An Extraction Method for Mobility Degradation and Contact Resistance of Graphene Transistors

Abstract

The intrinsic mobility degradation coefficient, contact resistance and the transconductance parameter of graphene field-effect transistors (GFETs) are extracted for different technologies by considering a novel transport model embracing mobility degradation effects within the charge channel control description. By considering the mobility degradation-based model, a straightforward extraction methodology, not provided before, is enabled by applying the concept of the well-known Y-function to the I-V device characteristics. The method works regardless the gate device architecture. An accurate description of experimental data of fabricated devices is achieved with the underlying transport equation by using the extracted parameters. An evaluation of the channel resistance, enabled by the extracted parameters here, has been also provided.

A Scalable Compact Model for the Static Drain Current of Graphene FETs

“…The basic parameters (VG0, Rds, μ, θint, Δ) are extracted from experimental data of each GFET under test according to [29] at low VDS, while VS-related usat and b parameters can be derived from high VDS regime especially at shorter channel lengths [16]; Rds, μ are calculated separately for pand n-type regions to consider asymmetries. Geometrical scaling parameters (cf.…”

“…so as to enable distinct μp(n) [32] and Rdsp(n) (Rs=Rd=Rds here) models for pand n-type conduction regions, respectively (see Appendix for explicit derivations); Rs=Rd are placed between internal and external source and drain nodes in the Verilog-A model code, respectively, and thus, ID decrease due to Rds, is correctly calculated. Qgr is the total graphene charge [5, §2.1] while μp(n) reduction due to θint [29], is included in μup(n) terms. Velocity saturation (VS) induced effective mobility μueffp(n), and consequently effective length…”

“…Geometrical variations have been earlier experimentally studied for Dirac voltage VDirac (VTH equivalent in GFETs) in [17], [18], for Rd(s) in [20]- [23], for μ in [17], [23]- [27] and for impuritiesrelated residual charge nres in [26], however, such [23], [25], [28]. For the extraction of the basic parameters of the model (VDirac-related flat-band voltage VG0, Rd(s), μ, intrinsic mobility degradation θint [29] and nres-related parameter Δ) [5] several methodologies have been proposed [29], [30] where the one presented in [29], is applied here. IV hysteresis effects are also modelled, provided that trap-affected and trap-reduced measurement setups are available [31].…”

Characterization of the Intrinsic and Extrinsic Resistances of a Microwave Graphene FET Under Zero Transconductance Conditions

“…The other resistance contribution independent of the gate voltage is Rθγ, which accounts for the mobility degradation within the graphene [14]. Finally, the bias-dependent term in ( 6) can be expressed as [11]:…”

A Parameter Extraction Methodology for Graphene Field-Effect Transistors

“…The timeliness of the topic was recently accentuated by a review paper urging for consistency in reporting and benchmarking emerging FET technologies [1]. Moreover, the recent application of the Y-method for characterizing GFETs shows that still today great efforts are spent on finding reliable and consistent methodologies for extracting GFET model parameters [2].…”