AVS 45th International Symposium
    Thin Films Division Tuesday Sessions
       Session TF-TuA

Paper TF-TuA10
The Interaction of Al Atoms with Surface-Bound Organic Functional Groups Studied by In-situ XPS, Infrared Spectroscopy and ToF-SIMS

Tuesday, November 3, 1998, 5:00 pm, Room 310

Session: In-situ Characterization of Thin Films
Presenter: A.E. Hooper, Pennsylvania State University
Authors: A.E. Hooper, Pennsylvania State University
G.L. Fisher, Pennsylvania State University
R.L. Opila, Bell Laboratories, Lucent Technologies
N. Winograd, Pennsylvania State University
D.L. Allara, Pennsylvania State University
Correspondent: Click to Email
The interaction of vapor-deposited Al atoms with self-assembled monolayers of structure HS(CH2)15CH3 and HS(CH2)15COOCH3 was studied with multiple in-situ techniques over a range of Al coverages from submonolayer to multilayers. XPS and IR show the Al to be unreactive with the CH2 units but highly reactive with the oxygen atoms in the ester group to form a 1:1 Al:ester bridged type of complex with an intact CH3 group and a loss of double bond character for the C=O group. In the case of the CH3-termimnated surface, ToF-SIMS shows the Al atoms penetrate into the organic monolayer and diffuse to the Au-S interface. Both XPS and ToF-SIMS indicates that subsequent reaction with the S atoms appears to occur, but in such a way as not to disturb the packing of the monolayer hydrocarbon chains. A dynamic fluctuation mechanism is proposed to explain the Al atom penetration in the CH3 case. In the ester-terminated film, penetration appears to be thwarted by the rapid reaction of the Al atoms with the ester terminal groups to form a dense monolayer of organometallic species.