Growth and Characterization of an a-Plane InxGa1-xN on a r-Plane Sapphire

The non-polar a-plane (110) InxGa1−xN alloys with different indium compositions (0.074 ≤ x ≤ 0.555) were grown on r-plane (102) sapphire substrates by metalorganic chemical vapor deposition, and the indium compositions x are estimated from x-ray diffraction measurements. The in-plane orientation of the InxGa1−xN with respect to the r-plane substrate is confirmed to be [100]sapphire|| [110]InxGa1−xN and [101]sapphire|| [0001]InxGa1−xN. The effects of substrate temperature, reactor pressure and trimethylindium input flow on the indium incorporation and growth rate are investigated. The morphology of the a-plane InxGa1−xN is found to be significantly improved with the decreasing indium composition x and growth rate. Moreover, the in-plane anisotropic structural characteristics are revealed by high resolution x-ray diffraction employing azimuthal dependence, and the degree of anisotropy decreases with the increase of indium composition.