A gas-source MBE growth study of strained Ga1-xInxP layers on GaAs

The growth of strained Ga1-xInxP alloys on GaAs substrate with the indium c omposition varying from 0 (GaP) to 1 (InP) was studied by means of reflecti on high-energy electron diffraction (RHEED). Compressive layers (x > 0.48) exhibit an InGaAs-like behavior. Below 2% misfit strain (x less than or equ al to 0.75) plastic relaxation occurs before the 2D-3D growth mode transiti on for which the lattice parameter relaxation is observed directly on the R HEED pattern. However, growth temperature has not a strong influence on the relaxation behavior as in the InGaAs/InP system, an the other hand, if lay ers under tensile strain have a normal behavior at low temperature, the cri tical thickness is found to be independent of the composition for x < 0.35 at higher temperature (520 degrees C). This unusual behavior, as compared t o strained InGaAs on InP layers for instance, could be associated to a spin odal decomposition of the GaInP alloy. (C) 1999 Elsevier Science B.V. All r ights reserved.