Thermal annealing effect on the interface structure of high- κ LaSc O3 on silicon

Abstract

The thermal stability of LaSc O3 on Si was examined by various transmission electron microscopy techniques. The film remained amorphous up to 700 °C and became polycrystalline at 800 °C. All samples showed an interfacial layer about 3.5 nm thick, except for the 1000 °C -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 °C, indicating that this interfacial layer itself may be used as a gate dielectric. © 2007 American Institute of Physics.