Direct nanotransfer printing of metal electrodes with sub-15-nm gaps
S. Harrer, S. Strobel, G. Scarpa, G. Abstreiter, M. Tornow, P. Lugli
Technische Universitaet Muenchen, DE
Keywords: nanotransfer, nanofabrication, MBE
Abstract:Nanoscale transfer printing (nTP) and microcontact printing (µCP) are modifications of nanoimprint lithography (NIL), a new manufacturing technology which has demonstrated sub-10-nm resolution and high throughput at low cost. Melosh et. al. have applied molds fabricated by molecular beam epitaxy (MBE) in superlattice nanowire transfer (SNAP) processes creating metal nanowires in the sub-10-nm region. But SNAP technology sacrifices the stamp in each transfer step, and relies on additional etching steps for transferring material from the mold onto the substrate. Our approach merges the ultra-high-resolution provided by the SNAP technology with the conceptual simplicity of nTP processes into a new nTP scheme for the sub-15-nm region that does not incorporate any SAM layers or release agents and preserves the stamp during the transfer process. We demonstrate direct nTP of PdAu lines from a hard mold onto a hard substrate at room-temperature without employing any flexible buffer layers or organic adhesion promoters or release agent layers. The molds used in these experiments were GaAs/AlGaAs sandwich structures fabricated by MBE that we selectively etched after cleaving. We created gaps in PdAu alloy (20/80) thin films comprising widths significantly smaller than 15 nm by performing the developed direct nTP process with custom-fabricated MBE-molds.