Effect of atomic-hydrogen treatment of (001) GaAs substrate at `high temperatures' on rf plasma-assisted molecular beam epitaxy of cubic GaN

Growth of high quality c-GaN on atomic-H treated (001) GaAs was examined by rf plasma-assisted MBE. First the initial growth stages (atomic-H treatment of GaAs, nitridation/deposition of a thin GaN buffer layer, the post deposition annealing of the buffer layer, and epitaxy of c-GaN) were studied by RHEED and AFM observations. It was found that atomically flat GaAs surface with one monolayer-height steps and ragged step edges could be obtained by the atomic-H treatment at high temperatures. It was found that the atomic-H treated GaAs surface was preferable to grow high quality c-GaN; the FWHM of the X-ray rocking curve for the (002) c-GaN was as small as 70-90 arcsec.