Chemical beam epitaxy of GaN using triethylgallium and ammonia

GaN films were successfully grown on Al₂O₃(0 0 0 1) and 6H-SiC(0 0 0 1) substrates by chemical beam epitaxy (CBE) using triethylgallium (TEG) and ammonia (NH₃) as group III and group V sources. Reflection high-energy electron diffraction (RHEED), atomic force microscopy (AFM) and X-ray diffraction (XRD) were used to characterize the growth processes, surface morphologies and the film qualities of GaN. It was found that the GaN growth mode was two-dimensional and that the GaN quality was improved by increasing the NH₃ supply. XRD measurements show that the quality of GaN films grown on 6H-SiC(0 0 0 1) substrates is better than that grown on Al₂O₃(0 0 0 1) substrates. AFM characterizations illustrate that the surface morphologies of GaN are greatly influenced by the NH₃ flow rates.