Abstract
Interfacial reactions of ultrahigh-vacuum-deposited Cu thin films on atomically cleaned (111)Si have been studied by transmission electron microscopy, x-ray diffractometry, and Auger electron spectroscopy. An interface compound, CuSix with x=11.2–14 at. %, was observed to be present at the Cu/Si interface. η″-Cu3Si was found to form in samples annealed at 200 °C for 1 h. Solid-phase-epitaxial growth of silicon on (111)Si through a transport media (Cu or Cu3Si) was observed to occur at a temperature as low as 200 °C. Preferentially oriented η″-Cu3Si is the only phase present in samples annealed at 200–800 °C. In samples annealed at or higher than 850 °C, a mixture of η′-Cu3Si and η″-Cu3Si was found to be present.