Alumina bulk crystal growth methods include:

1）Kyropoulos (KY), top seeded crystal growth method utilizing large crucibles to grow very large sapphire boules of high quality

2）Heat Exchange (HEM), bottom-seeded crystal growth method to grow high quality, uniform sized boules of high quality

3）HDSM – Horizontal Direction solidification systems are used to produce large rectangular crystals for high quality window applications

4）Czochralski (CZ)  Ingot-style crystal growth method used to grow very high quality sapphire for small and medium diameter window and optical applications