METALORGANIC VAPOR-PHASE EPITAXY GROWTH FEATURES OF ALGAAS IN TETRAHEDRAL-SHAPED RECESSES ON GAAS (111)B SUBSTRATES

We have investigated the compositional modulation of AlGaAs layers gro wn in tetrahedral-shaped recesses (TSRs) on n-type GaAs (111)B substra tes using scanning electron microscopy, photoluminescence and cathodol uminescence. Growth hardly occurred between the TSRs, and complicated facets were seen in the TSR. Gallium-rich regions were formed around t he edges between sidewalls rather than at the center of sidewalls and at the bottom region rather than the top region. To observe the facett ing process during growth, GaAs/AlGaAs multilayers were also grown in TSRs. Aluminum compositional modulation is dependent not only on the d ifference in migration distances of Ga and Al atoms but also on the di fferences in the incorporating process among different facets.