Effects of Precursor Gas Pretreatment and Deposited Layers on Film Quality in MNVPE

Abstract

To improve the quality and growth efficiency of AlN films prepared by Metal Nitride Vapor Phase Epitaxy(MNVPE), AlN was deposited at different temperature stages on sapphire substrates treated with N₂ and Al vapor, followed by the epitaxial growth of AlN films. The morphology, stress, and other properties of the AlN films were analyzed. It was found that after treating the sapphire substrate with Al vapor, the AlN film grown under 1300°C for 20 min exhibited the best quality, the full width at half maximum (FWHM) of the (0002) and X-ray rocking curves was 436 arcsec and the surface roughness (RMS) reached 3.64 nm. Analysis revealed that the Al vapor etches the sapphire substrate and promotes grain coalescence and grain boundary reduction during the deposition of the intermediate-temperature AlN layer, providing driving forces for dislocation bending and annihilation in subsequent AlN growth. This work explores the effects of different precursor gases on substrate pretreatment and the mechanism by which the deposited layers influence film quality, offering significant insights for the preparation of high-quality AlN films.