The structural properties of Si- and Mg-doped and undoped Al0.13Ga0.87N layers, grown onto sapphire substrates by metal-organic chemical vapor deposition, were studied by using high-resolution X-ray diffraction and transmission electron microscopy. For both low SiH4 and low Cp2Mg flow rates, the full-width at half-maximum values of rocking curves and total threading dislocation densities in Al0.13Ga0.87N layers decreased rapidly due to an increased island size caused by surfactant effects. The origin of the broadening of high-resolution X-ray diffraction rocking curves in Al0.13Ga0.87N layers, with high SiH4 and Cp2Mg flow rates, resulted from increases in the total threading dislocation density and stacking-fault density, respectively. It was also observed that, in the case of Si doping, the lattice constant decreased continuously with SiH4 flow rate. However, the lattice constant of Mg-doped AlGaN layers was rapidly increased by a Cp2Mg flow rate of 3.172μmol/min.

Structural Properties of Si- and Mg-Doped and Undoped Al0.13Ga0.87N Layers Grown by Metalorganic Chemical Vapor Deposition. H.K.Cho, J.Y.Lee, S.R.Jeon, G.M.Yang: Journal of Crystal Growth, 2001, 233[4], 667-72