Development of the vertical Bridgman technique for 6-inch diameter c-axis sapphire growth supported by numerical simulation

Role of Internal Radiation in Oxide Crystal Growth by Heat Exchanger Method

“…In some other studies, internal radiation was dealt with by P 1 -approximation [20][21][22] or treated as a surface phenomenon [23,24] assuming that the oxide crystal is totally transparent and internal radiation only acts between surfaces. Some researchers took into account internal radiation rigorously in their simulations [25][26][27][28][29][30][31]. For instance, Brandon and Derby [25,26] performed the first modeling of internal radiation heat transfer in oxide crystal by VB process using a rigorous finite element method and found that the absorption coefficient significantly affects the position and curvature of the melt-crystal interface.…”

“…Ma and Wu et al [28][29][30] established global heater transfer model, taking into account internal radiation by the finite volume method (FVM), for sapphire crystal growth by HEM and investigated the effects of crucible cover and crucible location on heat transfer during the solidification process. Miyagawa et al [31] performed numerical simulations, considering internal radiation by a combination of ray tracing and discrete ordinate (DO) approach, for the seeding interface shapes during the VB process for sapphire crystal. Most of the above referenced numerical studies mainly focused on the effect of internal radiation on the melt-crystal interface and melt convection during the oxide crystal growth process by the DS-like techniques.…”

Analysis of thermal stress through finite element analysis during vertical Bridgman crystal growth of 2 inch sapphire

“…VB 공정은 기존 HEM과 비교하여 hot zone 내 온도구배와 결정성장 속도의 제어가 용이하 며 [7][8][9], 성장시 hot zone 하단에 저온부가 형성되므로 CZ, KY 등의 공정과 비교하여 대류의 영향에서 자유로 운 장점이 있다. 또한 기판에 쓰이는 c-축 방향으로 직 접 성장이 가능하고 대구경화에 용이하여 향후 LED용 사파이어 기판 제조에 적극 활용될 것으로 기대된다 [10]. 사파이어 제조공정 중 성장되는 결정은 seed에서 점진 적으로 성장시켜 나가는 공정 특성상 필연적으로 온도구 배에 영향을 받게 된다.…”