Chemical structure and interface reaction of LaCoO3/Si thin-film system

An LaCoO3 thin film was prepared on Si(111) substrate successfully using an amorphous heteronuclear complex, LaCo(DTPA). 6H(2)O, as a precursor. The s urface chemical structures and interface reaction of LaCoO3/Si thin film we re studied by XPS and AES techniques. The AES depth profile analysis indica ted that the composition of the LaCoO3 thin film was relatively homogeneous with depth. Interface diffusion and chemical reaction took place at the in terface between the LaCoO3 layer and the Si substrate during thermal treatm ent. The linear least-squares fitting of the AES depth profile analysis ind icated that the LaCoO3 decomposed into simple a oxide of La and Co at the i nterface. An SiO2 species also formed at the interface when the sample was treated at relatively high temperature. Interface diffusion and reaction we re intensified with increasing calcination temperature and time. When the t emperature was < 650 degreesC, the interface species were mainly La2O3 and CoO simple oxides. After the temperature reached 700 degreesC, the interfac e species were La2O3, CoO and SiO2. Copyright (C) 2001 John Wiley & Sons, L td.