Reduction of the inter-probe distance in multi-probe and double-tip STM down to the nanometer scale has been a longstanding and technically difficult challenge. Recent multi-probe systems have allowed for significant progress by achieving distances of around 30 nm using two individually driven, traditional metal wire tips. For situations where simple alignment and a fixed separation can be advantageous, we here present the fabrication of on-chip double-tip devices that incorporate two mechanically fixed gold tips with a tip separation of only 35 nm. We utilize the excellent mechanical, insulating and dielectric properties of high quality SiN as a base material to realize easy-to-implement, lithographically defined and mechanically stable tips. With their large contact pads and adjustable footprint these novel tips can be easily integrated with most existing commercial combined STM/AFM systems.
@article{arxiv.2011.00769,
title = {Fabrication of on-chip probes for double-tip scanning tunneling microscopy},
author = {Maarten Leeuwenhoek and Freek Groenewoud and Kees van Oosten and Tjerk Benschop and Milan P. Allan and Simon Gröblacher},
journal= {arXiv preprint arXiv:2011.00769},
year = {2020}
}