Unintentionally doped GaN epitaxial layers with a conventional single low-temperature GaN buffer layer and with multiple MgxNy/GaN buffer layers were grown on sapphire substrates by metal organic chemical vapor deposition. The multiple MgxNy/GaN buffer layers exhibited 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 revealed 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 low-temperature GaN buffer layer.

Dislocation Reduction in GaN with Multiple MgxNy/GaN Buffer Layers by Metal Organic Chemical Vapor Deposition. C.J.Tun, C.H.Kuo, Y.K.Fu, C.W.Kuo, C.J.Pan, G.C.Chi: Applied Physics Letters, 2007, 90[21], 212109 (3pp)