A microspectroscopic study of cap damage in annealed RE-doped AlN-capped GaN

Nogales, Emilio and Lorenz, K. and Wang, K and Roqan, I. S. and Martin, R.W. and O'Donnell, K.P. and Alves, E. and Ruffenach, S. and Briot, O.; Kuball, M. and Mukai, T. and Myers, T.H. and Redwing, J.M., eds. (2006) A microspectroscopic study of cap damage in annealed RE-doped AlN-capped GaN. In: GaN, AIN, InN and Related Materials. Materials research society symposium proceedings . Materials Research Society, USA, pp. 625-630. ISBN 9781558998469

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Abstract

Integrated AIN nanocaps are used to protect gallium nitride epilayers during high temperature annealing treatments following high-energy implantation of rare earth (RE) ions. Cracks formed in thicker caps due to the lattice mismatch between AIN and GaN lead to the creation of microscopic surface defects at annealing temperatures higher than around 1200 degrees C. GaN dissociates locally to produce holes in the caps. Simultaneous cathodoluminescence/wavelength dispersive X-ray microanalysis in a modified electron probe microanalyzer allows study of the compositional and light emission variations near these microscopic defects. The intensity of the D-5(0) - F-7(2) transition related emission is enhanced and spectral changes can be observed, which indicate changes in the structure and/or composition of a very thin layer that forms the walls of holes in the caps. We also report some preliminary observations on the influence of the annealing atmosphere (nitrogen or ammonia) on cap damage.