光学质量大尺寸蓝宝石单晶工艺研究

Growth technique of optical quality large-size single-crystal sapphire

分析了泡生法生长大尺寸、光学质量蓝宝石单晶工艺,探讨了影响蓝宝石晶体生长的9大因素:1温场的轴向和径向温度梯度大小对晶体生长的影响;2氧化锆层对晶体质量的影响;3原料对晶体生长的影响;4籽晶的质量和晶向对晶体生长的影响;5引晶对晶体中残余应力、位错和晶界的影响;6放肩角度对晶体的影响;7等径生长速度对晶体的影响;8收尾拉脱与否对晶体质量的影响;9退火时间长短对晶体的影响.通过分析各影响因素,改进生长工艺,成功生长出70 kg蓝宝石单晶.对其进行表征发现,在晶体气泡、晶体方向和应力等方面均达到发光二极管芯片衬底要求.

We analyze the large-size optical quality single-crystal sapphire growth technique through the Kyropoulos method and discuss the effects of nine factors, including effects of the thermal field＇s axial and radial temperature gradient, A1203 material, the quality and orientation of seed crystal on crystal growth, the effects of ZrO2 insulation layer and separated and adhesive tail on crystal quality, the effect of seeding on residual stress, dislocation and boundary of crystal and the effects of shouldering angle, growth rate in isometric stage and annealing duration on crystal. By analyzing the effects of various factors and then optimizing the crystal growth process, we succeed in the formation of a 70 kg single crystal sapphire which can meet the performance requirements of LED （light emitting diode） chips substrate in aspects of bubble, direction and stress of crystal.