Dislocation interactions in strained-layer structures grown on GaAs and Si substrates

Abstract A study of dislocation behavior and an assessment of critical layer thickness in heteroepitaxial In x Ga 1− x As/GaAs 1− y P y ( y ∼2 x ) SLS and GaAs 1− y P y layers grown by MOCVD on GaAs and Si substrates have been investigated using X-ray topography (XRT), electron beam induced current (EBIC), and transmission electron microscopy (TEM) techniques. The observations made by these techniques were compared to study the behavior of dislocations. Transmission XRT clearly showed the onset of misfit dislocations in GaAs 1− y P y single layers. EBIC revealed misfit dislocations located at interfaces within the SLS. Three dimensional configuration of dislocations in the SLS were obtained by the combined use of XRT and EBIC on the same epilayers grown on GaAs substrates. It was shown by TEM that dislocations originating from the GaAs/Si interface can be forced to bend by the interfacial strain in the SLS. The dislocations that were present in a SLS grown on a Si substrate were compared to those on a GaAs substrate.