Epitaxial Growth and Interface Parameters of Si Layers on GaAs(001) and AlAs(001)Substrates

摘要

Thin Silicon epitaxial layers (1-14 monolayers) were fabricated by molecular beamepitaxy on Galium Arsenide (001) and AlAs(001) substrates also obtained by molecular beam epitaxy on Gallium Arsenide (001) wafers. In situ studies by monochromatic X-ray photoemission show initial layer-by-layer Silicon growth on both substrates with only minor Si indiffusion. Reflection high energy electron diffraction analysis shows good epitaxy with some indication of three-dimensional growth at Si coverages higher than 4-8 monolayers. The photoemission-determined valence band offset is -0.39 eV for Si-GaAs(001) and -1.02 eV for Si-AlAs(001). Comparison with recent heterojunction theories suggests that the best predictions are obtained with the model solid approach, using deformation potentials to describe the effect of strain. The Si epitaxial layers are found to remain stable upon growth of AlAs or GaAs layers on top of the Si layers.