Overgrowth of trenches with (AlGa)As using metalorganic vapor-phase epitaxy (MOVPE)

A detailed study of the regrowth of (AlGa)As over trenches etched into (InG a)P, an important step in the fabrication of index-guided laser structures, is presented. The resulting Al concentration profile depends on the growth conditions in metalorganic vapor-phase epitaxy and on the trench orientati on. While for [0 - 11]-oriented trenches the V/III ratio strongly affects t he Al profile, no influence is observed for [0 1 1]-trenches. The observed dependencies are explained from the different As coverage of the different growth facets and the resulting Ga-diffusion towards the sidewalls of the t renches. (C) 1998 Elsevier Science B.V. All rights reserved.