A sandwiched multi-structure made of alternatively undoped and vanadium-doped GaN layers was grown onto SiN-treated (00•1) sapphire substrates by atmospheric-pressure metal-organic chemical vapour deposition. The V diffusion in GaN was investigated at 1000 to 1100C by using secondary ion mass spectroscopy. The diffusion coefficients were obtained through a data-fitting program based upon Fick's first law. The results suggested that V diffused faster near to the GaN/sapphire interface. During annealing, V redistributed via both in- and out-diffusion mechanisms. An activation energy of 2.9eV was estimated for V diffusion in GaN.

Diffusion Behaviour of Vanadium in GaN Thin Films Studied by Secondary Ion Mass Spectrometry. A.Bchetnia, C.Saidi, M.Souissi, T.Boufaden, B.El Jani: Semiconductor Science and Technology, 2009, 24[9], 095020