Epitaxial SrTiO3 film on silicon with narrow rocking curve despite huge defect density

The structural perfection and defect microstructure of epitaxial (001) SrTiO3 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 SrTiO3 rocking curves with full width at half-maximum below 0.03 degrees for films ranging from 2 to 300 nm thick, but this is because this particular peak is insensitive to the similar to 8 x 10(11) cm(-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.