the SiC surface and it can form on a flat (0001) sapphire surface. A modified Stillinger-Weber potential is used in order to investigate the relative stability of the two atomic configurations which have comparable energy in AIN, whereas the 1/2〈101¯1〉{12¯10} atomic configuration should be more stable in GaN and InN. Experimental evidence is shown in the case of AIN and GaN from high-resolution electron microscopy. Observations carried out in plan-view show the 1/2〈101¯1〉{12¯10} atomic configuration in GaN layers. The 1/6〈202¯3〉 configuration was found in small areas inside the AIN buffer layer in cross-section observations. It folds rapidly to the basal plane, and when back in the prismatic plane it bears the 1/2〈101¯1〉{12¯10} atomic configuration.