GROWTH OF ALN, GAN AND ALXGA1-XN THIN-FILMS ON VICINAL AND ON-AXIS 6H-SIC(0001) SUBSTRATES

Monocrystalline GaN(0001) thin films were grown at 950 degrees C on Al N(0001) buffer layers previously deposited at 1100 degrees C on alpha( 6H)-SiC(0001)(Si) substrates via metallorganic chemical vapor depositi on (MOCVD). Films of AlxGa1-xN (0 less than or equal to x less than or equal to 1) were grown directly on the same SiC surface at 1100 degre es C. X-ray rocking curves for the GaN(0004) reflection for 1.4 mu m f ilms revealed FWHM values of 58 and 151 arc sec for materials grown on on-axis and off-axis substrates, respectively. Cathodoluminescence ex hibited strong near band-edge emission for all materials. Controlled n -type Si-doping in GaN and AlxGa1-xN (for x less than or equal to 0.4) was achieved with net carrier concentrations ranging from approximate ly 2 x 10(17) cm(-3) to 2 x 10(19) (AlxGa1-xN) or to 1 x 10(20) (GaN) cm(-3). Mg-doped, p-type GaN and AlxGa1-xN (for x less than or equal t o 0.13) was achieved with n(A)-n(D) approximate to 3 x 10(17) cm(-3). (C) 1997 Elsevier Science Limited.