Effect of high-temperature annealing on AlN thin film grown by metalorganic chemical vapor deposition

• Published in: Chinese physics B 2014-08, Vol.23 (8), p.87810-1-087810-5
• Main Authors: Wang, Wei-Ying, Jin, Peng, Liu, Gui-Peng, Li, Wei, Liu, Bin, Liu, Xing-Fang, Wang, Zhan-Guo
• Format: Article
• Language: English
• Subjects: Aluminum nitride; Annealing; Band spectra; Emission; Metalorganic chemical vapor deposition; Photoluminescence; Temperature; Thin films
• ISSN: 1674-1056; 1741-4199
• DOI: 10.1088/1674-1056/23/8/087810

The effect of high-temperature annealing on AlN thin film grown by metalorganic chemical vapor deposition was investigated using atomic force microscopy, Raman spectroscopy, and deep ultra-violet photoluminescence (PL) with the excitation wavelength as short as ~ 177 nm. Annealing experiments were carried out in either N sub(2) or vacuum atmosphere with the annealing temperature ranging from 1200 [degrees]C to 1600 [degrees]C. It is found that surface roughness reduced and compressive strain increased with the annealing temperature increasing in both annealing atmospheres. As to optical properties, a band-edge emission peak at 6.036 eV and a very broad emission band peaking at about 4.7 eV were observed in the photoluminescence spectrum of the as-grown sample. After annealing, the intensity of the band-edge emission peak varied with the annealing temperature and atmosphere. It is also found that a much stronger emission band ranging from 2.5 eV to 4.2 eV is superimposed on the original spectra by annealing in either N sub(2) or vacuum atmosphere. We attribute these deep-level emission peaks to the V sub(AL)-O sub(N) complex in the AlN material.