助熔剂法生长氮化镓单晶的氮源溶解-传输机制研究

项目名称： 助熔剂法生长氮化镓单晶的氮源溶解-传输机制研究

项目编号： No.61504160

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 无线电电子学、电信技术

项目作者： 刘宗亮

作者单位： 中国科学院苏州纳米技术与纳米仿生研究所

项目金额： 24万元

中文摘要： 助熔剂法生长GaN体单晶近年来进展很快，将助熔剂法和HVPE法结合，是一种非常具有产业化前景的GaN单晶制备技术路线。在特定的助熔剂环境所形成的GaN生长相图体系中，氮源的有效供给与传输是该生长技术的核心，决定了生长速度、晶体质量、尺寸控制。因此，深入理解该生长体系中氮源溶解-传输-结晶的机制和相关物理显得尤为关键。本项目拟采用HVPE生长的高质量GaN作为籽晶，利用自主设计加工的助熔剂法用高压釜，深入研究生长温度、生长压力等条件对助熔剂法生长体系中氮源溶解-传输过程的影响。结合第一性原理计算及液相传质动力学理论，系统研究生长体系中添加剂含量、种类等对氮源溶解-传输-结晶过程的影响和作用机理，并构建晶体生长动力学模型，提升GaN籽晶外延生长速率与结晶质量，并通过优化生长条件，得到缺陷密度小于10^4/cm^2的GaN体单晶。

中文关键词： GaN单晶；助熔剂法；C添加剂；溶解-传输机制；动力学模型

英文摘要： Growth of GaN bulk single crystal by Na Flux method is progressing rapidly in recent years. To combine Na Flux method with HVPE growth technology, it is a great potential to realize the industrialized production. In the GaN single crystal growth system with a certain Na Flux method condition, the nitrogen dissolution-transport is the kernel of this method, which decides the growth rate, crystal quality and crystal size. Thus, deeply understanding the mechanism of nitrogen dissolution-transport process in Na flux method system is crucial. In this proposal, GaN bulk single crystals will be grown on HVPE seed by Na flux method, with the help of high-temperature and high-pressure self-developed autoclave. A detailed study on the effect of growth temperature and growth pressure on the nitrogen dissolution-transport process will be carried out. Based on the first-principles calculation and the liquid phase mass-transfer kinetic theory, a detailed study on the effect of carbon types and ratio on the nitrogen dissolution-transport process will be carried out. A kinetic model of GaN single crystal growth by Na flux method will be built. And GaN single crystal growth rate and quality will be improved. By optimizing the growth conditions, high quality GaN single crystal will be grown (dislocation density less than 10^4/cm^2).

英文关键词： GaN single crystal;Na Flux method;Carbon additive;dissolution-transport Mechanism;kinetic model