富铟熔体生长InP晶体中的微观缺陷

Micro Defects in InP Crystal Obtained in the In-Rich Melt

通过原位磷注入液封直拉(LEC)法在富铟熔体中生长了<100>方向的磷化铟单晶,并研究了晶体内缺陷形态及形成机制。在富铟熔体中生长的磷化铟晶锭中发现,多种形态富铟夹杂物镶嵌在磷化铟基体中。在晶片的抛光过程中,由于局部受力不均匀导致富铟夹杂周围的晶体出现裂纹。通过研究发现,除了磷化铟晶体的各向异性外,局部的冷却条件也控制着晶体凝固过程,进而控制着富铟夹杂物的形态。由于磷化铟基体与富铟夹杂物的热膨胀系数不同,在富铟多面体夹杂物产生了很大的应力,进而导致富铟夹杂物附近出现了位错聚集现象。经讨论给出了这些夹杂物的形成机制及其对晶体质量的影响。

InP crystals were grown along -（100） direction from In-rich melt by P-injection in-situ synthesis LEC method. The morphology and formation mechanism of the defects in the crystal induced by the In-rich melt were studied. The In-rich inclusions with various morphologies were observed in the InP matrix. Due to the non-uniform forces of the matrix and In-rich inclusion during the polishing process of the InP wafers, the crack near by the In-rich inclusions was pro- duced in the InP matrix. Through reasearch, it is found that besides the anisotropy of InP crystal, the solidification process of the In-rich dropletsis also controlled by the local cooling rate, which influences the final shape of the In-rich inclusions. Due to the different thermal expansion coefficients of the InP matrix and In-rich inclusion, the strong local stress is induced for the In-rich polyhedral inclusion, further resulting in a significant increase in the dislocation density near the In-rich inclusions. The formation mechanism and the influence of the In-rich inclusions on the crystal quality are given.