AVS 49th International Symposium
    Surface Science Wednesday Sessions
       Session SS-WeP

Paper SS-WeP16
Oxygen Adsorption on Cu-9%Al(111) Studied by LEED and AES

Wednesday, November 6, 2002, 11:00 am, Room Exhibit Hall B2

Session: Surface Science Poster Session
Presenter: M. Yoshitake, National Institute for Materials Science, Japan
Authors: M. Yoshitake, National Institute for Materials Science, Japan
S. Bera, National Institute for Materials Science, Japan
Y. Yamauchi, National Institute for Materials Science, Japan
W. Song, National Institute for Materials Science, Japan
Correspondent: Click to Email
Cu-based alloys have been used for electric cables for long time. In the field of microelectronics, Al had been used for electrical wiring. However, it became clear that electro-migration occurs in Al that causes breaking of wires in minute wirings. Due to this problem, Cu wiring is used in most-advanced microprocessors. Cu metal is more corrosive than Al and Cu-based alloys with a small amount of Al is expected to solve problems both on electro-migration and corrosion. The initial stage of corrosion is oxygen adsorption. We studied surface segregation of Al on Cu-9%Al(111) and oxygen adsorption on the surface with/without Al segregation in UHV by LEED and AES. It was found that Al segregates on the surface to form (@sr@3x@sr@3) structure and the structure vanishes above 320C to give (1x1) structure while Al still segregates. The specimen was exposed to oxygen at different temperatures. The amount of oxygen uptake was not structure dependent but temperature dependent. Below 320C, only a small amount of oxygen adsorbed. Between 325 and 600C, oxygen adsorbed surface showed amorphous LEED pattern. The specimen was annealed at 800C after oxygen exposure. When the specimen was exposed oxygen below 600C, the oxygen Auger intensity decreased significantly by annealing and the annealed surface showed (@sr@3x@sr@3) structure at room temperature. When the specimen was exposed to oxygen at 600C, diffused spots developed newly in LEED pattern but the pattern disappeared after 800C annealing while oxygen Auger intensity stayed almost constant. Exposing the specimen to oxygen at 725C resulted in clear spots in LEED pattern, which were attributed to (7/@sr@3x7/@sr@3) structure.