Formation of aluminum nitride clusters by cyclic vapor-solid process

By cyclic vapor-solid (VS) process, aluminum nitride (AlN) clusters were fo rmed on the surface of polycrystal AIN substrate. These clusters can be cla ssified into three types: single crystal, polycrystal and particle clusters . it was observed that the single crystal had similar morphology as crystal linity suggests, while the polycrystal was configured by terrace, which aga in was constructed by plate-like AlN single crystals. Particle clusters wer e actually a porous network of AlN particles. Further investigation showed that the formation of clusters was greatly influenced by two factors: polyc rystal AlN substrate and repeated heat treatment. Based on the observed fac ts, a growth process of the clusters was discussed. (C) 2001 Elsevier Scien ce B.V. All rights reserved.