Investigation of stacking faults in MOVPE-grown zincblende GaN by XRD and TEM
Investigation of stacking faults in MOVPE-grown zincblende GaN by XRD and TEM
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DOI：
10.1063/1.5082846
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发表时间：
2019-03-14
影响因子：
3.2
通讯作者：
Oliver, Rachel A.
中科院分区：
文献类型：
--
作者：
Lee, Lok Yi;Frentrup, Martin;Oliver, Rachel A.
利用X射线衍射和明场透射电子显微镜研究了在3C-SiC/Si（001）衬底上用金属有机物气相外延生长的高相纯度异质外延锌掺杂GaN外延层中{111}型堆垛层错（SF）的分布和密度。研究发现，衬底向[110]方向的4度错切可以防止不需要的反相畴的形成，对不同{111}面上SF的相对密度有深远的影响。在[-110]区中的SF的两个取向（其中，SF与GaN/SiC界面的倾斜角被4 °错切改变）显示出密度的显著差异，其中在距离GaN/SiC界面380 nm处，较陡的（1 - 11）SF比较浅的（-1-11）SF多出近似5倍。相反，在不受错切影响的[110]区中的SF的两个取向具有与[-110]区中的（-1-11）SF相当的密度。一个简单的模型，模拟的传播和湮灭的SF在zincredGaN外延层，再现TEM数据中观察到的局部SF束的存在。该模型还验证了在GaN/SiC界面处的两个取向的相交{111} SF在同一区域中的起始密度的差异降低了SF湮灭的效率。因此，与其他三个{111}面上的SF相比，（111）SF具有更高的密度，这是由于它们在GaN/SiC界面处由错切引起的优先形成。
X-ray diffraction and bright-field transmission electron microscopy are used to investigate the distribution and density of {111}-type stacking faults (SFs) present in a heteroepitaxial zincblende GaN epilayer with high phase purity, grown on a 3C-SiC/Si (001) substrate by metalorganic vapour-phase epitaxy. It is found that the 4 degrees miscut towards the [110] direction of the substrate, which prevents the formation of undesirable antiphase domains, has a profound effect on the relative densities of SFs occurring on the different {111} planes. The two orientations of SFs in the [-110] zone, where the SF inclination angle with the GaN/SiC interface is altered by the 4 miscut, show a significant difference in density, with the steeper (111) SFs being more numerous than the shallower (-1-11) SFs by a factor of similar to 5 at 380 nm from the GaN/SiC interface. In contrast, the two orientations of SFs in the [110] zone, which is unaffected by the miscut, have densities comparable with the (-1-11) SFs in the [-110] zone. A simple model, simulating the propagation and annihilation of SFs in zincblende GaN epilayers, reproduces the presence of local SF bunches observed in TEM data. The model also verifies that a difference in the starting density at the GaN/SiC interface of the two orientations of intersecting {111} SFs in the same zone reduces the efficiency of SF annihilation. Hence, (111) SFs have a higher density compared with SFs on the other three {111} planes, due to their preferential formation at the GaN/SiC interface caused by the miscut.