The diffusion of magnesium was studied in GaN layers grown onto sapphire

substrate by atmospheric pressure metal-organic vapour-phase-epitaxy in a socalled

home-made reactor. Secondary ion mass spectroscopy was used to visualise

the Mg profiles in two kinds of multi-sublayer GaN structure. One structure was

grown with a variable flow of Ga precursor and the second one using a variable

growth temperature. In both cases, the Mg dopant precursor (Cp2Mg) flow was

kept constant. Using Fick's second law to fit the experimental secondary ion mass

spectroscopy data, an increasing and then a saturating Mg diffusion coefficient as a

function of Mg concentration was deduced. The Mg incorporation was found to

increase at lower growth rates, i.e. when the Ga precursor flow was reduced.

Furthermore, based upon the temperature-related behaviour, it was found that the

activation energy for Mg diffusion coefficient in GaN was 1.9eV. It was suggested

that Mg diffused via substitutional sites.

Magnesium Diffusion Profile in GaN Grown by MOVPE. Z.Benzarti, I.Halidou,

Z.Bougrioua, T.Boufaden, B.El Jani: Journal of Crystal Growth, 2008, 310[14],

3274-7