Structure and stability of Pr₂O₃/Si(0 0 1) heterostructures grown by molecular beam epitaxy using a high temperature effusion source

The structure of epitaxially grown Pr2O3 on Si(0 0 1) has been investigated by grazing incidence x-ray diffraction and x-ray reflectivity. We report experimental results from measurements made in situ, after growth, and during annealing to determine the stability of Pr2O3 at temperatures relevant for complementary metal oxide semiconductor (CMOS) processing. Pr6O11 is evaporated and converted to Pr2O3 using an effusion source operating at 1970 °C. Two different phases of Pr2O3 have been identified in the as-grown films in addition to a silicate layer that forms upon nucleation at the Si interface. The cubic Pr2O3 nucleates as a single crystal and grows in greater proportion to the polycrystalline hexagonal Pr2O3. The crystal structure of the as-grown film is stable during annealing up to about 800 °C at which point the Pr2O3 is consumed at the expense of the silicate phase.