Optimization of the metamorphic growth of GaAs for long wavelength VCSELs

In this paper, we present the study of the growth conditions of metamorphic GaAs on InP(0 0 1) substrate using gas source molecular beam epitaxy (GSMB E). We examined the influence of various growth parameters, such as growth temperature and Group V pressure, and determined optimized conditions to pr oduce low roughness (11.6 Angstrom rms) GaAs. We also demonstrate the exist ence of a critical thickness limit under which dislocations are generated, or propagate, in the substrate. We experimented different types of post-gro wth cooling rates, annealing and observed their influence on the localizati on of the substrate dislocations. Altogether, these experiments indicate th at the metamorphic growth of GaAs on InP is a valid approach for long wavel ength vertical cavity surface emitting lasers. (C) 1999 Elsevier Science B. V. All rights reserved.