GROWTH OF SiO_2 AT THE Sc_2O_3/Si(100) INTERFACE DURING ANNEALING

摘要

The deposition and analysis of Sc_2O_3 layers on Si(100) by e-beam evaporation and the growth of the interfacial layer during subsequent annealing are described. The films were analysed by x-ray photoelectron spectroscopy (XPS) and transmission electron microscopy coupled with electron energy-loss spectroscopy. Results show that as-deposited films are stoichiometric, with interfacial layers <0.1 nm thick. Exposure of these films to air formed an interfacial SiO_2 layer 0.8-0.9 nm thick. Deposition in an O_2 atmosphere at a pressure of 1.3-1.7 mPa resulted in the formation of an interfacial layer 0.5-0.6 nm thick which was probably silicate or suboxide. No silicides were found at the interface after a 10 s anneal at 780 °C in vacuum (pressure <3x10~(-8) Torr). The SiO_2 layer thickness can be well controlled by controlling the oxygen partial pressure during annealing. Capping the films with a gold layer eliminates the formation of the air-grown interfacial layer. Possible diffusion mechanisms through the nanocrystalline films and the impact of these observations in terms of microstructural observations are discussed.