A hybrid molecular beam epitaxy approach for atomic-layer controlled growth of high-quality SrTiO3 films with scalable growth rates was developed. The approach uses an effusion cell for Sr, a plasma source for oxygen, and a metal-organic source (titanium tetra isopropoxide) for Ti. SrTiO3 films were investigated as a function of cation flux ratio on (001) SrTiO3 and (LaAlO3) 0.3 (Sr2 AlTaO6) 0.7 (LSAT) substrates. Growth conditions for stoichiometric insulating films were identified. Persistent (>180 oscillations) reflection high-energy electron diffraction oscillation characteristic of layer-by-layer growth were observed. The full widths at half maximum of x-ray diffraction rocking curves were similar to those of the substrates, i.e., 34 arc sec on LSAT. The film surfaces were nearly ideal with root mean square surface roughness values of less than 0.1 nm. The relationship between surface reconstructions, growth modes, and stoichiometry is discussed.
|Original language||English (US)|
|Number of pages||4|
|Journal||Journal of Vacuum Science and Technology A: Vacuum, Surfaces and Films|
|State||Published - 2009|
Bibliographical noteFunding Information:
This research was supported by the National Science Foundation through the UCSB MRL (Award No. DMR 05-20415) and by DOE (Grant No. DE-FG02-06ER45994). Acquisition of the oxide MBE system was made possible through a NSF MRI grant (NSF Grant No. DMR-0619698). One of the authors (R.E.-H.) thanks the Alexander-von-Humboldt Foundation for support through the Feodor Lynen program.