GaN growth on sapphire and 6H-SiC by metalorganic molecular beam epitaxy

GaN was grown on sapphire(0 0 0 1), SiC(O O O 1)Si and SiC(O O O (1) over bar)C by MOMBE using TEGa and N-2 cracked in RF plasma. GaN grown with a GaN buffer layer on sapphire at a substrate temperature of 700 degrees C showed a specular surface with n-type conduction. In the case of GaN growth on SIG, it is necessary to grow a GaN buffer layer at a low temperature to obtain a sufficient growth rate. The difference of the growth rates between both polarities of the SiC substrate is explained in terms of the stacking of atoms at the interface of GaN/SiC. (C) 1998 Elsevier Science B.V. All rights reserved.