AVS 49th International Symposium
    Surface Science Thursday Sessions
       Session SS+EL+OF-ThM

Paper SS+EL+OF-ThM1
Fixation of Alkyl Groups on Si(111) Surface through C-Si Single Covalent Bond formed by Reaction of Grignard Reagent and H:Si(111)

Thursday, November 7, 2002, 8:20 am, Room C-112C

Session: Reactions and Patterning of Organics on Silicon
Presenter: T. Yamada, Waseda University, Japan
Authors: T. Yamada, Waseda University, Japan
T. Inoue, Waseda University, Japan
K. Yamada, Waseda University, Japan
N. Takano, Waseda University, Japan
T. Osaka, Waseda University, Japan
H. Harada, Kumamoto University, Japan
K. Nishiyama, Kumamoto University, Japan
I. Taniguchi, Kumamoto University, Japan
Correspondent: Click to Email
Alkyl adsorbates that are directly bonded to the outermost atoms of silicon wafer surfaces have prospective properties for application in nanometer-scale fabrication and surface functionalization.@footnote 1@ Several methods have been proposed to deposit alkyl groups on hydrogen-terminated H:Si(111).@footnote 2@ The conversion of the H-Si bonds in H:Si(111) into C-Si bonds caused by chemical processes is an important issue in preparing the organic adlayers. In this work, high-resolution electron energy loss spectroscopy (HREELS) was utilized to prove the formation of single covalent bonds between Si(111) surface atoms and alkyl groups by the chemical reaction of a Grignard reagent and hydrogen-terminated H:Si(111)(1x1).@footnote 2@ The reaction was performed by heating a piece of H:Si(111) in 1M tetrahydrofuran (at 65°C) or diethylether solution (at 30°C) of desired alkylmagnesium halide for 18 hours under Ar atmosphere. By this reaction condition, somewhat 20% of the product surface were still covered with residual hydrogen. The bending vibration mode of the residual hydrogen (630 cm@super -1@) obscured the alkyl signals in the range of 600 - 700 cm@super -1@. By using deuterium-terminated D:Si(111), the vibration at 680 cm@super -1@, assigned to the C-Si bond, was isolated within the spectrum of CH@sub 3@-. The CH@sub 3@ groups were thermally stable at temperatures below 600 K. Similar features were observed for C@sub 2@H@sub 5@-, phenyl- and so on. The C-Si bonds are essential for enhancing the stability and lowering the mobility of alkyl moieties. Such properties of alkyl moieties of will lead to a new prospective science and technology in nanometer-scale fabrication. @FootnoteText@ @footnote 1@T. Yamada, N. Takano, K. Yamada, S. Yoshitomi, T. Inoue, and T. Osaka, Jpn. J. Appl. Phys. 40 (2001) 4845.@footnote 2@R. Boukherroub, S. Morin, F. Bensebaa and D. D. M. Wayner, Langmuir 15 (1999) 3831.