In situ and ex situ evaluation of mechanisms of lateral epitaxial overgrowth

Watson, I.M. and Liu, C. and Kim, K.S. and Kim, H.S. and Deatcher, C.J. and Girkin, J.M. and Dawson, M.D. and Edwards, P.R. and Trager-Cowan, C. and Martin, R.W. (2001) In situ and ex situ evaluation of mechanisms of lateral epitaxial overgrowth. Physica Status Solidi A, 188 (2). pp. 743-746. ISSN 1862-6300

Abstract

Metal organic chemical vapour deposition was used for lateral epitaxial overgrowth of GaN on stripe-patterned SiO2 masks 200 and 500 nm in thickness. Overgrowths were conducted under constant conditions, at a nominal temperature of 1140 degreesC. Mechanistic aspects were investigated by a combination of ex situ imaging methods and in situ optical reflectometry. Short growth times resulted in non-coalesced GaN with horizontal (0001) and sloping [1122] side facets. but vertical [1120] facets completely replaced the [1122] facets before coalescence. Reflectance versus time plots from stripe-masked areas suggest an interplay of two distinct interference effects. These data indicate a constant vertical growth rate of approximate to2.6 mum/h after coalescence, and are consistent with enhancement in growth rate in the early stages. associated with transport of precursor species from SiO2 mask regions.

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