TRANSITION FROM ISLAND TO CONTINUOUS INP LAYER GROWTH ON (001)GAAS BYMOCVD

Low pressure metal-organic chemical vapour deposition grown InP/GaAs l ayers were analysed using scanning and transmission electron microscop y and Rutherford backscattering spectroscopy to characterize the evolu tion of the InP layer morphology from the initial stages of the growth up to the complete substrate coverage. Up to nominal thicknesses of a bout 100-150 nm, an appreciable fraction of the GaAs substrate is not covered by InP. For higher thicknesses, a sudden transition to an enha nced lateral growth leading to island coalescence was observed. Finall y, a third growth stage leads to the complete filling of the valleys, leading to continuous layers. The results are discussed in terms of th e phenomenological models proposed in the literature.