We report on new results in AlN bulk crystal growth by sublimation sandwich method. The single crystals of 12 mm in diameter and up to 5 min long have been obtained with the growth rate up to 0.5 min/h. Growth was carried out in a nitrogen environment at temperatures of 1900-2300degreesC and atmospheric pressure. 4H- and 6H-SiC both of (0001)C and (0001)Si orientations were used as seeds. Growth kinetics and operating conditions favorable for improving the long-term process stability and crystal quality are discussed on the basis of both experimental and theoretical studies. The grown AlN crystals are characterized by X-ray diffraction and Raman scattering.