Dislocation annihilation in GaN with multiple MgxNy/GaN buffer layers by metal organic chemical vapor deposition

Unintentionally doped GaN epitaxial layers with a conventional single low-temperature (LT) GaN buffer layer and with multiple MgxNy/GaN buffer layers were grown on sapphire substrates by metal organic chemical vapor deposition (MOCVD). X-ray Photoelectron Spectroscopy (XPS) result reveals Mg 2p core-level spectra from the 12 pairs of MgxNy/GaN buffer layers. The multiple MgxNy/GaN buffer layers exhibit a low nuclei density, increasing the volume of defect-free regions and reducing the dislocations associated with the grain boundaries. Therefore, the GaN with multiple MgxNy/GaN buffer layers reveals an asymmetrical reflection (102) with a small full-width at half-maximum (FWHM), and a higher mobility, lower background concentration and lower etching pit density (EPD) than the GaN with the LT GaN buffer layer.