Ion beam analysis of defects and strain in swift heavy ion irradiated InGaAs/GaAs heterostructures

摘要

Analysis of defects by Channeling in strain relaxed In_(0.18)Ga_(0.82)As/GaAs heterostructures before and after swift heavy ion irradiation has been reported. Energy dependence of dechanneling parameter has been analyzed which indicates a thickness dependence of defects, involving dislocations (for 36 and 96 nm) and stacking faults (for 60 nm). The dislocation density reduces upon irradiation and the possibilities for the same have been discussed in detail. The cross-sectional transmission electron microscopy (TEM) analysis indicates the presence of stacking faults in 60 nm and dislocations in 96 nm irradiated samples complementing the dechanneling studies. Angular scans along off-normal axis have been carried out for strain analysis. A strong strain relaxation as a function of thickness is observed from the strain measurements. The strain values are almost same after irradiation compared with unirradiated ones. The flux distribution of channeled ions at smaller thicknesses is discussed in detail.