Influence of electron-beam lithography exposure current level on the transport characteristics of graphene field effect transistors

Journal Article · Mon Mar 28 00:00:00 EDT 2016 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4944599· OSTI ID:22594515

Kang, Sangwoo; Movva, Hema C. P.; Sanne, Atresh; Rai, Amritesh; Banerjee, Sanjay K. ^[1]

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1. Microelectronics Research Center, The University of Texas at Austin, Austin, Texas 78758 (United States)

Many factors have been identified to influence the electrical transport characteristics of graphene field-effect transistors. In this report, we examine the influence of the exposure current level used during electron beam lithography (EBL) for active region patterning. In the presence of a self-assembled hydrophobic residual layer generated by oxygen plasma etching covering the top surface of the graphene channel, we show that the use of low EBL current level results in higher mobility, lower residual carrier density, and charge neutrality point closer to 0 V, with reduced device-to-device variations. We show that this correlation originates from the resist heating dependent release of radicals from the resist material, near its interface with graphene, and its subsequent trapping by the hydrophobic polymer layer. Using a general model for resist heating, we calculate the difference in resist heating for different EBL current levels. We further corroborate our argument through control experiments, where radicals are either intentionally added or removed by other processes. We also utilize this finding to obtain mobilities in excess of 18 000 cm{sup 2}/V s on silicon dioxide substrates. We believe these results are applicable to other 2D materials such as transition metal dichalcogenides and nanoscale devices in general.

• OSTI ID: 22594515
• Journal Information: Journal of Applied Physics, Vol. 119, Issue 12; Other Information: (c) 2016 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
CARRIER DENSITY
ELECTRON BEAMS
ETCHING
FIELD EFFECT TRANSISTORS
GRAPHENE
HEATING
LAYERS
MASKING
NANOSTRUCTURES
OXYGEN
PLASMA
POLYMERS
SILICON
SILICON OXIDES
SUBSTRATES
SURFACES
TRANSITION ELEMENTS