The Effect of AlN Nucleation Temperature on the Growth of AlN Films via Metalorganic Chemical Vapor Deposition
The Effect of AlN Nucleation Temperature on the Growth of AlN Films via Metalorganic Chemical Vapor Deposition
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DOI：
10.1007/s11664-011-1798-3
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发表时间：
2012-03
影响因子：
2.1
通讯作者：
H. Wang;S. L. Li;H. Xiong;Z. H. Wu;J. Dai;Y. Tian;Y. Fang;C. Chen
中科院分区：
文献类型：
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作者：
H. Wang;S. L. Li;H. Xiong;Z. H. Wu;J. Dai;Y. Tian;Y. Fang;C. Chen
AlN外延层直接生长在蓝宝石（0001）衬底上使用组合的生长方案，包括低温成核层和第二层生长的高温脉冲原子层外延通过金属有机化学气相沉积。重点关注成核层，其生长温度在470 ° C至870 ° C之间变化，观察到整个AlN外延层的表面形态、晶体质量和应变状态存在明显差异。基于原子力显微镜，X-射线衍射，和拉曼光谱的结果，这些差异归因于成核位点和随后的晶粒尺寸。由于Al原子的迁移率随温度的升高而增强，成核位置减少，随后的晶粒尺寸增加，导致在570 ° C下生长的成核层获得原子级平坦的AlN外延层，具有良好的晶体质量。然而，在较高的成核层生长温度下，由于可能出现未对准的AlN颗粒，AlN外延层的性能会恶化。还根据所有观察结果建立了一个模型。
AlN epilayers were grown directly on sapphire (0001) substrates using a combined growth scheme, consisting of a low-temperature nucleation layer and a second layer grown by high-temperature pulsed atomic layer epitaxy via metalorganic chemical vapor deposition. With an emphasis on the nucleation layer, its growth temperature was varied from 470°C to 870°C, and obvious differences in the surface morphology, crystal quality, and strain states of the overall AlN epilayers were observed. Based on atomic force microscopy, x-ray diffraction, and Raman spectroscopy results, these differences are ascribed to the nucleation sites and the subsequent grain size. Due to the enhanced mobility of Al adatoms with increasing temperature, the nucleation sites decrease and the subsequent grain size increases, leading to the achievement of atomically flat AlN epilayers with good crystal quality for the nucleation layer grown at 570°C. However, at higher nucleation layer growth temperature, the properties of the AlN epilayers deteriorate due to the possible appearance of misaligned AlN grains. A model is also developed according to all observations.