| 题名 | 结合动态蒙特卡洛法与分子动力学研究c面蓝宝石衬底的氮化现象; Kinetic Process of Nitridation on the α-sapphire Surface in the Combination of KMC and MD |
| 作者 | 汤星舟 |
| 答辩日期 | 2014 ; 2014 |
| 导师 | 李书平 |
| 关键词 | 氮化 KMC MD MBE Nitridation KMC MD MBE |
| 英文摘要 | 随着技术的进步和需求的增加，高质量薄膜材料的制备技术有了很大的发展。其中，在宽禁带半导体材料中，AlGaN材料因为其高频率、大功率、耐高温、化学稳定性好及可以在强辐射环境中工作等特点的受到了人们越来越多的关注。然而，高质量的AlN薄膜制作非常困难。首先在于缺乏合适的衬底材料以及由此引起的高缺陷密度。本文主要研究AlGaN薄膜制作中的氮化工艺，为生长高质量的AlGaN基LED材料奠定基础。 本文提出采用动力学外延生长模拟，结合动力学蒙塔卡洛法（KMC）和分子动力学法（MD）对表面的氮化过程和界面的渗氮现象进行研究和分析。本文在KMC模拟过程中，利用Morse势描述原子团之间的相互作用情况以及表面的氮化过程，分析生长中产生的精密结构，并且通过统计所有表面原子的状态来确定表面的性质。本文亦通过动力学蒙塔卡洛法（KMC）研究不同外延温度下的表面氮化情况，借此分析总结表面氮化的相关机理。利用分子动力学方法（MD），可以对界面处的渗氮现象进行仿真模拟，根据动态过程，可以分析氮化和过度氮化的相关原理。本文除了利用仿真方法分析和研究氮化和过度氮化的机理，也确定了合理的氮化条件。 此外，为了验证仿真模拟方法的可行性，本研究利用MBE设备，对c面蓝宝石衬底进行氮化，通过RHEED观察与分析氮化过程。通过对实验现象和理论研究的结论的比对，本文提出的氮化机理有据可依，确定的氮化条件可行有效，为后期的AlGaN生长奠定了基础。; Nitride compound semiconductors are widely used for optoelectronic devices as LEDs and laser diodes. And AlGaN/GaN based LEDs are focused by large amount of researchers as it is a nice choice for emitting DUV light with large band gap, strong polarization effects, high critical field strength, high electron saturation velocity and thermal conductivity and other outstanding features. However, it is very difficult to reduce defect, QCSE and polarized light emitting as it is not easy to operate a nice process of growth on α-sapphire surface. Nitridation of α-sapphire is an important operation to improve this situation and to obtain high quality semiconductors. Several studies have reported the formation of AlN layer on α-sapphire(0001) surface by exposing ammonia, N-radical or N2-plasma in MBE as well as MOVPE. And the discussion of calculated result of energy pointed the mode of growth is varied with conditions. Despite these experimental efforts, the atomic-scale understanding of dynamic process by nitrogen on α-sapphire and the mechanism of over nitridation are still unclear. In this paper, we investigate the dynamic process of N atoms on the α-sapphire surface by the combination of kinetic Monte Carlo (KMC) and molecule dynamics (MD) method to clarify the process on the surface and under the layer. A stable layer of α-sapphire(0001) to absorb N atoms is developed and calculated by Vienna Ab-initio Simulation Package (VASP). We observed the dynamic process of nitridation in MBE system through RHEED under different temperature. A combination of the experiment and simulation clarify the mechanism of nitridation and over-nitridation as well as confine the best condition of nitridation.; 学位：工学硕士; 院系专业：物理与机电工程学院_半导体物理与器件; 学号：19820111152856 |
| 语种 | zh_CN |
| 出处 | http://210.34.4.13:8080/lunwen/detail.asp?serial=46718 |
| 内容类型 | 学位论文 |
| 源URL | [http://dspace.xmu.edu.cn/handle/2288/84117]  |
| 专题 | 物理技术－学位论文 |
| 推荐引用方式 GB/T 7714 | 汤星舟. 结合动态蒙特卡洛法与分子动力学研究c面蓝宝石衬底的氮化现象, Kinetic Process of Nitridation on the α-sapphire Surface in the Combination of KMC and MD[D]. 2014, 2014. |
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