An experimental study of the relaxation behaviour of strained Ga/sub 1-x/In/sub x/P layers grown on GaAs

The growth of strained Ga/sub 1-x/In/sub x/P alloys on GaAs substrate with the indium composition varying from 0 (GaP) to 1 (InP) was studied by means of reflection high energy electron diffraction (RHEED). Compressive layers (x>0.48) exhibit an InGaAs-like behaviour. Below 2% misfit strain (x/spl les/0.75) plastic relaxation occurs before the 2D-3D growth mode transition for which the lattice parameter relaxation is observed directly on the RHEED pattern. However, growth temperature has not a strong influence on the relaxation behaviour as in the InGaAs/InP system. On the other hand, if layers under tensile strain have a normal behaviour at low temperature, the critical thickness is found to be independent of the composition for x