Oval Defects in the MBE Grown AlGaAs/InGaAs/GaAs and InGaAs/GaAs Structures

Abstract

Oval defects were investigated on the surface of complex AlGaAs/InGaAs/GaAs and InGaAs/GaAs multilayer structures grown by molecular beam epitaxy and the results were compared with that obtained for bulk GaAs layers grown by the same technique. The oval defect density was correlated with the gallium effusion cell temperature and also with the substrate temperature. Different mechanisms for defect nucleation depending on the substrate temperature are expected. Oval defect nucleation and formation mechanisms are essentially the same for AlGaAs, InGaAs and GaAs layers.