基于球差矫正电镜在原子尺度探究氮化铝在蓝宝石衬底上的生长过程

基于球差矫正电镜在原子尺度探究氮化铝在蓝宝石衬底上的生长过程

窦志鹏^1，2#, 陈召龙^3#, 李宁², 刘秉尧², 张敬民²，魏同波⁴, 刘志强⁴，罗强⁵，廖蕾^1*, 高鹏^2，5，6*

( 1.湖南大学物理与电子学院微/纳米光电器件重点实验室，湖南  长沙 410082；2. 北京大学电子显微镜实验室，北京 100871；3.北京大学化学与分子工程学院纳米化学中心，北京100871；4.中国科学院半导体研究所固态照明国家重点实验室，北京第三代半导体材料与应用工程研究中心，北京 100083；5. 北京大学物理学院量子材料研究中心，北京100871；6. 量子物质科学协同创新中心，北京 100871 )

摘要   Ⅲ族氮化物在光电器件方面有着广泛的应用。探究Ⅲ族氮化物的外延生长机制对于制备高质量薄膜材料器件具有重要意义。本文利用球差矫正透射电子显微镜，揭示了金属有机化学气相沉积方法（MOCVD）生长的氮化铝（AlN）在蓝宝石（Al₂O₃）衬底上的界面原子结构，探究了异质外延的生长机制。分析发现，Al₂O₃衬底在氨气的氛围下退火后，表面率先被氮化，生成一层AlN。在进一步生长AlN的时候，铝（Al）原子优先填补Al₂O₃表面高位铝的位置，然后按照AlN的晶格结构生长。此外，该方法生长的AlN在界面附近是非金属（N）极性。这些发现加深了我们对氮化物薄膜的外延生长动力学的认识，为更好地控制界面的成核、极性提供了有用的信息。

关键词    球差矫正电镜；AlN；蓝宝石；界面原子结构；极性

中图分类号：TG115.21⁺5.3；TN304   文献标识码：A       doi:10.3969/j.issn.1000-6281.2019.03.002

Investigation of AlN growth on sapphire substrate at atomic scale based on spherical aberration correction electron microscope

DOU Zhi-peng^1，2，CHEN Zhao-long³，LI Ning²，LIU Bing-yao²，ZHANG Jing-min²，WEI Tong-bo⁴，LIU Zhi-qiang⁴，LUO Qiang⁵，LIAO Lei^1*，GAO Peng^2，5，6*

(1.Key Laboratory for Micro-/Nano-Optoelectronic Devices ofMinistryof Education, School ofPhysicsand Electronics, Hunan University, ChangshaHunan 410082；2.Electron Microscopy Laboratory, School ofPhysics, Peking University, Beijing 100871; 3.Center forNanochemistry (CNC), Beijing Science and Engineering Center forNanocarbons, College of Chemistry andMolecular Engineering, Peking University, Beijing 100871; 4.State Key Laboratory of Solid-State Lighting, Institute of Semiconductors, Chinese Academy ofSciences, Beijing 100083; Beijing Engineering Research Center forthe 3rd Generation Semiconductor Materials andApplication, Beijing 100083; 5.International Center for Quantum Materials, Peking University, Beijing 100871; 6.Collaborative Innovation Centreof Quantum Matter, Beijing 100871，China)

Abstract  Group Ⅲnitrides have attracted much attention due to their applications in optoelectronic devices. Here, we try to reveal the growth mechanism of AlN on sapphire substrate by revealing the atomic structure of their interface via spherical aberration correction transmission electron microscopy (Cs-TEM). Wefindthat the sapphire surface isnitridated firstly after annealing in ammonia atmosphere to form an atomic layer of AlN and followed by filling the high-position of Al atoms on the surface. Then the growth of AlN follows the lattice structure of AlN. Furthermore,weobserve that the AlN is nonmetallic (N) polarity near the interface. These findings are of great significance for understanding the growth mechanism of epitaxial growth of nitrides and also provide valuable insights into controlling the nucleation and polarity ofⅢnitrides.

Keywords   spherical aberration correction electron microscopy；AlN；sapphire；atomic structure of interface；polarity

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