GFET Asymmetric Transfer Response Analysis through Access Region Resistances

TL;DR

This paper uses numerical simulations to analyze how access region resistances influence the asymmetric transfer response of GFETs, highlighting their impact on RF performance and device behavior.

Contribution

It provides a detailed analysis of access region effects on GFET transfer response, including the influence of conductivity modulation and imperfections, which was previously underexplored.

Findings

Access regions significantly affect GFET transfer asymmetry.

Modulating access region conductivity alters device response.

Imperfections like charge puddles impact RF performance.

Abstract

Graphene-based devices are planned to augment the functionality of Si and III-V based technology in radio-frequency (RF) electronics. The expectations in designing graphene {field-effect} transistors (GFETs) with enhanced RF performance have attracted significant experimental efforts, mainly concentrated on achieving high mobility samples. However, little attention has been paid, so far, to the role of the access regions in these devices. \mbox{Here, we analyse} in detail, via numerical simulations, how the GFET transfer response is severely impacted by these regions, showing that they play a significant role in the asymmetric saturated behaviour commonly observed in GFETs. We also investigate how the modulation of the access region conductivity (i.e., by the influence of a back gate) and the presence of imperfections in the graphene layer (e.g., charge puddles) affects the transfer response. The analysis is extended to assess the application of GFETs for RF applications, by~evaluating their cut-off frequency.