Studies of Defect Structure in Epitaxial AlN/GaN Films Grown on (111) 3C-SiC

Several aspects such as the growth relation between the layers of the GaN/AlN/SiC heterostructure, the consistency of the interfaces, and elemental diffusion are achieved by High Resolution Transmission Electron Microscopy (HR-TEM). In addition, the dislocation densities together with the defect cor...

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Bibliographic Details
Published in:Nanomaterials (Basel, Switzerland) Switzerland), 2021-05, Vol.11 (5), p.1299
Main Authors: Serban, Andreea, Ene, Vladimir, Dinescu, Doru, Zai, Iulia, Djourelov, Nikolay, Vasile, Bogdan, Leca, Victor
Format: Article
Language:English
Subjects:
Aluminum nitride
Aluminum oxide
Comparative analysis
defect density
Defects
Diffusion
Diffusion layers
Diffusion length
Dislocation
Dislocation density
Epitaxial growth
epitaxial thin films
gallium nitride
Gallium nitrides
Heterostructures
High resolution
High resolution electron microscopy
Interfaces
Optics
positron diffusion length
Sensors
Silicon carbide
Silicon substrates
Spectroscopy
Spectrum analysis
Transmission electron microscopy
X-ray diffraction
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Summary:Several aspects such as the growth relation between the layers of the GaN/AlN/SiC heterostructure, the consistency of the interfaces, and elemental diffusion are achieved by High Resolution Transmission Electron Microscopy (HR-TEM). In addition, the dislocation densities together with the defect correlation lengths are investigated via High-Resolution X-ray Diffraction (HR-XRD) and the characteristic positron diffusion length is achieved by Doppler Broadening Spectroscopy (DBS). Moreover, a comparative analysis with our previous work (i.e., GaN/AlN/Si and GaN/AlN/Al2O3) has been carried out. Within the epitaxial GaN layer defined by the relationship F4¯3m (111) 3C-SiC || P63mc (0002) AlN || P63mc (0002) GaN, the total dislocation density has been assessed as being 1.47 × 1010 cm−2. Compared with previously investigated heterostructures (on Si and Al2O3 substrates), the obtained dislocation correlation lengths (Le = 171 nm and Ls =288 nm) and the mean distance between two dislocations (rd = 82 nm) are higher. This reveals an improved crystal quality of the GaN with SiC as a growth template. In addition, the DBS measurements upheld the aforementioned results with a higher effective positron diffusion length LeffGaN2 = 75 ± 20 nm for the GaN layer.
ISSN:2079-4991
2079-4991
DOI:10.3390/nano11051299