Study of Edge and Screw Dislocation Density in GaN/Al2O3 Heterostructure
Study of Edge and Screw Dislocation Density in GaN/Al2O3 Heterostructure
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DOI：
10.3390/ma12244205
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发表时间：
2019-12-02
期刊：
影响因子：
3.4
通讯作者：
Andronescu, Ecaterina
中科院分区：
文献类型：
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作者：
Ene, Vladimir Lucian;Dinescu, Doru;Andronescu, Ecaterina
本研究评估了一种商用GaN/AlN/Al_2O_3晶片的特性(刃位错密度和螺位错密度)。用高分辨X射线衍射仪(HR-X射线衍射仪)、高分辨透射电子显微镜(HR-TEM)和多普勒展宽谱(DBS)对异质结构进行了表征。对结果进行了数学模拟，提取了GaN薄膜中的缺陷密度和缺陷关联长度。用高分辨透射电子显微镜研究了GaN薄膜、AlN衬底、Al_2O_3衬底的结构及其生长关系。用DBS研究了GaN薄膜的有效正电子扩散长度。在由[GaN P63mc(0 0 0 2)||P6 3mc AlN(0 0 0 2)||(0 0 0 2)R3c Al_2O_3]关系定义的外延层中，对于GaN薄膜，缺陷密度、缺陷关联长度和正电子扩散长度之间存在很强的相关性。在GaN的289 nm层中，缺陷密度ed=6.131010cm2，S d=1.361010cm2，以及缺陷相关长度Le=155 nm和ls=229 nm，可解释约60 nm的正电子有效扩散长度L。
This study assesses the characteristics (edge and screw dislocation density) of a commercially available GaN/AlN/Al2O3 wafer. The heterostructure was evaluated by means of high-resolution X-ray di ffraction (HR-XRD), high-resolution transmission electron microscopy (HR-TEM), and Doppler-Broadening Spectroscopy (DBS). The results were mathematically modeled to extract defect densities and defect correlation lengths in the GaN film. The structure of the GaN film, AlN bu ffer, Al2O3 substrate and their growth relationships were determined through HR-TEM. DBS studies were used to determine the e ffective positron di ffusion length of the GaN film. Within the epitaxial layers, defined by a [GaN P63mc (0 0 0 2) || P63mc AlN (0 0 0 2) || (0 0 0 2) R3c Al2O3] relationship, regarding the GaN film, a strong correlation between defect densities, defect correlation lengths, and positron diffusion length was assessed. The defect densities e d = 6.13 1010 cm 2, s d = 1.36 1010 cm 2, along with the defect correlation lengths Le = 155 nm and Ls = 229 nm found in the 289 nm layer of GaN, account for the effective positron diffusion length L-eff similar to 60 nm.