Growth of self-assembled nanovoids embedded AlN layer on a low-temperature buffer by metal organic chemical vapor deposition

摘要

In this study, we demonstrate a high-quality aluminum nitride (AlN) film with a thickness of 2.5 um grown on 4H-SiC substrate using a three-dimensional (3D) buffer via high-temperature metal-organic chemical vapor deposition. For the buffer layer, 3D structure morphology without polycrystals was selected by the temperature change from 850 to 1350 degrees C. The main layer was grown on the 3D buffer, and self-assembled nanovoids were formed, enabling the growth of a high-quality AlN film without cracks. However, many cracks occurred in the sample without a buffer. The full width at half maximum of the X-ray rocking curve was 144/368 arcsec for (002)/(102) planes, respectively. Cross-sectional transmission electron microscopy showed nanovoids and a rapid defect reduction effect at the interface of the buffer layer.