Effects of the presence of native silicon oxide at the Fe/Si interface on the formation of silicides studied by Auger spectroscopy

• Published in: Applied surface science 1993-06, Vol.68 (2), p.173-177
• Main Authors: Chemelli, C., D'Angelo, D., Girardi, G., Pizzini, S.
• Format: Article
• Language: English
• Subjects: Chemistry; Exact sciences and technology; General and physical chemistry; Solid-gas interface; Surface physical chemistry
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/0169-4332(93)90118-U

Auger lineshape analysis on SiLVV and FeLMM transitions was used to investigate the mechanisms of iron mono- and disilicide formation at the Fe/Si interface in the absence and in the presence of a native oxide layer (SiO x ) approximately 0.5 nm thick on the silicon surface. Fe films, 0.3 to 2 nm thick, were evaporated on Si(111) and on SiO x /Si(111) surfaces in UHV environment. Thereafter thermal treatments up to 580°C were performed in situ. Besides the well known mechanism of silicide formation via silicon diffusion at the Fe/Si interface, it was demonstrated that silicide formation in the presence of native oxide is inhibited at room temperature while, at T≥450°C, it occurs at the SiO x /Si interface via Fe diffusion through the oxide layer. This ends in a Fe/SiO x /FeSi/Si or Fe/SiO x /FeSi 2/Si type of structure. The kinetics of silicide formation in the presence of an oxide layer are therefore dominated by the diffusion of the metal through the oxide.