Epitaxial SrTi O 3 film on silicon with narrow rocking curve despite huge defect density

The structural perfection and defect microstructure of epitaxial (001) $\mathrm{SrTi}{\mathrm{O}}_{3}$ films grown on (001) Si was assessed by a combination of x-ray diffraction and scanning transmission electron microscopy. Conditions were identified that yield 002 $\mathrm{SrTi}{\mathrm{O}}_{3}$ rocking curves with full width at half-maximum below 0.03\ifmmode^\circ\else\textdegree\fi{} for films ranging from 2 to 300 nm thick, but this is because this particular peak is insensitive to the $\ensuremath{\sim}8\ifmmode\times\else\texttimes\fi{}{10}^{11}\phantom{\rule{0.16em}{0ex}}\mathrm{c}{\mathrm{m}}^{--2}$ density of threading dislocations with pure edge character and extended defects containing dislocations and out-of-phase boundaries. Our results show that one narrow rocking curve peak is insufficient to characterize the structural perfection of epitaxial films.