Formation of Anti-Etching Nanopatterns in Field-Emission Scanning Probe Lithography on Calixarene Films

Abstract

Low-energy field-emission scanning probe lithography (FE-SPL) is a benchtop technique that allows fabrication of sub-10 nanometer scale nanostructures in a photoresist transferable to the underlying silicon substrate. Understanding the mechanism of the interaction between low-energy electrons and organic molecule films in the FE-SPL process is crucial for advancing the lithographic resolution. In this paper, we investigated the fabricated patterns on ultrathin calixarene films by FE-SPL and revealed the formation of a silicon oxide layer at the organic molecule/silicon interface by means of nano Fourier transform infrared spectroscopy (nano-FTIR). Our results unraveled that the thin anti-etching layer ensures that the patterns are faithfully transferred into the silicon substrate in the following cryogenic plasma treatment. The evolution of silicon oxides as a function of exposure doses during FE-SPL process was systematically studied. The understanding of the underlying mechanism may assist the further design of molecular photoresists in FE-SPL and expand its application to advanced functional materials.