High-Performance Two-Dimensional InSe Field-Effect Transistors with Novel Sandwiched Ohmic Contact for Sub-10 nm Nodes: a Theoretical Study

Abstract

Two-dimensional (2D) InSe-based field effect transistor (FET) has shown remarkable carrier mobility and high on-off ratio in experimental reports. Theoretical investigations also predicated the high performance can be well preserved at sub-10 nm nodes in the ballistic limit. However, both experimental experience and theoretical calculations pointed out achieving high-quality ohmic has become the main limiting factor for high-performance 2D FET. In this work, we proposed a new sandwiched ohmic contact with indium for InSe FET and comprehensively evaluated its performance from views of material and device based on ab initio methods. The material properties denote that all of fundamental issues of ohmic contact including tunneling barrier, the Schottky barrier, and effective doping are well concerned by introducing the sandwiched structure, and excellent contact resistance was achieved. At device performance level, devices with gate length of 7, 5, and 3 nm were investigated. All metrics of sandwiched contacted devices far exceed requirement of the International Technology Roadmap for Semiconductors (ITRS) and exhibit obvious promotion as compared to conventional structures. Maximum boost of current with 69.4%, 50%, and 49% are achieved for devices with 7, 5, and 3 nm gate length, respectively. Meanwhile, maximum reduction of the intrinsic delay with 20.4%, 16.7%, and 18.9% are attained. Moreover, a benchmark of energy-delay product (EDP) against other 2D FETs is presented. All InSe FETs with sandwiched ohmic contact surpass MoS 2 FETs as well as requirement from ITRS 2024. The best result approaches the upper limit of ideal BP FET, denoting superior preponderance of sandwiched structures for InSe FETs in the next generation of complementary metal-oxide semiconductor (CMOS) technology.

Strain and Electric Field Controllable Schottky Barriers and Contact Types in Graphene-MoTe2 van der Waals Heterostructure

“…Combining the advantages of MoTe 2 and graphene, fabricating a type of heterostructure by graphene and MoTe 2 for device applications could be considered. Actually, recently vertical heterostructures based on 2D-layered-structure materials have been attracted increasing interests [26][27][28][29][30][31][32][33] due to the absence of dangling bonds at the surfaces of isolated components and weak Femi level pinning. For graphene-TMDs-based vertical heterostructures, experiments have confirmed their excellent high on-off ratio, high photo-response, low dark current, and good quantum efficiency [34][35][36][37][38], as compared with simple TMDs-based types.…”