Study on the controllability of the fabrication of single-crystal silicon nanopores/nanoslits with a fast-stop ionic current-monitored TSWE method

Hao Hong; Jiangtao Wei; Xin Lei; Haiyun Chen; Pasqualina M Sarro; Guoqi Zhang; Zewen Liu

doi:10.1038/s41378-023-00532-0

Study on the controllability of the fabrication of single-crystal silicon nanopores/nanoslits with a fast-stop ionic current-monitored TSWE method

Microsyst Nanoeng. 2023 May 16:9:63. doi: 10.1038/s41378-023-00532-0. eCollection 2023.

Authors

Hao Hong^{1

2}, Jiangtao Wei², Xin Lei³, Haiyun Chen⁴, Pasqualina M Sarro¹, Guoqi Zhang¹, Zewen Liu²

Affiliations

¹ Department of Microelectronics, Delft University of Technology, 2628 CD Delft, The Netherlands.
² School of Integrated Circuits, Tsinghua University, 100084 Beijing, China.
³ School of Chemistry, Beihang University, 100084 Beijing, China.
⁴ School of Electronic and Information Engineering, Beijing Jiaotong University, 100084 Beijing, China.

Abstract

The application of single-crystal silicon (SCS) nanopore structures in single-molecule-based analytical devices is an emerging approach for the separation and analysis of nanoparticles. The key challenge is to fabricate individual SCS nanopores with precise sizes in a controllable and reproducible way. This paper introduces a fast-stop ionic current-monitored three-step wet etching (TSWE) method for the controllable fabrication of SCS nanopores. Since the nanopore size has a quantitative relationship with the corresponding ionic current, it can be regulated by controlling the ionic current. Thanks to the precise current-monitored and self-stop system, an array of nanoslits with a feature size of only 3 nm was obtained, which is the smallest size ever reported using the TSWE method. Furthermore, by selecting different current jump ratios, individual nanopores of specific sizes were controllably prepared, and the smallest deviation from the theoretical value was 1.4 nm. DNA translocation measurement results revealed that the prepared SCS nanopores possessed the excellent potential to be applied in DNA sequencing.

Keywords: Nanopores.