Structural characterization of InGaAs/INalAs quantum wells grown on (111)-InP substrates

摘要

Structure of HEMT's made of an InGaAs/InalAs strained quantum well grown on (111) InP substrates has been analyzed via transmission electron microscopy. Threading dislocations and stacking falults crossing the upper layer towards the sample surface, as well as twinned regions parallel to the interfaces and large V-shaped defect complexes are found to nucleate a few nanometers away from the quantum-well/cladding-layer interface. This defect structure is very different from the one expected for (100) heterostructures, suggesting that other growth considerations about the nucleation of defects must be taken into account together w ith the conventional ones related to the lattice mismatch.