Selective distribution of arsenic precipitates in low-temperature-grown III-V heterostructures

We have investigated arsenic precipitation in arsenide heterostructures gro wn at low temperature by molecular beam epitaxy. In these heterostructures, both doping and bond strength are found to affect arsenic precipitation du ring thermal annealing. For GaAs/Al0.3Ga0.7As multiple quantum wells, where GaAs is Be doped and Al0.3Ga0.7As is Si doped, arsenic precipitates prefer entially appear in the GaAs region after annealing. For In0.1Ga0.9As/GaAs/I n0.1Al0.9As heterostructures, whether they are doped or not, arsenic precip itates always tend to condense in the In0.1Ga0.9As region, indicating that the bond strength effect dominates the process of arsenic precipitation ove r the doping effect. (C) 1999 American Institute of Physics. [S0003-6951(99 )03627-X].