Homoepitaxial growth of non-polar AlN crystals using molecular dynamics simulations

J Leathersich and P Suvarna and M Tungare and F Shahedipour-Sandvik, SURFACE SCIENCE, 617, 36-41 (2013).

DOI: 10.1016/j.susc.2013.07.017

Homoepitaxial growth of AlN on (11-20) a-plane and (1-100) m-plane under varying deposition temperatures and aluminum to nitrogen flux ratios was carried out using molecular dynamics (MD) simulations with a Tersoff based interatomic potential. The results indicate that much thicker overgrown films are obtained on m-plane as compared to the a-plane, for the same temperature, N:Al flux, and number of precursor atoms. Crystallinity of the depositions improves as the temperature is increased above 1000 K, accompanied with a better stoichiometry due to increased adatom mobility. Improvement in crystal quality with a N:Al ratio greater than 1 is seen because N atoms desorb more easily than Al atoms. Increasing the N:Al ratio too high limits Al adatom mobility as well as causes site blocking for Al atoms and degrades the deposition quality. The optimum value for N:Al flux ratio was found to be between 1.2 and 1.8 for the deposition temperatures tested based on crystallinity and stoichiometry. (C) 2013 Elsevier B.V. All rights reserved.

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