[22a-H121-1~11] 15.4 III-V-group nitride crystals

▲ [22a-H121-5] Structural quality of AlN epilayer grown on atomic layer deposition (ALD)-Al₂O₃/ sapphire substrate

〇(PC)RYAN BANAL¹, Masataka Imura¹, Koide Yasuo¹ (1.NIMS)

Keywords:AlN,ALD-Al2O3,MOVPE

AlN is a candidate material for optoelectronic and power electronic devices owing to its wide bandgap (6.05 eV), excellent thermal conductivity (3.4 W/cm×K), high electrical resistivity (>10¹⁴ W/cm), high breakdown electric field (10⁷ V/cm), excellent dielectric property (k = 9) and chemical stability. Recently, we reported the successful elimination of small-angle grain boundary (SAGB) in AlN grown on sapphire substrate upon the introduction of low-temperature AlN buffer layer technique [1]. An atomically-smooth surface was achieved and the x-ray diffraction (XRD) linewidth of symmetric (0002) w-scan was ~66 arcsec, indicating the high quality of AlN. However, the linewidth of asymmetric (10-12) w-scan was still broad (~1443 arcsec). To further improve the epitaxial quality of AlN, a thin amorphous Al₂O₃ layer was deposited on sapphire substrate by atomic layer deposition (ALD) technique.