AVS 65th International Symposium & Exhibition
    2D Materials Focus Topic Wednesday Sessions
       Session 2D+MN+NS+SS-WeA

Paper 2D+MN+NS+SS-WeA2
High Density H2 and He Plasmas: Can They be used to Treat Graphene?

Wednesday, October 24, 2018, 2:40 pm, Room 201B

Session: IoT Session: Surface Chemistry, Functionalization, Bio and Sensor Applications
Presenter: Hasan-Al Mehedi, Laboratoire des Technologies de la Microélectronique, CNRS-UJF, France
Authors: H-A. Mehedi, Laboratoire des Technologies de la Microélectronique, CNRS-UJF, France
D. Ferrah, Cea, Leti, Minatec, France
J. Dubois, Laboratoire des Technologies de la Microélectronique, CNRS-UJF
C. Petit-Etienne, Laboratoire des Technologies de la Microélectronique, CNRS-UJF
H. Okuno, Cea, Inac/sp2m/lemma
V. Bouchiat, Institut Néel, CNRS-UJF-INP
O.J. Renault, CEA/LETI-University Grenoble Alpes, France
G. Cunge, Laboratoire des Technologies de la Microélectronique, CNRS-UJF, France
Correspondent: Click to Email
Since graphene and other 2D materials have no bulk, a major issue is their sensitivity to surface contaminations, and the development of cleaning processes is mandatory. High density plasmas are attractive to treat (clean, dope, pattern) 2D materials because they are a mature industrial technology adapted to large area wafer. However, in these plasmas the substrate is bombarded by a high flux of both thermal radicals and reactive ions with typical energy above 10 eV, which can easily damage atomic layer thin materials. We have investigated systematically the interaction of H2 and He inductively coupled plasmas (ICP) with graphene in industrial reactors. We report a specific issue associated with the use of H2 plasma: they etch the inner part of plasma reactor walls, thus releasing impurities in the plasma, most notably O atoms that etch graphene and Si atoms which stick on it. The presence of parasitic oxygen presumably explains the discrepancies found in the literature regarding the impact of reactive plasmas on graphene damages. To get rid of this issue we propose to use a fluorinated aluminum chamber. In this case, fluorine atoms which are shown to be harmless to graphene are the only impurity in the plasma. Under such conditions H2 ICP plasma is shown to clean graphene without damages if the ion energy is kept below about 15 eV.