Pendeo-epitaxial growth and characterization of thin films of gallium nitride and related materials on SiC(0001) and si(111) substrates

Monocrystalline GaN and Al(x)Gal(1-x) films have been grown via the pendeo- epitaxy (PE) [1] technique with and without Si3N4 masks on GaN/AlN/6H-SiC(0 001) and GaN(0001)/AlN(0001)/3C-SiC(111)/Si(111) substrates using organomet allic vapor phase deposition. Scanning and transmission electron microscopi es were used to evaluate the external microstructures and the distribution of dislocations, respectively. The dislocation densities in the PE grown fi lms were reduced at least five orders of magnitude relative to the initial GaN seed layers. Tilting to 0.2 degrees in the portion of the coalesced GaN epilayers grown over the silicon nitride masks was observed via X-ray diff raction. Neither tilting nor low angle boundaries were observed within area s of coalescence in the material grown on substrates without the masks.