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在LEC-In P晶体生长过程中,孪晶的产生是一个影响In P单晶率的突出问题。生长高质量、大直径的单晶是当前In P晶体生长的发展方向,减少孪晶一直是In P单晶生长技术的研究重点。国内外学者研究了影响孪晶产生的相关因素,但具体产生机制仍未确定。大量的实验研究表明In P晶体中的孪晶通常出现在三相界面处的边缘小平面上,且不论内砍还是外切孪晶均产生在{111}面上。晶体生长转肩过程中改变提拉速度会导致边缘过冷度增加,很容易产生孪晶。研究表明可以调整降温速率来实现对晶体直径的控制,减少拉速改变的频率避免造成边缘处过冷度增大,使得晶体生长实现平滑转肩,减小转肩时孪晶的产生概率。
During the growth of LEC-In P crystals, the generation of twins is a prominent issue affecting the In P single crystal rate. Growth of high quality, large diameter single crystal is the current direction of InP crystal growth, reducing twins has been InP single crystal growth technology research focus. Scholars at home and abroad have studied the related factors that affect the twin formation, but the exact mechanism has not been established yet. A large number of experimental studies have shown that the twins in In P crystals usually appear on the edge facets at the three-phase interface and are generated on the {111} plane, both inside and outside. Crystal growth Shoulder changes in the process of pulling speed will lead to increased edge undercooling, it is easy to produce twins. The research shows that the cooling rate can be adjusted to control the crystal diameter, and the frequency of pulling speed can be reduced to avoid the increase of the degree of supercooling at the edge, so that the crystal growth can be smooth and the twins can be reduced.