GROWTH AND DOPING VIA GAS-SOURCE MOLECULAR-BEAM EPITAXY OF SIC AND SIC ALN HETEROSTRUCTURES AND THEIR MICROSTRUCTURAL AND ELECTRICAL CHARACTERIZATION/

Gas-source molecular beam epitaxy has been employed to grown thin film s of SiC and AlN on vicinal and on-axis 6H-SiC(0001). Growth using the SiH4-C2H4 system resulted In 3C-SiC(111) epilayers under all conditio ns of reactant gas flow and temperatures. Films of 6H-SiC(0001) were d eposited on vicinal 6H-SiC(001) substrates using the SiH4-C2H4-H-2 sys tem at deposition temperatures greater than or equal to 1350 degrees C . In situ doping was achieved by intentional introduction of nitrogen and aluminum into the growing crystal, Monocrystalline AlN was deposit ed using evaporated Al and ECR plasma derived N of NH3. Films <50 Angs trom grown on the vicinal substrates had higher defect densities compa red to those on the on-axis substrates due to the higher density of in version boundaries forming at most SiC steps in the former material, M etal/AlN/6H-SiC(0001) thin film heterostructures which had a density o f trapped charges as low as of 1 x 10(11) cm(-2) at room temperature w ere prepared without post growth treatment. Superior single crystal Al N/SiC heterostructures were achieved when very thin AIN was deposited on the on-axis substrates. Single phase monocrystalline solid solution s of (AlN)(x)(SiC)(1-x) were deposited between 0.2 less than or equal to x less than or equal to 0.8. A transition from the zinchlende to th e wurtzite structure was observed at x approximate to 0.25, (C) 1997 E lsevier Science S.A.