Reactive Removal Of Misfit Dislocations From Ingaas On Gaas By Lateral Oxidation

Layers of hypercritical thickness InGaAs/AlAs/GaAs have been shown to strain relax when the underlying AlAs layer is laterally oxidized. InxGa1-xAs layers of composition 0.2 less than or equal to x less than or equal to 0.4 have been investigated at thicknesses in the range 5-20 times the Matthews-Blakeslee critical thickness h(c). The amount of strain relieved does not depend on the InGaAs-layer thickness, the initial strain state, or the composition of the material, but it does strongly depend on the oxidation temperature. The structure of the strain-relaxed InGaAs layer has been investigated using plan-view transmission electron microscopy. It is shown that the misfit dislocation density in In0.3Ga0.7As grown to 15 times the critical thickness (660 Angstrom) has been reduced by two orders of magnitude after lateral oxidation. It is proposed that this is due to interfacial oxidation, which consumes the misfit dislocation cores. (C) 2000 American Institute of Physics. [S0003-6951(00)04232-7].