Interfacial reaction in the growth of epitaxial SrTi O3 thin films on (001) Si substrates

The SrTi O3 Si interface was investigated by transmission electron microscopy for SrTi O3 films grown on (001) Si by molecular-beam epitaxy with different native oxide (Si O2) removal treatments, and SrTi flux ratios. The interface and film microstructure were independent of the process used to remove the native oxide, but the interface reactivity was dependent on the SrTi flux ratio. A low SrTi flux ratio (~0.8) resulted not only in a layer of amorphous material at the filmsubstrate interface but also in the formation of crystalline C49 Ti Si2 precipitates at that interface. These results are consistent with thermodynamic expectations in which it is paramount to maintain separation between Ti O2 and the underlying silicon.