Behaviour of copper atoms in annealed Cu/SiO x/Si systems

• Published in: Applied surface science Vol. 153; no. 2; pp. 79 - 84
• Main Authors: Benouattas, N, Mosser, A, Raiser, D, Faerber, J, Bouabellou, A
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 2000
• Subjects: Annealing; Copper; Epitaxy; Silicides; Silicon oxide; EE; Annealing; ALN; Silicides; IM; Epitaxy; 82.65−Yh; EL; 82.80−d; ER; CU; SF; TI; Silicon oxide; XBD; Copper; 68.55−a
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/S0169-4332(99)00366-9

Copper thin films of thickness 1000 Å are evaporated on (100) and (111) single crystal Si wafers in the presence of interfacial native silicon oxide (SiO x ). The behavior of copper and the mechanism of compound formation at the Cu/Si interface are studied at different temperatures using scanning electron microscopy (SEM), X-ray diffraction (XRD) and Rutherford backscattering (RBS). Annealing in the 600–750°C temperature range leads to the formation of islands of two copper-rich silicides Cu 3Si and Cu 4Si. On the Si(100), after annealing at 750°C, we observe epitaxially grown Cu 3Si crystallites with square and rectangular shapes. However, on Si(111) annealing at the same temperature yields Cu 3Si and Cu 4Si crystallites with droplet-like shapes and no sign of epitaxy. The presence of oxygen, after heat treatment under vacuum, is closely related to the formation of copper silicide crystallites.