Growth evolution of high-quality MOCVD aluminum nitride using nitrogen as carrier gas on the sapphire substrate

We report the growth evolution of high-quality epitaxial aluminum nitride using nitrogen as carrier gas on the sapphire substrate using MOCVD. A series of samples were grown with thickness varying from 1 to 4 μm utilizing a two-step process without any interlayer. SEM/AFM data showed voids up to 3 µm thickness along the growth direction, aiding to grow thicker layers and achieve low dislocation densities. For the 4 μm thick sample, XRD studies showed the FWHM of 289 arcsec of the rocking curve for (10ī2) plane and total calculated dislocation density 1.1 × 109 cm−2 using Williamson and Hall procedure. Raman's study showed the E2 (high) phonon peak linewidth of 3.4 cm−1 at around 659 cm−1, showing significantly low compressive stress of 0.59 GPa for 4 µm thick AlN. This study shows a simplified and economical method to grow high-quality AlN using N2 as a carrier gas.