A THEORETICAL-MODEL FOR THE TILT OF THE GAAS SI EPILAYERS/

The crystallographic tilt of the epilayers with respect to their subst rates has been observed in many heteroepitaxial systems. Many models h ave been proposed to explain this phenomenon, but none of them is suit able for the large mismatched system, such as GaAs/Si. Here a new mode l is proposed for GaAs/Si epilayers, which can also be used in other l arge mismatched systems. The magnitude of the tilt calculated from thi s model coincide well with the experimental results. Especially, this model can correctly predict the tilt direction of the GaAs/Si epilayer s.