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Original Research ARTICLE Provisionally accepted The full-text will be published soon. Notify me

Front. Mater. | doi: 10.3389/fmats.2019.00203

Improving the Consistency of Nanoscale Etching for Atomic Force Microscopy Tomography Applications

  • 1University College London, United Kingdom
  • 2Soochow University, China
  • 3Guangdong Technion-Israel Institute of Technology (GTIIT), China

The atomic force microscope empowers research into nanoscale structural and functional material properties. Recently, the scope of application has broadened with the arrival of conductance tomography, a technique for mapping current in three-dimensions in electronic devices by gradually removing sample material with the scanning probe. This technique has been valuable in studying resistance switching memories and solar cells, although its broader use has been hindered by a lack of understanding of its reliability and practicality. Implementation can be preclusive, owing to difficulties in characterizing tip-sample interactions and accounting for probe degradation, both of which are crucial factors in process efficacy. This work follows the existing conductance tomography literature, presenting an insight into the repeatability and reliability of the material removal processes. The consistency of processes on a hard oxide and a softer metal are investigated, to understand the critical differences in etching behavior that might affect tomography measurements on heterostructures. Individual probe behavior stabilizes following a wearing-in stage and etching processes are consistent between probes, in particular on oxide. However, process inconsistency increases with applied force on metal. The effects of scan angle, tip speed and feedback gain are therefore explored and their tuning found to improve the spatial consistency of material removal. With these findings, we aim to present a critical study of the implementation of tomography with the atomic force microscope in order to contribute to its methodological development.

Keywords: Atomic Force Microscopy, Tomography, etching, lithography, machining, scratching, wear, Electronic devices

Received: 26 Mar 2019; Accepted: 06 Aug 2019.

Edited by:

Federico Bosia, University of Turin, Italy

Reviewed by:

Patrick J. Shamberger, Texas A&M University, United States
Hugo Bender, Interuniversity Microelectronics Centre (IMEC), Belgium  

Copyright: © 2019 Buckwell, Ng, Hudziak, Mehonic, Lanza and Kenyon. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Dr. Mark Buckwell, University College London, London, United Kingdom, M.buckwell@ee.ucl.ac.uk