Reduction of threading dislocations in nonpolar 4H-AlN on 4H-SiC (1120) grown by molecular-beam epitaxy with slightly Al-rich conditions

摘要

Growth of AlN on (1120) 4H-SiC a-plane face substrates by molecular-beam epitaxy has been investigated. Nonpolar (1120) 4H-AlN was isopolytypically grown on (1120) 4H-SiC substrates under slightly Al-rich conditions. When growth was performed under slightly N-rich conditions, (1120) 2H-AlN with high stacking fault density was obtained. A reduced density of defects such as stacking faults and threading dislocations was achieved by growing in slightly Al-rich conditions. For the best sample, the stacking fault density was 2 x 10~5 cm~(-1), and the partial and perfect threading dislocation densities were 7 x 10~7 cm~(-2) and 1 x 10~7 cm~(-2), respectively.