Epitaxial Graphene Transistors on SiC Substrates

Abstract

Abstract:This paper describes the behavior of top gated transistors fabricated using carbon, particularly epitaxial graphene on SiC, as the active material. In the past decade research has identified carbon-based electronics as a possible alternative to silicon-based electronics. This enthusiasm was spurred by high carbon nanotube carrier mobilities. However, nanotube production, placement, and control are all serious issues. Graphene, a thin sheet of graphitic carbon, can overcome some of these problems and therefore is a promising new electronic material.Although graphene devices have been built before, in this work we provide the first demonstration and systematic evaluation of arrays of a large number of transistors entirely produced using standard microelectronics methods. Graphene devices presented feature high-k dielectric, mobilities up to 5000 cm 2 /Vs and, I on /I off ratios of up to 7, and are methodically analyzed to provide insight into the substrate properties.Typical of graphene, these micron-scale devices have negligible band gaps and therefore large leakage currents.NOTE: This work has been submitted to the IEEE for possible publication. Copyright may be transferred without notice, after which this version may no longer be accessible.

Half integer quantum Hall effect in high mobility single layer epitaxial graphene

“…Note that epitaxial graphene surfaces can be immaculately cleaned by heating in vacuum to 1000 • C 9 . Also the conventional (local) top gating methods used for applications 20 cannot be used to demonstrate the QHE.…”

Anisotropic growth of long isolated graphene ribbons on the C face of graphite-capped6H-SiC

“…5 The method investigated in this work consists in a controlled sublimation of few atomic layers of Si from a mono crystalline SiC substrate. 6 Such epitaxial growth (EG) of graphene seems to be the most suitable option for industrial applications, 7 but for easy control, it necessitates large and homogeneous sheets of monolayer or few layers of graphene (FLG) covering either a full-wafer surface or a specific area, like an open window in an AlN pre-patterned SiC substrate. 8 Unfortunately, whatever the SiC polytype under investigation (4H, 6H or even 3C), the sublimation conditions pressure varying from UHV (Ultra-High Vacuum) below 10 -9 Torr to more standard SV (Secondary Vacuum) conditions in the range of 10 -8 to 10 -6 Torr, it is still challenging to grow FLG with homogeneous domain sizes larger than few hundred nanometers.…”

“…We know already that such growth conditions allow the formation of FLG flakes over the whole SiC sample but not homogeneously. 7,15,16 This is because the process is not just intrinsic (simple sublimation of Si and reorganization of the C atoms to form graphene). In most cases, defects facilitate graphitization.…”

“…These FLG form the well known structure shown by AFM in Figure 1d with an average domain size which hardly reaches 1 µm wide. 7,17,18 Such a growth process is not expected to produce a large and homogeneous pavement of graphene over the whole SiC wafer. That is why a new, radically different growth process has been developed.…”

Effect of a gap opening on the conductance of graphene superlattices

“…One can overcome such difficulties by generating a gap in the electronic spectrum. The band gap is a measure of the threshold voltage and the onoff ratio of the field effect transistors [17,18]. Therefore, it is essential to induce a band gap at the Dirac points in order to control the transport of the carriers and integrating graphene into the semiconductor technology.…”