Seeded growth of AlN bulk single crystals by sublimation

Abstract AlN bulk single crystals were grown by sublimation of AlN powder at temperatures of 2100–2300°C in an open crucible geometry in a 400 Torr nitrogen atmosphere. Small, single crystalline AlN c -platelets, prepared by vaporization of Al in a nitrogen atmosphere, were used as seeds. Seeded growth occurred preferentially in the crystallographic c -direction, with growth rates exceeding 500 μm/h, while the seed crystals grew only marginally in the c- plane. Transparent, centimeter-sized AlN single crystals were grown within 24 h. Characterization by X-ray diffraction showed that rocking curves around the (0 0 0 2) reflection were very narrow (25 arcsec full-width at half-maximum), thus indicating very high crystalline quality of the material grown on the seeds.