Contact Resistance Parallel Model for Edge-Contacted 2D Material Back-Gate FET

Fei Cai,Guangsheng Deng,Fujiang Lin,Xiangxiang Li

doi:10.3390/electronics9122110

Abstract

Because 2D materials have adjust band gap, high mobility ratio, bipolar, anisotropy and flexibility characters, they have become the new direction for FET’s channel materials. According to the characteristics of the layers of 2D materials, the current transport characteristics can be improved by using the edge-contacted electrode. Moreover, the research on the current transfer mechanism between channel layers is the basis of the practical application of 2D transistors. In the research, the 2D material-MoS2 is used as the channel material, the back-gate transistors with different layers are prepared by dry etching and edge-contacted electrode structure. We also discuss the current transport mechanism of channel and established the channel resistance parallel transport model. The parallel model and TLM are used to analyze the contact resistance of the edge-contacted structure, and the total resistance, total contact resistance, and single-layer contact resistance of different layers are calculated. The parallel model is verified by dc test data. The number of channel layers is closely related to contact resistance, total resistance, and mobility. In addition, the of single MoS2 is about 7.27 kΩ·um. This contact resistance parallel model can also be applied to other 2D materials edge-contacted FET.

Highlights

Since graphene was discovered, more and more 2D materials have been found, such as TMDs (Transition Metal Dichalcogenides), BP (Black Phosphorus), etc. [1,2,3,4]
Few layered 2D materials can be obtained by mechanical exfoliation [5]
MoS2, which was used as the channel material, is a member of the TMDC family and has emerged as the prototypical 2D semiconductor

Summary

Introduction

More and more 2D (two-dimensional) materials have been found, such as TMDs (Transition Metal Dichalcogenides), BP (Black Phosphorus), etc. [1,2,3,4]. The first type is the graphene-like family, including graphene, boron nitride, etc. There are some layered materials of other structures, like as black phosphorus [6] These 2D materials have different properties, such as graphene, which is a Dirac semi-metal, and transition metal dichalcogenides, which is an excellent semiconductor, while boron nitride is an excellent insulator. These transition metal dichalcogenides have the mechanical, electrical, and optical advantages of graphene, and have the natural optical band gap that graphene does not have. The varied physical properties of 2D materials displayed increasingly.

Application

Fabrication

Results and Discussion on FET’s

Conclusions