Observation of inversion domain boundaries in Mg-doped AlGaN layers grown by metalorganic chemical vapor deposition

We have investigated the formation of inversion domain boundaries in Al _0.13 Ga _0.87 N layers grown on sapphire substrates by metalorganic chemical vapor deposition using transmission electron microscopy (TEM). We found that the shape of inversion domain boundaries strongly depends on Mg source flow rate in the Mg-doped Al _0.13 Ga _0.87 N layers. By increasing the Mg source flow rate, the shape of inversion domain boundaries is changed from the vertical shape to the horizontal shape. In addition, the change of polarity by the horizontal shape inversion domain boundary (IDB) resulted in the inverted rotation of pyramidal shape IDB within the Mg-doped Al _0.13 Ga _0.87 N layers.