Photoreactivity of Alkylsilane Self-Assembled Monolayers on Silicon Surfaces and Its Application to Preparing Micropatterned Ternary Monolayers

Abstract

The photoreactivity of an n-octadecyltrimethoxysilane self-assembled monolayer (ODS-SAM) on a Si substrate was investigated under the irradiation of vacuum ultraviolet (VUV) light of 172 nm in wavelength. The results of water contact angle, film thickness, and X-ray photoelectron spectroscopy analysis showed that the ODS-SAM decomposed gradually due to the VUV light exposure. Oxidized products, that is, -COOH groups, had formed before the ODS-SAM was completely decomposed and removed from the substrate. Coplanar ternary organosilane SAM microstructures have been successfully fabricated by employing the reaction between -OCH3 functional groups with -COOH groups on the VUV-modified ODS-SAM.

Scanning Probe Lithography on Organic Monolayers

“…Nano and micropatterning of organic monolayers have attracted attentions for applications to biological systems in which proteins or DNA are fixed. Photolithography, microcontact printing, and electron beam lithography have usually been used as patterning techniques for organic monolayers Hong et al, 2003;Saito et al, 2003;Hahn et al, 2004;Kidoaki & Matsuda, 1999). Although the electronbeam lithography can fabricate very small patterns, it requires an ultra-high vacuum system (Harnett et al, 2001).…”

Vapor‐Phase Deposition of Monofunctional Alkoxysilanes for Sub‐Nanometer‐Level Biointerfacing on Silicon Oxide Surfaces

“…[22] Indeed, vapor-phase deposition of trialkoxysilane SAMs with a variety of terminal functional groups has been achieved on oxide surfaces previously. [23][24][25][26][27][28] However, these trifunctional silanes are also known to polymerize in either aqueous-or vapor-phase deposition methods over a wide range of temperatures and environmental conditions. [29][30][31][32][33] Consequently, highquality monolayer formation may require very stringent and specialized processing conditions, making them more challenging to integrate with very-large-scale integration (VLSI) or wafer scale microelectronic devices and processes.…”

Surface characterization on binary nano/micro-domain composed of alkyl- and amino-terminated self-assembled monolayer

“…Several studies have dealt with the fabrication of surfaces with binary functional groups, e.g., Fang et al and Finnie et al In addition, binary organosilane SAMs were fabricated using the vacuum ultraviolet (VUV) lithography technique [6][7][8]. However, fabrication of SAMs at nanometer scale is difficult to achieve through conventional photolithography process.…”

“…atomic force microscope (AFM), a Kelvin probe force microscope (KPFM) [6][7][8][19][20][21] and X-ray photoelectron spectroscopy (XPS). In addition, we investigated the wetting and electrokinetic characterization of OTS SAMs, binary SAMs with amino/methyl terminated groups, and AHAPS SAM by considering the dynamic water contact angles, static water contact angles by water droplets with different pH, and zeta-potential measurement.…”