Dislocation reduction in GaN with multiple Mg_xN_y/GaN buffer layers by metal organic chemical vapor deposition

摘要

Unintentionally doped GaN epitaxial layers with a conventional single low temperature (LT) GaN buffer layer and with multiple Mg_xN_y/GaN buffer layers were grown on sapphire substrates by metal organic chemical vapor deposition. The multiple Mg_xN_y/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 Mg_xN_y/GaN buffer layers reveals an asymmetrical reflection (102) with a small full width at half maximum, and a higher mobility, lower background concentration, and lower etching pit density than the GaN with the LT GaN buffer layer.