Thermal annealing effect on the interface structure of high-κ LaScO_3 on silicon

摘要

The thermal stability of LaScO_3 on Si was examined by various transmission electron microscopy techniques. The film remained amorphous up to 700℃ and became polycrystalline at 800 ℃. All samples showed an interfacial layer about 3.5 nm thick, except for the 1000 ℃-annealed sample, which had a thicker interfacial layer containing a thin silicate layer close to the interface with the substrate. Although the chemical composition of the bulk film was stoichiometric, the interfacial layer was oxygen-rich after postannealing. The interfacial layer remained amorphous up to 1000 ℃, indicating that this interfacial layer itself may be used as a gate dielectric.