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In situ CCVD grown graphene transistors with ultra-high on-off-current ratio in silicon CMOS compatible processing

: Wessely, P.J.; Wessely, F.; Birinci, E.; Riedinger, B.; Schwalke, U.

Postprint urn:nbn:de:0011-n-2364534 (3.8 MByte PDF)
MD5 Fingerprint: 28647af3c0d318112c8d0be3e2096880
Erstellt am: 13.11.2013

Advances in science and technology 77 (2013), S.258-265
ISSN: 1662-0356
Deutsche Forschungsgemeinschaft DFG
Zeitschriftenaufsatz, Elektronische Publikation
Fraunhofer IWM ()
graphene transistor; growth on insulator; silicon CMOS compatible; transfer-free

We invented a novel method to fabricate graphene transistors on oxidized silicon wafers without the need to transfer graphene layers. By means of catalytic chemical vapor deposition (CCVD) the in-situ grown monolayer graphene field-effect transistors (MoLGFETs) and bilayer graphene transistors (BiLGFETs) are realized directly on oxidized silicon substrate, whereby the number of stacked graphene layers is determined by the selected CCVD process parameters. In-situ grown MoLGFETs exhibit the expected Dirac point together with the typical low on/off-current ratios between 16 (hole conduction) and 8 (electron conduction), respectively. In contrast, our BiLGFETs possess unipolar p-type device characteristics with an extremely high on/off-current ratio up to 1E7 exceeding previously reported values by several orders of magnitude. We explain the improved device characteristics by a combination of effects, in particular graphene-substrate interactions, hydrogen doping and Schottky-barrier effects at the source/drain contacts as well. Besides the excellent device characteristics, the complete CCVD fabrication process is silicon CMOS compatible. This will allow the usage of BiLGFETs for digital applications in a hybrid silicon CMOS environment.