The crystallization of aluminum nitride (AlN) hetero-epitaxial seeding on silicon carbide (SiC) by physical vapor transport (PVT), was systematically studied using XRD, UV–Vis, PL, SIMS, Raman and stress simulation. The evolution of crystal quality, transmittance, purity and residual stress of 2-inch AlN crystal in the growth process are described. The crystal quality of AlN growth layer gradually improves with the crystal thickness, as reflected in the decrease of XRD full width at half maximum (FWHM) from higher than 300 arcsec to 85 arcsec, SIMS yielded Si concentrations decreases from 1020 cm−3 to 1018 cm−3, absorbance coefficient @320 nm from 56 cm−1 to 9 cm−1, and simulated residual stress from 270 MPa to 50 MPa, indicating a comprehensively improved quality by simply increasing the crystal thickness of AlN crystal on SiC seed. Furthermore, a 2-inch crack-free AlN single crystal with high quality was successfully fabricated by inducing a layered structure.