INTERFACIAL REACTIONS OF ULTRAHIGH-VACUUM-DEPOSITED CU THIN-FILMS ON ATOMICALLY CLEANED (111)SI .1. PHASE-FORMATION AND INTERFACE STRUCTURE

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