IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Organic Films and Devices Wednesday Sessions
       Session OF+TF+EL-WeA

Paper OF+TF+EL-WeA8
Possibilities of Electron Beam Nanometer-scale Fabrication of Si(111) Using Alkyl Monolayers

Wednesday, October 31, 2001, 4:20 pm, Room 131

Session: Growth of Organic Thin Films
Presenter: T. Yamada, Waseda University, Japan
Authors: T. Yamada, Waseda University, Japan
N. Takano, Waseda University, Japan
K. Yamada, Waseda University, Japan
S. Yoshitomi, Waseda University, Japan
T. Inoue, Waseda University, Japan
T. Osaka, Waseda University, Japan
Correspondent: Click to Email
Utilization of monolayer materials covering Si wafer surfaces is prospective in mass-production of nanometer-scale patterns generated by electron beam drawing, maintaining the spatial resolution. This paper presents application or monolayers of organic moieties bonded on Si(111) for electron-beam patterning and successive chemical metal deposition processes over the patterns. For the purpose of passivation and chemical alteration of Si(111) surface, alkyl groups were deposited by contacting H:Si(111)(1x1) with Grignard reagents (C@sub n@H@sub 2n+1@MgX, X=Cl, Br, I, as tetrahydrofuran solutions).@footnote 1@ Vibrational spectroscopy by FT-IR and HREELS indicated that the bonds in alkyl groups delivered as the Grignard reagent remained unbroken, and that most of the terminating H atoms were replaced by the alkyl groups. STM revealed the original step/terrace structure of Si(111) uniformly covered with a monolayer of organics. The alkyl groups were arranged in a rather disordered manner within the monolayer. Auger electron spectroscopy resulted that the number of alkyl groups per a unit area is constant with respect to the chain length n in the range of 1 ~ 18. All these facts indicate that the alkyl groups are covalently bonded to Si(111). Electron bombardment in vacuum did not introduce useful alteration of the adlayer, and patterning by electron beam (incident energy <3 kV) with ambient O@sub 2@ atmosphere (<10@super -6@ Torr) deposited SiOx on the irradiated portions. Metals such as Ni and Cu were deposited only over the patterns by immersion into aqueous solutions including metal ions. The electron beam patterns were even visualized as metal-deposited area limited by the passivation effect of alkyl monolayer. Application of this entire process to the patterns of <100 nm is now attempted to explore the spatial resolution limit on the nanometer scale. @FootnoteText@ @footnote 1@R. Boukherroub, S. Morin, F. Bensebaa and D. D. M. Wayner: Langmuir 15 (1999) 3831.