Hydride Vapor Phase Epitaxy of GaN on NdGaO3 Substrate and Realization of Freestanding GaN Wafers with 2-inch Scale

GaN thick film is grown on NdGaO3 substrate using hydride vapor phase epitaxy. To avoid decomposition of NdGaO3 substrate by NH3, a low-temperature grown GaN protective layer is adopted. Using NdGaO3 substrate and a low-temperature GaN protective layer simultaneously, 2-inch-scale GaN wafers are realized. The photoluminescence (PL) spectrum indicates strong band-edge emission without deep-level related emission. Both plan-view transmission electron microscope and cathode luminescence images suggest that the dislocation density of freestanding GaN wafers is expected to be as low as 106 cm-2.