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Experimental study of two-step growth of thin AlN film on 4H-SiC substrate by Metalorganic Chemical Vapor Deposition

H. YU1,* , M. OZTURK1, P. DEMIREL1, H. CAKMAK1, T. BUYUKLIMANLI2, W. OU2, E. OZBAY3

Affiliation

  1. Nanotechnology Research Center, Bilkent University, Bilkent, 06800 Ankara, Turkey
  2. Evans Analytical Group, East Windsor, NJ 08520
  3. Nanotechnology Research Center, Department of Physics, and Department of Electrical and Electronics Engineering, Bilkent University, Bilkent, 06800 Ankara, Turkey

Abstract

We report growth optimizations of the thin AlN film on (0001) 4H-SiC substrates by metalorganic chemical vapor deposition. The influence of growth conditions, such as growth temperature and the V/III molar ratio, on the material quality of AlN film is studied. The surface morphology and crystalline quality of the epitaxial layers are investigated by atomic force microscope, X-ray diffraction, and transmission electronic microscope. A new approach is demonstrated to improve the crystalline quality of a 100 nm-thick AlN film by the use of a 5 nm-thick low temperature AlN nucleation layer. Compared to a conventional AlN layer directly grown on SiC substrate at high temperature, the surface morphology of two-step AlN film is remarkably improved along with a decreasing of defect density, leading to the improvement of crystalline quality for the subsequently grown GaN layer. The mechanisms of crystalline quality improvement by use of a low temperature AlN nucleation layer are also investigated and discussed..

Keywords

AIN, Thin film, Metalorganic CVD.

Submitted at: Oct. 28, 2010
Accepted at: Nov. 25, 2010

Citation

H. YU, M. OZTURK, P. DEMIREL, H. CAKMAK, T. BUYUKLIMANLI, W. OU, E. OZBAY, Experimental study of two-step growth of thin AlN film on 4H-SiC substrate by Metalorganic Chemical Vapor Deposition, Journal of Optoelectronics and Advanced Materials Vol. 12, Iss. 12, pp. 2406-2412 (2010)