Low-temperature growth of GaN by atomic nitrogen based on a dielectric barrier discharge

GaN films were deposited on sapphire(0 0 0 1) and Si (1 0 0) subsrmtes by M OCVD using an atomic nitrogen source based on a dielectric barrier discharg e (DBD) method. Molecule nitrogen and trimethylgallium (TMG) were separatel y delivered to the substrates. Wurtzite GaN films, with no trace of cubic G aN. were successfully grown on alpha-Al2O3 substrates even at relatively lo w temperatures ( < 800 degrees C). Sapphire subrtrate RMS roughness was 5.0 1 and 1.93 Angstrom before and after the exposure to DBD N-source. respecti vely. This shows negligible irradiation damage of accelerated N-2(+) ion as well as the effect of smoothening the substrate surfaces with DBD N-source . The PL results exhibited small luminescence at the spectral region of blu e and UV but a luminescence around the yellow region (2.5 eV) was detected. This is caused by oxygen impurity from AES analysis. (C) 2000 Elsevier Sci ence B.V. All rights reserved.