6-inch AlN epitaxial films with low dislocation densities via MOCVD

Abstract High-quality AlN epitaxial layers with low dislocation densities and uniform crystal quality are essential for next-generation optoelectronic and power devices. This study reports the epitaxial growth of 6-inch AlN films on 17 nm AlN/sapphire templates using metal−organic chemical vapor deposition (MOCVD). Comprehensive characterization reveals significant advancements in crystal quality and uniformity. Atomic force microscopy (AFM) shows progressive surface roughness reduction during early growth stages, achieving stabilization at a root mean square (RMS) roughness of 0.216 nm within 3 min, confirming successful 2D growth mode. X-ray rocking curve (XRC) analysis indicates a marked reduction in the (0002) reflection full width at half maximum (FWHM), from 445 to 96 arcsec, evidencing effective dislocation annihilation. Transmission electron microscopy (TEM) demonstrates the elimination of edge dislocations near the AlN template interface. Stress analysis highlights the role of a highly compressive 17 nm AlN template (5.11 GPa) in facilitating threading dislocation bending and annihilation, yielding a final dislocation density of ~1.5 × 10 7 cm −2 . Raman spectroscopy and XRC mapping confirm excellent uniformity of stress and crystal quality across the wafer. These findings demonstrate the feasibility of this method for producing high-quality, large-area, atomically flat AlN films, advancing applications in optoelectronics and power electronics.