磷注入原位合成InP熔体的反应机理及相关晶体生长缺陷研究

The method of in situ P-injection synthesis can quickly synthesize InP melt. Thus, the combine between in-situ synthesis and crystal growth can obtain high purity of InP crystals, which is one of the most promising techniques for the preparation of InP single crystal. Although in situ P-injection synthesis can be basically controlled from the point of technical process, the reaction mechanism of thermodynamics and kinetics of the whole synthesis system has not yet in-depth studied. Thus, technological breakthrough is a challenge and the cost of the preparation of InP single crystal remains high. In addition, the influences of the melt composition after synthesis on solid-liquid interface morphology of InP crystal and the formation of crystal defect are not comprehensively and systematically studied. For the problems above mentioned, this project mainly studies the processes of decomposition of the solid phosphorus, phosphorus transfer, the interface reaction between gas phosphorus and indium melt, and the diffusion of phosphorus atom in the melt. The studies will reveal the synthesis mechanism in the whole system, and provide guidance for the stability control of the process of the in situ synthesis. The studies will also reveal the association relationship among the melt composition, the condition of crystal growth, the stability of the solid-liquid interface and the related defects caused by deviation from the stoichiometric composition. This project will provide theory and technology support for improving the quality and yield of InP single crystal. So this project is significative for both theory and practical application.

磷注入原位合成技术能够快速合成InP熔体。磷注入原位合成与晶体生长结合能够获得高纯晶体，是制备磷化铟晶体最有前途的方法之一。尽管目前在工艺上已经基本实现了对磷注入式InP熔体合成的控制，但由于对整个原位合成体系的反应热力学与动力学机制尚未进行深入研究，造成工艺突破困难、磷化铟晶体制备成本居高不下。另外，合成后的熔体成分对晶体固液界面形貌和晶体缺陷的影响也缺乏系统的认识。本项目拟对上述问题，研究在合成体系中固体磷的分解、传输、气态磷与铟熔体的界面反应和熔体中磷原子的扩散过程，从而揭示体系的合成机理，进而实现对磷-铟熔体合成过程的稳定控制；同时探索合成后的熔体配比度、晶体生长条件、晶体固液界面稳定性和相关缺陷形成之间的联系，探索最佳熔体配比成分范围。本项目研究将为提高晶体的成晶率提供理论和工艺基础，具有重要的理论和应用意义。

本项目首先通过亚正规模型研究了In-P熔体与不同结构的磷气体（P(g)、P2(g)和P4(g)）与铟-磷熔体的热力学平衡，为研究原位注入合成动力学提供了数据。通过实验及理论计算研究了磷的升华动力学、磷气体在磷源炉内的传输、不同结构的磷气体在合成熔体界面的热力学条件及磷气体与铟熔体反应的界面动力学机制。通过热重-差热分析（TG-DSC）方法测定In-P熔体的分解动力学曲线，并通过理论计算获得了不同结构的磷气体与熔体反应的动力学系数，建立磷注入铟熔体的动力学模型，模型预测与实验数据符合较好。本项目在不同熔体配比度下研究了晶体固液界面温度梯度和晶体提拉速率对晶体小平面界面形貌的影响，进而揭示不同生长条件下铟夹杂物和气孔形成机理。针对位错团簇的形成，通过测试及理论分析提出了两种第二相夹杂物周围位错运动模型。通过XRD、PL Mapping、SEM及光学显微镜研究了熔体配比度，生长条件与晶体内缺陷形成的关联关系，进而给出了最佳的熔体配比度范围。