The controllable creation of nanometer-sized patterns is critical for applications such as biosensing and electronics.  In this study, two self-assembled monolayers, octadecyltrichlorosilane (OTS) and octadecyldimethylchlorosilane (ODMS), were formed on a SiO2/Silicon (100) substrate and characterized through ellipsometry and contact angle measurements.  Despite similar structure and bonds to the surface, the methyl groups in ODMS lead to a significantly thinner and less well packed monolayer than that of OTS.  Stemming from this difference in packing, atomic force microscopy based patterning of these two layers, under nearly identical conditions, resulted in drastically different patterns.  At low applied load, rearrangement, but not removal, of the ODMS monolayer was observed.  Interestingly, the behavior of the patterning in the ODMS monolayer depends consistently on the relative humidity under which the patterning was performed. The water from ambient humidity may play a significant role in the etching process and this role is being investigated.

Formation and patterning of octadecyl silane monolayers on a silicon substrate via atomic force microscopy

241st National Meeting (2011)

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