GROWTH OF SIC AND III-V NITRIDE THIN-FILMS VIA GAS-SOURCE MOLECULAR-BEAM EPITAXY AND THEIR CHARACTERIZATION

Silicon carbide (SiC) and aluminum nitride (ALN) thin films have been grown on 6H-SiC(0001) substrates by gas-source molecular beam epitaxy (GSMBE) at 1050 degrees C, Step flow, step bunching and the deposition of 6H-SiC occurred at the outset of the exposure of the (1x1) vicinal substrate surface to C2H4/Si2H6 gas flow ratios of 1, 2 and 10. Subse quent deposition resulted in step flow and continued growth of 6H film s or formation and coalescence of 3C-SiC islands using the gas flow ra tio of one or the ethylene-rich ratios, respectively. The (3 x 3) surf ace reconstruction observed using the former ratio is believed to enha nce the diffusion lengths of the adatoms, which in turn promotes step flow growth, Essentially atomically flat monocrystalline AIN surfaces were obtained using on-axis substrates. Island-like features were obse rved on the vicinal surface. The coalescence of the latter features at steps gave rise to inversion domain boundaries (IDBs) as a result of the misalignment of the Si/C bilayer steps with the AIN bilayers in th e growing film. The quality of thicker AIN films is strongly influence d by the concentration of IDBs. Undoped, highly resistive (10(2) Omega . cm) and Mg-doped, p-type (0.3 Omega . cm) monocrystalline GaN films having a thickness of 0.4-0.5 mu m have also been grown via the same technique on ALN buffer layers without post-processing annealing.