Polarity control of AlN layers grown on sapphire substrates by oxygen doping during AlN nucleation

• Published in: Journal of crystal growth 2014-01, Vol.386, p.76-79
• Main Authors: Kinoshita, Toru, Yanagi, Hiroyuki, Inoue, Shin-ichiro
• Format: Article
• Language: English
• Subjects: A1. Crystal structure; A3. Metalorganic chemical vapor deposition; Aluminum nitride; B1. Nitrides; B2. Semiconducting aluminum compounds; Chemical vapor deposition (including plasma-enhanced cvd, mocvd, etc.); Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Crystal structure; Density; Doping; Equations of state, phase equilibria, and phase transitions; Exact sciences and technology; General studies of phase transitions; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Nucleation; Nuclei; Physics; Polarity; Sapphire; Structure of solids and liquids; crystallography; Structure of specific crystalline solids
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/j.jcrysgro.2013.09.023

We report on the polarity control of the crystal polarity of AlN layers grown on sapphire substrates by oxygen doping during AlN nucleation. Oxygen concentration amongst AlN nuclei as well as the resulting impact on surface morphology and crystalline quality was investigated using isotopic oxygen as a dopant. We observed that the density of AlN nuclei increased with increasing oxygen concentration, and that AlN films with Al-polar can be obtained with an oxygen concentration of over 1021cm−3 in the AlN nucleation layer. The results agree well with the surface morphologies and (101̄2) full width at half maximum values of the X-ray ω-rocking curve of AlN overgrowth layers, indicating that the proposed method with the optimized oxygen concentration can be used to control the polarity and obtain AlN films with a smooth surface and good crystalline quality. •The crystal polarity control of AlN layers grown on sapphire substrates by oxygen doping during AlN nucleation is reported.•The density of AlN nuclei increased with increasing oxygen concentration.•Al-polar AlN films could be obtained with an oxygen concentration of over 1021cm−3 in the AlN nucleation layer.•Higher oxygen concentration resulted in smoother surface morphology but broader (101̄2) FWHM of the X-ray ω-rocking curves.