High-temperature AlN growth by metalorganic vapor phase epitaxy on sputtered AlN with various thicknesses

High-quality AlN is directly grown on sputtered AlN (Sp-AlN) without pretreatment, using jet stream gas flow metalorganic vapor phase epitaxy (MOVPE). For the 12 nm-thick Sp-AlN sample, a full width at half maximum (FWHM) of 16 arcseconds was observed in the 0002 X-ray diffraction (XRD) ω scan, along with atomic steps with high linearity were observed despite the short AlN growth time of 15 min. Although the FWHMs of MOVPE-AlN 0002 ω scans improved as the thickness of Sp-AlN decreased, MOVPE-AlN 1 0 1 ̅ 2 FWHMs were not so different across the Sp-AlN thicknesses. Correlations were also confirmed between cross-sectional transmission electron microscopy (TEM) observations and the XRD ω scan. The c -axis lattice constants of MOVPE-AlN remained nearly constant, close to that of unstrained AlN. These results suggest that no additional compressive strain is introduced into MOVPE-AlN, even when using compressively strained Sp-AlN and high-temperature growth.