EPITAXIAL-GROWTH OF CUBIC GAN ON (111)GAAS BY METALORGANIC CHEMICAL-VAPOR-DEPOSITION

We are reporting the first comprehensive investigation of the structural properties of cubic GaN grown on (111) GaAs substrates by low-pressure metalorganic chemical vapor deposition. The minimum full width at half maximum (FWHM) of the x-ray diffraction (XRD) peak of (111) GaN was found to be similar to 12 min. The use of low temperature GaN buffers helps to reduce the FWHM of the XRD. Cross-sectional transmission electron microscopy (XTEM) revealed the presence of columnar structures in the GaN film with widths of the order of 500 Angstrom, Selected area electron diffraction (SAD) patterns at the interface confirmed that cubic (111) GaN was grown in-plane with the (111) GaAs substrate. High-resolution transmission electron microscopy (HRTEM) showed that the interface characteristics of GaN on (111)A GaAs substrate were better than those of the GaN on (111)B GaAs substrate.