Nonpolar 4H-AlN grown on 4H-SiC (1(1)over-bar00) with reduced stacking fault density realized by persistent layer-by-layer growth

Abstract

Nonpolar AlN layers were grown on 4H-SiC (1[overline 1]00) substrates by plasma-assisted molecular-beam epitaxy. By using SiC substrates with well-formed step-and-terrace structures, stable layer-by-layer growth of 4H-AlN (1[overline 1]00) can be realized. The layer-by-layer growth is confirmed by observations of anisotropic two-dimensional AlN islands on the grown surface as well as persistent reflection high-energy electron diffraction intensity oscillations. Cross-sectional transmission electron microscopy observations reveal that stacking fault generation during growth is suppressed and the stacking fault density is reduced to 1×106 cm−1.