Fragmentation of dodecanethiol molecules: application to self-assembled monolayer damage in atom lithography

Atom lithography commonly employs self-assembled monolayers (SAMs) of alkan ethiols which act as resists to protect prepared surfaces. Metastable atomi c species such as helium are used to damage the resist, enabling pattern tr ansfer via mask lithography, followed by wet chemical etching. The damage m echanism is, however, not well understood. Were we report studies of fragme ntation of dodecanethiol (DDT) molecules embedded in helium nanodroplets th at have been irradiated by an electron beam. The results of the charge-tran sfer fragmentation process provide the first experimental data on the damag e mechanisms that occur in the metastable helium/SAM interaction.