Thermal stability of amorphous LaScO3 films on silicon

The thermal stability of amorphous LaScO3 thin films deposited by molecular-beam deposition directly on (001) Si was investigated by high-resolution transmission electron microscopy (HRTEM), transmission infrared absorption spectroscopy (IRAS), and x-ray diffraction (XRD). IRAS indicated that the as-deposited films contained <0.1Å of SiO2 at the interface between LaScO3 and silicon. XRD studies showed that the films remained amorphous after annealing in N2 at 700°C, although HRTEM showed structural order on an ∼1nm length scale even in the as-deposited films. By 800°C, the LaScO3 had started to crystallize and formed a ∼5nm thick Sc-deficient interlayer between it and silicon.