Abstract
GaAs-on-Si films grown by Molecular Beam Epitaxy (MBE) on vicinal (100) Si substrates were examined by means of Transmission Electron Microscopy in order to study the dependence of threading dislocations' density on the formation of planar defects. We found that the threading dislocations' density slightly changes in the mid-range angles (1.5°-6°) and is in the order of 10 8 cm -2. The dislocation density is minimised significantly for tilting angles below 1°. However a large number of planar defects appears for very small and large angles. The appearance of microtwins in a narrow zone is characteristic for 0.5° tilting angle while the anisotropic growth of stacking faults characterises films grown on large angle tilted Si substrate. © 1999 Trans Tech Publications.