STM WRITING OF ARTIFICIAL NANOSTRUCTURES IN ULTRATHIN PMMA AND SAM RESISTS AND SUBSEQUENT PATTERN TRANSFER IN A MO SI MULTILAYER BY REACTIVE ION ETCHING/

We report on the fabrication of artificial nanostructures in ultrathin resist films patterned by STM lithography in ultrahigh vacuum ambienc e. Two different types of resists, polymethylmethacrylate (PMMA) and a lkanethiol-type self-assembled monolayer (SAM), have been patterned by an UHV-STM. The PMMA patterns were analyzed by atomic force microscop y (AFM); the SAM patterns were investigated by STM. Lines widths down to 75 nm were reproducibly achieved in PMMA with bias voltages up to 1 0 V and tip currents of 1 nA. Carbon build-up due to contamination wri ting and resist removal was observed with the STM patterning the SAM. The PMMA pattern was successfully transferred into the underlying Mo/S i multilayer substrate by fluorine reactive ion etching (RTE), showing STM lithography as an attractive alternative to conventional e-beam l ithography for the fabrication of lateral nanostructures in multilayer s.