Layers of Si with nominal thicknesses of 30 to 40 monolayers were grown, at 400C, onto GaAs(001)-c(4 x 4) surfaces under excess As or Al fluxes. An investigation was made of the microstructural changes which were caused by the expected high As or Al incorporation into the Si layers. It was found that Si epitaxial layers which were grown under an As flux had a structure which was similar to that of control samples in which the Si layer was grown in the absence of any excess anion or cation flux. The only microstructural modification which was caused by the excess As was a somewhat higher density of extended defects at the interface. On the other hand, the use of an excess Al flux during growth produced large microstructural modifications, when compared with control samples. A relatively thick highly-disordered quaternary layer appeared to form over most of the surface, while Ga islands were also observed; sometimes with the inclusion of Al clusters.

Transmission Electron Microscopy Studies of the Microstructure of Si Layers Grown on GaAs(001) under an Excess As or Al Flux E.Carlino, L.Sorba, A.Franciosi, S.Heun, B.H.Müller: Philosophical Magazine B, 2000, 80[5], 1055-69