采用跨尺度研究方法优化氮化镓薄膜的生长均匀性

项目名称： 采用跨尺度研究方法优化氮化镓薄膜的生长均匀性

项目编号： No.51476068

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 能源与动力工程

项目作者： 方海生

作者单位： 华中科技大学

项目金额： 83万元

中文摘要： 白光大功率LED被誉为21世纪的绿色照明光源，主要通过氮化镓（GaN）基蓝光激发黄色荧光粉实现，GaN薄膜的生长均匀性严重影响其可靠性、出光率和耐久性。本项目基于多场跨尺度的建模框架和方法，结合实验验证，对MOCVD制备GaN过程进行研究和优化。多场模型体现在对生长过程中流动、传热、化学反应、热应力等多场输运现象的耦合动态求解，而跨尺度模拟体现在结合上述宏观模型和基于动力学蒙特卡罗方法的微观模型对生长过程的耦合研究。GaN 薄膜的生长均匀性包括厚度、热应力和组分及相关晶体缺陷分布的均匀性，由于受到宏观输运理论和微观扩散机理的影响，只能采用动态跨尺度的方法进行研究和优化。本项目通过结合工程热物理和晶体材料学的基本原理，从理论上提出跨尺度关系，阐明GaN 的主要晶体缺陷和生长均匀性的影响机制，优化薄膜的制备过程，为白光大功率LED 的制造提供材料上的保证，因而具有重要的理论意义和实际应用价值。

中文关键词： 流动与传热；半导体薄膜；外延生长；多尺度；生长均匀性

英文摘要： High-power LED, known as the green lighting source of the 21st Century, is mainly generated through stimulating yellow fluorescent powder with GaN-based blue light. Its reliability, light output and durability are influenced by GaN crystal growth uniformity. The project develops a dynamic multi-scale model to simulate MOCVD GaN growth process, and to optimize uniformity of epitaxial growth by combining real-time experimental study. Dynamic model is reflected by solving the macroscopic fields of fluid flow, heat transfer, chemical reaction and thermal stresses, while multi-scale simulation is embodied in the combination of the above macroscopic models and microscopic models based on Kinetic Monte Carlo (KMC) method for the study of transport phenomena during thin-film crystal growth. Growth uniformity mainly includes thin-film thickness uniformity, thermal stress uniformity, species uniformity and their associated defect uniformity, which are significantly affected by macroscopic transport theories and microscopic diffusion mechanisms, and can only be optimized using both dynamic multi-scale modeling and experimental study. The project couples the principles of engineering thermophysics and material sciences, theoretically proposes multi-scale relationships, clarifies the mechanisms of GaN defect formation and growth uniformity, and experimentally optimizes the quality and properties of GaN thin films. It provides material guarantee for fabrication of high-power LED, so it undoubtedly has theoretical significance and application value.

英文关键词： Fluid flow and heat transfer;Semiconductor thin film;Epitaxial growth;Multiscale;Growth uniformity