Strain relaxation of InxGa1-xAs during lateral oxidation of underlying AlAs layers

Strain relaxation of hypercritical thickness InxGa1-xAs layers has been observed during lateral oxidation of underlying AlAs layers. Strain relaxation of InxGa1-xAs layers was studied as a function of indium composition and the AlAs oxidation temperature. It is proposed that the enhanced strain relaxation is due to two factors. The first is enhanced motion of threading dislocations due to stresses generated during the lateral oxidation process. The second is the porous nature of the InxGa1-xAs/Al2O3 interface that minimizes the interaction of threading dislocations with existing misfit dislocation segments. The extent of strain relaxation increases with increasing oxidation temperature, whereas the efficiency of strain relaxation was found to decrease with increasing indium composition. (C) 1999 American Institute of Physics. [S0003-6951(99)02541-3].