Amplification of Misorientation of Ge Films on Si (100) During Ion-Assisted Molecular Beam Epitaxy

We have observed significant increases in the misorientation of Ge films on Si (001) grown by ion-assisted molecular beam epitaxy. The misorientation between the Ge films and Si substrates was found to be a function of the ion-to-atom flux ratio and growth temperature. The parametric dependence of the misorientation on the growth conditions suggests that defects generated by low energy ion bombardment are responsible for the observed increase in misorientation. The amplification of misorientation produced by concurrent low energy ion bombardment during epitaxial growth was attributed to an increase in the fraction of misfit strain accommodated by threading dislocations.