{
  "id": "2012.09046",
  "version": "v1",
  "published": "2020-12-16T16:08:10.000Z",
  "updated": "2020-12-16T16:08:10.000Z",
  "title": "Thermal stability of monolayer $WS_2$ in BEOL conditions",
  "authors": [
    "Simona Pace",
    "Marzia Ferrera",
    "Domenica Convertino",
    "Giulia Piccinini",
    "Michele Magnozzi",
    "Neeraj Mishra",
    "Stiven Forti",
    "Francesco Bisio",
    "Maurizio Canepa",
    "Filippo Fabbri",
    "Camilla Coletti"
  ],
  "comment": "21 pages, 5 figures",
  "categories": [
    "cond-mat.mes-hall",
    "cond-mat.mtrl-sci"
  ],
  "abstract": "Monolayer tungsten disulfide ($WS_2$) has recently attracted large interest as a promising material for advanced electronic and optoelectronic devices such as photodetectors, modulators, and sensors. Since these devices can be integrated in a silicon (Si) chip via back-end-of-line (BEOL) processes, the stability of monolayer $WS_2$ in BEOL fabrication conditions should be studied. In this work, the thermal stability of monolayer single-crystal $WS_2$ at typical BEOL conditions is investigated; namely (i) heating temperature of $300$ $^\\circ C$, (ii) pressures in the medium- ($10^{-3}$ mbar) and high- ($10^{-8}$ mbar) vacuum range; (iii) heating times from $30$ minutes to $20$ hours. Structural, optical and chemical analyses of $WS_2$ are performed via scanning electron microscopy (SEM), Raman spectroscopy, photoluminescence (PL) and X-ray photoelectron spectroscopy (XPS). It is found that monolayer single-crystal $WS_2$ is intrinsically stable at these temperature and pressures, even after $20$ hours of thermal treatment. The thermal stability of $WS_2$ is also preserved after exposure to low-current electron beam ($12$ pA) or low-fluence laser ($0.9$ $mJ/\\mu m^2$), while higher laser fluencies cause photo-activated degradation upon thermal treatment. These results are instrumental to define fabrication and in-line monitoring procedures that allow the integration of $WS_2$ in device fabrication flows without compromising the material quality.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2020-12-16T16:08:10.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "thermal stability",
      "monolayer single-crystal",
      "thermal treatment",
      "device fabrication flows",
      "beol fabrication conditions"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 21,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}