Studies of Defect Structure in Epitaxial AlN/GaN Films Grown on (111) 3C-SiC
Andreea Bianca Serban,
Vladimir Lucian Ene,
Doru Dinescu,
Iulia Zai,
Nikolay Djourelov,
Bogdan Stefan Vasile,
Victor Leca
Affiliations
Andreea Bianca Serban
Doctoral School in Engineering and Applications of Lasers and Accelerators, University Politehnica of Bucharest, 060042 Bucharest, Romania
Vladimir Lucian Ene
Extreme Light Infrastructure-Nuclear Physics (ELI-NP), “Horia Hulubei” National R&D Institute for Physics and Nuclear Engineering (IFIN-HH), 30 Reactorului Street, 077125 Măgurele, Romania
Doru Dinescu
Doctoral School in Engineering and Applications of Lasers and Accelerators, University Politehnica of Bucharest, 060042 Bucharest, Romania
Iulia Zai
Extreme Light Infrastructure-Nuclear Physics (ELI-NP), “Horia Hulubei” National R&D Institute for Physics and Nuclear Engineering (IFIN-HH), 30 Reactorului Street, 077125 Măgurele, Romania
Nikolay Djourelov
Extreme Light Infrastructure-Nuclear Physics (ELI-NP), “Horia Hulubei” National R&D Institute for Physics and Nuclear Engineering (IFIN-HH), 30 Reactorului Street, 077125 Măgurele, Romania
Bogdan Stefan Vasile
Department of Science and Engineering of Oxide Materials and Nanomaterials, Faculty of Applied Chemistry and Materials Science, University Politehnica of Bucharest, 060042 Bucharest, Romania
Victor Leca
Extreme Light Infrastructure-Nuclear Physics (ELI-NP), “Horia Hulubei” National R&D Institute for Physics and Nuclear Engineering (IFIN-HH), 30 Reactorului Street, 077125 Măgurele, Romania
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.
