An AlGaN/GaN superlattice grown on the top of a GaN buffer induced the broadening of the full-width at half-maximum of (102) and (002) X-ray diffraction rocking curves. With an increase in the Si-doped concentration in the GaN wells, the full-width at half-maximum of the (102) rocking curves decreased, while that of the (002) rocking curves increased. A significant increase in the full width at the half maximum of the (002) rocking curves when, the doping concentration reached 2.5 x 1019/cm3, indicated a substantial increase in the inclined threading dislocation. High-level doping of the AlGaN/GaN superlattice could greatly reduce the biaxial stress and optimize the surface roughness of the structures grown on top of it.

Effect of Si Doping in Wells of AlGaN/GaN Superlattice on the Characteristics of Epitaxial Layer. Z.Wei, J.S.Xue, X.W.Zhou, Z.Yue, Z.Y.Liu, J.C.Zhang, H.Yue: Chinese Physics B, 2012, 21[7], 077103