Organosilane self-assembled monolayers modified with focused ion beam as studied by scanning probe microscopy

I. Ikeda, H. Sugimura and O. Takai

Department of Material Processing Engineering, Graduate School of Engineering,
Nagoya University, Chikusa, Nagoya 464-8603, Japan

Electron and ion beam lithographic techniques have been used to create nanostructures. By means of focused ion beam (FIB), we have fabricated nanostructures on an organosilane self-assembled monolayer (SAM) as well. Onto cleaned Si substrates covered with native oxide, the SAM was formed by chemical vapor deposition (CVD) using octadecyltrimethoxysilane [ODS:CH3(CH2)17Si(OCH3)3] as a precursor [1]. The ODS-SAM was modified by FIB with a Ga liquid-metal ion source at a beam energy of 30 kV. The modified regions were observed by atomic force microscopy (AFM), lateral force microscopy (LFM) and Kelvin-probe force microscopy (KFM). The regions were clearly imaged by these microscopies due to distinct contrasts on topogaraphy, friction and surface potential between the modified and unmodified regions. By optimizing patterning conditions, nanopatterns of ca. 40 nm in width could be fabricated.

[1] A. Hozumi, K. Ushiyama, H. Sugimura and O. Takai, Langmuir 15 7600 (1999).