Atom-by-Atom and Sheet-by-Sheet Chemical Mechanical Polishing of Diamond Assisted by OH Radicals: A Tight-Binding Quantum Chemical Molecular Dynamics Simulation Study

Kentaro Kawaguchi, Yang Wang, Jingxiang Xu, Yusuke Ootani, Yuji Higuchi, Nobuki Ozawa, Momoji Kubo

Research output: Contribution to journalArticlepeer-review

Abstract

Ultraflat and damage-free single-crystal diamond is a promising material for use in electronic devices such as field-effect transistors. Diamond surfaces are conventionally prepared by the chemical mechanical polishing (CMP) method, although the CMP efficiency remains a critical issue owing to the extremely high hardness of diamond. Recently, OH radicals have been demonstrated to be potentially useful for improving the CMP efficiency for diamond; however, the underlying mechanisms are still elusive. In this work, we applied our previously developed CMP-specialized tight-binding quantum chemical molecular dynamics simulator to comprehensively elucidate the CMP mechanisms of diamond assisted by OH radicals. Our simulation results indicate that the diamond surface is oxidized by reactions with OH radicals and then a concomitant surface reconstruction takes place due to the distorted and unstable nature of the oxidized diamond surface structure. Furthermore, we interestingly reveal that the reconstruction of the diamond surface ultimately leads to two distinct removal mechanisms: (i) gradual atom-by-atom removal through the desorption of gaseous molecules (e.g., CO2 and H2CO3) and (ii) drastic sheet-by-sheet removal through the exfoliation of graphitic ring structures. Hence, we propose that promoting the oxidation-induced graphitization of the diamond surface may provide a route to further improving the CMP efficiency.

Original languageEnglish
Pages (from-to)41231-41237
Number of pages7
JournalACS Applied Materials and Interfaces
Volume13
Issue number34
DOIs
Publication statusPublished - 2021 Sep 1

Keywords

  • chemical mechanical polishing
  • diamond
  • friction
  • graphitization
  • molecular dynamics simulation
  • OH radical

ASJC Scopus subject areas

  • Materials Science(all)

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