Large area GaN substrates

Free-standing GaN substrates were fabricated by hydride-metal organic vapor phase epitaxy (H-MOVPE) on closely lattice-matched LiGaO2 substrates. The key to obtaining GaN films on LiGaO2 was the initial surface nitridation step. Nitriding and cooling processes were found to be critical film–substrate self-separation. The GaN surface morphology of the GaN was determined by AFM; the structural quality was analyzed by XRD; the chemical composition was investigated by AES, ESCA, and SIMS. Raman spectroscopy was applied for film and substrate characterization.