High Mobility and High N concentration of GaN{sub}xAs{sub}(1-x) Thin Films Grown by Metal Organic Chemical Vapor Deposition

摘要

GaN{sub}xAs{sub}(1-x) thin films had been successfully grown on semi-insulating GaAs (001) substrates by metal organic chemical vapour deposition (MOCVD) method. The precursors used were trimethylgallium (TMGa), dimethylhydrazine (DMHy), and tris-dimethylaminoarsenic (TDMAAs). GaN{sub}xAs{sub}(1-x) thin films of 1.2 - 2.4 μm thick were grown at the total reactor pressure of 50 torr, H{sub}2 and N{sub}2 flow rate of 300 sccm, temperatures range of 560 - 590°C, and the ratio of TDMAAs/TMGa and DMHy/TDMAAs flow rate of 4.5 and 0.8, respectively. The growth rate of GaN{sub}xAs{sub}(1-x) thin films are in the range of 0.8 - 1.6 μm/h. The N concentration of GaN{sub}xAs{sub}(1-x) thin films was studied by HR-XRD measurements and was calculated using Vegard's law from symmetric and asymmetric reflection. From this study, it found that the N concentration of GaN{sub}xAs{sub}(1-x) thin films were in the range of 4.9 and 5.5%. The measured electron mobility using Hall-van der Pauw method is in order of 3270 and 3380 cm{sup}2 V{sup}(-1) s{sup}(-1) at x = 4.9% and 5.5%, respectively.