Electrical activity of misfit dislocations in GaAs-based heterostructures

Abstract

Electrical properties of lattice-mismatch induced defects in GaAs/InGaAs and GaAs/GaAsSb heterostructures have been studied by means of electron-beam induced current (EBIC) in a scanning electron microscope and deep-level transient spectroscopy (DLTS). DLTS measurements, carried out with p-n junctions formed near the heterostructure interfaces, revealed one electron trap and one hole trap induced by the lattice mismatch. The electron trap has been attributed to electron states associated with threading dislocations in the ternary compound close to the interface, whereas the hole trap has been ascribed to misfit dislocations at the heterostructure interface. Detailed investigation of the dependence of DLTS-line amplitude and its shape on the filling time of the traps with charge carriers allowed us to specify the type of electronic states related to both traps.