Influence of Al x Ga 1-x N nucleation layers on MOVPE-grown zincblende GaN epilayers on 3C-SiC/Si(001)
Influence of Al x Ga 1-x N nucleation layers on MOVPE-grown zincblende GaN epilayers on 3C-SiC/Si(001)
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Al x Ga 1-x N 成核层对 3C-SiC/Si(001) 上 MOVPE 生长的闪锌矿 GaN 外延层的影响
DOI：
10.1088/1361-6463/ac4c58
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发表时间：
2022
期刊：
影响因子：
--
通讯作者：
Gundimeda A
中科院分区：
文献类型：
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作者：
Gundimeda A
用X射线光电子能谱、原子力显微镜和X射线衍射仪研究了不同Al含量x的AlxGa1−xN成核层对闪锌矿结构GaN在(0 0 1)3C-SiC上的金属有机气相外延的适用性。随着AlN组分的增加，生长的NLS表面呈现出细长的岛状结构，这些岛状结构横向减少为更小的、更等轴的岛屿。在NH_3和H_2混合气氛中的高温退火过程中，Al含量较低的样品的成核岛成熟且尺寸增大，而在Al含量较高的样品中，这种影响不太明显。当x=0.29时，NLS的面内压缩应变随AlN组分的增加而增大。在Al含量较低的NLS衬底上生长的GaN外延层具有较高的立方闪锌矿相纯度，并且相对于3C-SiC有轻微的压缩应变。然而，由于在Zb-GaN的不同{111}面上形成了纤锌矿夹杂物，测量到的NL中Al含量高于0.29的样品主要是六方纤锌矿相，从而表明了生长相纯的Zb-GaN外延层的最佳Al组分。
The suitability of Al x Ga 1− x N nucleation layers (NLs) with varying Al fraction x for the metal organic vapour phase epitaxy of zincblende GaN on (001) 3C-SiC was investigated, using x-ray photoelectron spectroscopy, atomic force microscopy, and x-ray diffraction. The as-grown NLs exhibited elongated island structures on their surface, which reduce laterally into smaller, more equiaxed islands with increasing AlN composition. During high-temperature annealing in a mixture of NH 3 and H 2 the nucleation islands with low Al fraction ripened and increased in size, whereas this effect was less pronounced in samples with higher Al fraction. The compressive biaxial in-plane strain of the NLs increases with increasing AlN composition up to x= 0.29. GaN epilayers grown over NLs that have low Al fraction have high cubic zincblende phase purity and are slightly compressively strained relative to 3C-SiC. However, those samples with a measured Al fraction in the NL higher than 0.29 were predominantly of the hexagonal wurtzite phase, due to formation of wurtzite inclusions on various {111} facets of zb-GaN, thus indicating the optimal Al composition for phase-pure zb-GaN epilayer growth.