High Mobility and High N concentration of GaNxAs1-x Thin Films Grown by Metal Organic Chemical Vapor Deposition

GaN_xAs_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_xAs_1-x thin films of 1.2-2.4 mum thick were grown at the total reactor pressure of 50 torr, H₂ and N₂ flow rate of 300 sccm, temperatures range of 560 - 590degC, and the ratio of TDMAAs/TMGa and DMHy/TDMAAs flow rate of 4.5 and 0.8, respectively. The growth rate of GaN_xAs_1-x thin films are in the range of 0.8 - 1.6 mum/h. The N concentration of GaN_xAs_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_xAs_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 cm² V^-1 s^-1 at x = 4.9% and 5.5%, respectively.