A MICROSTRUCTURAL COMPARISON OF THE INITIAL GROWTH OF ALN AND GAN LAYERS ON BASAL-PLANE SAPPHIRE AND SIC SUBSTRATES BY LOW-PRESSURE METALORGANIC CHEMICAL-VAPOR-DEPOSITION
T. George et al., A MICROSTRUCTURAL COMPARISON OF THE INITIAL GROWTH OF ALN AND GAN LAYERS ON BASAL-PLANE SAPPHIRE AND SIC SUBSTRATES BY LOW-PRESSURE METALORGANIC CHEMICAL-VAPOR-DEPOSITION, Journal of electronic materials, 24(4), 1995, pp. 241-247
The initial growth by low pressure metalorganic chemical vapor deposit
ion and subsequent thermal annealing of AlN and GaN epitaxial layers o
n SiC and sapphire substrates is examined using high resolution transm
ission electron microscopy and atomic force microscopy. Growth under l
ow pressure conditions on sapphire substrates is significantly differe
nt from that reported for conventional (atmospheric pressure) conditio
ns. Smooth, single crystal AlN and GaN layers were deposited on sapphi
re in the initial low temperature (600 degrees C) growth step. Interfa
cial banding and not lattice mismatch was found to be the determining
factor for obtaining good crystallinity for the epitaxial layers as in
dicated by the growth results on SiC substrates.