Ion beam induced modification of lattice strains in In 0.1Ga 0.9As/GaAs system

Abstract

The effects of 150 MeV Ag ion irradiation on the molecular beam epitaxially grown In 0.1Ga 0.9As/GaAs samples have been studied using high resolution X-ray diffraction (HRXRD). Our earlier experiments suggest that the compressive strain will decrease due to ion beam mixing effects in an initially strained system. Similarly a tensile strain will be induced in an initially lattice matched system. These studies are being performed to explore the possibility of spatial bandgap tuning for the integration of optoelectronics circuits. Here we present a systematic study to understand the effects of ion fluence and the initial strain/layer thickness on the modification of strain. Strain measurements are performed using HRXRD by determining the angular shift in the layer peak position with respect to that of the substrate peak. Substrate peak broadens with ion fluence due to the implantation effects at the end of the ion range (∼13 μm). However, the thin InGaAs layer and the substrate region near to this layer will not be affected. It is shown that the Swift Heavy Ion induced mixing can alter the lattice strain at room temperature without loss of the quality of the structure.