Journal of Crystal Growth, Vol.395, 80-89, 2014
Vertical Bridgman growth of sapphire-Seed crystal shapes and seeding characteristics
The growth of sapphire by the traditional vertical Bridgman (VB) method was studied by using various shapes of seed crystals and tungsten (W) crucibles shaped to match the seeds. Approximately 2-in. diameter, c-axis sapphire single crystals were reproducibly grown from three kinds of seed: thin, tapered and full diameter Factors relating seed type to single crystal growth are discussed, including the reproducibility of seeding processes, and the generation and elimination of low angle grain boundaries (LAGBs). What was learned facilitated the subsequent growth of large diameter, 3-, 4- and 6-in., c-axis single crystal sapphires from full diameter seeds. (C) 2014 Elsevier B.V. All rights reserved.
Keywords:Bridgman technique;Growth from melt;Seed crystals;Single crystal growth;Sapphire;Light emitting diodes